/*
 * Miscellaneous helpers for common operations.
 */

// TOP

#define scope_attachment(app,S,I,T) ((T*)managed_scope_get_attachment((app), (S), (I), sizeof(T)))
#define set_custom_hook(app,ID,F) set_custom_hook((app),(ID),(Void_Func*)(F))

////////////////////////////////

internal Token_Array
get_token_array_from_buffer(Application_Links *app, Buffer_ID buffer){
    Token_Array result = {};
    Managed_Scope scope = buffer_get_managed_scope(app, buffer);
    Async_Task *lex_task_ptr = scope_attachment(app, scope, buffer_lex_task, Async_Task);
    if (lex_task_ptr != 0){
        async_task_wait(app, &global_async_system, *lex_task_ptr);
    }
    Token_Array *ptr = scope_attachment(app, scope, attachment_tokens, Token_Array);
    if (ptr != 0){
        result = *ptr;
    }
    return(result);
}

////////////////////////////////

internal Buffer_Seek
seek_location(ID_Line_Column_Jump_Location location){
    return(seek_line_col(location.line, location.column));
}

internal Buffer_Seek
seek_location(ID_Pos_Jump_Location location){
    return(seek_pos(location.pos));
}

internal Buffer_Seek
seek_location(Name_Line_Column_Location location){
    return(seek_line_col(location.line, location.column));
}

internal Buffer_Seek
seek_jump(Parsed_Jump jump){
    return(seek_location(jump.location));
}

////////////////////////////////

View_Context_Block::View_Context_Block(Application_Links *a, View_ID v,
                                       View_Context *ctx){
    this->app = a;
    this->view = v;
    view_push_context(a, v, ctx);
}

View_Context_Block::~View_Context_Block(){
    view_pop_context(this->app, this->view);
}

////////////////////////////////

internal Character_Predicate
character_predicate_from_function(Character_Predicate_Function *func){
    Character_Predicate predicate = {};
    i32 byte_index = 0;
    for (u32 i = 0; i <= 255;){
        b8 v[8];
        for (i32 bit_index = 0; bit_index < 8; i += 1, bit_index += 1){
            v[bit_index] = func((u8)i);
        }
        predicate.b[byte_index] = (
                                   (v[0] << 0) |
                                   (v[1] << 1) |
                                   (v[2] << 2) |
                                   (v[3] << 3) |
                                   (v[4] << 4) |
                                   (v[5] << 5) |
                                   (v[6] << 6) |
                                   (v[7] << 7)
                                   );
        byte_index += 1;
    }
    return(predicate);
}

internal Character_Predicate
character_predicate_from_character(u8 character){
    Character_Predicate predicate = {};
    predicate.b[character/8] = (1 << (character%8));
    return(predicate);
}

#define character_predicate_check_character(p, c) (((p).b[(c)/8] & (1 << ((c)%8))) != 0)

internal Character_Predicate
character_predicate_or(Character_Predicate *a, Character_Predicate *b){
    Character_Predicate p = {};
    for (i32 i = 0; i < ArrayCount(p.b); i += 1){
        p.b[i] = a->b[i] | b->b[i];
    }
    return(p);
}

internal Character_Predicate
character_predicate_and(Character_Predicate *a, Character_Predicate *b){
    Character_Predicate p = {};
    for (i32 i = 0; i < ArrayCount(p.b); i += 1){
        p.b[i] = a->b[i] & b->b[i];
    }
    return(p);
}

internal Character_Predicate
character_predicate_not(Character_Predicate *a){
    Character_Predicate p = {};
    for (i32 i = 0; i < ArrayCount(p.b); i += 1){
        p.b[i] = ~(a->b[i]);
    }
    return(p);
}

internal i64
buffer_seek_character_class_change__inner(Application_Links *app, Buffer_ID buffer, Character_Predicate *positive, Character_Predicate *negative, Scan_Direction direction, i64 start_pos){
    i64 pos = start_pos;
    switch (direction){
        case Scan_Backward:
        {
            String_Match m1 = buffer_seek_character_class(app, buffer, negative, direction, pos);
            String_Match m2 = buffer_seek_character_class(app, buffer, positive, direction, m1.range.min);
            pos = m2.range.min;
            if (m1.buffer == buffer && m2.buffer == buffer){
                pos += 1;
            }
        }break;
        case Scan_Forward:
        {
            pos -= 1;
            String_Match m1 = buffer_seek_character_class(app, buffer, positive, direction, pos);
            String_Match m2 = buffer_seek_character_class(app, buffer, negative, direction, m1.range.min);
            pos = m2.range.min;
        }break;
    }
    return(pos);
}

internal i64
buffer_seek_character_class_change_1_0(Application_Links *app, Buffer_ID buffer, Character_Predicate *predicate, Scan_Direction direction, i64 start_pos){
    Character_Predicate negative = character_predicate_not(predicate);
    return(buffer_seek_character_class_change__inner(app, buffer, predicate, &negative, direction, start_pos));
}

internal i64
buffer_seek_character_class_change_0_1(Application_Links *app, Buffer_ID buffer, Character_Predicate *predicate, Scan_Direction direction, i64 start_pos){
    Character_Predicate negative = character_predicate_not(predicate);
    return(buffer_seek_character_class_change__inner(app, buffer, &negative, predicate, direction, start_pos));
}

////////////////////////////////

internal i64
view_pos_from_xy(Application_Links *app, View_ID view, Vec2_f32 p){
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadVisible);
    Rect_f32 region = view_get_buffer_region(app, view);
    f32 width = rect_width(region);
    Face_ID face_id = get_face_id(app, buffer);
    Buffer_Scroll scroll_vars = view_get_buffer_scroll(app, view);
    i64 line = scroll_vars.position.line_number;
    p = (p - region.p0) + scroll_vars.position.pixel_shift;
    return(buffer_pos_at_relative_xy(app, buffer, width, face_id, line, p));
}

internal Buffer_Point
view_move_buffer_point(Application_Links *app, View_ID view, Buffer_Point buffer_point, Vec2_f32 delta){
    delta += buffer_point.pixel_shift;
    Line_Shift_Vertical shift = view_line_shift_y(app, view, buffer_point.line_number, delta.y);
    buffer_point.line_number = shift.line;
    buffer_point.pixel_shift = V2f32(delta.x, delta.y - shift.y_delta);
    return(buffer_point);
}

internal void
view_zero_scroll(Application_Links *app, View_ID view){
    Buffer_Scroll scroll = {};
    view_set_buffer_scroll(app, view, scroll, SetBufferScroll_SnapCursorIntoView);
}

internal Vec2_f32
view_relative_xy_of_pos(Application_Links *app, View_ID view, i64 base_line, i64 pos){
    Rect_f32 rect = view_relative_box_of_pos(app, view, base_line, pos);
    return(rect_center(rect));
}

internal void
view_set_cursor_and_preferred_x(Application_Links *app, View_ID view, Buffer_Seek seek){
    view_set_cursor(app, view, seek);
    Buffer_Cursor cursor = view_compute_cursor(app, view, seek);
    Vec2_f32 p = view_relative_xy_of_pos(app, view, cursor.line, cursor.pos);
    view_set_preferred_x(app, view, p.x);
}

function i64
view_set_pos_by_character_delta(Application_Links *app, View_ID view, i64 pos, i64 character_delta){
    Buffer_Cursor cursor = view_compute_cursor(app, view, seek_pos(pos));
    i64 character = view_relative_character_from_pos(app, view, cursor.line, cursor.pos);
    i64 new_pos = view_pos_from_relative_character(app, view, cursor.line, character + character_delta);
    return(new_pos);
}

function i64
view_set_cursor_by_character_delta(Application_Links *app, View_ID view, i64 character_delta){
    i64 pos = view_get_cursor_pos(app, view);
    i64 new_pos = view_set_pos_by_character_delta(app, view, pos, character_delta);
    view_set_cursor_and_preferred_x(app, view, seek_pos(new_pos));
    return(new_pos);
}

function i64
view_correct_cursor(Application_Links *app, View_ID view){
    i64 pos = view_get_cursor_pos(app, view);
    i64 new_pos = view_set_pos_by_character_delta(app, view, pos, 0);
    view_set_cursor(app, view, seek_pos(new_pos));
    return(new_pos);
}

function i64
view_correct_mark(Application_Links *app, View_ID view){
    i64 pos = view_get_mark_pos(app, view);
    i64 new_pos = view_set_pos_by_character_delta(app, view, pos, 0);
    view_set_mark(app, view, seek_pos(new_pos));
    return(new_pos);
}

function Vec2_f32
buffer_point_difference(Application_Links *app, Buffer_ID buffer, f32 width, Face_ID face_id,
                        Buffer_Point a, Buffer_Point b){
    f32 y_difference = buffer_line_y_difference(app, buffer, width, face_id, a.line_number, b.line_number);
    Vec2_f32 result = a.pixel_shift - b.pixel_shift;
    result.y += y_difference;
    return(result);
}

function Vec2_f32
view_point_difference(Application_Links *app, View_ID view, Buffer_Point a, Buffer_Point b){
    f32 y_difference = view_line_y_difference(app, view, a.line_number, b.line_number);
    Vec2_f32 result = a.pixel_shift - b.pixel_shift;
    result.y += y_difference;
    return(result);
}

////////////////////////////////

internal Range_i64
buffer_range(Application_Links *app, Buffer_ID buffer){
    Range_i64 range = {};
    range.end = buffer_get_size(app, buffer);
    return(range);
}

internal i64
buffer_side(Application_Links *app, Buffer_ID buffer, Side side){
    return(range_side(buffer_range(app, buffer), side));
}

internal Range_i64
get_view_range(Application_Links *app, View_ID view){
    return(Ii64(view_get_cursor_pos(app, view), view_get_mark_pos(app, view)));
}

internal void
set_view_range(Application_Links *app, View_ID view, Range_i64 range){
    i64 c = view_get_cursor_pos(app, view);
    i64 m = view_get_mark_pos(app, view);
    if (c < m){
        view_set_cursor_and_preferred_x(app, view, seek_pos(range.min));
        view_set_mark(app, view, seek_pos(range.max));
    }
    else{
        view_set_mark(app, view, seek_pos(range.min));
        view_set_cursor_and_preferred_x(app, view, seek_pos(range.max));
    }
}

internal b32
is_valid_line(Application_Links *app, Buffer_ID buffer_id, i64 line){
    i64 max_line = buffer_get_line_count(app, buffer_id);
    return(1 <= line && line <= max_line);
}

internal b32
is_valid_line_range(Application_Links *app, Buffer_ID buffer_id, Range_i64 range){
    i64 max_line = buffer_get_line_count(app, buffer_id);
    return(1 <= range.first && range.first <= range.end && range.end <= max_line);
}

internal i64
get_line_number_from_pos(Application_Links *app, Buffer_ID buffer, i64 pos){
    Buffer_Cursor cursor = buffer_compute_cursor(app, buffer, seek_pos(pos));
    return(cursor.line);
}

internal i64
buffer_get_character_legal_pos_from_pos(Application_Links *app, Buffer_ID buffer, f32 width, Face_ID face, i64 pos){
    Buffer_Cursor cursor = buffer_compute_cursor(app, buffer, seek_pos(pos));
    i64 character = buffer_relative_character_from_pos(app, buffer, width, face, cursor.line, pos);
    return(buffer_pos_from_relative_character(app, buffer, width, face, cursor.line, character));
}

internal i64
view_get_character_legal_pos_from_pos(Application_Links *app, View_ID view, i64 pos){
    Buffer_Cursor cursor = view_compute_cursor(app, view, seek_pos(pos));
    i64 character = view_relative_character_from_pos(app, view, cursor.line, pos);
    return(view_pos_from_relative_character(app, view, cursor.line, character));
}

internal Buffer_Cursor
get_line_side(Application_Links *app, Buffer_ID buffer, i64 line_number, Side side){
    i64 character_index = (side == Side_Min)?(1):(-1);
    return(buffer_compute_cursor(app, buffer, seek_line_col(line_number, character_index)));
}
internal i64
get_line_side_pos(Application_Links *app, Buffer_ID buffer, i64 line_number, Side side){
    i64 pos = -1;
    Buffer_Cursor cursor = get_line_side(app, buffer, line_number, side);
    if (cursor.line != 0){
        pos = cursor.pos;
    }
    return(pos);
}

internal Buffer_Cursor
get_line_start(Application_Links *app, Buffer_ID buffer, i64 line_number){
    return(get_line_side(app, buffer, line_number, Side_Min));
}
internal i64
get_line_start_pos(Application_Links *app, Buffer_ID buffer, i64 line_number){
    return(get_line_side_pos(app, buffer, line_number, Side_Min));
}

// NOTE(allen): The position returned has the index of the terminating newline character,
// not one past the newline character.
internal Buffer_Cursor
get_line_end(Application_Links *app, Buffer_ID buffer, i64 line_number){
    return(get_line_side(app, buffer, line_number, Side_Max));
}
internal i64
get_line_end_pos(Application_Links *app, Buffer_ID buffer, i64 line_number){
    return(get_line_side_pos(app, buffer, line_number, Side_Max));
}

// NOTE(allen): The range returned does not include the terminating newline character
internal Range_Cursor
get_line_range(Application_Links *app, Buffer_ID buffer, i64 line_number){
    b32 success = false;
    Range_Cursor result = {};
    result.start = get_line_start(app, buffer, line_number);
    if (result.start.line != 0){
        result.end = get_line_end(app, buffer, line_number);
        if (result.end.line != 0){
            success = true;
        }
    }
    if (!success){
        block_zero_struct(&result);
    }
    return(result);
}

// NOTE(allen): The range returned does not include the terminating newline character
internal Range_i64
get_line_pos_range(Application_Links *app, Buffer_ID buffer, i64 line_number){
    Range_Cursor range = get_line_range(app, buffer, line_number);
    Range_i64 result = {};
    if (range.start.line != 0 && range.end.line != 0){
        result = Ii64(range.start.pos, range.end.pos);
    }
    return(result);
}

internal Range_i64
make_range_from_cursors(Range_Cursor range){
    return(Ii64(range.start.pos, range.end.pos));
}

internal i64
get_line_side_pos_from_pos(Application_Links *app, Buffer_ID buffer, i64 pos, Side side){
    i64 line_number = get_line_number_from_pos(app, buffer, pos);
    return(get_line_side_pos(app, buffer, line_number, side));
}
internal i64
get_line_start_pos_from_pos(Application_Links *app, Buffer_ID buffer, i64 pos){
    return(get_line_side_pos_from_pos(app, buffer, pos, Side_Min));
}
internal i64
get_line_end_pos_from_pos(Application_Links *app, Buffer_ID buffer, i64 pos){
    return(get_line_side_pos_from_pos(app, buffer, pos, Side_Max));
}

internal Token*
get_first_token_from_line(Application_Links *app, Buffer_ID buffer, Token_Array tokens, i64 line){
    i64 line_start = get_line_start_pos(app, buffer, line);
    return(token_from_pos(&tokens, line_start));
}

////////////////////////////////

internal i64
scan_any_boundary(Application_Links *app, Boundary_Function *func, Buffer_ID buffer, Scan_Direction direction, i64 pos){
    i64 a = func(app, buffer, Side_Min, direction, pos);
    i64 b = func(app, buffer, Side_Max, direction, pos);
    i64 result = 0;
    if (direction == Scan_Forward){
        result = Min(a, b);
    }
    else{
        result = Max(a, b);
    }
    return(result);
}

internal i64
scan(Application_Links *app, Boundary_Function *func, Buffer_ID buffer, Scan_Direction direction, i64 pos){
    Side side = (direction == Scan_Forward)?(Side_Max):(Side_Min);
    return(func(app, buffer, side, direction, pos));
}

internal i64
scan(Application_Links *app, Boundary_Function_List funcs, Buffer_ID buffer, Scan_Direction direction, i64 start_pos){
    i64 result = 0;
    if (direction == Scan_Forward){
        i64 size = buffer_get_size(app, buffer);
        result = size + 1;
        for (Boundary_Function_Node *node = funcs.first;
             node != 0;
             node = node->next){
            i64 pos = scan(app, node->func, buffer, direction, start_pos);
            result = Min(result, pos);
        }
    }
    else{
        result = -1;
        for (Boundary_Function_Node *node = funcs.first;
             node != 0;
             node = node->next){
            i64 pos = scan(app, node->func, buffer, direction, start_pos);
            result = Max(result, pos);
        }
    }
    return(result);
}

internal void
push_boundary(Arena *arena, Boundary_Function_List *list, Boundary_Function *func){
    Boundary_Function_Node *node = push_array(arena, Boundary_Function_Node, 1);
    sll_queue_push(list->first, list->last, node);
    list->count += 1;
    node->func = func;
}

internal Boundary_Function_List
push_boundary_list__innerv(Arena *arena, va_list args){
    Boundary_Function_List list = {};
    for (;;){
        Boundary_Function *func = va_arg(args, Boundary_Function*);
        if (func == 0){
            break;
        }
        push_boundary(arena, &list, func);
    }
    return(list);
}
internal Boundary_Function_List
push_boundary_list__inner(Arena *arena, ...){
    va_list args;
    va_start(args, arena);
    Boundary_Function_List result = push_boundary_list__innerv(arena, args);
    va_end(args);
    return(result);
}
#define push_boundary_list(a,...) push_boundary_list__inner((a), __VA_ARGS__, 0)

internal i64
boundary_predicate(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos, Character_Predicate *predicate){
    i64 result = 0;
    switch (side){
        case Side_Min:
        {
            result = buffer_seek_character_class_change_0_1(app, buffer, predicate, direction, pos);
        }break;
        case Side_Max:
        {
            result = buffer_seek_character_class_change_1_0(app, buffer, predicate, direction, pos);
        }break;
    }
    return(result);
}

internal i64
boundary_non_whitespace(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    return(boundary_predicate(app, buffer, side, direction, pos, &character_predicate_non_whitespace));
}

internal i64
boundary_base10(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    return(boundary_predicate(app, buffer, side, direction, pos, &character_predicate_base10));
}

internal i64
boundary_base10_colon(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    internal Character_Predicate predicate = {};
    internal b32 first_call = true;
    if (first_call){
        first_call = false;
        Character_Predicate colon = character_predicate_from_character((u8)':');
        predicate = character_predicate_or(&character_predicate_base10, &colon);
    }
    return(boundary_predicate(app, buffer, side, direction, pos, &predicate));
}

internal i64
boundary_base16(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    return(boundary_predicate(app, buffer, side, direction, pos, &character_predicate_base16));
}

internal i64
boundary_alpha_numeric(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    return(boundary_predicate(app, buffer, side, direction, pos, &character_predicate_alpha_numeric));
}

internal i64
boundary_alpha_numeric_unicode(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    return(boundary_predicate(app, buffer, side, direction, pos, &character_predicate_alpha_numeric_underscore_utf8));
}

internal i64
boundary_alpha_numeric_underscore(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    return(boundary_predicate(app, buffer, side, direction, pos, &character_predicate_alpha_numeric_underscore));
}

internal i64
boundary_alpha_numeric_underscore_utf8(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    return(boundary_predicate(app, buffer, side, direction, pos, &character_predicate_alpha_numeric_underscore_utf8));
}

internal i64
boundary_alpha_numeric_camel(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    i64 an_pos = boundary_alpha_numeric(app, buffer, side, direction, pos);
    String_Match m = buffer_seek_character_class(app, buffer, &character_predicate_uppercase, direction, pos);
    i64 cap_pos = m.range.min;
    if (side == Side_Max){
        i64 an_left_pos = boundary_alpha_numeric(app, buffer, flip_side(side), flip_direction(direction), an_pos);
        if (cap_pos == an_left_pos){
            m = buffer_seek_character_class(app, buffer, &character_predicate_uppercase, direction, cap_pos);
            cap_pos = m.range.min;
        }
    }
    i64 result = 0;
    if (direction == Scan_Backward){
        result = Max(an_pos, cap_pos);
    }
    else{
        result = Min(an_pos, cap_pos);
    }
    return(result);
}

internal i64
boundary_inside_quotes(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    internal Character_Predicate predicate = {};
    internal b32 first_call = true;
    if (first_call){
        first_call = false;
        predicate = character_predicate_from_character((u8)'"');
        predicate = character_predicate_not(&predicate);
    }
    return(boundary_predicate(app, buffer, side, direction, pos, &predicate));
}

internal i64
boundary_token(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
    i64 result = boundary_non_whitespace(app, buffer, side, direction, pos);
    Token_Array tokens = get_token_array_from_buffer(app, buffer);
    if (tokens.tokens != 0){
        switch (direction){
            case Scan_Forward:
            {
                i64 buffer_size = buffer_get_size(app, buffer);
                result = buffer_size;
                if (tokens.count > 0){
                    Token_Iterator_Array it = token_iterator_pos(0, &tokens, pos);
                    Token *token = token_it_read(&it);
                    if (token->kind == TokenBaseKind_Whitespace){
                        token_it_inc_non_whitespace(&it);
                        token = token_it_read(&it);
                    }
                    if (token != 0){
                        if (side == Side_Max){
                            result = token->pos + token->size;
                        }
                        else{
                            if (token->pos <= pos){
                                token_it_inc_non_whitespace(&it);
                                token = token_it_read(&it);
                            }
                            if (token != 0){
                                result = token->pos;
                            }
                        }
                    }
                }
            }break;
            
            case Scan_Backward:
                            {
            result = 0;
                if (tokens.count > 0){
                                                                                    Token_Iterator_Array it = token_iterator_pos(0, &tokens, pos);
                                                                                                                                                                                                                                                                                                                        Token *token = token_it_read(&it);
if (token->kind == TokenBaseKind_Whitespace){
                                                                    token_it_dec_non_whitespace(&it);
token = token_it_read(&it);
                                                                                }
                    if (token != 0){
                                                                                        if (side == Side_Min){
                                                                                                                                                            if (token->pos >= pos){
                                                                                                                                                                                                                                token_it_dec_non_whitespace(&it);
token = token_it_read(&it);
                                                                                                            }
                            result = token->pos;
                                }
                        else{
                        if (token->pos + token->size >= pos){
                                                                                            token_it_dec_non_whitespace(&it);
token = token_it_read(&it);
                                                                                        }
                            result = token->pos + token->size;
                                        }
                        }
                    }
                }break;
            }
            }
        return(result);
}

                                internal i64
boundary_line(Application_Links *app, Buffer_ID buffer, Side side, Scan_Direction direction, i64 pos){
                                                                                                            i64 line_number = get_line_number_from_pos(app, buffer, pos);
                                                                                                                                                                                                                                                                                                                                        i64 new_pos = get_line_side_pos(app, buffer, line_number, side);
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        if (direction == Scan_Backward && new_pos >= pos){
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            if (line_number > 1){
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                new_pos = get_line_side_pos(app, buffer, line_number - 1, side);
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        }
        else{
        new_pos = 0;
                    }
            }
        else if (direction == Scan_Forward && new_pos <= pos){
                                                                                                new_pos = get_line_side_pos(app, buffer, line_number + 1, side);
                                                                                                                                        if (new_pos <= pos){
                                                                                                                                                                                                            new_pos = (i32)buffer_get_size(app, buffer);
                                                                                                                                                                                                                                                                                                                                                                                    }
        }
    return(new_pos);
}
        
                                        ////////////////////////////////

// TODO(allen): these need a little more rewrite
internal void
seek_string_forward(Application_Links *app, Buffer_ID buffer, i64 pos, i64 end, String_Const_u8 needle, i64 *result){
                                                                                                                                                            if (end == 0){
    end = (i32)buffer_get_size(app, buffer);
                                                               }
    String_Match match = {};
match.range.first = pos;
            for (;;){
        match = buffer_seek_string(app, buffer, needle, Scan_Forward, (i32)match.range.first);
                                                                                                                                                                                                                                                                                                        if (HasFlag(match.flags, StringMatch_CaseSensitive) ||
                                                                                                                                                                                                                                                                                                                                                                                                                                    match.buffer != buffer || match.range.first >= end) break;
                                                                                                                                                                                                            }
    if (match.range.first < end && match.buffer == buffer){
                                                                                            *result = match.range.first;
}
                                        else{
    *result = buffer_get_size(app, buffer);
                                                              }
        }
        
    internal void
seek_string_backward(Application_Links *app, Buffer_ID buffer, i64 pos, i64 min, String_Const_u8 needle, i64 *result){
                                                                                                                                                                                                                  String_Match match = {};
    match.range.first = pos;
        for (;;){
            match = buffer_seek_string(app, buffer, needle, Scan_Backward, match.range.first);
                                                                                                                                                                     if (HasFlag(match.flags, StringMatch_CaseSensitive) ||
                                                                                                                                                                                                      match.buffer != buffer || match.range.first < min) break;
                                                                                                                                                                                                                                                                                           }
    if (match.range.first >= min && match.buffer == buffer){
                                    *result = match.range.first;
}
                    else{
    *result = -1;
    }
        }
        
    internal void
seek_string_insensitive_forward(Application_Links *app, Buffer_ID buffer, i64 pos, i64 end, String_Const_u8 needle, i64 *result){
                                                                                                                                                                                                                                                                                      if (end == 0){
    end = (i32)buffer_get_size(app, buffer);
        }
            String_Match match = buffer_seek_string(app, buffer, needle, Scan_Forward, pos);
                                                                                        if (match.range.first < end && match.buffer == buffer){
                                                                                                                                                                *result = match.range.first;
        }
            else{
            *result = buffer_get_size(app, buffer);
        }
                    }

    internal void
seek_string_insensitive_backward(Application_Links *app, Buffer_ID buffer, i64 pos, i64 min, String_Const_u8 needle, i64 *result){
                                                                                                                                                                                           String_Match match = buffer_seek_string(app, buffer, needle, Scan_Backward, pos);
                                                                                                                                                                                                                                                                                                      if (match.range.first >= min && match.buffer == buffer){
                                                                                                                                                                                                                                                                                                                                                                                      *result = match.range.first;
        }
        else{
    *result = -1;
    }
    }
        
        internal void
        seek_string(Application_Links *app, Buffer_ID buffer_id, i64 pos, i64 end, i64 min, String_Const_u8 str, i64 *result, Buffer_Seek_String_Flags flags){
                                                                                                                                                                                                                                                                                        switch (flags & 3){
    case 0:
    {
    seek_string_forward(app, buffer_id, pos, end, str, result);
    }break;
        
        case BufferSeekString_Backward:
                {
                seek_string_backward(app, buffer_id, pos, min, str, result);
}break;
    
    case BufferSeekString_CaseInsensitive:
        {
        seek_string_insensitive_forward(app, buffer_id, pos, end, str, result);
                }break;
    
                case BufferSeekString_Backward|BufferSeekString_CaseInsensitive:
        {
    seek_string_insensitive_backward(app, buffer_id, pos, min, str, result);
                    }break;
                            }
                        }
            
        ////////////////////////////////
    
internal Range_i64
get_line_range_from_pos_range(Application_Links *app, Buffer_ID buffer, Range_i64 pos_range){
                                                                                      Range_i64 line_range = {};
                                                                                      line_range.first = get_line_number_from_pos(app, buffer, pos_range.first);
        if (line_range.first != 0){
                                                          line_range.end = get_line_number_from_pos(app, buffer, pos_range.one_past_last);
if (line_range.end == 0){
             line_range.first = 0;
              }
                         }
                return(line_range);
              }
            
        // NOTE(allen): The end of the returned range does not include the terminating newline character of
// the last line.
internal Range_i64
get_pos_range_from_line_range(Application_Links *app, Buffer_ID buffer, Range_i64 line_range){
                                                                                          Range_i64 pos_range = {};
                                                                                          if (is_valid_line_range(app, buffer, line_range)){
                                                         pos_range.first = get_line_start_pos(app, buffer, line_range.first);
pos_range.one_past_last = get_line_end_pos(app, buffer, line_range.end);
                                                                                }
    return(pos_range);
    }
    
    internal Range_i64
 enclose_boundary(Application_Links *app, Buffer_ID buffer, Range_i64 range,
Boundary_Function *func){
 i64 new_min       = func(app, buffer, Side_Min, Scan_Backward, range.min + 1);
        i64 new_min_check = func(app, buffer, Side_Max, Scan_Backward, range.min + 1);
                                                                                                                                                                                                                                                  if (new_min_check <= new_min && new_min < range.min){
    range.min = new_min;
          }
          i64 new_max       = func(app, buffer, Side_Max, Scan_Forward, range.max - 1);
        i64 new_max_check = func(app, buffer, Side_Min, Scan_Forward, range.max);
                                                    if (new_max_check >= new_max && new_max > range.max){
    range.max = new_max;
        }
        return(range);
        }
        
        internal Range_i64
    left_enclose_boundary(Application_Links *app, Buffer_ID buffer, Range_i64 range,
Boundary_Function *func){
         i64 new_min       = func(app, buffer, Side_Min, Scan_Backward, range.min + 1);
                            i64 new_min_check = func(app, buffer, Side_Max, Scan_Backward, range.min + 1);
                                                                                                                                                                                                                                                               if (new_min_check <= new_min && new_min < range.min){
    range.min = new_min;
                  }
                  return(range);
                  }
                  
                      internal Range_i64
                right_enclose_boundary(Application_Links *app, Buffer_ID buffer, Range_i64 range,
Boundary_Function *func){
         i64 new_max       = func(app, buffer, Side_Max, Scan_Forward, range.max - 1);
                                                                                             i64 new_max_check = func(app, buffer, Side_Min, Scan_Forward, range.max - 1);
if (new_max_check >= new_max && new_max > range.max){
          range.max = new_max;
                              }
                             return(range);
                     }
        
            internal Range_i64
    enclose_non_whitespace(Application_Links *app, Buffer_ID buffer, Range_i64 range){
return(enclose_boundary(app, buffer, range, boundary_non_whitespace));
                                                     }
                     internal Range_i64
enclose_pos_non_whitespace(Application_Links *app, Buffer_ID buffer, i64 pos){
                                                     return(enclose_boundary(app, buffer, Ii64(pos), boundary_non_whitespace));
}

internal Range_i64
              enclose_tokens(Application_Links *app, Buffer_ID buffer, Range_i64 range){
                                                                          return(enclose_boundary(app, buffer, range, boundary_token));
    }
    internal Range_i64
                    enclose_pos_tokens(Application_Links *app, Buffer_ID buffer, i64 pos){
return(enclose_boundary(app, buffer, Ii64(pos), boundary_token));
    }
    
    internal Range_i64
                  enclose_base10(Application_Links *app, Buffer_ID buffer, Range_i64 range){
                                                                     return(enclose_boundary(app, buffer, range, boundary_base10));
    }
    internal Range_i64
                      enclose_pos_base10(Application_Links *app, Buffer_ID buffer, i64 pos){
return(enclose_boundary(app, buffer, Ii64(pos), boundary_base10));
    }
    
    internal Range_i64
                        enclose_base16(Application_Links *app, Buffer_ID buffer, Range_i64 range){
                                                                        return(enclose_boundary(app, buffer, range, boundary_base16));
    }
    internal Range_i64
                      enclose_pos_base16(Application_Links *app, Buffer_ID buffer, i64 pos){
return(enclose_boundary(app, buffer, Ii64(pos), boundary_base16));
    }
    
    internal Range_i64
             enclose_base10_colon(Application_Links *app, Buffer_ID buffer, Range_i64 range){
                                                                            return(enclose_boundary(app, buffer, range, boundary_base10_colon));
    }
    internal Range_i64
                                  enclose_pos_base10_colon(Application_Links *app, Buffer_ID buffer, i64 pos){
                                                          return(enclose_boundary(app, buffer, Ii64(pos), boundary_base10_colon));
}

internal Range_i64
       enclose_alpha_numeric(Application_Links *app, Buffer_ID buffer, Range_i64 range){
                                                                      return(enclose_boundary(app, buffer, range, boundary_alpha_numeric));
    }
    internal Range_i64
                            enclose_pos_alpha_numeric(Application_Links *app, Buffer_ID buffer, i64 pos){
                                                                 return(enclose_boundary(app, buffer, Ii64(pos), boundary_alpha_numeric));
}

internal Range_i64
      enclose_alpha_numeric_unicode(Application_Links *app, Buffer_ID buffer, Range_i64 range){
                                                                     return(enclose_boundary(app, buffer, range, boundary_alpha_numeric_unicode));
}
 internal Range_i64
                          enclose_pos_alpha_numeric_unicode(Application_Links *app, Buffer_ID buffer, i64 pos){
                                                                              return(enclose_boundary(app, buffer, Ii64(pos), boundary_alpha_numeric_unicode));
                                                                      }
                                                                      
                                                                      internal Range_i64
                                                                                         enclose_alpha_numeric_underscore(Application_Links *app, Buffer_ID buffer, Range_i64 range){
                                                                     return(enclose_boundary(app, buffer, range, boundary_alpha_numeric_underscore));
                                                                       }
                                                                       internal Range_i64
                                                                                      enclose_pos_alpha_numeric_underscore(Application_Links *app, Buffer_ID buffer, i64 pos){
                                                                           return(enclose_boundary(app, buffer, Ii64(pos), boundary_alpha_numeric_underscore));
                                                                             }
                                                                             internal Range_i64
                                                                                            right_enclose_alpha_numeric_underscore(Application_Links *app, Buffer_ID buffer,
                                                                       Range_i64 range){
                        return(right_enclose_boundary(app, buffer, range, boundary_alpha_numeric_underscore));
                                                                                                                                                                                            }
    
internal Range_i64
enclose_alpha_numeric_underscore_utf8(Application_Links *app, Buffer_ID buffer, Range_i64 range){
return(enclose_boundary(app, buffer, range, boundary_alpha_numeric_underscore_utf8));
}
internal Range_i64
    enclose_pos_alpha_numeric_underscore_utf8(Application_Links *app, Buffer_ID buffer, i64 pos){
return(enclose_boundary(app, buffer, Ii64(pos), boundary_alpha_numeric_underscore_utf8));
    }
    internal Range_i64
    right_enclose_alpha_numeric_underscore_utf8(Application_Links *app, Buffer_ID buffer,
    Range_i64 range){
return(right_enclose_boundary(app, buffer, range, boundary_alpha_numeric_underscore_utf8));
                                    }


                             internal Range_i64
enclose_alpha_numeric_camel(Application_Links *app, Buffer_ID buffer, Range_i64 range){
return(enclose_boundary(app, buffer, range, boundary_alpha_numeric_camel));
}
internal Range_i64
enclose_pos_alpha_numeric_camel(Application_Links *app, Buffer_ID buffer, i64 pos){
return(enclose_boundary(app, buffer, Ii64(pos), boundary_alpha_numeric_camel));
}

internal Range_i64
enclose_pos_inside_quotes(Application_Links *app, Buffer_ID buffer, i64 pos){
                                                                                                                                              return(enclose_boundary(app, buffer, Ii64(pos), boundary_inside_quotes));
}

internal Range_i64
enclose_whole_lines(Application_Links *app, Buffer_ID buffer, Range_i64 range){
    return(enclose_boundary(app, buffer, range, boundary_line));
}
internal Range_i64
enclose_pos_whole_lines(Application_Links *app, Buffer_ID buffer, i64 pos){
                                                                       return(enclose_boundary(app, buffer, Ii64(pos), boundary_line));
    }
    
    ////////////////////////////////
    
    internal Range_i64
                    get_snipe_range(Application_Links *app, Boundary_Function_List funcs, Buffer_ID buffer, i64 pos, Scan_Direction direction){
                                                                                                                         Range_i64 result = {};
                                                                                                                            i64 buffer_size = buffer_get_size(app, buffer);
    i64 pos0 = pos;
    i64 pos1 = scan(app, funcs, buffer, direction, pos0);
if (0 <= pos1 && pos1 <= buffer_size){
i64 pos2 = scan(app, funcs, buffer, flip_direction(direction), pos1);
                                        if (0 <= pos2 && pos2 <= buffer_size){
if (direction == Scan_Backward){
     pos2 = clamp_bot(pos2, pos0);
                 }
else{
        pos2 = clamp_top(pos2, pos0);
    }
    result = Ii64(pos1, pos2);
    }
           }
           return(result);
          }
    
    internal Range_i64
                      get_snipe_range(Application_Links *app, Boundary_Function *func, Buffer_ID buffer, i64 pos, Scan_Direction direction){
                                                                                                                                      Scratch_Block scratch(app);
                return(get_snipe_range(app, push_boundary_list(scratch, func), buffer, pos, direction));
        }
    
    ////////////////////////////////

internal String_Const_u8
push_buffer_range(Application_Links *app, Arena *arena, Buffer_ID buffer, Range_i64 range){
                                 String_Const_u8 result = {};
                                 i64 length = range_size(range);
    if (length > 0){
    Temp_Memory restore_point = begin_temp(arena);
    u8 *memory = push_array(arena, u8, length);
    if (buffer_read_range(app, buffer, range, memory)){
    result = SCu8(memory, length);
                         }
                   else{
                 end_temp(restore_point);
}
}
return(result);
}

internal String_Const_u8
                    push_token_lexeme(Application_Links *app, Arena *arena, Buffer_ID buffer, Token *token){
                                                                                     return(push_buffer_range(app, arena, buffer, Ii64(token)));
              }
        
        internal String_Const_u8
               push_buffer_line(Application_Links *app, Arena *arena, Buffer_ID buffer, i64 line_number){
        return(push_buffer_range(app, arena, buffer, get_line_pos_range(app, buffer, line_number)));
}

internal String_Const_u8
                      push_whole_buffer(Application_Links *app, Arena *arena, Buffer_ID buffer){
    return(push_buffer_range(app, arena, buffer, buffer_range(app, buffer)));
                 }
                                                                            
                                                                            internal String_Const_u8
                                                                                                push_view_range_string(Application_Links *app, Arena *arena, View_ID view){
                                                                                                                                                                            Buffer_ID buffer = view_get_buffer(app, view, Access_ReadVisible);
    return(push_buffer_range(app, arena, buffer, get_view_range(app, view)));
                                                                 }

                                                               internal String_Const_u8
    push_view_range_string(Application_Links *app, Arena *arena){
                                                                                                              View_ID view = get_active_view(app, Access_Always);
return(push_view_range_string(app, arena, view));
}

internal String_Const_u8
push_enclose_range_at_pos(Application_Links *app, Arena *arena, Buffer_ID buffer, i64 pos, Enclose_Function *enclose){
                                                                                                                                                                                                              Range_i64 range = enclose(app, buffer, Ii64(pos));
    return(push_buffer_range(app, arena, buffer, range));
    }

////////////////////////////////
    
    internal String_Const_u8
    token_it_lexeme(Application_Links *app, Arena *arena, Token_Iterator_Array *it){
                                                                                String_Const_u8 result = {};
                                                                              Token *token = token_it_read(it);
if (token != 0){
        result = push_token_lexeme(app, arena, (Buffer_ID)it->user_id, token);
                                                                                                          }
return(result);
}

internal b32
token_it_check_and_get_lexeme(Application_Links *app, Arena *arena, Token_Iterator_Array *it, Token_Base_Kind kind, String_Const_u8 *lexeme_out){
                                                                                                                                                                                                                                                         Token *token = token_it_read(it);
    b32 result = {};
    if (token != 0 && token->kind == kind){
                          result = true;
    *lexeme_out = push_token_lexeme(app, arena, (Buffer_ID)it->user_id, token);
    }
return(result);
                }

          internal String_Const_u8
            token_it_lexeme(Application_Links *app, Arena *arena, Token_Iterator_List *it){
    String_Const_u8 result = {};
    Token *token = token_it_read(it);
if (token != 0){
result = push_token_lexeme(app, arena, (Buffer_ID)it->user_id, token);
}
return(result);
    }
 
     internal b32
         token_it_check_and_get_lexeme(Application_Links *app, Arena *arena, Token_Iterator_List *it, Token_Base_Kind kind, String_Const_u8 *lexeme_out){
    Token *token = token_it_read(it);
    b32 result = {};
    if (token != 0 && token->kind == kind){
                   result = true;
                       *lexeme_out = push_token_lexeme(app, arena, (Buffer_ID)it->user_id, token);
         }
            return(result);
           }
                       
                               ////////////////////////////////
        
    internal b32
buffer_has_name_with_star(Application_Links *app, Buffer_ID buffer){
                               Scratch_Block scratch(app);
String_Const_u8 str = push_buffer_unique_name(app, scratch, buffer);
                                                              return(str.size > 0 && str.str[0] == '*');
    }
    
    internal u8
        buffer_get_char(Application_Links *app, Buffer_ID buffer_id, i64 pos){
                                                                               i64 buffer_size = buffer_get_size(app, buffer_id);
                                                                   u8 result = ' ';
                                                                           if (0 <= pos && pos < buffer_size){
        buffer_read_range(app, buffer_id, Ii64(pos, pos + 1), &result);
                                                                            }
        return(result);
}

internal b32
       line_is_valid_and_blank(Application_Links *app, Buffer_ID buffer, i64 line_number){
b32 result = false;
if (is_valid_line(app, buffer, line_number)){
Scratch_Block scratch(app);
                       String_Const_u8 line = push_buffer_line(app, scratch, buffer, line_number);
    result = true;
    for (u64 i = 0; i < line.size; i += 1){
                                if (!character_is_whitespace(line.str[i])){
                                                   result = false;
                                                                   break;
}
    }
 }
 return(result);
      }

        ////////////////////////////////
    
    internal i64
    get_pos_past_lead_whitespace_from_line_number(Application_Links *app, Buffer_ID buffer, i64 line_number){
    Scratch_Block scratch(app);
    Range_i64 line_range = get_line_pos_range(app, buffer, line_number);
String_Const_u8 line = push_buffer_range(app, scratch, buffer, line_range);
                                                i64 result = line_range.end;
                      for (u64 i = 0; i < line.size; i += 1){
                if (!character_is_whitespace(line.str[i])){
                                                                          result = line_range.start + i;
break;
        }
     }
     return(result);
            }
            
            internal i64
            get_pos_past_lead_whitespace(Application_Links *app, Buffer_ID buffer, i64 pos){
                                                                                   i64 line_number = get_line_number_from_pos(app, buffer, pos);
i64 result = get_pos_past_lead_whitespace_from_line_number(app, buffer, line_number);
result = clamp_bot(pos, result);
          return(result);
     }

    internal void
        move_past_lead_whitespace(Application_Links *app, View_ID view, Buffer_ID buffer){
                                                                           i64 pos = view_get_cursor_pos(app, view);
                         i64 new_pos = get_pos_past_lead_whitespace(app, buffer, pos);
view_set_cursor_and_preferred_x(app, view, seek_pos(new_pos));
                                }

                                                  internal void
                move_past_lead_whitespace(Application_Links *app, View_ID view){
Buffer_ID buffer = view_get_buffer(app, view, Access_ReadVisible);
    move_past_lead_whitespace(app, view, buffer);
    }

internal b32
line_is_blank(Application_Links *app, Buffer_ID buffer, i64 line_number){
                                             Scratch_Block scratch(app);
                                           String_Const_u8 line = push_buffer_line(app, scratch, buffer, line_number);
                                                                   b32 is_blank = true;
for (u64 i = 0; i < line.size; i += 1){
    if (!character_is_whitespace(line.str[i])){
    is_blank = false;
        break;
          }
          }
          return(is_blank);
    }
    
    internal i64
get_line_number_of__whitespace_status_line(Application_Links *app, Buffer_ID buffer, Scan_Direction direction, i64 line_number_start, b32 get_blank_line){
i64 line_count = buffer_get_line_count(app, buffer);
      i64 line_number = line_number_start + direction;
                                                 for (;1 <= line_number && line_number <= line_count; line_number += direction){
b32 is_blank = line_is_blank(app, buffer, line_number);
if (is_blank == get_blank_line){
                                                        break;
                                                         }
    }
    line_number = clamp(1, line_number, line_count);
   return(line_number);
                 }

        internal i64
    get_line_number_of_non_blank_line(Application_Links *app, Buffer_ID buffer, Scan_Direction direction, i64 line_number_start){
        return(get_line_number_of__whitespace_status_line(app, buffer, direction, line_number_start, false));
}

internal i64
                                                                                                   get_line_number_of_blank_line(Application_Links *app, Buffer_ID buffer, Scan_Direction direction, i64 line_number_start){
                return(get_line_number_of__whitespace_status_line(app, buffer, direction, line_number_start, true));
                                                                                  }
                                                                                  
                                                                                  internal i64
                                                                                          get_pos_of_blank_line(Application_Links *app, Buffer_ID buffer, Scan_Direction direction, i64 pos_start){
                                    i64 line_number_start = get_line_number_from_pos(app, buffer, pos_start);
                                                                i64 blank_line = get_line_number_of_blank_line(app, buffer, direction, line_number_start);
                                                                           i64 pos = get_line_start_pos(app, buffer, blank_line);
    return(pos);
}

      internal i64
          get_line_number_of_blank_line_grouped(Application_Links *app, Buffer_ID buffer, Scan_Direction direction, i64 line_number_start){
                                                                                                                                                                                                                              i64 line_number = line_number_start;
    if (line_is_blank(app, buffer, line_number)){
                                                    line_number = get_line_number_of_non_blank_line(app, buffer, direction, line_number);
                                                                  }
    line_number = get_line_number_of_blank_line(app, buffer, direction, line_number);
    return(line_number);
    }
    
    internal i64
    get_pos_of_blank_line_grouped(Application_Links *app, Buffer_ID buffer, Scan_Direction direction, i64 pos_start){
i64 line_number_start = get_line_number_from_pos(app, buffer, pos_start);
                                         i64 blank_line = get_line_number_of_blank_line_grouped(app, buffer, direction, line_number_start);
                                                                                   i64 pos = get_line_start_pos(app, buffer, blank_line);
                                                                                                                                    return(pos);
    }
    
    internal Indent_Info
    get_indent_info_range(Application_Links *app, Buffer_ID buffer, Range_i64 range, i32 tab_width){
        Scratch_Block scratch(app);
                                                                                                                  String_Const_u8 s = push_buffer_range(app, scratch, buffer, range);

                                             Indent_Info info = {};
info.first_char_pos = range.end;
    info.is_blank = true;
    info.all_space = true;
   
        for (u64 i = 0; i < s.size; i += 1){
                                    u8 c = s.str[i];
                                         if (!character_is_whitespace(c)){
    info.is_blank = false;
    info.all_space = false;
info.first_char_pos = range.start + (i64)i;
    break;
    }
    if (c == ' '){
    info.indent_pos += 1;
    }
    else{
info.all_space = false;
}
if (c == '\t'){
              info.indent_pos += tab_width;
                      }
      }
    
    return(info);
                            }
    
    internal Indent_Info
    get_indent_info_line_number_and_start(Application_Links *app, Buffer_ID buffer, i64 line_number, i64 line_start, i32 tab_width){
    i64 end = get_line_side_pos(app, buffer, line_number, Side_Max);
return(get_indent_info_range(app, buffer, Ii64(line_start, end), tab_width));
        }
    
        ////////////////////////////////
                    
                            internal History_Group
            history_group_begin(Application_Links *app, Buffer_ID buffer){
            History_Group group = {};
            group.app = app;
            group.buffer = buffer;
                   group.first = buffer_history_get_current_state_index(app, buffer);
        group.first += 1;
        return(group);
                }
                
        internal void
            history_group_end(History_Group group){
        History_Record_Index last = buffer_history_get_current_state_index(group.app, group.buffer);
            if (group.first < last){
                    buffer_history_merge_record_range(group.app, group.buffer, group.first, last, RecordMergeFlag_StateInRange_MoveStateForward);
}
}

////////////////////////////////

internal void
     replace_in_range(Application_Links *app, Buffer_ID buffer, Range_i64 range, String_Const_u8 needle, String_Const_u8 string){
    // TODO(allen): rewrite
    History_Group group = history_group_begin(app, buffer);
    i64 pos = range.min - 1;
    i64 new_pos = 0;
            seek_string_forward(app, buffer, pos, range.end, needle, &new_pos);
                                                             i64 shift = replace_range_shift(needle.size, string.size);
                                                                            for (; new_pos + (i64)needle.size <= range.end;){
                                      Range_i64 needle_range = Ii64(new_pos, new_pos + (i32)needle.size);
    buffer_replace_range(app, buffer, needle_range, string);
                                range.end += shift;
pos = new_pos + (i32)string.size - 1;
                                                                seek_string_forward(app, buffer, pos, range.end, needle, &new_pos);
                                 }
                        history_group_end(group);
}
                              
                                          internal Range_i64
                                                   swap_lines(Application_Links *app, Buffer_ID buffer, i64 line_1, i64 line_2){
Range_i64 result = {};
i64 line_count = buffer_get_line_count(app, buffer);
                                                         if (1 <= line_1 && line_2 <= line_count){
    Range_i64 range_1 = get_line_pos_range(app, buffer, line_1);
                                                                Range_i64 range_2 = get_line_pos_range(app, buffer, line_2);
                                            
                                                                                                            Scratch_Block scratch(app);
                                                                                                                                      
                                                                                                                                          String_Const_u8 text_1 = push_buffer_range(app, scratch, buffer, range_1);
        String_Const_u8 text_2 = push_buffer_range(app, scratch, buffer, range_2);
        
        History_Group group = history_group_begin(app, buffer);
    buffer_replace_range(app, buffer, range_2, text_1);
buffer_replace_range(app, buffer, range_1, text_2);
                                         history_group_end(group);

i64 shift = replace_range_shift(range_1, text_2.size);
    result.min = range_1.min;
result.max = range_2.min + shift;
                                           }
        return(result);
}
    
                      internal i64
             move_line(Application_Links *app, Buffer_ID buffer, i64 line_number, Scan_Direction direction){
        i64 line_1 = 0;
        i64 line_2 = 0;
                               if (direction == Scan_Forward){
    line_1 = line_number;
line_2 = line_number + 1;
        }
        else{
        line_1 = line_number - 1;
                           line_2 = line_number;
                                         }
                                         Range_i64 line_starts = swap_lines(app, buffer, line_1, line_2);
        i64 result = 0;
        if (line_starts.min < line_starts.max){
        if (direction == Scan_Forward){
        result = line_starts.max;
        }
        else{
        result = line_starts.min;
        }
        }
            else{
        result = get_line_side_pos(app, buffer, line_number, Side_Min);
        }
        return(result);
        }
        
        internal void
        clear_buffer(Application_Links *app, Buffer_ID buffer){
            buffer_replace_range(app, buffer, buffer_range(app, buffer), string_u8_litexpr(""));
                                                                                    }
        
        ////////////////////////////////

    internal String_Match_List
        find_all_matches_all_buffers(Application_Links *app, Arena *arena, String_Const_u8_Array match_patterns, String_Match_Flag must_have_flags, String_Match_Flag must_not_have_flags){
    String_Match_List all_matches = {};
for (Buffer_ID buffer = get_buffer_next(app, 0, Access_Always);
    buffer != 0;
                                                                                 buffer = get_buffer_next(app, buffer, Access_Always)){
String_Match_List buffer_matches = {};
                    for (i32 i = 0; i < match_patterns.count; i += 1){
    Range_i64 range = buffer_range(app, buffer);
    String_Match_List pattern_matches = buffer_find_all_matches(app, arena, buffer, i, range, match_patterns.vals[i],
    &character_predicate_alpha_numeric_underscore_utf8, Scan_Forward);
    string_match_list_filter_flags(&pattern_matches, must_have_flags, must_not_have_flags);
if (pattern_matches.count > 0){
if (buffer_matches.count == 0){
                   buffer_matches = pattern_matches;
                               }
                              else{
buffer_matches = string_match_list_merge_front_to_back(&buffer_matches, &pattern_matches);
}
}
}
all_matches = string_match_list_join(&all_matches, &buffer_matches);
                                                                  }
            return(all_matches);
    }
    
    internal String_Match_List
  find_all_matches_all_buffers(Application_Links *app, Arena *arena, String_Const_u8 pattern, String_Match_Flag must_have_flags, String_Match_Flag must_not_have_flags){
                                                                                                String_Const_u8_Array array = {&pattern, 1};
            return(find_all_matches_all_buffers(app, arena, array, must_have_flags, must_not_have_flags));
            }

////////////////////////////////
            
            internal b32
            is_modified(User_Input *input){
                            return(is_modified(&input->event));
                                    }
            
            internal String_Const_u8
                                        to_writable(User_Input *in){
                return(to_writable(&in->event));
                    }
                
                internal b32
                            has_modifier(User_Input *in, Key_Code key_code){
                                                       b32 result = false;
                Input_Modifier_Set *mods = get_modifiers(&in->event);
       if (mods != 0){
    result = has_modifier(mods, key_code);
        }
        return(result);
        }
        
        internal b32
    match_key_code(User_Input *in, Key_Code key_code){
    return(match_key_code(&in->event, key_code));
    }
    
internal b32
match_core_code(User_Input *in, Key_Code core_code){
return(match_core_code(&in->event, core_code));
}

internal String_Const_u8
backspace_utf8(String_Const_u8 string){
                                             if (string.size > 0){
u64 i = string.size - 1;
                                 for (; i > 0; --i){
        if (string.str[i] <= 0x7F || string.str[i] >= 0xC0){
                                                                           break;
                                            }
    }
    string.size = i;
    }
    return(string);
    }
    
    ////////////////////////////////
    
Query_Bar_Group::Query_Bar_Group(Application_Links *app){
                                     this->app = app;
    this->view = get_active_view(app, Access_Always);
}

Query_Bar_Group::Query_Bar_Group(Application_Links *app, View_ID view){
                                                                this->app = app;
                                                                                this->view = view;
}

Query_Bar_Group::~Query_Bar_Group(){
clear_all_query_bars(this->app, this->view);
    }
    
    internal b32
        query_user_general(Application_Links *app, Query_Bar *bar, b32 force_number, String_Const_u8 init_string){
// NOTE(allen|a3.4.4): It will not cause an *error* if we continue on after failing to.
// start a query bar, but it will be unusual behavior from the point of view of the
    // user, if this command starts intercepting input even though no prompt is shown.
// This will only happen if you have a lot of bars open already or if the current view
                                                                           // doesn't support query bars.
            if (start_query_bar(app, bar, 0) == 0){
                                                   return(false);
            }
                
                if (init_string.size > 0){
                     String_u8 string = Su8(bar->string.str, bar->string.size, bar->string_capacity);
            string_append(&string, init_string);
        bar->string.size = string.string.size;
        }
        
    b32 success = true;
    
    for (;;){
            // NOTE(allen|a3.4.4): This call will block until the user does one of the input
// types specified in the flags.  The first set of flags are inputs you'd like to
                                                                                                                                              // intercept that you don't want to abort on.  The second set are inputs that
    // you'd like to cause the command to abort.  If an event satisfies both flags, it
// is treated as an abort.
    User_Input in = get_next_input(app, EventPropertyGroup_AnyKeyboardEvent,
    EventProperty_Escape|EventProperty_MouseButton);
    
    // NOTE(allen|a3.4.4): The responsible thing to do on abort is to end the command
                                                                    // without waiting on get_next_input again.
if (in.abort){
success = false;
        break;
      }

      Scratch_Block scratch(app);
                                b32 good_insert = false;
String_Const_u8 insert_string = to_writable(&in);
    if (insert_string.str != 0 && insert_string.size > 0){
                           insert_string = string_replace(scratch, insert_string,
            string_u8_litexpr("\n"),
                                     string_u8_litexpr(""));
                     insert_string = string_replace(scratch, insert_string,
            string_u8_litexpr("\t"),
        string_u8_litexpr(""));
        if (force_number){
if (string_is_integer(insert_string, 10)){
        good_insert = true;
        }
        }
        else{
        good_insert = true;
                 }
}

// NOTE(allen|a3.4.4): All we have to do to update the query bar is edit our
        // local Query_Bar struct!  This is handy because it means our Query_Bar
                                                                                                                            // is always correct for typical use without extra work updating the bar.
        if (in.event.kind == InputEventKind_KeyStroke &&
                                                                (in.event.key.code == KeyCode_Return || in.event.key.code == KeyCode_Tab)){
                                                                break;
                                                                        }
                                                                        else if (in.event.kind == InputEventKind_KeyStroke &&
        in.event.key.code == KeyCode_Backspace){
                                  bar->string = backspace_utf8(bar->string);
        }
        else if (good_insert){
            String_u8 string = Su8(bar->string.str, bar->string.size, bar->string_capacity);
                                string_append(&string, insert_string);
                        bar->string.size = string.string.size;
                                                                }
                                                           else{
                                                                    leave_current_input_unhandled(app);
                         }
                  }
                  
                                                          return(success);
                  }

                                          internal b32
      query_user_string(Application_Links *app, Query_Bar *bar){
                return(query_user_general(app, bar, false, string_u8_empty));
                }
                
            internal b32
    query_user_number(Application_Links *app, Query_Bar *bar){
return(query_user_general(app, bar, true, string_u8_empty));
        }
        
        internal b32
                              query_user_number(Application_Links *app, Query_Bar *bar, i32 x){
        Scratch_Block scratch(app);
                           String_Const_u8 string = push_u8_stringf(scratch, "%d", x);
                                                                                                                                                                                       return(query_user_general(app, bar, true, string));
            }
            
        ////////////////////////////////
        
        internal Buffer_Identifier
                              buffer_identifier(char *str, i32 len){
            Buffer_Identifier identifier;
            identifier.name = str;
            identifier.name_len = len;
                          identifier.id = 0;
            return(identifier);
                }
                
                     internal Buffer_Identifier
        buffer_identifier(String_Const_u8 str){
            return(buffer_identifier((char*)str.str, (i32)str.size));
            }
            
        internal Buffer_Identifier
    buffer_identifier(Buffer_ID id){
    Buffer_Identifier identifier;
    identifier.name = 0;
identifier.name_len = 0;
identifier.id = id;
return(identifier);
                 }
         
             internal Buffer_ID
             buffer_identifier_to_id(Application_Links *app, Buffer_Identifier identifier){
Buffer_ID id = 0;
               if (identifier.id != 0){
id = identifier.id;
    }
    else{
    String_Const_u8 name = SCu8(identifier.name, identifier.name_len);
    id = get_buffer_by_name(app, name, Access_Always);
    if (id == 0){
    id = get_buffer_by_file_name(app, name, Access_Always);
    }
    }
    return(id);
    }
    
        internal Buffer_ID
            buffer_identifier_to_id_create_out_buffer(Application_Links *app, Buffer_Identifier buffer_id){
    Buffer_ID result = 0;
    if (buffer_id.name != 0 && buffer_id.name_len > 0){
    String_Const_u8 buffer_name = SCu8(buffer_id.name, buffer_id.name_len);
    Buffer_ID buffer_attach_id = get_buffer_by_name(app, buffer_name, Access_Always);
    if (buffer_attach_id != 0){
    result = buffer_attach_id;
                         }
else{
buffer_attach_id = create_buffer(app, buffer_name, BufferCreate_AlwaysNew|BufferCreate_NeverAttachToFile);
if (buffer_attach_id != 0){
buffer_set_setting(app, buffer_attach_id, BufferSetting_ReadOnly, true);
        buffer_set_setting(app, buffer_attach_id, BufferSetting_Unimportant, true);
                                                                             result = buffer_attach_id;
}
}
}
else{
result = buffer_id.id;
    }
    return(result);
    }
    
    ////////////////////////////////
    
    function void
place_begin_and_end_on_own_lines(Application_Links *app, char *begin, char *end){
            View_ID view = get_active_view(app, Access_ReadWriteVisible);
                                                   Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
        
        Range_i64 range = get_view_range(app, view);
                                                                         Range_i64 lines = get_line_range_from_pos_range(app, buffer, range);
                                                                                                                                                                                   range = get_pos_range_from_line_range(app, buffer, lines);

Scratch_Block scratch(app);
              
                                     b32 min_line_blank = line_is_valid_and_blank(app, buffer, lines.min);
        b32 max_line_blank = line_is_valid_and_blank(app, buffer, lines.max);
    
                                                                      if ((lines.min < lines.max) || (!min_line_blank)){
        String_Const_u8 begin_str = {};
        String_Const_u8 end_str = {};
    
            i64 min_adjustment = 0;
            i64 max_adjustment = 0;
            
        if (min_line_blank){
            begin_str = push_u8_stringf(scratch, "\n%s", begin);
                                           min_adjustment += 1;
                                       }
                                       else{
                                           begin_str = push_u8_stringf(scratch, "%s\n", begin);
                                                       }
                         if (max_line_blank){
end_str = push_u8_stringf(scratch, "%s\n", end);
                }
            else{
    end_str = push_u8_stringf(scratch, "\n%s", end);
                                                                                       max_adjustment += 1;
}

max_adjustment += begin_str.size;
Range_i64 new_pos = Ii64(range.min + min_adjustment, range.max + max_adjustment);
    
    History_Group group = history_group_begin(app, buffer);
    buffer_replace_range(app, buffer, Ii64(range.min), begin_str);
                                   buffer_replace_range(app, buffer, Ii64(range.max + begin_str.size), end_str);
                                                                                                          history_group_end(group);
    
    set_view_range(app, view, new_pos);
                                   }
    else{
    String_Const_u8 str = push_u8_stringf(scratch, "%s\n\n%s", begin, end);
                                              buffer_replace_range(app, buffer, range, str);
    i64 center_pos = range.min + cstring_length(begin) + 1;
          view_set_cursor_and_preferred_x(app, view, seek_pos(center_pos));
                                        view_set_mark(app, view, seek_pos(center_pos));
    }
        }

                                                                                               ////////////////////////////////
                                      
                                              function Face_ID
            get_view_face_id(Application_Links *app, View_ID view){
            Buffer_ID buffer = view_get_buffer(app, view, Access_Always);
                                                              return(get_face_id(app, buffer));
            }
            
        function Face_Metrics
        get_view_face_metrics(Application_Links *app, View_ID view){
                                                                                                                 Face_ID face = get_view_face_id(app, view);
            return(get_face_metrics(app, face));
                                                                }
            
            function f32
            get_view_line_height(Application_Links *app, View_ID view){
        Face_Metrics metrics = get_view_face_metrics(app, view);
        return(metrics.line_height);
                                                  }

internal View_ID
        open_view(Application_Links *app, View_ID view_location, View_Split_Position position){
            View_ID result = 0;
                                                  if (view_location != 0 && view_exists(app, view_location)){
                                                                                                                        Panel_ID panel_id = view_get_panel(app, view_location);
        if (panel_id != 0){
        Dimension split = (position == ViewSplit_Left ||
    position == ViewSplit_Right)?Dimension_X:Dimension_Y;
                      Side side = (position == ViewSplit_Left ||
                                      position == ViewSplit_Top)?Side_Min:Side_Max;
            if (panel_split(app, panel_id, split)){
        Panel_ID new_panel_id = panel_get_child(app, panel_id, side);
                                                                                            if (new_panel_id != 0){
View_ID new_view_id = panel_get_view(app, new_panel_id,
        Access_Always);
        if (new_view_id != 0){
    result = new_view_id;
    }
    }
}
}
}
return(result);
}

internal View_ID
get_first_view_with_buffer(Application_Links *app, Buffer_ID buffer_id){
                                                            View_ID result = {};
        if (buffer_id != 0){
for (View_ID test = get_view_next(app, 0, Access_Always);
test != 0;
              test = get_view_next(app, test, Access_Always)){
    Buffer_ID test_buffer = view_get_buffer(app, test, Access_Always);
                                                                                  if (test_buffer == buffer_id){
    result = test;
        break;
        }
        }
        }
                return(result);
                     }
                 
                         internal b32
open_file(Application_Links *app, Buffer_ID *buffer_out, String_Const_u8 file_name, b32 background, b32 never_new){
    b32 result = false;
Buffer_ID buffer = get_buffer_by_name(app, file_name, Access_ReadVisible);
              b32 exists = buffer_exists(app, buffer);
                if (!exists){
                                                          Buffer_Create_Flag flags = 0;
            if (background){
                     flags |= BufferCreate_Background;
                                       }
                                                                             if (never_new){
                   flags |= BufferCreate_NeverNew;
                }
                buffer = create_buffer(app, file_name, flags);
                              exists = buffer_exists(app, buffer);
                                             }
                                                         if (exists){
                                                                               if (buffer_out != 0){
            *buffer_out = buffer;
                }
            result = true;
        }
    return(result);
    }

internal b32
view_open_file(Application_Links *app, View_ID view, String_Const_u8 file_name, b32 never_new){
                                                                                               b32 result = false;
                                                                                                   if (view != 0){
    Buffer_ID buffer = 0;
    if (open_file(app, &buffer, file_name, false, never_new)){
    view_set_buffer(app, view, buffer, 0);
    result = true;
        }
}
      return(result);
}

internal void
view_disable_highlight_range(Application_Links *app, View_ID view){
            Managed_Scope scope = view_get_managed_scope(app, view);
                                     Managed_Object *highlight = scope_attachment(app, scope, view_highlight_range, Managed_Object);
            if (*highlight != 0){
            managed_object_free(app, *highlight);
                }
                    managed_scope_attachment_erase(app, scope, view_highlight_range);
managed_scope_attachment_erase(app, scope, view_highlight_buffer);
                                                     }
                                                     
                                                     internal void
                                                         view_set_highlight_range(Application_Links *app, View_ID view, Range_i64 range){
    view_disable_highlight_range(app, view);
    
    Buffer_ID buffer = view_get_buffer(app, view, Access_Always);
                                                         Managed_Scope scope = view_get_managed_scope(app, view);
                                                                      Managed_Object *highlight = scope_attachment(app, scope, view_highlight_range, Managed_Object);
                                                                                                                     *highlight = alloc_buffer_markers_on_buffer(app, buffer, 2, &scope);
Marker markers[2] = {};
markers[0].pos = range.min;
                markers[1].pos = range.max;
        managed_object_store_data(app, *highlight, 0, 2, markers);
            Buffer_ID *highlight_buffer = scope_attachment(app, scope, view_highlight_buffer, Buffer_ID);
    *highlight_buffer = buffer;
}
    
    function void
             view_look_at_region(Application_Links *app, View_ID view, i64 major_pos, i64 minor_pos){
                                                                              Range_i64 range = Ii64(major_pos, minor_pos);
                                                                                                               b32 bottom_major = false;
            if (major_pos == range.max){
        bottom_major = true;
}

Buffer_Cursor top = view_compute_cursor(app, view, seek_pos(range.min));
    if (top.line > 0){
    Buffer_Cursor bottom = view_compute_cursor(app, view, seek_pos(range.max));
            if (bottom.line > 0){
        Rect_f32 region = view_get_buffer_region(app, view);
    f32 view_height = rect_height(region);
f32 skirt_height = view_height*.1f;
             Range_f32 acceptable_y = If32(skirt_height, view_height*.9f);
                           
                               f32 target_height = view_line_y_difference(app, view, bottom.line + 1, top.line);

f32 line_height = get_view_line_height(app, view);
        if (target_height + 2*line_height > view_height){
    i64 major_line = bottom.line;
                               if (range.min == major_pos){
    major_line = top.line;
            }

    Buffer_Scroll scroll = view_get_buffer_scroll(app, view);
    scroll.target.line_number = major_line;
    scroll.target.pixel_shift.y = -skirt_height;
        view_set_buffer_scroll(app, view, scroll, SetBufferScroll_SnapCursorIntoView);
    }
else{
    Buffer_Scroll scroll = view_get_buffer_scroll(app, view);
                                                                                         Vec2_f32 top_p = view_relative_xy_of_pos(app, view, scroll.position.line_number, range.min);
    top_p -= scroll.position.pixel_shift;
if (top_p.y < acceptable_y.min){
                             scroll.target.line_number = top.line;
                                       scroll.target.pixel_shift.y = -skirt_height;
                                                                       view_set_buffer_scroll(app, view, scroll, SetBufferScroll_NoCursorChange);
                }
    else{
                  Vec2_f32 bot_p = view_relative_xy_of_pos(app, view, scroll.position.line_number, range.max);
                                                                                                bot_p -= scroll.position.pixel_shift;
        if (bot_p.y > acceptable_y.max){
             scroll.target.line_number = bottom.line;
        scroll.target.pixel_shift.y = skirt_height - view_height;
            view_set_buffer_scroll(app, view, scroll, SetBufferScroll_NoCursorChange);
                }
            }
                }
}
            }
                }

                                    function void
            view_look_at_region(Application_Links *app, View_ID view, Range_i64 range){
                                                  view_look_at_region(app, view, range.min, range.max);
                    }
                    
                    ////////////////////////////////
                
                function Buffer_ID
                                  get_buffer_next_looped(Application_Links *app, Buffer_ID buffer, Access_Flag access){
                buffer = get_buffer_next(app, buffer, access);
        if (buffer == 0){
buffer = get_buffer_next(app, 0, access);
                }
                return(buffer);
                }
                
            ////////////////////////////////
                
                internal View_ID
                                  get_next_view_looped_all_panels(Application_Links *app, View_ID view_id, Access_Flag access){
view_id = get_view_next(app, view_id, access);
                                                           if (view_id == 0){
                view_id = get_view_next(app, 0, access);
}
                    return(view_id);
                    }
                
                    internal View_ID
                      get_prev_view_looped_all_panels(Application_Links *app, View_ID view_id, Access_Flag access){
                    view_id = get_view_prev(app, view_id, access);
                        if (view_id == 0){
                    view_id = get_view_prev(app, 0, access);
                                               }
                                                   return(view_id);
                                                   }
                                                   
                                                   ////////////////////////////////
                    
                internal Buffer_Kill_Result
                    try_buffer_kill(Application_Links *app, Buffer_ID buffer, View_ID gui_view_id, Buffer_Kill_Flag flags){
                        Buffer_Kill_Result result = buffer_kill(app, buffer, flags);
                            if (result == BufferKillResult_Dirty){
                        if (do_buffer_kill_user_check(app, buffer, gui_view_id)){
                                                                               result = buffer_kill(app, buffer, BufferKill_AlwaysKill);
}
                }
            return(result);
            }
            
        ////////////////////////////////
        
    internal String_Const_u8
get_query_string(Application_Links *app, char *query_str, u8 *string_space, i32 space_size){
                                                                                                                                                   Query_Bar_Group group(app);
Query_Bar bar = {};
bar.prompt = SCu8((u8*)query_str);
bar.string = SCu8(string_space, (u64)0);
bar.string_capacity = space_size;
if (!query_user_string(app, &bar)){
                     bar.string.size = 0;
     }
             return(bar.string);
    }

internal Token*
                get_token_from_pos(Application_Links *app, Token_Array *array, u64 pos){
            Token *result = 0;
    if (array->count > 0){
    i64 index = token_index_from_pos(array, pos);
result = array->tokens + index;
}
return(result);
}

internal Token*
get_token_from_pos(Application_Links *app, Buffer_ID buffer, u64 pos){
                                                                                                                                                                               Token_Array array = get_token_array_from_buffer(app, buffer);
return(get_token_from_pos(app, &array, pos));
}

internal String_Const_u8
                                 push_token_or_word_under_pos(Application_Links *app, Arena *arena, Buffer_ID buffer, u64 pos){
                                                                                                                                                                                                         String_Const_u8 result = {};
Token *token = get_token_from_pos(app, buffer, pos);
if (token != 0 && token->size > 0 && token->kind != TokenBaseKind_Whitespace){
                                     Range_i64 range = Ii64(token);
                                     result = push_buffer_range(app, arena, buffer, range);
                          }
        return(result);
}
        
        internal String_Const_u8
        push_token_or_word_under_active_cursor(Application_Links *app, Arena *arena){
            View_ID view = get_active_view(app, Access_Always);
            Buffer_ID buffer = view_get_buffer(app, view, Access_Always);
                                                                                                         i64 pos = view_get_cursor_pos(app, view);
return(push_token_or_word_under_pos(app, arena, buffer, pos));
                                                    }
    
    ////////////////////////////////
    
    internal b32
file_exists(Application_Links *app, String_Const_u8 file_name){
    Scratch_Block scratch(app);
                                                     File_Attributes attributes = system_quick_file_attributes(scratch, file_name);
return(attributes.last_write_time > 0);
        }

            internal b32
                            file_exists_and_is_file(Application_Links *app, String_Const_u8 file_name){
                                                                                                            Scratch_Block scratch(app);
File_Attributes attributes = system_quick_file_attributes(scratch, file_name);
    return(attributes.last_write_time > 0 && !HasFlag(attributes.flags, FileAttribute_IsDirectory));
                                                                                           }
    
    internal b32
    file_exists_and_is_folder(Application_Links *app, String_Const_u8 file_name){
    Scratch_Block scratch(app);
File_Attributes attributes = system_quick_file_attributes(scratch, file_name);
    return(attributes.last_write_time > 0 && HasFlag(attributes.flags, FileAttribute_IsDirectory));
                                                                                                                                                                                                                    }

internal Data
           dump_file_handle(Arena *arena, FILE *file){
Data result = {};
        if (file != 0){
       fseek(file, 0, SEEK_END);
        u64 size = ftell(file);
             char *mem = push_array(arena, char, size);
    if (mem != 0){
    fseek(file, 0, SEEK_SET);
           fread(mem, 1, (size_t)size, file);
                                 result = make_data(mem, size);
                                                  }
                                                  }
    return(result);
    }
    
internal String_Const_u8
push_file_search_up_path(Application_Links *app, Arena *arena, String_Const_u8 start_path, String_Const_u8 file_name){
String_Const_u8 result = {};
String_Const_u8 path = start_path;
for (;path.size > 0;){
                    Temp_Memory temp = begin_temp(arena);
                            if (character_is_slash(string_get_character(path, path.size - 1))){
    path = string_chop(path, 1);
    }
 String_Const_u8 full_path = push_u8_stringf(arena, "%.*s/%.*s",
                                                                     string_expand(path),
string_expand(file_name));
                              if (file_exists(app, full_path)){
    result = full_path;
    break;
      }
    path = string_remove_last_folder(path);
    end_temp(temp);
        }
        return(result);
        }
        
                internal FILE*
                              open_file_try_current_path_then_binary_path(Application_Links *app, char *file_name){
                                                                            FILE *file = fopen(file_name, "rb");
    if (file == 0){
Scratch_Block scratch(app);
    List_String_Const_u8 list = {};
    string_list_push(scratch, &list, system_get_path(scratch, SystemPath_Binary));
    string_list_push_overlap(scratch, &list, '/', SCu8(file_name));
                                                                                   String_Const_u8 str = string_list_flatten(scratch, list, StringFill_NullTerminate);
file = fopen((char*)str.str, "rb");
}
return(file);
}

internal FILE*
open_file(Arena *scratch, String_Const_u8 name){
Temp_Memory temp = begin_temp(scratch);
                                                     String_Const_u8 name_copy = push_string_copy(scratch, name);
                                                                                                                                                         FILE *file = fopen((char*)name_copy.str, "rb");
                                                                                               end_temp(temp);
            return(file);
                          }
                        
                         internal File_Name_Data
           dump_file(Arena *arena, String_Const_u8 file_name){
File_Name_Data result = {};
        FILE *file = open_file(arena, file_name);
if (file != 0){
    result.file_name = file_name;
                      result.data = dump_file_handle(arena, file);
fclose(file);
        }
return(result);
    }
    
    internal File_Name_Data
          dump_file_search_up_path(Application_Links *app, Arena *arena, String_Const_u8 path, String_Const_u8 file_name){
                                                                                                   File_Name_Data result = {};
        String_Const_u8 full_path = push_file_search_up_path(app, arena, path, file_name);
            if (full_path.size > 0){
                        result = dump_file(arena, full_path);
}
return(result);
}

internal void
sort_pairs_by_key__quick(Sort_Pair_i32 *pairs, i32 first, i32 one_past_last){
        i32 dif = one_past_last - first;
    if (dif >= 2){
    i32 pivot = one_past_last - 1;
        Sort_Pair_i32 pivot_pair = pairs[pivot];
        i32 j = first;
            b32 interleave = false;
        for (i32 i = first; i < pivot; i += 1){
        Sort_Pair_i32 pair = pairs[i];
        if (pair.key < pivot_pair.key){
        pairs[i] = pairs[j];
        pairs[j] = pair;
        j += 1;
}
  else if (pair.key == pivot_pair.key){
                                     if (interleave){
                                     pairs[i] = pairs[j];
        pairs[j] = pair;
        j += 1;
        }
        interleave = !interleave;
        }
        }
        pairs[pivot] = pairs[j];
        pairs[j] = pivot_pair;
        sort_pairs_by_key__quick(pairs, first, j);
                                                 sort_pairs_by_key__quick(pairs, j + 1, one_past_last);
        }
        }
        
        internal void
        sort_pairs_by_key(Sort_Pair_i32 *pairs, i32 count){
        sort_pairs_by_key__quick(pairs, 0, count);
            }

            internal Range_i32_Array
                        get_ranges_of_duplicate_keys(Arena *arena, i32 *keys, i32 stride, i32 count){
                                           Range_i32_Array result = {};
        result.ranges = push_array(arena, Range_i32, count);
u8 *ptr = (u8*)keys;
        i32 start_i = 0;
    for (i32 i = 1; i <= count; i += 1){
    b32 is_end = false;
     if (i == count){
                                                is_end = true;
    }
        else if (*(i32*)(ptr + i*stride) != *(i32*)(ptr + start_i*stride)){
    is_end = true;
                                        }
        if (is_end){
        Range_i32 *new_range = &result.ranges[result.count++];
    new_range->first = start_i;
new_range->one_past_last = i;
                      start_i = i;
                      }
                                  }
                  pop_array(arena, Range_i32, count - result.count);
    return(result);
    }
    
    internal void
    no_mark_snap_to_cursor(Application_Links *app, Managed_Scope view_scope){
    b32 *snap_to_cursor = scope_attachment(app, view_scope, view_snap_mark_to_cursor, b32);
                                                                                                                                                                                                                         *snap_to_cursor = false;
                                                                         }
                                                                                                                                                                                                                                   
                                                                                                                                                                                                                                   internal void
                                                                                                                                                                                                                                      no_mark_snap_to_cursor(Application_Links *app, View_ID view_id){
                                                            Managed_Scope scope = view_get_managed_scope(app, view_id);
        no_mark_snap_to_cursor(app, scope);
                      }
                          
                              internal void
            no_mark_snap_to_cursor_if_shift(Application_Links *app, View_ID view_id){
                Scratch_Block scratch(app);
                Input_Modifier_Set mods = system_get_keyboard_modifiers(scratch);
                                                                                                                                        if (has_modifier(&mods, KeyCode_Shift)){
no_mark_snap_to_cursor(app, view_id);
            }
        }
    
        internal b32
                            view_has_highlighted_range(Application_Links *app, View_ID view){
b32 result = false;
                                                                      if (fcoder_mode == FCoderMode_NotepadLike){
                                                             i64 pos = view_get_cursor_pos(app, view);
i64 mark = view_get_mark_pos(app, view);
result = (pos != mark);
}
return(result);
}

internal b32
    if_view_has_highlighted_range_delete_range(Application_Links *app, View_ID view_id){
        b32 result = false;
    if (view_has_highlighted_range(app, view_id)){
                        Range_i64 range = get_view_range(app, view_id);
        Buffer_ID buffer = view_get_buffer(app, view_id, Access_ReadWriteVisible);
        buffer_replace_range(app, buffer, range, string_u8_litexpr(""));
                result = true;
        }
        return(result);
        }

            internal void
            begin_notepad_mode(Application_Links *app){
            fcoder_mode = FCoderMode_NotepadLike;
for (View_ID view = get_view_next(app, 0, Access_Always);
                                                                         view != 0;
view = get_view_next(app, view, Access_Always)){
                                                            i64 pos = view_get_cursor_pos(app, view);
                                                 view_set_mark(app, view, seek_pos(pos));
}
}

////////////////////////////////

         internal void
seek_pos_of_textual_line(Application_Links *app, Side side){
                                                    View_ID view = get_active_view(app, Access_ReadVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadVisible);
    i64 pos = view_get_cursor_pos(app, view);
i64 new_pos = get_line_side_pos_from_pos(app, buffer, pos, side);
    view_set_cursor_and_preferred_x(app, view, seek_pos(new_pos));
        no_mark_snap_to_cursor_if_shift(app, view);
                                     }

internal void
seek_pos_of_visual_line(Application_Links *app, Side side){
                                           View_ID view = get_active_view(app, Access_ReadVisible);
    i64 pos = view_get_cursor_pos(app, view);
    Buffer_Cursor cursor = view_compute_cursor(app, view, seek_pos(pos));
                                                                                                              Vec2_f32 p = view_relative_xy_of_pos(app, view, cursor.line, pos);
                                                                                                        p.x = (side == Side_Min)?(0.f):(max_f32);
i64 new_pos = view_pos_at_relative_xy(app, view, cursor.line, p);
        view_set_cursor_and_preferred_x(app, view, seek_pos(new_pos));
                no_mark_snap_to_cursor_if_shift(app, view);
        }
        
        CUSTOM_COMMAND_SIG(seek_beginning_of_textual_line)
                                                         CUSTOM_DOC("Seeks the cursor to the beginning of the line across all text.")
{
    seek_pos_of_textual_line(app, Side_Min);
                                                  }

        CUSTOM_COMMAND_SIG(seek_end_of_textual_line)
CUSTOM_DOC("Seeks the cursor to the end of the line across all text.")
                {
          seek_pos_of_textual_line(app, Side_Max);
        }
    
    CUSTOM_COMMAND_SIG(seek_beginning_of_line)
                                               CUSTOM_DOC("Seeks the cursor to the beginning of the visual line.")
{
    seek_pos_of_visual_line(app, Side_Min);
        }
        
        CUSTOM_COMMAND_SIG(seek_end_of_line)
                          CUSTOM_DOC("Seeks the cursor to the end of the visual line.")
                          {
        seek_pos_of_visual_line(app, Side_Max);
                                                                                }
        
        CUSTOM_COMMAND_SIG(goto_beginning_of_file)
        CUSTOM_DOC("Sets the cursor to the beginning of the file.")
{
View_ID view = get_active_view(app, Access_ReadVisible);
view_set_cursor_and_preferred_x(app, view, seek_pos(0));
    no_mark_snap_to_cursor_if_shift(app, view);
              }
       
                   CUSTOM_COMMAND_SIG(goto_end_of_file)
                     CUSTOM_DOC("Sets the cursor to the end of the file.")
    {
     View_ID view = get_active_view(app, Access_ReadVisible);
       Buffer_ID buffer_id = view_get_buffer(app, view, Access_ReadVisible);
                                                                                i32 size = (i32)buffer_get_size(app, buffer_id);
                                                                                                                          view_set_cursor_and_preferred_x(app, view, seek_pos(size));
no_mark_snap_to_cursor_if_shift(app, view);
                                                                  }
    
    ////////////////////////////////
    
    internal b32
view_set_split(Application_Links *app, View_ID view, View_Split_Kind kind, f32 t){
   b32 result = false;
                         if (view != 0){
    Panel_ID panel_id = view_get_panel(app, view);
                    if (panel_id != 0){
                                                    Panel_ID parent_panel_id = panel_get_parent(app, panel_id);
if (parent_panel_id != 0){
        Panel_ID min_child_id = panel_get_child(app, parent_panel_id, Side_Min);
                                                                         if (min_child_id != 0){
    b32 panel_is_min = (min_child_id == panel_id);
Panel_Split_Kind panel_kind = ((kind == ViewSplitKind_Ratio)?
                                                                                                                         (panel_is_min?PanelSplitKind_Ratio_Min:PanelSplitKind_Ratio_Max):
(panel_is_min?PanelSplitKind_FixedPixels_Min:PanelSplitKind_FixedPixels_Max));
                                                            result = panel_set_split(app, parent_panel_id, panel_kind, t);
                                                                                                                                                                                                      }
}
}
}
return(result);
                                                                                                                                            }

internal b32
                                                                                                                                                                 view_set_split_proportion(Application_Links *app, View_ID view, f32 t){
return(view_set_split(app, view, ViewSplitKind_Ratio, t));
    }
    
    internal b32
view_set_split_pixel_size(Application_Links *app, View_ID view, i32 t){
    return(view_set_split(app, view, ViewSplitKind_FixedPixels, (f32)t));
                                }
                             
                                                                                                                                                                                                                                                                                                                                                                                                               ////////////////////////////////

internal Record_Info
get_single_record(Application_Links *app, Buffer_ID buffer_id, History_Record_Index index){
Record_Info record = buffer_history_get_record_info(app, buffer_id, index);
                             if (record.error == RecordError_NoError && record.kind == RecordKind_Group){
    record = buffer_history_get_group_sub_record(app, buffer_id, index, record.group_count - 1);
    }
    return(record);
    }
    
    ////////////////////////////////
                      
                                 function Nest_Delimiter_Kind
    get_nest_delimiter_kind(Token_Base_Kind kind, Find_Nest_Flag flags){
    Nest_Delimiter_Kind result = NestDelim_None;
    switch (kind){
    case TokenBaseKind_ScopeOpen:
    {
    if (HasFlag(flags, FindNest_Scope)){
    result = NestDelim_Open;
    }
    }break;
case TokenBaseKind_ScopeClose:
{
if (HasFlag(flags, FindNest_Scope)){
result = NestDelim_Close;
}
}break;
case TokenBaseKind_ParentheticalOpen:
{
if (HasFlag(flags, FindNest_Paren)){
result = NestDelim_Open;
}
}break;
case TokenBaseKind_ParentheticalClose:
{
if (HasFlag(flags, FindNest_Paren)){
result = NestDelim_Close;
}
}break;
}
return(result);
}

function b32
find_nest_side(Application_Links *app, Buffer_ID buffer, i64 pos,
Find_Nest_Flag flags, Scan_Direction scan, Nest_Delimiter_Kind delim,
Range_i64 *out){
b32 result = false;

          b32 balanced = HasFlag(flags, FindNest_Balanced);
    if (balanced){
    if ((delim == NestDelim_Open && scan == Scan_Forward) ||
    (delim == NestDelim_Close && scan == Scan_Backward)){
    balanced = false;
    }
}
    
    Managed_Scope scope = buffer_get_managed_scope(app, buffer);
    Token_Array *tokens = scope_attachment(app, scope, attachment_tokens, Token_Array);
if (tokens != 0 && tokens->count > 0){
Token_Iterator_Array it = token_iterator_pos(0, tokens, pos);
i32 level = 0;
for (;;){
Token *token = token_it_read(&it);
Nest_Delimiter_Kind token_delim = get_nest_delimiter_kind(token->kind, flags);

if (level == 0 && token_delim == delim){
*out = Ii64_size(token->pos, token->size);
result = true;
break;
}

if (balanced && token_delim != NestDelim_None){
level += (token_delim == delim)?-1:1;
}

b32 good = false;
if (scan == Scan_Forward){
good = token_it_inc(&it);
              }
else{
good = token_it_dec(&it);
    }
if (!good){
          break;
    }
    }
       }
 
              return(result);
}

                    function b32
find_nest_side(Application_Links *app, Buffer_ID buffer, i64 pos,
Find_Nest_Flag flags, Scan_Direction scan, Nest_Delimiter_Kind delim,
                                                                                                    i64 *out){
Range_i64 range = {};
                                   b32 result = find_nest_side(app, buffer, pos, flags, scan, delim, &range);
if (result){
            if (HasFlag(flags, FindNest_EndOfToken)){
                                                 *out = range.end;
            }
                    else{
        *out = range.start;
            }
        }
          return(result);
                }
                
                function b32
                        find_surrounding_nest(Application_Links *app, Buffer_ID buffer, i64 pos,
        Find_Nest_Flag flags, Range_i64 *out){
b32 result = false;
                Range_i64 range = {};
  if (find_nest_side(app, buffer, pos - 1, flags|FindNest_Balanced,
Scan_Backward, NestDelim_Open, &range.start) &&
    find_nest_side(app, buffer, pos, flags|FindNest_Balanced|FindNest_EndOfToken,
            Scan_Forward, NestDelim_Close, &range.end)){
                                                                                                            *out = range;
                                                        result = true;
                                                                                                              }
                                                                                                             return(result);
                                                                                                                             }
                                                                                                             
                                                                                                                                             function void
            select_scope(Application_Links *app, View_ID view, Range_i64 range){
            view_set_cursor_and_preferred_x(app, view, seek_pos(range.first));
        view_set_mark(app, view, seek_pos(range.end));
    view_look_at_region(app, view, range.first, range.end);
    no_mark_snap_to_cursor(app, view);
            }
    
    ////////////////////////////////

    function Line_Ending_Kind
guess_line_ending_kind_from_buffer(Application_Links *app, Buffer_ID buffer){
                                                          u64 size = buffer_get_size(app, buffer);
        size = clamp_top(size, KB(8));
                Scratch_Block scratch(app);
                              String_Const_u8 string = push_buffer_range(app, scratch, buffer, Ii64(0, size));
                                                                                   return(string_guess_line_ending_kind(string));
                }
                
                ////////////////////////////////
                
                function i32
                          get_command_id(Custom_Command_Function *func){
            i32 result = -1;
            for (i32 i = 0; i < ArrayCount(fcoder_metacmd_table); i += 1){
            if (func == fcoder_metacmd_table[i].proc){
result = i;
            break;
            }
                }
             return(result);
            }
            
                    function Command_Metadata*
    get_command_metadata(Custom_Command_Function *func){
Command_Metadata *result = 0;
                                              i32 id = get_command_id(func);
                     if (id >= 0){
         result = &fcoder_metacmd_table[id];
                    }
                    return(result);
                    }
                    
                    ////////////////////////////////

                                       // TODO(allen): REWRITE THIS EXACTLY HOW YOU WANT IT --- start ---
                                            
                                            internal Child_Process_Set_Target_Flags
    flags_system_command(Command_Line_Interface_Flag flags){
                                                                                               Child_Process_Set_Target_Flags set_buffer_flags = 0;
                if (!HasFlag(flags, CLI_OverlapWithConflict)){
    set_buffer_flags |= ChildProcessSet_FailIfBufferAlreadyAttachedToAProcess;
    }
if (HasFlag(flags, CLI_CursorAtEnd)){
                                       set_buffer_flags |= ChildProcessSet_CursorAtEnd;
}
return(set_buffer_flags);
    }
    
    internal b32
    set_buffer_system_command(Application_Links *app, Child_Process_ID process, Buffer_ID buffer, Command_Line_Interface_Flag flags){
                                                                                                                                  b32 result = false;
Child_Process_Set_Target_Flags set_buffer_flags = flags_system_command(flags);
                                                                               if (child_process_set_target_buffer(app, process, buffer, set_buffer_flags)){
                                                                                                                                          clear_buffer(app, buffer);
        if (HasFlag(flags, CLI_SendEndSignal)){
              buffer_send_end_signal(app, buffer);
                                                    }
result = true;
}
return(result);
}

internal b32
exec_system_command(Application_Links *app, View_ID view, Buffer_Identifier buffer_id,
                                                                                                                                         String_Const_u8 path, String_Const_u8 command, Command_Line_Interface_Flag flags){
    b32 result = false;
Child_Process_ID child_process_id = create_child_process(app, path, command);
                                                                                                                                   if (child_process_id != 0){
result = true;
Buffer_ID buffer_attach_id = buffer_identifier_to_id_create_out_buffer(app, buffer_id);
    if (buffer_attach_id != 0){
    if (set_buffer_system_command(app, child_process_id, buffer_attach_id, flags)){
                                                                                  if (view != 0){
    view_set_buffer(app, view, buffer_attach_id, 0);
                   view_set_cursor(app, view, seek_pos(0));
                                      }
                                      }
                                      }
                                      }
                                      return(result);
                  }

                  // TODO(allen): --- end ---

// BOTTOM