define([
    "dojo/Deferred",
    "dojo/Evented",
    "dojo/_base/declare",
    "dojo/_base/json",
    "dojo/_base/lang",
    "dojo/request"
], function(Deferred, Evented, declare, json, lang, request) {
    var Session = declare([Evented], {
        info: null,
        get: function() {
            return this.info;
        },
        restore: function() {
            return request('/api/login', {
                method: "GET",
                handleAs: "json"
            }).then(lang.hitch(this,function(res) {
                return this._set(res);
            }), lang.hitch(this,function() {
                return new Deferred().reject(this._set(null));
            }));
        },
        login: function(username, password) {
            return request('/api/login', {
                method: "POST",
                handleAs: "json",
                data: {
                    username: username,
                    password: password
                }
            }).then(lang.hitch(this,function(res) {
                return this._set(res);
            }), lang.hitch(this,function() {
                return new Deferred().reject(this._set(null));
            }));
        },
        logout: function() {
            return request('/api/logout', {
                method: "POST",
                handleAs: "json"
            }).then(lang.hitch(this,function(res) {
                return this._set(null);
            }), lang.hitch(this,function() {
                return this._set(null);
            }));
        },
        _set: function(newInfo) {
            if (newInfo !== this.info) {
                this.info = newInfo;
                this.emit('change', this.info);
            }
            return this.info;
        }
    });

    return new Session();
});