import { JSDOM } from "jsdom";

export class DOMShim
{
  private static _instance:DOMShim = null;
  

  static get $():DOMShim
  {
    if ( this._instance )
    {
      return this._instance
    }

    this._instance = new DOMShim();
    return this._instance;
  } 

  private _applied = false;
  private _jsDOM:JSDOM;

  constructor()
  {
    this._apply();
  }

  setDocument( html:string )
  {
    this._jsDOM = new JSDOM( html );
    ( global as any ).window   = this._jsDOM.window;
    ( global as any ).document = this._jsDOM.window.document;
  }

  get jsdom(){ return this._jsDOM; }
  
  private _apply()
  {
    if ( this._applied )
    {
      return;
    }
    
    this._addHTMLNodeDefinition();
    this._addDOMParser();    

    this._applied = true;
  }

  
  private _addHTMLNodeDefinition()
  {
    ( global as any ).Node = 
    {
      ELEMENT_NODE: 1,
      ATTRIBUTE_NODE: 2,
      TEXT_NODE:3,
      CDATA_SECTION_NODE:4,
      PROCESSING_INSTRUCTION_NODE:7,
      COMMENT_NODE:8,
      DOCUMENT_NODE:9,
      DOCUMENT_TYPE_NODE:10,
      DOCUMENT_FRAGMENT_NODE:11
    }
  }
  
  private _addDOMParser()
  {
    DOMParserShim.implementation = ( html:string, type:string = "html" )=>
    {
      return new JSDOM( html, {contentType:type} ).window.document;
    }

    global.DOMParser = DOMParserShim;
  }


}

export class DOMParserShim
{  
  static implementation:( html:string, type:string )=>Document;
  parseFromString( html:string, type:string ):Document
  {
    return DOMParserShim.implementation( html, type );
  }
}