/**
 * EGroupware Custom Html Elements - Multi Video Web Components
 *
 * @license http://opensource.org/licenses/gpl-license.php GPL - GNU General Public License
 * @package etemplate
 * @subpackage api
 * @link https://www.egroupware.org
 * @author Hadi Nategh <hn[at]egroupware.org>
 * @copyright EGroupware GmbH
 */

/*
	This web component allows to merge multiple videos and display them as one single widget/element
	most of the html video attributes and methodes are supported. No controls attribute supported yet.
 */

type VideoTagsArray = Array<{
	node: HTMLVideoElement;
	loadedmetadata: boolean;
	timeupdate: boolean;
	duration: number;
	previousDurations: number;
	currentTime: number;
	active: boolean;
	index: number
}>;

// Create a class for the element
class multi_video extends HTMLElement {

	/**
	 * shadow dom container
	 * @private
	 */
	private readonly _shadow = null;
	/**
	 * wrapper container holds video tags
	 * @private
	 */
	private readonly _wrapper : HTMLDivElement;
	/**
	 * Styling contianer
	 * @private
	 */
	private readonly _style : HTMLStyleElement;
	/**
	 * contains video objects of type VideoTagsArray
	 * @private
	 */
	private _videos : VideoTagsArray = [];
	/**
	 * keeps duration time internally
	 * @private
	 */
	private _duration : number = 0;
	/**
	 * keeps currentTime internally
	 * @private
	 */
	private _currentTime : number = 0;
	/**
	 * Keeps video playing state internally
	 * @private
	 */
	private __playing: boolean = false;

	constructor() {

		super();

		// Create a shadow root
		this._shadow = this.attachShadow({mode: 'open'});

		// Create videos wrapper
		this._wrapper = document.createElement('div');
		this._wrapper.setAttribute('class','wrapper');

		// Create some CSS to apply to the shadow dom
		this._style = document.createElement('style');

		this._style.textContent = '.wrapper {' +
			'width: 100%;' +
			'height: auto;' +
			'display: block;' +
			'}'+
			'.wrapper video {' +
			'width: 100%;'+
			'height: auto;'+
			'}';

		// attach to the shadow dom
		this._shadow.appendChild(this._style);
		this._shadow.appendChild(this._wrapper);
	}

	/**
	 * set observable attributes
	 * @return {string[]}
	 */
	static get observedAttributes() {
		return ['src', 'type'];
	}

	/**
	 * Gets called on observable attributes changes
	 * @param name attribute name
	 * @param _
	 * @param newVal new value
	 */
	attributeChangedCallback(name, _, newVal) {
		switch(name)
		{
			case 'src':
				this.__buildVideoTags(newVal);
				break;
			case 'type':
				this._videos.forEach(_item => {
					_item.node.setAttribute('type', newVal);
				});
				break;
		}
	}

	/**
	 * Calls load method for all its sub videos
	 * https://developer.mozilla.org/en-US/docs/Web/API/HTMLMediaElement/load
	 */
	load()
	{
		this._videos.forEach(_item =>{_item.node.load()});
	}

	/**
	 * init/update video tags
	 * @param _value
	 * @private
	 */
	private __buildVideoTags (_value)
	{
		let value = _value.split(',');
		let video = null;
		let duration = 0;
		for (let i=0;i<value.length;i++)
		{
			video = document.createElement('video');

			if (value[i].match(/&duration=/))
			{
				// get duration from url duration param which is necessary for setting duration time of webm file
				let params = new URLSearchParams(value[i]);
				duration = parseInt(params.get('duration'));
				value[i] = value[i].replace(/&duration.*/, '');
			}
			video.src = value[i];
			this._videos[i] = {
				node:this._wrapper.appendChild(video),
				loadedmetadata: false,
				timeupdate: false,
				duration: duration ? duration : 0,
				previousDurations: 0,
				currentTime: 0,
				active: false,
				index:i
			};

			// loadmetadata event
			this._videos[i]['node'].addEventListener("loadedmetadata", function(_i, _event){
				this._videos[_i]['loadedmetadata'] = true;
				this.__check_loadedmetadata();
			}.bind(this, i));

			//timeupdate event
			this._videos[i]['node'].addEventListener("timeupdate", function(_i, _event){
				this._currentTime = this._videos[i]['previousDurations'] + _event.target.currentTime;

				// push the next video to start otherwise the time update gets paused as it ends automatically
				// with the current video being ended
				if (this._videos[i].node.ended && !this.ended) this.currentTime = this._currentTime + 0.1;

				this.__pushEvent('timeupdate');
			}.bind(this, i));
		}
	}

	/**
	 * calculates duration of videos
	 * @return {number} returns accumulated durations
	 * @private
	 */
	private __duration() {
		let duration = 0;
		this._videos.forEach(_item => {
			duration += _item.duration;
		});
		return duration;
	}

	/**
	 * Get current active video
	 * @return {*[]} returns an array of object consist of current video displayed node
	 * @private
	 */
	private __getActiveVideo()
	{
		return this._videos.filter(_item=>{
			return (_item.active);
		});
	}

	/**
	 * check if all meta data from videos are ready then pushes the event
	 * @private
	 */
	private __check_loadedmetadata ()
	{
		let allReady = true;
		this._videos.forEach((_item) => {
			allReady = allReady && _item.loadedmetadata;
		});
		if (allReady) {
			this._videos.forEach(_item => {
				_item.duration = _item.duration ? _item.duration : _item.node.duration;
				_item.previousDurations = _item.index > 0 ? this._videos[_item.index-1]['duration'] + this._videos[_item.index-1]['previousDurations'] : 0;
			});
			this.duration = this.__duration();
			this.currentTime = 0;
			this.__pushEvent('loadedmetadata');
		}
	}

	/**
	 * Creates event and dispatches it
	 * @param _name
	 */
	private __pushEvent(_name: string)
	{
		let event = document.createEvent("Event");
		event.initEvent(_name, true, true);
		this.dispatchEvent(event);
	}

	/**************************** PUBLIC ATTRIBUTES & METHODES *************************************************/

	/****************************** ATTRIBUTES **************************************/

	/**
	 * set src
	 * @param _value
	 */
	set src(_value)
	{
		let value = _value.split(',');
		this._wrapper.children.forEach(_ch=>{
			_ch.remove();
		});
		this.__buildVideoTags(value);
	}

	/**
	 * get src
	 * @return string returns comma separated sources
	 */
	get src ()
	{
		return this.src;
	}

	/**
	 * currentTime
	 * @param _time
	 */
	set currentTime(_time : number)
	{
		let ctime = _time;
		this._currentTime = _time;
		this._videos.forEach(_item=>{
			if ((ctime < _item.duration + _item.previousDurations)
				&& ((ctime == 0 && _item.previousDurations == 0) || ctime > _item.previousDurations))
			{
				if (this.__playing && _item.node.paused) _item.node.play();
				_item.currentTime = Math.abs(_item.previousDurations-ctime);
				_item.node.currentTime = _item.currentTime;
				_item.active = true;
			}
			else
			{
				_item.active = false;
				_item.node.pause();
			}
			_item.node.hidden = !_item.active;
		});
	}

	/**
	 * get currentTime
	 * @return {number}
	 */
	get currentTime()
	{
		return this._currentTime;
	}

	/**
	 * set video duration time attribute
	 * @param _value
	 */
	set duration (_value : number)
	{
		this._duration = _value;
	}

	/**
	 * get video duration time
	 */
	get duration()
	{
		return this._duration;
	}

	/**
	 * get paused attribute
	 */
	get paused()
	{
		return this.__getActiveVideo()[0]?.node?.paused;
	}

	/**
	 * set muted attribute
	 * @param _value
	 */
	set muted(_value: boolean)
	{
		this._videos.forEach(_item => {
			_item.node.muted = _value;
		});
	}

	/**
	 * get muted attribute
	 */
	get muted()
	{
		return this.__getActiveVideo()[0]?.node?.muted;
	}

	/**
	 * get video ended attribute
	 */
	get ended()
	{
		return this._videos[this._videos.length-1]?.node?.ended;
	}

	/**
	 * set playbackRate
	 * @param _value
	 */
	set playbackRate(_value: number)
	{
		this._videos.forEach(_item => {
			_item.node.playbackRate = _value;
		});
	}

	/**
	 * get playbackRate
	 */
	get playbackRate()
	{
		return this.__getActiveVideo()[0]?.node?.playbackRate;
	}

	/**
	 * set volume
	 */
	set volume(_value: number)
	{
		this._videos.forEach(_item => {
			_item.node.volume = _value;
		});
	}

	/**
	 * get volume
	 */
	get volume()
	{
		return this.__getActiveVideo()[0]?.node?.volume;
	}


	/************************************************* METHODES ******************************************/

	/**
	 * Play video
	 */
	play()
	{
		this.__playing = true;
		return this.__getActiveVideo()[0]?.node?.play();
	}

	/**
	 * pause video
	 */
	pause()
	{
		this.__playing = false;
		this.__getActiveVideo()[0]?.node?.pause();
	}
}

// Define the new multi-video element
customElements.define('multi-video', multi_video);