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

export abstract class BuildContextBase {
    _attrs = {};

    _children = new Array();

    _created: boolean = false;

    visitNext(v: any) {
        if (isNull(v))
            return;

        if (isPlainObject(v)) {

            if (this._created)
                this._setAttrs(v);
            else
                mixin(this._attrs, v);

        } else {
            if (this._created)
                this._addChild(v);
            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.getDomElement();
        } else {
            throw new Error("Invalid parameter");
        }
    }

    abstract _getDomElement(): HTMLElement;

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

    getDomElement() {
        this.ensureCreated();
        return this._getDomElement();
    }

    abstract _addChild(child: any): void;

    abstract _setAttrs(attrs: object): void;

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