import { ClassFlag } from "./ClassFlag";
import { ElementAttribute } from "./ElementAttribute";
import { ElementType } from "./ElementType";

export class Fullscreen
{
  static readonly flag = new ClassFlag( "is-fullscreen" );

  static _listensToChange = false;

  static setFlagOnChange()
  {
    if ( Fullscreen._listensToChange )
    {
      return;
    }

    Fullscreen._listensToChange = true;

    document.addEventListener( "fullscreenchange",
      () => 
      {
        Fullscreen.flag.setAs( document.body, Fullscreen.isFullscreen() );
      }
    );
  }
  
  static isFullscreen(): boolean
  {
    let anyDocument:any = document;

    if ( anyDocument.fullscreenElement != null )
    {
      return true;
    }

    if ( anyDocument.webkitFullscreenElement != null )
    {
      return true;
    }

    if ( anyDocument.mozFullScreenElement != null )
    {
      return true;
    }

    if ( anyDocument.msFullscreenElement != null )
    {
      return true;
    }

    return false;
  }

  protected static async enterFullscreen( element:HTMLElement ): Promise<void>
  {
    let anyElement:any = element;

    

    if ( element.requestFullscreen != null )
    {
      return element.requestFullscreen();
    }

    if ( anyElement.webkitRequestFullscreen != null )
    {
      return anyElement.webkitRequestFullscreen();
    }

    if ( anyElement.mozRequestFullScreen != null )
    {
      return anyElement.mozRequestFullScreen();
    }

    if ( anyElement.msRequestFullscreen != null )
    {
      return anyElement.msRequestFullscreen();
    }

    return Promise.reject( new Error( "fullscreen api not supported" ));
  }

  static async exitFullscreen(): Promise<void>
  {
    let anyDocument: any = document;

    if ( anyDocument.exitFullscreen != null )
    {
      return anyDocument.exitFullscreen();
    }

    if ( anyDocument.webkitExitFullscreen != null )
    {
      return anyDocument.webkitExitFullscreen();
    }

    if ( anyDocument.mozCancelFullScreen != null )
    {
      return anyDocument.mozCancelFullScreen();
    }

    if ( anyDocument.msExitFullscreen != null )
    {
      return anyDocument.msExitFullscreen();
    }

    return Promise.reject( new Error( "fullscreen exit not supported" ));
  }

  static async lockOrientation( orientation:string ): Promise<void>
  {
    let anyScreen: any = ( screen as any );
    let api: any = screen.orientation != null
                    ? screen.orientation
                    : anyScreen.orientation != null
                      ? anyScreen.orientation
                      : anyScreen.msOrientation;

    if ( api == null || typeof api.lock !== "function" )
    {
      return;
    }

    try
    {
      await api.lock( orientation );
    }
    catch
    {
      // fail quietly
    }
  }

  static unlockOrientation(): void
  {
    let anyScreen: any = ( screen as any );
    let api: any = screen.orientation != null
                    ? screen.orientation
                    : anyScreen.orientation != null
                      ? anyScreen.orientation
                      : anyScreen.msOrientation;

    if ( api == null || typeof api.unlock !== "function" )
    {
      return;
    }

    try
    {
      api.unlock();
    }
    catch
    {
      // fail quietly
    }
  }

  static async toggleFullscreen( videoContainer:HTMLElement, handleOrientation:"auto"|"portrait"|"landscape"=null ): Promise<void>
  {
    let videoElement = ElementType.video.query( videoContainer );
    ElementAttribute.playsinline.to( videoContainer );
    ( videoContainer as any ).playsInline = true;

    if ( Fullscreen.isFullscreen() )
    {
      await Fullscreen.exitFullscreen();

      if ( handleOrientation )
      { 
        Fullscreen.unlockOrientation();
      }
      
      return Promise.resolve();
    }

    let target:string = null;

    if ( handleOrientation !== null )
    {
      if ( handleOrientation === "auto" )
      {
        let vw = videoElement.videoWidth || videoElement.clientWidth || 16;
        let vh = videoElement.videoHeight || videoElement.clientHeight || 9;

        target = vw >= vh ? "landscape" : "portrait";
      }
      else
      {
        target = handleOrientation;
      }
    }

    await Fullscreen.enterFullscreen( videoContainer );

    if ( target != null )
    {
      await Fullscreen.lockOrientation( target );
    }

    return Promise.resolve();
  }
}