interface RegistryEntry
{
  suffix: string;
  editor: string;
}

export class FileEditorRegistry
{
  static readonly DefaultEntries: RegistryEntry[] =
  [
    { suffix: 'rojo', editor: 'RojoSettingsPanel' },
    { suffix: 'html', editor: 'HTMLEditorPanel' },
    { suffix: 'htm',  editor: 'HTMLEditorPanel' },
    { suffix: 'js',   editor: 'CodePanel' },
    { suffix: 'ts',   editor: 'CodePanel' },
    { suffix: 'css',  editor: 'CodePanel' },
    { suffix: 'json', editor: 'CodePanel' },
    { suffix: 'md',   editor: 'CodePanel' },
    { suffix: 'txt',  editor: 'CodePanel' },
    { suffix: 'svg',  editor: 'CodePanel' },
    { suffix: 'xml',  editor: 'CodePanel' },
    { suffix: 'yaml', editor: 'CodePanel' },
    { suffix: 'yml',  editor: 'CodePanel' },
    { suffix: 'sh',          editor: 'CodePanel' },
    { suffix: 'py',          editor: 'CodePanel' },
    { suffix: 'cs',          editor: 'CodePanel' },
    { suffix: 'gd',          editor: 'CodePanel' },
    { suffix: 'gdshader',    editor: 'CodePanel' },
    { suffix: 'gdshaderinc', editor: 'CodePanel' },
    { suffix: 'gdinclude',   editor: 'CodePanel' },
    { suffix: 'glsl',        editor: 'CodePanel' },
    { suffix: 'tscn',        editor: 'CodePanel' },
    { suffix: 'tres',        editor: 'CodePanel' },
    { suffix: 'gdextension', editor: 'CodePanel' },
  ];

  static readonly EditorTagNames: Record<string, string> =
  {
    'RojoSettingsPanel': 'rojo-settings-panel',
    'HTMLEditorPanel': 'html-editor-panel',
    'CodePanel': 'code-panel',
  };

  projectEntries: RegistryEntry[] | null = null;
  _loaded = false;

  async load( projectId: string ): Promise<void>
  {
    if ( this._loaded ) return;
    this._loaded = true;

    try
    {
      const res = await fetch( `/api/files/${projectId}/workspace/editor/file-editors.json` );
      if ( ! res.ok ) return;
      const data = await res.json();
      if ( Array.isArray( data ) ) this.projectEntries = data;
    }
    catch {}
  }

  resolve( filePath: string ): string | null
  {
    const filename = filePath.slice( filePath.lastIndexOf( '/' ) + 1 );

    if ( this.projectEntries !== null )
    {
      const editor = this._matchSuffix( filename, this.projectEntries );
      if ( editor !== null ) return this._resolveTag( editor );
    }

    const editor = this._matchSuffix( filename, FileEditorRegistry.DefaultEntries );
    if ( editor !== null ) return this._resolveTag( editor );

    return null;
  }

  _resolveTag( editorName: string ): string
  {
    return FileEditorRegistry.EditorTagNames[ editorName ] ?? editorName;
  }

  _matchSuffix( filename: string, entries: RegistryEntry[] ): string | null
  {
    for ( const entry of entries )
    {
      if ( filename.endsWith( '.' + entry.suffix ) )
      {
        return entry.editor;
      }
    }

    return null;
  }
}