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

export default class XHRClientDriver extends ClientDriver{

	/* (1) Creates a client driver
	*
	* @_resource<String>				Target resource
	*									(typically a hostname without trailing HTTP:// nor HTTPS://)
	* @_auth<AuthObject>				Authentication object
	*
	*
	* [fornat::AuthObject]
	* {
	*	ssl: <boolean>
	* }
	*
	---------------------------------------------------------*/
	constructor(_resource, _auth={ssl:true}){

		/* (0) Parent check */
		if( super(_resource, _auth).error ){
			this.force_close = true;
			return;
		}

		/* (1) Create useful attributes */
		this.xhr = null;

		/* (2) Manage _resource format (remove http://, https://) */
		this.resource = _resource.replace(/^https?:\/\//, '');

		/* (3) Manage @proto default values */
		this.proto = typeof _auth !== 'object' && _auth['ssl'] != null && _auth.ssl === true;
		this.proto = (this.proto) ? 'https://' : 'http://';

	}


	/* (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 XHR instance */
		this.xhr = (window.XMLHttpRequest) ? new XMLHttpRequest() : new ActiveXObject('Microsoft.XMLHttpRequest');

		/* (2) Manage after request callbacks */
		this.xhr.onreadystatechange = function(){

			switch(this.xhr.readyState){

				// Request sent
				case 4:

					// Got response
					if( this.xhr.status === 200 ){

						this.event.onreceive(this.xhr.responseText);
						this.event.onclose();

					// Request error
					}else
						this.event.onclose();

					break;

			}


		}.bind(this);

		/* (3) State is now CONNECTED (ready to send) */
		this.state = ClientDriver.STATE.CONNECTED;

		/* (4) Bind to callback onconnected() */
		this.event.onconnected();

		/* (5) Return success */
		return true;

	}


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

		/* (1) Fast argument check
		---------------------------------------------------------*/
		/* (1) Parent check */
		if( !super.send(_request) )
			return false;

		/* (2) Error: invalid _request.path */
		if( typeof _request.path !== 'string' ){
			this.state = ClientDriver.STATE.CONNECTED;
			return false;
		}

		/* (3) Default @http_token value */
		let http_token = null;
		if( typeof _request.http_token === 'string' )
			http_token = _request.http_token;


		/* (2) Manage _request.path argument
		---------------------------------------------------------*/
		/* (1) Error: invalid path format */
		if( !/^([A-Z]+) (.+)/i.test(_request.path) ){
			this.state = ClientDriver.STATE.CONNECTED;
			return;
		}


		/* (2) Extract path data */
		let http_method = RegExp.$1;
		let http_uri    = RegExp.$2;


		/* (3) Manage _request.form argument
		---------------------------------------------------------*/
		/* (1) Helpers */
		let is_object = typeof _request.form === 'object';
		let is_formdata = is_object && _request.form instanceof FormData;

		/* (2) Create default value for _request.form */
		var form_data = new FormData();

		/* (3) If already FormData object -> store as it is */
		if( is_object && is_formdata )
			form_data = _request.form;


		/* (4) If just a raw object -> convert to FormData */
		if( is_object && !is_formdata )
			Object.keys(_request.form).map( (k) => form_data.append(k, _request.form[k]) );


		/* (4) Open connection
		---------------------------------------------------------*/
		/* (1) Build full request URI */
		let request_uri = this.resource.split(/\/$/).concat(http_uri.split(/^\//)).filter((v) => v.trim().length).join('/');

		/* (2) Build protocol (http, https) and http_token */
		let protocol = http_token != null ? `${this.proto}${http_token}@` : this.proto;

		/* (3) Open connection */
		this.xhr.open(http_method, `${protocol}${request_uri}`, true);

		/* (4) Send request */
		this.xhr.send(form_data);

		return true;

	}


}