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

struct File_Language_Result
{
  File_Language_Kind kind;
  bool treat_as_code;
};

function File_Language_Result
identify_file_language(Application_Links* app, Buffer_ID buffer_id)
{
  Scratch_Block scratch(app);

  File_Language_Result result;
  block_zero_struct(&result);
  String_Const_u8 file_name = push_buffer_file_name(app, scratch, buffer_id);
  if (file_name.size <= 0) return result;
  String_Const_u8 file_extension = string_file_extension(file_name);
  result.kind = File_Language_Text;

  String_Const_u8 treat_as_code_string = def_get_config_string(scratch, vars_save_string_lit("treat_as_code"));
  String_Const_u8_Array extensions_to_treat_as_code = parse_extension_line_to_extension_list(app, scratch, treat_as_code_string);

  for (i32 i = 0; i < extensions_to_treat_as_code.count; ++i)
  {
    if (string_match(file_extension, extensions_to_treat_as_code.strings[i]))
    {
      result.treat_as_code = true;
      result.kind = File_Language_Unknown;

      if (string_match(file_extension, string_u8_litexpr("md")))
      {
        print_message(app, SCu8("Language Detected as Markdown\n"));
        result.kind = File_Language_Markdown;
      }
      else if (string_match(file_extension, string_u8_litexpr("c")))
      {
        print_message(app, SCu8("Language Detected as C\n"));
        result.kind = File_Language_CPP;
      }
      else if (string_match(file_extension, string_u8_litexpr("cpp")) ||
              string_match(file_extension, string_u8_litexpr("h")) ||
              string_match(file_extension, string_u8_litexpr("hpp")) ||
              string_match(file_extension, string_u8_litexpr("cc"))
      ){
        print_message(app, SCu8("Language Detected as Cpp\n"));
        result.kind = File_Language_CPP;
      }
      else if (string_match(file_extension, string_u8_litexpr("m"))){
        print_message(app, SCu8("Language Detected as ObjectiveC\n"));
        result.kind = File_Language_ObjectiveC;
      }
      else if (string_match(file_extension, string_u8_litexpr("hlsl"))){
        print_message(app, SCu8("Language Detected as HLSL\n"));
        result.kind = File_Language_HLSL;
      }
      else if (string_match(file_extension, string_u8_litexpr("glsl"))){
        print_message(app, SCu8("Language Detected as GLSL\n"));
        result.kind = File_Language_GLSL;
      }
      else if (string_match(file_extension, string_u8_litexpr("jai"))){
        print_message(app, SCu8("Language Detected as Jai\n"));
        result.kind = File_Language_Jai;
      }
      else if (string_match(file_extension, string_u8_litexpr("cs"))){
        print_message(app, SCu8("Language Detected as C#\n"));
        result.kind = File_Language_CSharp;
      }
      else if (string_match(file_extension, string_u8_litexpr("swift"))){
        print_message(app, SCu8("Language Detected as Swift\n"));
        result.kind = File_Language_Swift;
      }
      else if (string_match(file_extension, string_u8_litexpr("go"))){
        print_message(app, SCu8("Language Detected as Go\n"));
        result.kind = File_Language_Go;
      }
      else if (string_match(file_extension, string_u8_litexpr("rs"))){
        print_message(app, SCu8("Language Detected as Rust\n"));
        result.kind = File_Language_Rust;
      }
      else if (string_match(file_extension, string_u8_litexpr("js"))){
        print_message(app, SCu8("Language Detected as Javascript\n"));
        result.kind = File_Language_Javascript;
      }
      else if (string_match(file_extension, string_u8_litexpr("ts"))){
        print_message(app, SCu8("Language Detected as Typescript\n"));
        result.kind = File_Language_Typescript;
      }
      else if (string_match(file_extension, string_u8_litexpr("json"))){
        print_message(app, SCu8("Language Detected as JSON\n"));
        result.kind = File_Language_JSON;
      }
      else  if (string_match(file_extension, string_u8_litexpr("odin"))){
        print_message(app, SCu8("Language Detected as Odin\n"));
        result.kind = File_Language_Odin;
      }
      else if (string_match(file_extension, string_u8_litexpr("zig"))){
        print_message(app, SCu8("Language Detected as Zig\n"));
        result.kind = File_Language_Zig;
      }

      if (result.kind != File_Language_Unknown) break;
    }
  }

  return result;
}

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

  Scratch_Block scratch(app);

  File_Language_Result lang = identify_file_language(app, buffer_id);
  bool begin_parse_task = false;
  if (lang.treat_as_code) begin_parse_task = tree_sitter_begin_buffer(app, buffer_id, lang.kind);

  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 = (lang.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 (lang.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 (begin_parse_task)
  {
    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 (lang.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);
}