/**
 * Handle requests to the server
 */

import Request from 'superagent';
import { app } from '../core/app';

/**
 * Custom error handler, defined by the application
 */
var customErrorHandler;

export function onRequestError(handler) {
    customErrorHandler = handler;
}

class ServerRequest {

    /**
     * Create a request GET to the given URL
     * @param  {String} url The remote address
     * @param  {function} callback called when server answers
     * @return {Request}    Request object
     */
    get(url) {
        return this.promiseRequest(Request.get(this.checkContext(url)));
    }

    /**
     * Create a request POST to the given URL
     * @param  {String} url The remote address
     * @return {Request}    Request object
     */
    post(url, data) {
        return this.promiseRequest(Request.post(this.checkContext(url)).send(data ? data : {}));
    }

    /**
     * Send a delete post
     * @param  {String} url [description]
     * @return {Request}     [description]
     */
    delete(url) {
        return this.promiseRequest(Request.del(this.checkContext(url)));
    }

    checkContext(path) {
        return window.app.contextPath ? window.app.contextPath + path : path;
    }

    promiseRequest(request) {
        return new Promise((resolve, reject) => {
            request.use(auth).use(errorHandler).end((err, res) => {
                if (err) {
                    reject(err);
                } else {
                    resolve(res.body);
                }
            });
        });
    }
}

var server = new ServerRequest();

export { server };

function auth(req) {
    // authentication token is available ?
    var authToken = app.getAuthToken();
    if (authToken) {
        req.set('X-Auth-Token', authToken);
    }

    return req;
}

function errorHandler(req) {
    var cb = req.callback;

    req.callback = function (err, res) {
        if (err && !err.status) {
            err.message = 'Connection error';
        }

        cb.call(req, err, res);

        if (err && customErrorHandler) {
            customErrorHandler(err);
        }
    };

    return req;
}