import _ from 'lodash';
import {IDENTITY_KEY} from 'appConfig';

/**
 * Session Service stores current user data
 */
angular.module('superdesk.core.auth.session').service('session', [
    '$q',
    '$rootScope',
    'storage',
    'SESSION_EVENTS',
    function($q, $rootScope, storage, SESSION_EVENTS) {
        var TOKEN_KEY = 'sess:token';
        var TOKEN_HREF = 'sess:href';
        var SESSION_ID = 'sess:id';
        var IDENTITY_BLACKLIST = [
            'session_preferences',
            'user_preferences',
            'allowed_actions',
            'workspace',
        ];
        var defer;

        this.token = null;
        this.identity = null;
        this.sessionId = null;

        /**
     * Get identity when available
     *
     * @returns {object} promise
     */
        this.getIdentity = function() {
            if (this.identity && this.token) {
                return $q.when(this.identity);
            }

            defer = defer ? defer : $q.defer();
            return defer.promise;
        };

        /**
     * Update identity
     *
     * @param {object} updates
     * @returns {object} identity
     */
        this.updateIdentity = function(updates) {
            var identity = this.identity || {};

            _.extend(identity, updates);
            this.identity = _.omit(identity, IDENTITY_BLACKLIST);
            storage.setItem(IDENTITY_KEY, this.identity);
            return this.identity;
        };

        /**
     * Start a new session
     *
     * @param {object} session
     * @param {object} identity
     */
        this.start = function(session, identity) {
            this.token = session.token;
            this.sessionId = session._id;
            setToken(session.token);
            setSessionId(session._id);
            setSessionHref(session._links && session._links.self.href);
            this.identity = null;
            resolveIdentity(this.updateIdentity(identity));
            $rootScope.$broadcast(SESSION_EVENTS.LOGIN);
        };

        function resolveIdentity(identity) {
            if (defer) {
                defer.resolve(identity);
                defer = null;
            }
        }

        /**
     * Set current session expired
     */
        this.expire = function() {
            this.token = null;
            this.sessionId = null;
            setToken(null);
            setSessionId(null);
            $rootScope.$broadcast(SESSION_EVENTS.LOGOUT);
        };

        /**
     * Clear session info
     */
        this.clear = function() {
            this.expire();
            this.identity = null;
            setSessionHref(null);
            setSessionId(null);
            storage.clear();
        };

        /**
     * Return session url for delete
     *
     * @returns {string}
     */
        this.getSessionHref = function() {
            return localStorage.getItem(TOKEN_HREF);
        };

        /**
     * Setup test user with given id.
     *
     * @param {string} _id
     */
        this.testUser = function(_id) {
            this.token = 1;
            this.identity = {_id: _id};
            this.sessionId = 's' + _id;
        };

        $rootScope.$watch(getToken, angular.bind(this, function(token) {
            this.token = token;
            this.identity = storage.getItem(IDENTITY_KEY);
            this.sessionId = localStorage.getItem(SESSION_ID);
            if (this.identity && this.token) {
                resolveIdentity(this.identity);
            }
        }));

        /**
     * Save token into local storage
     *
     * @param {string} token
     */
        function setToken(token) {
            if (token) {
                localStorage.setItem(TOKEN_KEY, token);
            } else {
                localStorage.removeItem(TOKEN_KEY);
            }
        }

        /**
     * Save session id into local storage
     *
     * @param {string} sessionId
     */
        function setSessionId(sessionId) {
            if (sessionId) {
                localStorage.setItem(SESSION_ID, sessionId);
            } else {
                localStorage.removeItem(SESSION_ID);
            }
        }

        function setSessionHref(href) {
            if (href) {
                localStorage.setItem(TOKEN_HREF, href);
            } else {
                localStorage.removeItem(TOKEN_HREF);
            }
        }

        /**
     * Get token from local storage
     *
     * it's used via watch so it skips json serialization withing storage service
     *
     * @returns string
     */
        function getToken() {
            return localStorage.getItem(TOKEN_KEY) || null;
        }
    }]);