/**
 * UserSession class
 *
 *  Copyright (C) 2017 LoVullo Associates, Inc.
 *
 *  This file is part of the Liza Data Collection Framework.
 *
 *  liza is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as
 *  published by the Free Software Foundation, either version 3 of the
 *  License, or (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @todo this is very tightly coupled with LoVullo's system
 */

// php compatibility
var php   = require( 'php' ),
    Class = require( 'easejs' ).Class;


/**
 * Stores/retrieves user PHP session data from memcached
 */
module.exports = Class.extend( require( 'events' ).EventEmitter,
{
    /**
     * Session id
     * @type {string}
     */
    'private _id': '',

    /**
     * Memcache client
     * @tyep {memcache.Client}
     */
    'private _memcache': null,

    /**
     * Session data
     * @type {object}
     */
    'private _data': {},


    /**
     * Initializes a session from an existing PHP session
     *
     * @param String          id       session id
     * @param memcache.Client memcache memcache client used to access session
     *
     * @return undefined
     */
    __construct: function( id, memcache )
    {
        this._id       = id || '';
        this._memcache = memcache;
        this._data     = {};

        // parse the session data
        var _self = this;
        this._getSessionData( function( data )
        {
            _self._data = ( data === null ) ? {} : data;

            // session data is now available
            _self.emit( 'ready', data );
        } );
    },


    /**
     * Returns the session data
     *
     * @return Object session data
     */
    getData: function()
    {
        return this._data;
    },


    /**
     * Returns whether the user is currently logged in
     *
     * This is determined simply by whether the agent id is available.
     *
     * @return Boolean
     */
    isLoggedIn: function()
    {
        return ( this._data.agentID !== undefined )
            ? true
            : false;
    },


    /**
     * Gets the agent id, if available
     *
     * @return Integer|undefined agent id or undefined if unavailable
     */
    agentId: function()
    {
        return this._data.agentID || undefined;
    },


    /**
     * Gets the agent name, if available
     *
     * @return String|undefined agent name or undefined if unavailable
     */
    agentName: function()
    {
        return this._data.agentNAME || undefined;
    },


    /**
     * Whether the user is logged in as an internal user rather than a broker
     *
     * @return {boolean} true if internal user, otherwise false
     */
    isInternal: function()
    {
        return ( this.agentId() === '900000' )
            ? true
            : false;
    },


    'public setAgentId': function( id )
    {
        this._data.agentID = id;
        return this;
    },


    /**
     * Gets the broker entity id, if available
     *
     * @return Integer|undefined agent entity id or undefined if unavailable
     */
    agentEntityId: function()
    {
        return this._data.broker_entity_id || undefined;
    },


    /**
     * Set session redirect for Symfony
     *
     * This will perform a redirect after login.
     *
     * @param {string}      url      url to redirect to
     * @param {function()=} callback optional continuation
     *
     * @return {UserSession} self
     */
    'public setRedirect': function( url, callback )
    {
        this._appendSessionData(
            { s2_legacy_redirect: url },
            callback
        );

        return this;
    },


    'public setReturnQuoteNumber': function( number, callback )
    {
        this._appendSessionData(
            { lvqs_return_qn: +number },
            callback
        );

        return this;
    },


    'public getReturnQuoteNumber': function()
    {
        return this._data.lvqs_return_qn || 0;
    },


    'public clearReturnQuoteNumber': function( callback )
    {
        this._data.lvqs_return_qn = 0;
        this.setReturnQuoteNumber( 0, callback );

        return this;
    },


    /**
     * Appends data to a session
     *
     * XXX: Note that this is not a reliable means of modifying session
     * data---it servese its purpose for appending string data to a session, but
     * should not be used for anything else (such as modifying existing session
     * values).
     *
     * @param {Object}      data     key-value string data
     * @param {function()=} callback optional continuation
     *
     * @return {undefined}
     */
    'private _appendSessionData': function( data, callback )
    {
        var _self = this;

        this._memcache.get( this._id, function( orig )
        {
            if ( orig === null )
            {
                // well we gave it a good shot! (right now we don't indicate
                // error, because there's not much we can do about that...maybe
                // in the future we'll want to be notified of errors)...we just
                // don't want to potentially clear out all the session data
                callback && callback();
                return;
            }

            var newdata = orig;

            for ( var key in data )
            {
                newdata += key + '|' + php.serialize( data[ key ] );
            }

            _self._memcache.set( _self._id, newdata, function()
            {
                callback && callback();
            } );
        } );
    },


    /**
     * Parses PHP session data from memcache and returns an object with the data
     *
     * @param {function(data)} callback function to call with parsed data
     *
     * @return Object parsed session data
     */
    'private _getSessionData': function( callback )
    {
        this._memcache.get( this._id, function( data )
        {
            if ( data === null )
            {
                // failure
                callback( null );
                return;
            }

            var session_data = {};

            if ( data )
            {
                // Due to limitations of Javascript's regex engine, we need to do
                // this in a series of steps. First, split the string to find the
                // keys and their serialized values.
                var splits = data.split( /(\w+?)\|/ ),
                    len    = splits.length;

                // associate the keys with their values
                for ( var i = 1; i < len; i++ )
                {
                    var key = splits[ i ],
                        val = splits[ ++i ];

                    // the values are serialized PHP data; unserialize them
                    val = php.unserialize( val );

                    // add to the session data
                    session_data[ key ] = val;
                }
            }

            // return the parsed session data
            callback( session_data );
        } );
    },
} );