import { isNull, mixin } from "@implab/core-amd/safe";
import { isPlainObject, isNode, isBuildContext, DojoNodePosition, BuildContext } from "./traits";

import dom = require("dojo/dom-construct");
import registry = require("dijit/registry");

export abstract class BuildContextBase<TNode extends Node> implements BuildContext<TNode> {
    private _attrs = {};

    private _children = new Array();

    private _created: boolean = false;

    visitNext(v: any) {
        if (this._created)
            throw new Error("The Element is already created");

        if (isNull(v))
            return;

        if (isPlainObject(v)) {
            mixin(this._attrs, v);
        } else if (v instanceof Array) {
            v.forEach(x => this.visitNext(x));
        } else {
            this._children.push(v);
        }
    }

    getChildDom(v: any) {
        const tv = typeof v;
        if (tv === "string" || tv === "number" || tv === "boolean" || v instanceof RegExp || v instanceof Date) {
            return document.createTextNode(v.toString());
        } else if (isNode(v)) {
            return v;
        } else if (isBuildContext(v)) {
            return v.getDomNode();
        } else {
            throw new Error("Invalid parameter");
        }
    }

    ensureCreated() {
        if (!this._created) {
            this._create(this._attrs, this._children);
            this._children = [];
            this._attrs = {};
            this._created = true;
        }
    }

    /** @deprecated will be removed in 1.0.0, use getDomNode() */
    getDomElement() {
        return this.getDomNode();
    }

    /** Creates DOM node if not created. No additional actions are taken. */
    getDomNode() {
        this.ensureCreated();
        return this._getDomNode();
    }

    /** Creates DOM node if not created, places it to the specified position
     * and calls startup() method for all widgets contained by this node.
     *
     * @param {string | Node} refNode The reference node where the created
     *   DOM should be placed.
     * @param {DojoNodePosition} position Optional parameter, specifies the
     *   position relative to refNode. Default is "last" (i.e. last child).
     */
    placeAt(refNode: string | Node, position?: DojoNodePosition) {
        const domNode = this.getDomNode();
        dom.place(domNode, refNode, position);
        registry.findWidgets(domNode).forEach(w => w.startup());
    }

    abstract _create(attrs: object, children: any[]): void;

    abstract _getDomNode(): TNode;
}