/*
4coder_layout_rule.cpp - Built in layout rules and layout rule helpers.
*/

// TOP

function i64
layout_index_from_ptr(u8 *ptr, u8 *string_base, i64 index_base){
    return((i64)(ptr - string_base) + index_base);
}

function Layout_Item_List
get_empty_item_list(Range_i64 input_range){
    Layout_Item_List list = {};
    list.input_index_range = input_range;
    list.manifested_index_range = Ii64_neg_inf;
    return(list);
}

function void
layout_item_list_finish(Layout_Item_List *list, f32 bottom_padding){
    list->bottom_padding = bottom_padding;
    list->height += bottom_padding;
}

function void
layout_write(Arena *arena, Layout_Item_List *list, i64 index, u32 codepoint, Layout_Item_Flag flags, Rect_f32 rect){
    Temp_Memory restore_point = begin_temp(arena);
    Layout_Item *item = push_array(arena, Layout_Item, 1);
    
    Layout_Item_Block *block = list->first;
    if (block != 0){
        if (block->items + block->item_count == item){
            block->item_count += 1;
        }
        else{
            block = 0;
        }
    }
    if (block == 0){
        end_temp(restore_point);
        block = push_array(arena, Layout_Item_Block, 1);
        item = push_array(arena, Layout_Item, 1);
        sll_queue_push(list->first, list->last, block);
        list->node_count += 1;
        block->items = item;
        block->item_count = 1;
    }
    list->item_count += 1;
    
    list->manifested_index_range.min = min(list->manifested_index_range.min, index);
    list->manifested_index_range.max = max(list->manifested_index_range.max, index);
    
    if (!HasFlag(flags, LayoutItemFlag_Ghost_Character)){
        block->character_count += 1;
        list->character_count += 1;
    }
    
    item->index = index;
    item->codepoint = codepoint;
    item->flags = flags;
    item->rect = rect;
    list->height = max(list->height, rect.y1);
}

////

function Newline_Layout_Vars
get_newline_layout_vars(void){
    Newline_Layout_Vars result = {};
    result.newline_character_index = -1;
    return(result);
}

function void
newline_layout_consume_CR(Newline_Layout_Vars *vars, i64 index){
    if (!vars->consuming_newline_characters){
        vars->consuming_newline_characters = true;
        vars->newline_character_index = index;
    }
    vars->prev_did_emit_newline = false;
}

function i64
newline_layout_consume_LF(Newline_Layout_Vars *vars, i64 index){
    if (!vars->consuming_newline_characters){
        vars->newline_character_index = index;
    }
    vars->prev_did_emit_newline = true;
    vars->consuming_newline_characters = false;
    return(vars->newline_character_index);
}

function void
newline_layout_consume_default(Newline_Layout_Vars *vars){
    vars->consuming_newline_characters = false;
    vars->prev_did_emit_newline = false;
}

function b32
newline_layout_consume_finish(Newline_Layout_Vars *vars){
    return((!vars->prev_did_emit_newline));
}

////

function LefRig_TopBot_Layout_Vars
get_lr_tb_layout_vars(Face_Advance_Map *advance_map, Face_Metrics *metrics, f32 width){
    f32 text_height = metrics->text_height;
    f32 line_height = metrics->line_height;
    
    LefRig_TopBot_Layout_Vars result = {};
    result.advance_map = advance_map;
    result.metrics = metrics;
    result.line_to_text_shift = text_height - line_height;
    
    result.blank_dim = V2f32(metrics->space_advance, text_height);
    
    result.line_y = line_height;
    result.text_y = text_height;
    result.width = width;
    return(result);
}

function b32
lr_tb_crosses_width(LefRig_TopBot_Layout_Vars *vars, f32 advance, f32 width){
    return(vars->p.x + advance > width);
}

function b32
lr_tb_crosses_width(LefRig_TopBot_Layout_Vars *vars, f32 advance){
    return(vars->p.x + advance > vars->width);
}

function f32
lr_tb_advance(LefRig_TopBot_Layout_Vars *vars, u32 codepoint){
    return(font_get_glyph_advance(vars->advance_map, vars->metrics, codepoint));
}

function void
lr_tb_write_with_advance_with_flags(LefRig_TopBot_Layout_Vars *vars, f32 advance, Arena *arena, Layout_Item_List *list, i64 index, u32 codepoint, Layout_Item_Flag flags){
    if (codepoint == '\t'){
        codepoint = ' ';
    }
    vars->p.x = f32_ceil32(vars->p.x);
    f32 next_x = vars->p.x + advance;
    layout_write(arena, list, index, codepoint, flags,
                 Rf32(vars->p, V2f32(next_x, vars->text_y)));
    vars->p.x = next_x;
}

function void
lr_tb_write_with_advance(LefRig_TopBot_Layout_Vars *vars, f32 advance, Arena *arena, Layout_Item_List *list, i64 index, u32 codepoint){
    lr_tb_write_with_advance_with_flags(vars, advance, arena, list, index, codepoint, 0);
}

function void
lr_tb_write(LefRig_TopBot_Layout_Vars *vars, Arena *arena, Layout_Item_List *list, i64 index, u32 codepoint){
    f32 advance = lr_tb_advance(vars, codepoint);
    lr_tb_write_with_advance(vars, advance, arena, list, index, codepoint);
}

function void
lr_tb_write_ghost(LefRig_TopBot_Layout_Vars *vars, Arena *arena, Layout_Item_List *list, i64 index, u32 codepoint){
    f32 advance = lr_tb_advance(vars, codepoint);
    lr_tb_write_with_advance_with_flags(vars, advance, arena, list, index, codepoint, LayoutItemFlag_Ghost_Character);
}

function f32
lr_tb_advance_byte(LefRig_TopBot_Layout_Vars *vars){
    return(vars->metrics->byte_advance);
}

function void
lr_tb_write_byte_with_advance(LefRig_TopBot_Layout_Vars *vars, f32 advance, Arena *arena, Layout_Item_List *list, i64 index, u8 byte){
    Face_Metrics *metrics = vars->metrics;
    
    f32 final_next_x = vars->p.x + advance;
    u32 lo = ((u32)byte     )&0xF;
    u32 hi = ((u32)byte >> 4)&0xF;
    
    Vec2_f32 p = vars->p;
    p.x = f32_ceil32(p.x);
    f32 next_x = p.x + metrics->byte_sub_advances[0];
    f32 text_y = vars->text_y;
    
    Layout_Item_Flag flags = LayoutItemFlag_Special_Character;
    layout_write(arena, list, index, '\\', flags, Rf32(p, V2f32(next_x, text_y)));
    p.x = next_x;
    
    flags = LayoutItemFlag_Ghost_Character;
    next_x += metrics->byte_sub_advances[1];
    layout_write(arena, list, index, integer_symbols[hi], flags, Rf32(p, V2f32(next_x, text_y)));
    p.x = next_x;
    next_x += metrics->byte_sub_advances[2];
    layout_write(arena, list, index, integer_symbols[lo], flags, Rf32(p, V2f32(next_x, text_y)));
    
    vars->p.x = final_next_x;
}

function void
lr_tb_write_byte(LefRig_TopBot_Layout_Vars *vars,
                 Arena *arena, Layout_Item_List *list, i64 index, u8 byte){
    lr_tb_write_byte_with_advance(vars, vars->metrics->byte_advance,
                                  arena, list, index, byte);
}

function void
lr_tb_write_blank_dim(LefRig_TopBot_Layout_Vars *vars, Vec2_f32 dim,
                      Arena *arena, Layout_Item_List *list, i64 index){
    layout_write(arena, list, index, ' ', 0, Rf32_xy_wh(vars->p, dim));
    vars->p.x += dim.x;
}

function void
lr_tb_write_blank(LefRig_TopBot_Layout_Vars *vars,
                  Arena *arena, Layout_Item_List *list, i64 index){
    lr_tb_write_blank_dim(vars, vars->blank_dim, arena, list, index);
}

function void
lr_tb_next_line(LefRig_TopBot_Layout_Vars *vars){
    vars->p.x = 0.f;
    vars->p.y = vars->line_y;
    vars->line_y += vars->metrics->line_height;
    vars->text_y = vars->line_y + vars->line_to_text_shift;
}

function void
lr_tb_next_line_padded(LefRig_TopBot_Layout_Vars *vars, f32 top, f32 bot){
    vars->p.x = 0.f;
    vars->p.y = vars->line_y + top;
    vars->line_y += top + vars->metrics->line_height;
    vars->text_y = vars->line_y + vars->line_to_text_shift;
    vars->line_y += bot;
}

function void
lr_tb_advance_x_without_item(LefRig_TopBot_Layout_Vars *vars, f32 advance){
    vars->p.x += advance;
}

function void
lr_tb_align_rightward(LefRig_TopBot_Layout_Vars *vars, f32 align_x){
    vars->p.x = clamp_bot(align_x, vars->p.x);
}

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

function Layout_Item_List
layout_unwrapped_small_blank_lines(Application_Links *app, Arena *arena,
                                   Buffer_ID buffer, Range_i64 range, Face_ID face,
                                   f32 width){
    Layout_Item_List list = get_empty_item_list(range);
    
    Scratch_Block scratch(app);
    String_Const_u8 text = push_buffer_range(app, scratch, buffer, range);
    
    Face_Advance_Map advance_map = get_face_advance_map(app, face);
    Face_Metrics metrics = get_face_metrics(app, face);
    LefRig_TopBot_Layout_Vars pos_vars = get_lr_tb_layout_vars(&advance_map, &metrics, width);
    
    pos_vars.blank_dim = V2f32(metrics.space_advance, metrics.text_height*0.5f);
    
    if (text.size == 0){
        lr_tb_write_blank(&pos_vars, arena, &list, range.start);
    }
    else{
        Newline_Layout_Vars newline_vars = get_newline_layout_vars();
        
        b32 all_whitespace = true;
        for (umem i = 0; i < text.size; i += 1){
            if (!character_is_whitespace(text.str[i])){
                all_whitespace = false;
                break;
            }
        }
        
        if (!all_whitespace){
            pos_vars.blank_dim.y = metrics.text_height;
        }
        
        u8 *ptr = text.str;
        u8 *end_ptr = ptr + text.size;
        for (;ptr < end_ptr;){
            Character_Consume_Result consume = utf8_consume(ptr, (umem)(end_ptr - ptr));
            
            i64 index = layout_index_from_ptr(ptr, text.str, range.first);
            switch (consume.codepoint){
                case '\t':
                {
                    newline_layout_consume_default(&newline_vars);
                    Vec2_f32 dim = pos_vars.blank_dim;
                    dim.x = lr_tb_advance(&pos_vars, '\t');
                    lr_tb_write_blank_dim(&pos_vars, dim,
                                          arena, &list, index);
                }break;
                
                case ' ':
                case '\f':
                case '\v':
                {
                    newline_layout_consume_default(&newline_vars);
                    lr_tb_write_blank(&pos_vars, arena, &list, index);
                }break;
                
                default:
                {
                    newline_layout_consume_default(&newline_vars);
                    lr_tb_write(&pos_vars, arena, &list, index, consume.codepoint);
                }break;
                
                case '\r':
                {
                    newline_layout_consume_CR(&newline_vars, index);
                }break;
                
                case '\n':
                {
                    i64 newline_index = newline_layout_consume_LF(&newline_vars, index);
                    lr_tb_write_blank(&pos_vars, arena, &list, newline_index);
                    lr_tb_next_line(&pos_vars);
                }break;
                
                case max_u32:
                {
                    newline_layout_consume_default(&newline_vars);
                    lr_tb_write_byte(&pos_vars, arena, &list, index, *ptr);
                }break;
            }
            
            ptr += consume.inc;
        }
        
        if (newline_layout_consume_finish(&newline_vars)){
            i64 index = layout_index_from_ptr(ptr, text.str, range.first);
            lr_tb_write_blank(&pos_vars, arena, &list, index);
        }
    }
    
    layout_item_list_finish(&list, -pos_vars.line_to_text_shift);
    
    return(list);
}

function Layout_Item_List
layout_unwrapped(Application_Links *app, Arena *arena, Buffer_ID buffer,
                 Range_i64 range, Face_ID face, f32 width){
    Layout_Item_List list = get_empty_item_list(range);
    
    Scratch_Block scratch(app);
    String_Const_u8 text = push_buffer_range(app, scratch, buffer, range);
    
    Face_Advance_Map advance_map = get_face_advance_map(app, face);
    Face_Metrics metrics = get_face_metrics(app, face);
    LefRig_TopBot_Layout_Vars pos_vars = get_lr_tb_layout_vars(&advance_map, &metrics, width);
    
    if (text.size == 0){
        lr_tb_write_blank(&pos_vars, arena, &list, range.first);
    }
    else{
        Newline_Layout_Vars newline_vars = get_newline_layout_vars();
        
        u8 *ptr = text.str;
        u8 *end_ptr = ptr + text.size;
        for (;ptr < end_ptr;){
            Character_Consume_Result consume = utf8_consume(ptr, (umem)(end_ptr - ptr));
            
            i64 index = layout_index_from_ptr(ptr, text.str, range.first);
            switch (consume.codepoint){
                default:
                {
                    newline_layout_consume_default(&newline_vars);
                    lr_tb_write(&pos_vars, arena, &list, index, consume.codepoint);
                }break;
                
                case '\r':
                {
                    newline_layout_consume_CR(&newline_vars, index);
                }break;
                
                case '\n':
                {
                    i64 newline_index = newline_layout_consume_LF(&newline_vars, index);
                    lr_tb_write_blank(&pos_vars, arena, &list, newline_index);
                    lr_tb_next_line(&pos_vars);
                }break;
                
                case max_u32:
                {
                    newline_layout_consume_default(&newline_vars);
                    lr_tb_write_byte(&pos_vars, arena, &list, index, *ptr);
                }break;
            }
            
            ptr += consume.inc;
        }
        
        if (newline_layout_consume_finish(&newline_vars)){
            i64 index = layout_index_from_ptr(ptr, text.str, range.first);
            lr_tb_write_blank(&pos_vars, arena, &list, index);
        }
    }
    
    layout_item_list_finish(&list, -pos_vars.line_to_text_shift);
    
    return(list);
}

function Layout_Item_List
layout_wrap_anywhere(Application_Links *app, Arena *arena, Buffer_ID buffer,
                     Range_i64 range, Face_ID face, f32 width){
    Scratch_Block scratch(app);
    
    Layout_Item_List list = get_empty_item_list(range);
    
    String_Const_u8 text = push_buffer_range(app, scratch, buffer, range);
    
    Face_Advance_Map advance_map = get_face_advance_map(app, face);
    Face_Metrics metrics = get_face_metrics(app, face);
    LefRig_TopBot_Layout_Vars pos_vars = get_lr_tb_layout_vars(&advance_map, &metrics, width);
    
    if (text.size == 0){
        lr_tb_write_blank(&pos_vars, arena, &list, range.first);
    }
    else{
        b32 first_of_the_line = true;
        Newline_Layout_Vars newline_vars = get_newline_layout_vars();
        
        u8 *ptr = text.str;
        u8 *end_ptr = ptr + text.size;
        for (;ptr < end_ptr;){
            Character_Consume_Result consume = utf8_consume(ptr, (umem)(end_ptr - ptr));
            i64 index = layout_index_from_ptr(ptr, text.str, range.first);
            switch (consume.codepoint){
                default:
                {
                    newline_layout_consume_default(&newline_vars);
                    f32 advance = lr_tb_advance(&pos_vars, consume.codepoint);
                    if (!first_of_the_line && lr_tb_crosses_width(&pos_vars, advance)){
                        lr_tb_next_line(&pos_vars);
                    }
                    lr_tb_write_with_advance(&pos_vars, advance,
                                             arena, &list, index, consume.codepoint);
                    first_of_the_line = false;
                }break;
                
                case '\r':
                {
                    newline_layout_consume_CR(&newline_vars, index);
                }break;
                
                case '\n':
                {
                    i64 newline_index = newline_layout_consume_LF(&newline_vars, index);
                    lr_tb_write_blank(&pos_vars, arena, &list, newline_index);
                    lr_tb_next_line(&pos_vars);
                    first_of_the_line = true;
                }break;
                
                case max_u32:
                {
                    newline_layout_consume_default(&newline_vars);
                    f32 advance = lr_tb_advance_byte(&pos_vars);
                    if (!first_of_the_line && lr_tb_crosses_width(&pos_vars, advance)){
                        lr_tb_next_line(&pos_vars);
                    }
                    lr_tb_write_byte_with_advance(&pos_vars, advance,
                                                  arena, &list, index, *ptr);
                    first_of_the_line = false;
                }break;
            }
            ptr += consume.inc;
        }
        
        if (newline_layout_consume_finish(&newline_vars)){
            i64 index = layout_index_from_ptr(ptr, text.str, range.first);
            lr_tb_write_blank(&pos_vars, arena, &list, index);
        }
    }
    
    layout_item_list_finish(&list, -pos_vars.line_to_text_shift);
    
    return(list);
}

function Layout_Item_List
layout_wrap_whitespace(Application_Links *app, Arena *arena, Buffer_ID buffer,
                       Range_i64 range, Face_ID face, f32 width){
    Scratch_Block scratch(app);
    
    Layout_Item_List list = get_empty_item_list(range);
    
    String_Const_u8 text = push_buffer_range(app, scratch, buffer, range);
    
    Face_Advance_Map advance_map = get_face_advance_map(app, face);
    Face_Metrics metrics = get_face_metrics(app, face);
    LefRig_TopBot_Layout_Vars pos_vars = get_lr_tb_layout_vars(&advance_map, &metrics, width);
    
    if (text.size == 0){
        lr_tb_write_blank(&pos_vars, arena, &list, range.first);
    }
    else{
        b32 first_of_the_line = true;
        Newline_Layout_Vars newline_vars = get_newline_layout_vars();
        
        u8 *ptr = text.str;
        u8 *end_ptr = ptr + text.size;
        u8 *word_ptr = ptr;
        
        if (character_is_whitespace(*ptr)){
            goto consuming_whitespace;
        }
        
        consuming_non_whitespace:
        for (;ptr <= end_ptr; ptr += 1){
            if (ptr == end_ptr || character_is_whitespace(*ptr)){
                break;
            }
        }
        
        {
            newline_layout_consume_default(&newline_vars);
            
            String_Const_u8 word = SCu8(word_ptr, ptr);
            u8 *word_end = ptr;
            
            if (!first_of_the_line){
                f32 total_advance = 0.f;
                ptr = word.str;
                for (;ptr < word_end;){
                    Character_Consume_Result consume =
                        utf8_consume(ptr, (umem)(word_end - ptr));
                    if (consume.codepoint != max_u32){
                        total_advance += lr_tb_advance(&pos_vars, consume.codepoint);
                    }
                    else{
                        total_advance += lr_tb_advance_byte(&pos_vars);
                    }
                    ptr += consume.inc;
                }
                
                if (lr_tb_crosses_width(&pos_vars, total_advance)){
                    lr_tb_next_line(&pos_vars);
                }
            }
            
            ptr = word.str;
            
            for (;ptr < word_end;){
                Character_Consume_Result consume =
                    utf8_consume(ptr, (umem)(word_end - ptr));
                i64 index = layout_index_from_ptr(ptr, text.str, range.first);
                
                if (consume.codepoint != max_u32){
                    lr_tb_write(&pos_vars, arena, &list, index, consume.codepoint);
                }
                else{
                    lr_tb_write_byte(&pos_vars, arena, &list, index, *ptr);
                }
                
                ptr += consume.inc;
            }
            
            first_of_the_line = false;
        }
        
        consuming_whitespace:
        for (; ptr < end_ptr; ptr += 1){
            if (!character_is_whitespace(*ptr)){
                word_ptr = ptr;
                goto consuming_non_whitespace;
            }
            
            i64 index = layout_index_from_ptr(ptr, text.str, range.first);
            switch (*ptr){
                default:
                {
                    newline_layout_consume_default(&newline_vars);
                    f32 advance = lr_tb_advance(&pos_vars, *ptr);
                    if (!first_of_the_line && lr_tb_crosses_width(&pos_vars, advance)){
                        lr_tb_next_line(&pos_vars);
                    }
                    lr_tb_write_with_advance(&pos_vars, advance,
                                             arena, &list, index, *ptr);
                    first_of_the_line = false;
                }break;
                
                case '\r':
                {
                    newline_layout_consume_CR(&newline_vars, index);
                }break;
                
                case '\n':
                {
                    u64 newline_index = newline_layout_consume_LF(&newline_vars, index);
                    lr_tb_write_blank(&pos_vars, arena, &list, newline_index);
                    lr_tb_next_line(&pos_vars);
                    first_of_the_line = true;
                }break;
            }
        }
        
        if (newline_layout_consume_finish(&newline_vars)){
            i64 index = layout_index_from_ptr(ptr, text.str, range.first);
            lr_tb_write_blank(&pos_vars, arena, &list, index);
        }
    }
    
    layout_item_list_finish(&list, -pos_vars.line_to_text_shift);
    
    return(list);
}

function Layout_Item_List
layout_virt_indent_literal_unwrapped(Application_Links *app, Arena *arena,
                                     Buffer_ID buffer, Range_i64 range, Face_ID face,
                                     f32 width){
    Scratch_Block scratch(app);
    
    Layout_Item_List list = get_empty_item_list(range);
    
    String_Const_u8 text = push_buffer_range(app, scratch, buffer, range);
    
    Face_Advance_Map advance_map = get_face_advance_map(app, face);
    Face_Metrics metrics = get_face_metrics(app, face);
    LefRig_TopBot_Layout_Vars pos_vars = get_lr_tb_layout_vars(&advance_map, &metrics, width);
    
    if (text.size == 0){
        lr_tb_write_blank(&pos_vars, arena, &list, range.start);
    }
    else{
        b32 skipping_leading_whitespace = true;
        Newline_Layout_Vars newline_vars = get_newline_layout_vars();
        
        u8 *ptr = text.str;
        u8 *end_ptr = ptr + text.size;
        for (;ptr < end_ptr;){
            Character_Consume_Result consume = utf8_consume(ptr, (umem)(end_ptr - ptr));
            
            if (!character_is_whitespace(consume.codepoint)){
                skipping_leading_whitespace = false;
            }
            
            i64 index = layout_index_from_ptr(ptr, text.str, range.first);
            switch (consume.codepoint){
                case '\t':
                case ' ':
                {
                    newline_layout_consume_default(&newline_vars);
                    f32 advance = lr_tb_advance(&pos_vars, consume.codepoint);
                    if (!skipping_leading_whitespace){
                        lr_tb_write_with_advance(&pos_vars, advance,
                                                 arena, &list, index,
                                                 consume.codepoint);
                    }
                    else{
                        lr_tb_advance_x_without_item(&pos_vars, advance);
                    }
                }break;
                
                default:
                {
                    newline_layout_consume_default(&newline_vars);
                    lr_tb_write(&pos_vars, arena, &list, index, consume.codepoint);
                }break;
                
                case '\r':
                {
                    newline_layout_consume_CR(&newline_vars, index);
                }break;
                
                case '\n':
                {
                    i64 newline_index = newline_layout_consume_LF(&newline_vars, index);
                    lr_tb_write_blank(&pos_vars, arena, &list, newline_index);
                    lr_tb_next_line(&pos_vars);
                }break;
                
                case max_u32:
                {
                    newline_layout_consume_default(&newline_vars);
                    lr_tb_write_byte(&pos_vars, arena, &list, index, *ptr);
                }break;
            }
            
            ptr += consume.inc;
        }
        
        if (newline_layout_consume_finish(&newline_vars)){
            i64 index = layout_index_from_ptr(ptr, text.str, range.first);
            lr_tb_write_blank(&pos_vars, arena, &list, index);
        }
    }
    
    layout_item_list_finish(&list, -pos_vars.line_to_text_shift);
    
    return(list);
}

// BOTTOM