import { Logger } from '../Log/Logger.js';

/**
 * Request manager class.
 *
 * Used for pooling requests.
 *
 * @copyright  Dennis Eichhorn
 * @license    OMS License 1.0
 * @version    1.0.0
 * @since      1.0.0
 */
export class EventManager {
    /**
     * @constructor
     *
     * @since 1.0.0
     */
    constructor ()
    {
        this.logger    = Logger.getInstance();
        this.groups    = {};
        this.callbacks = {};
    };

    /**
     * Add event group (element)
     *
     * Adding the same event overwrites the existing one as "waiting"
     *
     * @param {string|int} group Group id
     * @param {string|int} id    Event id
     *
     * @return {void}
     *
     * @since 1.0.0
     */
    addGroup (group, id)
    {
        if (typeof this.groups[group] === 'undefined') {
            this.groups[group] = {};
        }

        this.groups[group][id] = false;
    };

    /**
     * Resets the group status
     *
     * @param {string|int} group Group id
     *
     * @return {void}
     *
     * @since 1.0.0
     */
    reset (group)
    {
        for (let id in this.groups[group]) {
            if (this.groups[group].hasOwnProperty(id)) {
                this.groups[group][id] = false;
            }
        }
    };

    /**
     * Does group have outstanding events
     *
     * @param {string|int} group Group id
     *
     * @return {boolean}
     *
     * @since 1.0.0
     */
    hasOutstanding (group)
    {
        if (typeof this.groups[group] === 'undefined') {
            return false;
        }

        for (let id in this.groups[group]) {
            if (!this.groups[group].hasOwnProperty(id) || !this.groups[group][id]) {
                return true;
            }
        }

        return false;
    };

    /**
     * Trigger event finished
     *
     * Executes the callback specified for this group if all events are finished
     *
     * @param {string|int} group  Group id
     * @param {string|int} [id]   Event id
     * @param {Object}     [data] Data for event
     *
     * @return {boolean}
     *
     * @since 1.0.0
     */
    trigger (group, id = '', data = null)
    {
        if (this.callbacks.hasOwnProperty(group)) {
            return this.triggerSingleEvent(group, id, data);
        }

        const allGroups = Object.keys(this.callbacks),
            regex = new RegExp(group),
            length = allGroups.length;

        let result = false;

        for (let i = 0; i < length; ++i) {
            if (regex.test(allGroups[i])) {
                result = result && this.triggerSingleEvent(allGroups[i], id, data);
            }
        }

        return result;
    };

    /**
     * Trigger event finished
     *
     * Executes the callback specified for this group if all events are finished
     *
     * @param {string|int} group  Group id
     * @param {string|int} [id]   Event id
     * @param {Object}     [data] Data for event
     *
     * @return {boolean}
     *
     * @since 1.0.0
     */
    triggerSingleEvent (group, id = '', data = null)
    {
        if (Math.abs(Date.now() - this.callbacks[group].lastRun) < 500) {
            return false;
        }

        if (typeof this.groups[group] !== 'undefined') {
            this.groups[group][id] = true;
        }

        if (!this.hasOutstanding(group)) {
            const length                  = this.callbacks[group].callbacks.length;
            this.callbacks[group].lastRun = Date.now();

            for (let i = 0; i < length; ++i) {
                this.callbacks[group].callbacks[i](data);
            }

            if (this.callbacks[group].remove) {
                this.detach(group);
            } else if (this.callbacks[group].reset) {
                this.reset(group);
            }

            return true;
        }

        return false;
    };

    /**
     * Detach event
     *
     * @param {string|int} group Group id
     *
     * @return {void}
     *
     * @since 1.0.0
     */
    detach (group)
    {
        return this.detachCallback(group) | this.detachGroup(group);
    };

    /**
     * Detach callback
     *
     * @param {string|int} group Group id
     *
     * @return {void}
     *
     * @since 1.0.0
     */
    detachCallback(group)
    {
        if (this.callbacks.hasOwnProperty(group)) {
            delete this.callbacks[group];

            return true;
        }

        return false;
    };

    /**
     * Detach group
     *
     * @param {string|int} group Group id
     *
     * @return {void}
     *
     * @since 1.0.0
     */
    detachGroup(group)
    {
        if (this.groups.hasOwnProperty(group)) {
            delete this.groups[group];

            return true;
        }

        return false;
    };

    /**
     * Attach callback to event group
     *
     * @param {string|int} group    Group id
     * @param {function}   callback Callback or route for the event
     * @param {boolean}    [remove] Should be removed after execution
     * @param {boolean}    [reset]  Reset after triggering
     *
     * @return {boolean}
     *
     * @since 1.0.0
     */
    attach (group, callback, remove = false, reset = false)
    {
        if (!this.callbacks.hasOwnProperty(group)) {
            this.callbacks[group] = {remove: remove, reset: reset, callbacks: [], lastRun: 0};
        }

        this.callbacks[group].callbacks.push(callback);

        return true;
    };

    /**
     * Count events
     *
     * @return {int}
     *
     * @since 1.0.0
     */
    count ()
    {
        return Object.keys(this.callbacks).length;
    };
};