import ClientDriver from './client-driver.js'

export default class WebSocketClientDriver extends ClientDriver{


	/* (1) Creates a client driver
	*
	* @_resource<String>				Target resource (typically an URL)
	* @_auth<AuthObject>				Authentication object
	*
	* [fornat::AuthObject]
	* {
	*	token: string
	* }
	*
	---------------------------------------------------------*/
	constructor(_resource, _auth={token:null}){

		/* (0) Parent check */
		if( !super().error )
			return;

		/* (1) Set inherited attributes */
		this.resource = _resource;
		let tmp = typeof _auth !== 'object' || _auth['token'] == null || typeof _auth.token !== 'string';
		this.auth = (tmp) ? { token: null } : { token: _auth.token };

		/* (2) When token response is OK */
		this.valid_token = false;

		/* (3) Create useful attributes */
		this.ws     = null;
		this.buffer = null; // useful when waiting for WebSocket to open

		/* (4) Manage connection opened */
		this.event.onconnected = function(){

			// update state
			this.state = ClientDriver.STATE.CONNECTED;

			// send token
			this.ws.send(JSON.stringify({ token: this.auth.token }));

		}.bind(this);


		/* (5) Manage response received */
		this.event.onreceive = function(_response){

			/* (1) set state from TRANSFERING to CONNECTED */
			this.state = ClientDriver.STATE.CONNECTED;

			/* (2) Try to parse JSON */
			var obj_resp = null;
			try{ obj_resp = JSON.parse(_response); }catch(e){}

			/* (3) JSON error -> send null */
			if( obj_resp === null )
				this.callback.onreceive( null );

			/* (4) if TOKEN VALIDATION */
			if( typeof obj_resp.error === 'number' ){

				// invalid token -> tell connection closed
				if( obj_resp.error !== 0 )
					return this.event.onclose();

				// valid token -> connected
				this.callback.onconnected();

				// if request(s) in stack -> pop & send them
				while( this.stack.length > 0 )
					this.send(this.stack.shift());

				return;

			}

			/* (5) Else -> pass message to callback */
			this.callback.onreceive(obj_resp);

		}.bind(this)

	}


	/* (2) Binds the client to the resource
	*
	* @return bound<boolean>			Whether the binding has been successful
	*
	---------------------------------------------------------*/
	bind(){

		/* (0) Parent check */
		if( !super.bind() )
			return false;

		/* (1) Create WebSocket client instance */
		this.ws = new WebSocket(this.resource);

		/* (2) Bind callback.onready */
		this.ws.onopen = this.event.onconnected;

		/* (3) Bind callback.onclose */
		this.ws.onclose = this.event.onclose;

		/* (4) Bind callback.onerror */
		this.ws.onerror = this.event.onclose;

		/* (5) Bind callback.onreceive */
		this.ws.onmessage = (_message_event) => this.event.onreceive(_message_event.data);


		/* (6) Return success */
		return true;

	}


	/* (3) Send request
	*
	* @_request<Object>					Request data
	*
	* @return sent<boolean>				Whether the request has been successful
	*
	---------------------------------------------------------*/
	send(_request){

		var buffer = null;

		/* (0) Parent check */
		if( !super.send(_request) )
			return false;

		this.state = ClientDriver.STATE.CONNECTED;

		/* (1) Error: invalid _request.buffer */
		if( typeof _request.buffer === 'object' )
			buffer = JSON.stringify(_request.buffer);

		else if( typeof _request.buffer === 'string' )
			buffer = _request.buffer;

		else
			return false;


		/* (2) Send message */
		this.ws.send(buffer);

		/* (3) Return success */
		return true;

	}


	/* (3) Closes the connection
	*
	* @return closed<boolean>			Whether the connection has been closed
	*
	---------------------------------------------------------*/
	close(){

		/* (0) Parent check */
		if( !super.close() )
			return false;

		/* (1) Close websocket */
		this.ws.close();

		/* (2) Return success */
		return true;

	}



}