"use strict";
/**
 * This is an internal module. See {@link MatrixInMemoryStore} for the public class.
 * @module store/memory
 */
 var utils = require("../utils");

/**
 * Construct a new in-memory data store for the Matrix Client.
 * @constructor
 * @param {Object=} opts Config options
 * @param {LocalStorage} opts.localStorage The local storage instance to persist
 * some forms of data such as tokens. Rooms will NOT be stored. See
 * {@link WebStorageStore} to persist rooms.
 */
module.exports.MatrixInMemoryStore = function MatrixInMemoryStore(opts) {
    opts = opts || {};
    this.rooms = {
        // roomId: Room
    };
    this.users = {
        // userId: User
    };
    this.syncToken = null;
    this.filters = {
        // userId: {
        //    filterId: Filter
        // }
    };
    this.localStorage = opts.localStorage;
};

module.exports.MatrixInMemoryStore.prototype = {

    /**
     * Retrieve the token to stream from.
     * @return {string} The token or null.
     */
    getSyncToken: function() {
        return this.syncToken;
    },

    /**
     * Set the token to stream from.
     * @param {string} token The token to stream from.
     */
    setSyncToken: function(token) {
        this.syncToken = token;
    },

    /**
     * Store the given room.
     * @param {Room} room The room to be stored. All properties must be stored.
     */
    storeRoom: function(room) {
        this.rooms[room.roomId] = room;
    },

    /**
     * Retrieve a room by its' room ID.
     * @param {string} roomId The room ID.
     * @return {Room} The room or null.
     */
    getRoom: function(roomId) {
        return this.rooms[roomId] || null;
    },

    /**
     * Retrieve all known rooms.
     * @return {Room[]} A list of rooms, which may be empty.
     */
    getRooms: function() {
        return utils.values(this.rooms);
    },

    /**
     * Retrieve a summary of all the rooms.
     * @return {RoomSummary[]} A summary of each room.
     */
    getRoomSummaries: function() {
        return utils.map(utils.values(this.rooms), function(room) {
            return room.summary;
        });
    },

    /**
     * Store a User.
     * @param {User} user The user to store.
     */
    storeUser: function(user) {
        this.users[user.userId] = user;
    },

    /**
     * Retrieve a User by its' user ID.
     * @param {string} userId The user ID.
     * @return {User} The user or null.
     */
    getUser: function(userId) {
        return this.users[userId] || null;
    },

    /**
     * Retrieve scrollback for this room.
     * @param {Room} room The matrix room
     * @param {integer} limit The max number of old events to retrieve.
     * @return {Array<Object>} An array of objects which will be at most 'limit'
     * length and at least 0. The objects are the raw event JSON.
     */
    scrollback: function(room, limit) {
        return [];
    },

    /**
     * Store events for a room. The events have already been added to the timeline
     * @param {Room} room The room to store events for.
     * @param {Array<MatrixEvent>} events The events to store.
     * @param {string} token The token associated with these events.
     * @param {boolean} toStart True if these are paginated results.
     */
    storeEvents: function(room, events, token, toStart) {
        // no-op because they've already been added to the room instance.
    },

    /**
     * Store a filter.
     * @param {Filter} filter
     */
    storeFilter: function(filter) {
        if (!filter) { return; }
        if (!this.filters[filter.userId]) {
            this.filters[filter.userId] = {};
        }
        this.filters[filter.userId][filter.filterId] = filter;
    },

    /**
     * Retrieve a filter.
     * @param {string} userId
     * @param {string} filterId
     * @return {?Filter} A filter or null.
     */
    getFilter: function(userId, filterId) {
        if (!this.filters[userId] || !this.filters[userId][filterId]) {
            return null;
        }
        return this.filters[userId][filterId];
    },

    /**
     * Retrieve a filter ID with the given name.
     * @param {string} filterName The filter name.
     * @return {?string} The filter ID or null.
     */
    getFilterIdByName: function(filterName) {
        if (!this.localStorage) {
            return null;
        }
        try {
            return this.localStorage.getItem("mxjssdk_memory_filter_" + filterName);
        }
        catch(e) {}
        return null;
    },

    /**
     * Set a filter name to ID mapping.
     * @param {string} filterName
     * @param {string} filterId
     */
    setFilterIdByName: function(filterName, filterId) {
        if (!this.localStorage) {
            return;
        }
        try {
            this.localStorage.setItem("mxjssdk_memory_filter_" + filterName, filterId);
        }
        catch (e) {}
    }

    // TODO
    //setMaxHistoryPerRoom: function(maxHistory) {},

    // TODO
    //reapOldMessages: function() {},
};