define([
    'jquery',
    'app/init',
    'app/util',
    'app/promises/promise.deferred',
    'app/promises/promise.queue'
], ($, Init, Util, DeferredPromise, PromiseQueue) => {
    'use strict';

    /**
     * abstract BaseModel class
     * -> custom/plugin modules must extend from it
     * @type {BaseModule}
     */
    let BaseModule = class BaseModule {

        constructor(config= {}){
            if(new.target === BaseModule){
                throw new TypeError('Cannot construct ' + this.constructor.name + ' instances directly');
            }

            // check for abstract methods to be implemented in child
            if(this.render === undefined){
                throw new TypeError('Abstract method render() missing in ' + new.target.name + ' class');
            }

            this._config = Object.assign({}, BaseModule.defaultConfig, config);
            this._updateQueue = new PromiseQueue();
        }

        /**
         * get current module configuration
         * @returns {*}
         */
        get config(){
            return this._config;
        }

        /**
         * get root node for this module
         * -> parent container for custom body HTML
         * @returns {HTMLElement}
         */
        get moduleElement(){
            if(!this._moduleEl){
                // init new moduleElement
                this._moduleEl = Object.assign(document.createElement('div'), {
                    className: `${BaseModule.className} ${this._config.className}`,
                    style: {
                        opacity: '0'
                    }
                }).setData('module', this);

                this._moduleEl.dataset.position = this._config.position;
                this._moduleEl.dataset.module = this.constructor.name;

                // module header
                this._moduleEl.append(this.newHeaderElement());
            }
            return this._moduleEl;
        }

        /**
         * module header element
         * -> dragHandler + headline
         * @param text
         * @returns {HTMLDivElement}
         */
        newHeaderElement(text){
            let headEl = this.newHeadElement();
            headEl.append(
                this.newHandlerElement(),
                this.newHeadlineElement(text || this._config.headline)
            );
            return headEl;
        }

        /**
         * module head element
         * @returns {HTMLDivElement}
         */
        newHeadElement(){
            return Object.assign(document.createElement('div'), {
                className: this._config.headClassName
            });
        }

        /**
         * module dragHandler element
         * @returns {HTMLHeadingElement}
         */
        newHandlerElement(){
            return Object.assign(document.createElement('h5'), {
                className: this._config.handlerClassName
            });
        }

        /**
         * module headline element
         * @param text
         * @returns {HTMLHeadingElement}
         */
        newHeadlineElement(text){
            return Object.assign(document.createElement('h5'), {
                textContent: typeof text === 'string' ? text : ''
            });
        }

        /**
         * module toolbar element (wrapper)
         * @returns {HTMLHeadingElement}
         */
        newHeadlineToolbarElement(){
            return Object.assign(document.createElement('h5'), {
                className: 'pull-right'
            });
        }

        /**
         * icon element
         * @param cls
         * @returns {HTMLElement}
         */
        newIconElement(cls = []){
            return Object.assign(document.createElement('i'), {
                className: ['fas', ...cls].join(' ')
            });
        }

        /**
         * HTTP request handler for internal (Pathfinder) ajax calls
         * @param args
         * @returns {Promise}
         */
        request(...args){
            return BaseModule.Util.request(...args);
        }

        /**
         * scoped instance for LocalStore for current module
         * @returns {LocalStore}
         */
        getLocalStore(){
            if(!this._localStore){
                // make accessible -> scope Store keys!
                this._localStore = BaseModule.Util.getLocalStore('module');
                this._localStore.scope = this.constructor.name;
            }
            return this._localStore;
        }

        /**
         * visual notification handler (UI popover)
         * -> can be used for info/error on-screen messages
         * @param args
         */
        showNotify(...args){
            return BaseModule.Util.showNotify(...args);
        }

        /**
         * responsible for dispatching all incoming method calls
         * @param handler
         * @param data
         * @returns {*}
         */
        handle(handler, ...data){
            try{
                if(BaseModule.handler.includes(handler)){
                    // .. run module handler
                    let returnData = this[handler].apply(this, data);
                    if(returnData instanceof Promise){
                        // log returned Promise from handler call resolved
                        returnData.then(() => { this.logHandler(handler, 0);});
                    }
                    // log handler call
                    this.logHandler(handler);

                    return returnData;
                }else{
                    console.error('Error in module %o. Invalid handler %o', this.constructor.name, handler);
                }
            }catch(e){
                console.error('Error in module %o in handler %s() %o', this.constructor.name, handler, e);
            }
        }

        /**
         * log handler calls for this instance
         * -> can be helpful for debugging
         * @param handler
         * @param increment
         */
        logHandler(handler, increment = 1){
            if(increment){
                if(!this._config.logHandler){
                    this._config.logHandler = {};
                }

                this._config.logHandler[handler] = (this._config.logHandler[handler] || 0) + increment;
            }
        }

        /**
         * init module
         */
        init(){}

        /**
         * update module
         * @param data
         * @returns {Promise}
         */
        update(data){
            return this._updateQueue.enqueue(() => Promise.resolve(data), 'end', 'upd');
        }

        beforeHide(){}

        beforeDestroy(){
            $(this.moduleElement).destroyPopover(true);

            // destroy DataTable instances
            for(let table of $(this.moduleElement).find('table.dataTable')){
                $(table).DataTable().destroy(true);
            }
        }

        /**
         * events from 'Sortable' lib
         * @see https://github.com/SortableJS/Sortable
         * @param name
         * @param e
         */
        onSortableEvent(name, e){
            if(name === 'onUnchoose' && this._sortableChoosePromise){
                this._sortableChoosePromise.resolve();
            }

            if(name === 'onChoose' && !this._sortableChoosePromise){
                this._sortableChoosePromise = BaseModule.newDeferredPromise();
                this._updateQueue.enqueue(() => this._sortableChoosePromise.then(() => {
                    this._sortableChoosePromise = null;
                }), 'start');
            }
        }

        static newDeferredPromise(){
            return new DeferredPromise();
        }
    };

    BaseModule.isPlugin = true;                             // module is defined as 'plugin'
    BaseModule.scope = 'system';                            // static module scope controls how module gets updated and what type of data is injected
    BaseModule.sortArea = 'a';                              // static default sortable area
    BaseModule.position = 0;                                // static default sort/order position within sortable area
    BaseModule.label = '???';                               // static module label (e.g. description)
    BaseModule.className = 'pf-module';                     // static CSS class name
    BaseModule.fullDataUpdate = false;                      // static module requires additional data (e.g. system description,...)
    BaseModule.Util = Util;                                 // static access to Pathfinders Util object

    BaseModule.handler = [
        'render',
        'init',
        'update',
        'beforeHide',
        'beforeDestroy',
        'onSortableEvent'
    ];

    BaseModule.defaultConfig = {
        position: 1,
        className: 'pf-base-module',                        // class for module
        headClassName: 'pf-module-head',                    // class for module header
        handlerClassName: 'pf-sortable-handle',             // class for "drag" handler
        sortTargetAreas: ['a', 'b', 'c'],                   // sortable areas where module can be dragged into
        headline: 'Base headline',                          // module headline
        bodyClassName: 'pf-module-body',                    // class for module body [optional: can be used]

        moduleHeadlineIconClass: 'pf-module-icon-button'    // class for toolbar icons in the head
    };

    return BaseModule;
});