import { argumentNotNull } from "@implab/core-amd/safe";
import { RenditionBase } from "./RenditionBase";
import { DojoNodePosition, isElementNode, isInPage, isWidget, placeAt } from "./traits";
import registry = require("dijit/registry");
import ContentPane = require("dijit/layout/ContentPane");
import { getItemDom, refHook } from "./render";

// tslint:disable-next-line: class-name
export interface _Widget {
    domNode: Node;

    containerNode?: Node;

    placeAt?(refNode: string | Node, position?: DojoNodePosition): void;
    startup?(): void;

    addChild?(widget: unknown, index?: number): void;
}

export type _WidgetCtor = new (attrs: object, srcNode?: string | Node) => _Widget;

export class WidgetRendition extends RenditionBase<Node> {
    readonly widgetClass: _WidgetCtor;

    _instance: _Widget | undefined;

    constructor(widgetClass: _WidgetCtor) {
        super();
        argumentNotNull(widgetClass, "widgetClass");

        this.widgetClass = widgetClass;
    }

    _addChild(child: unknown): void {
        const instance = this._getInstance();

        if (instance.addChild) {
            if (child instanceof WidgetRendition) {
                // layout containers add custom logic to addChild methods
                instance.addChild(child.getWidgetInstance());
            } else if (isWidget(child)) {
                instance.addChild(child);
            } else {
                const childDom = getItemDom(child);
                const w = isElementNode(childDom) ? registry.byNode(childDom) : undefined;

                if (w) {
                    instance.addChild(w);
                } else {
                    if (!instance.containerNode)
                        throw new Error("Failed to add DOM content. The widget doesn't have a containerNode");

                    // the current widget isn't started, it's children shouldn't start too
                    placeAt(getItemDom(child), instance.containerNode, "last");
                }
            }
        } else {
            if (!instance.containerNode)
                throw new Error("The widget doesn't have neither addChild nor containerNode");

            // the current widget isn't started, it's children shouldn't start too
            placeAt(getItemDom(child), instance.containerNode, "last");
        }
    }

    protected _create({ref, ...attrs}: {ref?: JSX.Ref<_Widget>}, children: unknown[]) {
        if (this.widgetClass.prototype instanceof ContentPane) {
            // a special case for the ContentPane this is for
            // compatibility with that heavy widget, all
            // regular containers could be easily manipulated
            // through `containerNode` property or `addChild` method.

            // render children to the DocumentFragment
            const content = document.createDocumentFragment();
            children.forEach(child => content.appendChild(getItemDom(child)));

            // set the content property to the parameters of the widget
            const _attrs = { ...attrs, content };
            this._instance = new this.widgetClass(_attrs);
        } else {
            this._instance = new this.widgetClass(attrs);
            children.forEach(x => this._addChild(x));
        }

        if (ref)
            refHook(this._instance, ref);
    }

    private _getInstance() {
        if (!this._instance)
            throw new Error("The instance of the widget isn't created");
        return this._instance;
    }

    protected _getDomNode() {
        if (!this._instance)
            throw new Error("The instance of the widget isn't created");
        return this._instance.domNode;
    }

    /** Overrides default placeAt implementation. Calls placeAt of the
     * widget and then starts it.
     *
     * @param refNode A node or id of the node where the widget should be placed.
     * @param position A position relative to refNode.
     */
    placeAt(refNode: string | Node, position?: DojoNodePosition) {
        this.ensureCreated();
        const instance = this._getInstance();
        if (typeof instance.placeAt === "function") {
            instance.placeAt(refNode, position);

            // fix the dojo startup behavior when the widget is placed
            // directly to the document and doesn't have any enclosing widgets
            const parentWidget = instance.domNode.parentNode ?
                registry.getEnclosingWidget(instance.domNode.parentNode) : null;
            if (!parentWidget && isInPage(instance.domNode) && typeof instance.startup === "function")
                instance.startup();
        } else {
            // the widget doesn't have a placeAt method, strange but whatever
            super.placeAt(refNode, position);
        }
    }

    getWidgetInstance() {
        this.ensureCreated();
        return this._getInstance();
    }

}