///////////////////////////////////////////////////////////////////////////
// Begin Buffer
///////////////////////////////////////////////////////////////////////////

BUFFER_HOOK_SIG(custom_begin_buffer){
  ProfileScope(app, "begin buffer");

  Scratch_Block scratch(app);

  Tree_Sitter_Language_Definition* language = tree_sitter_language_for_buffer(app, buffer_id);
  bool treat_as_code = language != 0;
  if (treat_as_code) tree_sitter_begin_buffer(app, buffer_id);

  String_ID file_map_id = vars_save_string_lit("keys_file");
  String_ID code_map_id = vars_save_string_lit("keys_code");

  Command_Map_ID map_id = (treat_as_code)?(code_map_id):(file_map_id);
  Managed_Scope scope = buffer_get_managed_scope(app, buffer_id);
  Command_Map_ID *map_id_ptr = scope_attachment(app, scope, buffer_map_id, Command_Map_ID);
  *map_id_ptr = map_id;

  Line_Ending_Kind setting = guess_line_ending_kind_from_buffer(app, buffer_id);
  Line_Ending_Kind *eol_setting = scope_attachment(app, scope, buffer_eol_setting, Line_Ending_Kind);
  *eol_setting = setting;

  // NOTE(allen): Decide buffer settings
  b32 wrap_lines = true;
  b32 use_lexer = false;
  if (treat_as_code){
      wrap_lines = def_get_config_b32(vars_save_string_lit("enable_code_wrapping"));
      // TODO(PS): @Remove - consider removing the lexer for now? later, replace in favor of tree-sitter
      use_lexer = true;
  }

  if (treat_as_code)
  {
    Async_Task* parse_task = scope_attachment(app, scope, buffer_tree_sitter_parse_task_id, Async_Task);
    *parse_task = async_task_no_dep(&global_async_system, tree_sitter_parse_async, make_data_struct(&buffer_id));
  }

  String_Const_u8 buffer_name = push_buffer_base_name(app, scratch, buffer_id);
  if (buffer_name.size > 0 && buffer_name.str[0] == '*' && buffer_name.str[buffer_name.size - 1] == '*'){
      wrap_lines = def_get_config_b32(vars_save_string_lit("enable_output_wrapping"));
  }

  if (use_lexer){
      ProfileBlock(app, "begin buffer kick off lexer");
      Async_Task *lex_task_ptr = scope_attachment(app, scope, buffer_lex_task, Async_Task);
      *lex_task_ptr = async_task_no_dep(&global_async_system, do_full_lex_async, make_data_struct(&buffer_id));
  }

  {
      b32 *wrap_lines_ptr = scope_attachment(app, scope, buffer_wrap_lines, b32);
      *wrap_lines_ptr = wrap_lines;
  }

  if (use_lexer){
      buffer_set_layout(app, buffer_id, layout_virt_indent_index_generic);
  }
  else{
      if (treat_as_code){
          buffer_set_layout(app, buffer_id, layout_virt_indent_literal_generic);
      }
      else{
          buffer_set_layout(app, buffer_id, layout_generic);
      }
  }

  // no meaning for return
  return(0);
}

///////////////////////////////////////////////////////////////////////////
// End Buffer
///////////////////////////////////////////////////////////////////////////

BUFFER_HOOK_SIG(custom_end_buffer){
  Marker_List *list = get_marker_list_for_buffer(buffer_id);
  if (list != 0) delete_marker_list(list);

  tree_sitter_end_buffer(app, buffer_id);
  default_end_buffer(app, buffer_id);
  return(0);
}

///////////////////////////////////////////////////////////////////////////
// Buffer Edit Range
///////////////////////////////////////////////////////////////////////////

BUFFER_EDIT_RANGE_SIG(custom_buffer_edit_range){
  // buffer_id, new_range, original_size
  ProfileScope(app, "default edit range");

  Range_i64 old_range = Ii64(old_cursor_range.min.pos, old_cursor_range.max.pos);

  buffer_shift_fade_ranges(buffer_id, old_range.max, (new_range.max - old_range.max));

  {
    code_index_lock();
    Code_Index_File *file = code_index_get_file(buffer_id);
    if (file != 0) code_index_shift(file, old_range, range_size(new_range));
    code_index_unlock();
  }

  i64 insert_size = range_size(new_range);
  i64 text_shift = replace_range_shift(old_range, insert_size);

  Scratch_Block scratch(app);

  Managed_Scope scope = buffer_get_managed_scope(app, buffer_id);

  { // Tree Sitter
    Buffer_Tree_Sitter_Data* tree_data = scope_attachment(app, scope, buffer_tree_sitter_data_id, Buffer_Tree_Sitter_Data);
    if (tree_data->tree)
    {
      Async_Task* tree_sitter_parse_task = scope_attachment(app, scope, buffer_tree_sitter_parse_task_id, Async_Task);
      if (async_task_is_running_or_pending(&global_async_system, *tree_sitter_parse_task))
      {
        // NOTE(jack): We dont want to wait for ts_tree delete, as it is slow for large files
        // (noticable spikes when it fires in 4coder_base_types.cpp ~200Kb)
        // And if we restart the next task before it attempts the delete we may be able to
        // avoid the delete entirely as the reference count may have increased from the next
        // parse attempt
        async_task_cancel_nowait(app, &global_async_system, *tree_sitter_parse_task);
        *tree_sitter_parse_task = 0;
      }

      i64 new_end_line = get_line_number_from_pos(app, buffer_id, new_range.end);
      i64 new_end_pos = new_range.end - get_line_start_pos(app, buffer_id, new_end_line);

      TSInputEdit edit;
      edit.start_byte = (u32)old_range.start;
      edit.old_end_byte = (u32)old_range.end;
      edit.new_end_byte = (u32)new_range.end;
      edit.start_point = {
        (u32)old_cursor_range.start.line,
        (u32)old_cursor_range.start.col
      };
      edit.old_end_point = {
        (u32)old_cursor_range.end.line,
        (u32)old_cursor_range.end.col
      };
      // TODO(PS): jack says this works but looks wrong???
      edit.new_end_point = {
        (u32)new_end_line - 1,
        (u32)new_end_pos + 1,
      };

      ts_tree_edit(tree_data->tree, &edit);
      *tree_sitter_parse_task = async_task_no_dep(&global_async_system, tree_sitter_parse_async, make_data_struct(&buffer_id));
    }
  }


  Async_Task *lex_task_ptr = scope_attachment(app, scope, buffer_lex_task, Async_Task);

  Base_Allocator *allocator = managed_scope_allocator(app, scope);
  b32 do_full_relex = false;

  if (async_task_is_running_or_pending(&global_async_system, *lex_task_ptr))
  {
    async_task_cancel(app, &global_async_system, *lex_task_ptr);
    buffer_unmark_as_modified(buffer_id);
    do_full_relex = true;
    *lex_task_ptr = 0;
  }

  Token_Array *ptr = scope_attachment(app, scope, attachment_tokens, Token_Array);
  if (ptr != 0 && ptr->tokens != 0)
  {
    ProfileBlockNamed(app, "attempt resync", profile_attempt_resync);

    i64 token_index_first = token_relex_first(ptr, old_range.first, 1);
    i64 token_index_resync_guess =
        token_relex_resync(ptr, old_range.one_past_last, 16);

    if (token_index_resync_guess - token_index_first >= 4000)
    {
      do_full_relex = true;
    }
    else
    {
      Token *token_first = ptr->tokens + token_index_first;
      Token *token_resync = ptr->tokens + token_index_resync_guess;

      Range_i64 relex_range = Ii64(token_first->pos, token_resync->pos + token_resync->size + text_shift);
      String_Const_u8 partial_text = push_buffer_range(app, scratch, buffer_id, relex_range);

      Token_List relex_list = lex_full_input_cpp(scratch, partial_text);
      if (relex_range.one_past_last < buffer_get_size(app, buffer_id))
      {
        token_drop_eof(&relex_list);
      }

      Token_Relex relex = token_relex(relex_list, relex_range.first - text_shift, ptr->tokens, token_index_first, token_index_resync_guess);

      ProfileCloseNow(profile_attempt_resync);

      if (!relex.successful_resync)
      {
        do_full_relex = true;
      }
      else
      {
        ProfileBlock(app, "apply resync");

        i64 token_index_resync = relex.first_resync_index;

        Range_i64 head = Ii64(0, token_index_first);
        Range_i64 replaced = Ii64(token_index_first, token_index_resync);
        Range_i64 tail = Ii64(token_index_resync, ptr->count);
        i64 resynced_count = (token_index_resync_guess + 1) - token_index_resync;
        i64 relexed_count = relex_list.total_count - resynced_count;
        i64 tail_shift = relexed_count - (token_index_resync - token_index_first);

        i64 new_tokens_count = ptr->count + tail_shift;
        Token *new_tokens = base_array(allocator, Token, new_tokens_count);

        Token *old_tokens = ptr->tokens;
        block_copy_array_shift(new_tokens, old_tokens, head, 0);
        token_fill_memory_from_list(new_tokens + replaced.first, &relex_list, relexed_count);
        for (i64 i = 0, index = replaced.first; i < relexed_count; i += 1, index += 1)
        {
          new_tokens[index].pos += relex_range.first;
        }
        for (i64 i = tail.first; i < tail.one_past_last; i += 1)
        {
          old_tokens[i].pos += text_shift;
        }
        block_copy_array_shift(new_tokens, ptr->tokens, tail, tail_shift);

        base_free(allocator, ptr->tokens);

        ptr->tokens = new_tokens;
        ptr->count = new_tokens_count;
        ptr->max = new_tokens_count;

        buffer_mark_as_modified(buffer_id);
      }
    }
  }

  if (do_full_relex)
  {
    *lex_task_ptr = async_task_no_dep(&global_async_system, do_full_lex_async,
                                      make_data_struct(&buffer_id));
  }

  loco_on_buffer_edit(app, buffer_id, old_range, new_range);

  // no meaning for return
  return(0);
}

///////////////////////////////////////////////////////////////////////////
// Render Buffer
///////////////////////////////////////////////////////////////////////////

function void custom_render_buffer(
  Application_Links *app,
  View_ID view_id,
  Face_ID face_id,
  Buffer_ID buffer,
  Text_Layout_ID text_layout_id,
  Rect_f32 rect
){
    ProfileScope(app, "render buffer");
    Scratch_Block scratch(app);

    View_ID active_view = get_active_view(app, Access_Always);
    b32 is_active_view = (active_view == view_id);
    Rect_f32 prev_clip = draw_set_clip(app, rect);

    Range_i64 visible_range = text_layout_get_visible_range(app, text_layout_id);

    // NOTE(allen): Cursor shape
    Face_Metrics metrics = get_face_metrics(app, face_id);
    u64 cursor_roundness_100 = def_get_config_u64(app, vars_save_string_lit("cursor_roundness"));
    f32 cursor_roundness = metrics.normal_advance*cursor_roundness_100*0.01f;
    f32 mark_thickness = (f32)def_get_config_u64(app, vars_save_string_lit("mark_thickness"));

    // NOTE(allen): Token colorizing
    Managed_Scope buffer_scope = buffer_get_managed_scope(app, buffer);
    Buffer_Tree_Sitter_Data* tree_data = scope_attachment(app, buffer_scope, buffer_tree_sitter_data_id, Buffer_Tree_Sitter_Data);
    TSTree* tree = tree_sitter_buffer_get_tree_copy(tree_data);

    Token_Array token_array = get_token_array_from_buffer(app, buffer);
    paint_text_color_fcolor(app, text_layout_id, visible_range, fcolor_id(defcolor_text_default)); // will get overridden by lang-specific token coloring below
    if (token_array.tokens != 0 && tree)
    {
      if (use_tree_sitter_token_coloring)
      {
        draw_tree_sitter_node_colors(app, text_layout_id, buffer);
      }
      else
      {
        draw_cpp_token_colors(app, text_layout_id, &token_array);
      }
    }

    i64 cursor_pos = view_correct_cursor(app, view_id);
    view_correct_mark(app, view_id);

    // NOTE(allen): Scope highlight
    b32 use_scope_highlight = def_get_config_b32(vars_save_string_lit("use_scope_highlight"));
    if (use_scope_highlight){
        Color_Array colors = finalize_color_array(defcolor_back_cycle);
        draw_scope_highlight(app, buffer, text_layout_id, cursor_pos, colors.vals, colors.count);
    }

    // NOTE(PS): QOL Column
    if (qol_col_cursor.pos >= 0){
      Buffer_Seek seek = seek_line_col(qol_col_cursor.line, qol_col_cursor.col);
      Buffer_Cursor cursor = buffer_compute_cursor(app, buffer, seek);
      Rect_f32 col_rect = text_layout_character_on_screen(app, text_layout_id, cursor.pos);
      if (col_rect.x1 > 0.f){
        col_rect.y0 = rect.y0;
        col_rect.y1 = rect.y1;
        draw_rectangle_fcolor(app, col_rect, 0.f, fcolor_id(defcolor_highlight_cursor_line));
      }
    }

    b32 use_error_highlight = def_get_config_b32(vars_save_string_lit("use_error_highlight"));
    b32 use_jump_highlight = def_get_config_b32(vars_save_string_lit("use_jump_highlight"));
    if (use_error_highlight || use_jump_highlight){
        // NOTE(allen): Error highlight
        String_Const_u8 name = string_u8_litexpr("*compilation*");
        Buffer_ID compilation_buffer = get_buffer_by_name(app, name, Access_Always);
        if (use_error_highlight){
            draw_jump_highlights(app, buffer, text_layout_id, compilation_buffer,
                                 fcolor_id(defcolor_highlight_junk));
        }

        // NOTE(allen): Search highlight
        if (use_jump_highlight){
            Buffer_ID jump_buffer = get_locked_jump_buffer(app);
            if (jump_buffer != compilation_buffer){
                draw_jump_highlights(app, buffer, text_layout_id, jump_buffer,
                                     fcolor_id(defcolor_highlight_white));
            }
        }
    }

    // NOTE(allen): Color parens
    b32 use_paren_helper = def_get_config_b32(vars_save_string_lit("use_paren_helper"));
    if (use_paren_helper){
        Color_Array colors = finalize_color_array(defcolor_text_cycle);
        draw_paren_highlight(app, buffer, text_layout_id, cursor_pos, colors.vals, colors.count);
    }

    // NOTE(allen): Line highlight
    b32 highlight_line_at_cursor = def_get_config_b32(vars_save_string_lit("highlight_line_at_cursor"));
    if (highlight_line_at_cursor && is_active_view){
        i64 line_number = get_line_number_from_pos(app, buffer, cursor_pos);
        draw_line_highlight(app, text_layout_id, line_number, fcolor_id(defcolor_highlight_cursor_line));
    }

    // NOTE(allen): Whitespace highlight
    b64 show_whitespace = false;
    view_get_setting(app, view_id, ViewSetting_ShowWhitespace, &show_whitespace);
    if (show_whitespace){
        if (token_array.tokens == 0){
            draw_whitespace_highlight(app, buffer, text_layout_id, cursor_roundness);
        }
        else{
            draw_whitespace_highlight(app, text_layout_id, &token_array, cursor_roundness);
        }
    }

    // NOTE(allen): Cursor
    switch (fcoder_mode){
        case FCoderMode_Original:
        {
            draw_original_4coder_style_cursor_mark_highlight(app, view_id, is_active_view, buffer, text_layout_id, cursor_roundness, mark_thickness);
        }break;
        case FCoderMode_NotepadLike:
        {
            draw_notepad_style_cursor_highlight(app, view_id, buffer, text_layout_id, cursor_roundness);
        }break;
    }

    // NOTE(allen): Fade ranges
    paint_fade_ranges(app, text_layout_id, buffer);

    // NOTE(allen): put the actual text on the actual screen
    draw_text_layout_default(app, text_layout_id);

    draw_set_clip(app, prev_clip);
}

function void
custom_render_caller(Application_Links *app, Frame_Info frame_info, View_ID view_id){
    ProfileScope(app, "default render caller");
    View_ID active_view = get_active_view(app, Access_Always);
    b32 is_active_view = (active_view == view_id);

    Rect_f32 region = draw_background_and_margin(app, view_id, is_active_view);
    Rect_f32 prev_clip = draw_set_clip(app, region);

    Buffer_ID buffer = view_get_buffer(app, view_id, Access_Always);
    Face_ID face_id = get_face_id(app, buffer);
    Face_Metrics face_metrics = get_face_metrics(app, face_id);
    f32 line_height = face_metrics.line_height;
    f32 digit_advance = face_metrics.decimal_digit_advance;

    // NOTE(allen): file bar
    b64 showing_file_bar = false;
    if (view_get_setting(app, view_id, ViewSetting_ShowFileBar, &showing_file_bar) && showing_file_bar){
        Rect_f32_Pair pair = layout_file_bar_on_top(region, line_height);
        draw_file_bar(app, view_id, buffer, face_id, pair.min);
        region = pair.max;
    }

    Buffer_Scroll scroll = view_get_buffer_scroll(app, view_id);

    Buffer_Point_Delta_Result delta = delta_apply(app, view_id,
                                                  frame_info.animation_dt, scroll);
    if (!block_match_struct(&scroll.position, &delta.point)){
        block_copy_struct(&scroll.position, &delta.point);
        view_set_buffer_scroll(app, view_id, scroll, SetBufferScroll_NoCursorChange);
    }
    if (delta.still_animating){
        animate_in_n_milliseconds(app, 0);
    }

    // NOTE(allen): query bars
    region = default_draw_query_bars(app, region, view_id, face_id);

    // NOTE(allen): FPS hud
    if (show_fps_hud){
        Rect_f32_Pair pair = layout_fps_hud_on_bottom(region, line_height);
        draw_fps_hud(app, frame_info, face_id, pair.max);
        region = pair.min;
        animate_in_n_milliseconds(app, 1000);
    }

    // NOTE(allen): layout line numbers
    b32 show_line_number_margins = def_get_config_b32(vars_save_string_lit("show_line_number_margins"));
    Rect_f32 line_number_rect = {};
    if (show_line_number_margins){
        Rect_f32_Pair pair = layout_line_number_margin(app, buffer, region, digit_advance);
        line_number_rect = pair.min;
        region = pair.max;
    }

    // NOTE(allen): begin buffer render
    Buffer_Point buffer_point = scroll.position;
    Text_Layout_ID text_layout_id = text_layout_create(app, buffer, region, buffer_point);

    // NOTE(allen): draw line numbers
    if (show_line_number_margins){
        draw_line_number_margin(app, view_id, buffer, face_id, text_layout_id, line_number_rect);
    }

    // NOTE(allen): draw the buffer
    custom_render_buffer(app, view_id, face_id, buffer, text_layout_id, region);
    loco_render_buffer(app, view_id, face_id, buffer, text_layout_id, region, frame_info);

    text_layout_free(app, text_layout_id);
    draw_set_clip(app, prev_clip);
}