/**
 * Represents the most basic and simple form of a Component.
 * It is mainly a collection of wrapper methods 
 * around the HTMLElement methods to make them chainable.
 * It serves as base for further functionallity extensions.
 * @extends StyleAndScriptStoringComponent
 * @inheritdoc
 * 
 */
class Component extends StyleAndScriptStoringComponent {
    /**
     * @type {boolean}
     */
    _isCompel;
    /**
     * @type {Array<any>}
     */
    _toRegister;
    /**
     * @type {boolean} 
     */
    _isContextMenu;


    /**
     * Initializes the component
     * @param {HTMLElement} element the base element
     * @param {Map<string,string>} attr Specific already known attributes
     */
    constructor(element, attr = {}) {
        super(element, attr);
        this._isCompel = false;
        this._isContextMenu = false;

        this._modifier = new Modifier()
            .margin(0);
        this._modifier._modifications['display'] = "flex";
        this._modifier._modifications["box-sizing"] = "border-box";

        this._toRegister = [];
    }

    /**
     * Adds a class to classList via HTMLElement.classList.add() method.
     * Further collects rules in a property until generate is called.
     * 
     * @CAUGHTION implementation is not safe to use, ignoring extStore is recommended;
     * 
     * @todo difference between stylings and classes, extStore logic in combination with the Page.register... logic
     * 
     * @override
     * 
     * @param {string} styleClass (without the '.' in the front)
     * @param {string|Modifier|map<string,string>} styling
     * @param {ExtStorage|ExtStoreType|ExtStorePosition|OverwriteBehaviour|EXPosConfer|ESOverwriteConfer} extStore 
     * if a unique definition is desired, all constants or configurator objects are allowed - they will be processed accordingly 
     * @returns {Component} this component object
     */
    addStyleClass(styleClass, styling = null, extStore = null) {
        if (!extStore) {
            extStore = this._styleClassesExtStore;
        } else if (extStore.isMissing()) {
            extStore = extStore.fillBy(this._styleClassesExtStore);
        }

        if (styling) {
            if (styling instanceof Modifier) {
                styling = styling._modifications;
            }

            Page.registerStyling('.' + styleClass, styling);
        }

        this._element.classList.add(styleClass);

        return this;
    }

    /**
     * 
     * @param {boolean} vertical Defines if the Component should overflow vertically (default: true)
     * @param {boolean} horizontal Defines if the Component should overflow horizontally (default: false)
     * @returns {Component}
     */
    overflow(vertical = true, horizontal = false ) {
        if (vertical || horizontal) {
            this._modifier.join(
                new Modifier()
                    .removeStyleRule("flex")
                    .setStyleRule("overflow", "hidden auto")
            );
            this.subscribeOnGenerate(CommonCompelGroups.OVERFLOWING);
        }

        if (vertical) {
            this._modifier._modifications["overflow-y"] = "hidden auto";
        }
        if (horizontal) {
            this._modifier._modifications["overflow-x"] = "hidden auto";
        }
        return this;
    }


    /**
     * 
     * @param {boolean} untilFound
     * @returns {Component}
     */
    hidden(untilFound = false) {
        let styleClass = "compel-mech-hidden";
        let hid = "hidden";
        Page.registerStyling("." + styleClass, { [hid]: hid });
        this.addStyleClass(styleClass);

        this._modifier.removeStyleRule("display");
        this.setAttribute(
            hid,
            (untilFound ? "until-found" : hid)
        );

        this.subscribeOnGenerate(CommonCompelGroups.HIDDEN_ON_START);

        return this;
    }

    /**
     * Subscribes element under higher_compel group
     * sets corr. variable true
     * setAttribute("data-compel-isHCompel", "true")
     * 
     * @returns {Component}
     */
    isHigherComponent() {
        this.subscribeOnGenerate(CommonCompelGroups.HIGHER_COMPEL);
        this._isCompel = true;
        this.addStyleClass("compel-higher");
        return this.setAttribute("data-compel-isHCompel", "true")
    }

    /**
     * 
     * @returns {string}
     */
    getHigherCompelSelector() {
        return this._element
            .closest('[data-compel-isHCompel="true"].compel-higher')
            .getAttribute("data-autocompel");
    }

    /**
     * Collects the given List in the _toRegister attribute.
     * When generate() is called, 
     * the created Element will be registered (added) in every list 
     * within the list. 
     * @param {*|string|Array<*>} listName 
     */
    subscribeOnGenerate(listName) {
        this._toRegister.push(listName);
        return this;
    }

    /**
     * 
     * @returns {Component}
     */
    registerAsContextMenu() {
        this.subscribeOnGenerate(CommonCompelGroups.IS_CONTEXT_MENU);
        this._isContextMenu = true;

        return this.addStyleClass('contextmenu')
            .hidden();
    }

    /**
     * @todo Positioning of the contextmenu element
     * @todo extract into an extra function(allity) provider
     * 
     * @param {Component} component 
     * @param {Sides|Function<HTMLElement|Event> => Sides} getRefPos 
     * @param {ExtStorage} [extStore=null] 
     * @returns {Component}
     */
    contextMenu(component, getRefPos = null, extStore = null) {
        if (!component._isContextMenu) {
            component.registerAsContextMenu();
        }
        if (!getRefPos) {
            getRefPos = function (cmEvent) {
                return new Sides()
                    .left(cmEvent.pageX)
                    .top(cmEvent.pageY);
            }
        }

        this.subscribeOnGenerate(CommonCompelGroups.HAS_CONTEXT_MENU);

        let identifier = component._compName;

        this.addEventListener(
            "contextmenu",
            DefaultContextMenu.openContextMenuAction(identifier, getRefPos)
        );

        return this.childContext(component);
    }

    /**
     * 
     * @param {DragAndDropImplementation} dadImpl 
     * @returns {Component}
     */
    draggable(dadImpl = new DragAndDropImplementation()) {
        this.subscribeOnGenerate(CommonCompelGroups.DRAGGABLE);
        this.subscribeOnGenerate(CommonCompelGroups.HAS_DRAG_EVENT);

        let addedClass = "comp-el-mech-draggable";
        let selector = this._element.getAttribute("data-autocompel");

        selector = `.${addedClass}[data-autocompel="${selector}"]`;

        return this.addStyleClass(addedClass)
            .setAttribute("draggable", "true")
            .setAttribute("dropEffect", "none")
            .addEventListener(
                CommonEvents.DRAG_START,
                dadImpl.dragStartAction("text/plain", selector)
            );
    }

    /**
     * 
     * @param {EventDrag} dragEvent 
     * @param {Function} action 
     */
    onDrag(dragEvent, action = (e) => { e.preventDefault(); }) {
        this.subscribeOnGenerate(CommonCompelGroups.HAS_DRAG_EVENT);
        let selector = `comp-el-mech-drag${dragEvent}`;

        return this.addEventListener(
            'drag' + dragEvent,
            action
        );
    }

    /**
     * 
     * @param {DragAndDropImplementation} dadImpl 
     * @returns {Component}
     */
    dropTarget(dadImpl = new DragAndDropImplementation()) {
        this.subscribeOnGenerate(CommonCompelGroups.DROP_TARGET);
        let specialClass = "comp-el-mech-droptarget";

        this.addStyleClass(specialClass)
            .onDrag(EventDrag.OVER);

        let selector = `.${specialClass}[data-autocompel="${this._compName}"]`

        this._element.addEventListener(
            "drop",
            dadImpl.dropEventAction("text/plain", selector)
        );

        return this;
    }


    /**
     * An echo of  Scope-Functions from kotlin for convenience
     * 
     * Executes a given function injects this component into the function.
     * @param {Function} func 
     * @returns {Component}
     */
    apply(func) {
        func(this);
        return this;
    }


    /**
     * An echo of  Scope-Functions from kotlin for convenience
     * 
     * Executes a given function injects the htmlelement of this component into the function.
     * @param {Function} func 
     * @returns {Component}
     */
    applyToEl(func) {
        func(this._element)
        return this;
    }


    /**
     * Ends chain. 
     * Applies all modifications on the element.
     * Processes all stored additions.
     * Returns the constructed HTMLElement of this Component.
     *
     * @param {CompelGenerator} generator 
     * @param {Modifier | undefined} [modifier=null] 
     * @param {ExtStorage | undefined} [styleStore=null] 
     * @param {ExtStorage | undefined} [functionStore=null] 
     * @param {ExtStorage} 
     * @returns {WebTrinity} the constructed HTMLElement of this Component.
     */
    generate(generator = singlepage, styleStore = null, functionStore = null) {
        /**
         * In the case that this component is a chainChild created one.
         * The generation chain needs to be setup in the proper order
         * so that the resulting element tree equals the expected/desired result. 
         * 
         * Therefore if this is a chainChild, 
         * it will be added to the parent via the regular childContext
         * and the generation of the parent will be returned. 
         * 
         * The parent will generate this component on its generate().
         */
        if (this._parentComponent) {
            let parent = this._parentComponent;
            this._parentComponent = null;
            return parent.childContext(this)
                .generate(generator, styleStore, functionStore);
        }

        return generator.generate(this, styleStore, functionStore);
    }
}