import { Object3D } from "three";

import type { Constructor } from "../../engine/engine_types.js";

const handlers: Map<any, ApplyPrototypeExtension> = new Map();

/** @internal */
export function applyPrototypeExtensions<T>(obj: any, prototype : Constructor<T>) {
    if (!obj) return;
    // const prototype = Object.getPrototypeOf(obj);
    // console.log("TEST", prototype)
    if (!prototype) {
        console.warn("No prototype found", obj, obj.prototype, obj.constructor);
        return;
    }
    const handler = handlers.get(prototype);
    if (handler) {
        // console.log("OK", prototype);
        handler.apply(obj);
    }
    // applyPrototypeExtensions(prototype);
}

/** @internal */
export function registerPrototypeExtensions<T>(type: Constructor<T>) {
    // console.log("Register", type.prototype.constructor.name);
    const handler = createPrototypeExtensionHandler(type.prototype);
    handlers.set(type, handler);
}


function createPrototypeExtensionHandler(prototype: any) {
    return new ApplyPrototypeExtension(prototype);
}

/** @internal */
export interface IApplyPrototypeExtension {
    apply(object: object): void;
}

class ApplyPrototypeExtension implements IApplyPrototypeExtension {

    private readonly $symbol: symbol;
    private readonly extensions: string[];
    private readonly descriptors: Array<PropertyDescriptor | undefined>;

    constructor(prototype: object) {
        this.$symbol = Symbol("prototype-extension");
        // used to decorate cloned object3D objects with the same added components defined above
        this.extensions = Object.keys(prototype);
        // console.log(this.extensions);
        this.descriptors = new Array<PropertyDescriptor | undefined>();
        for (let i = 0; i < this.extensions.length; i++) {
            const key = this.extensions[i];
            // console.log(key);
            const descriptor = Object.getOwnPropertyDescriptor(prototype, key);
            if (descriptor) {
                this.descriptors.push(descriptor);
            }
        }
    }

    apply(object: Object3D): void {

        if (object[this.$symbol]) return;
        object[this.$symbol] = true;

        // const prototype = object.constructor.prototype;

        for (let i = 0; i < this.extensions.length; i++) {
            const key = this.extensions[i];
            const desc = this.descriptors[i];
            if (desc) {
                // if (prototype) {
                //     const exists = Object.getOwnPropertyDescriptor(prototype, key);
                //     if (exists) {
                //         continue;
                //     }
                // }
                // console.warn("DEFINE", object, key);
                Object.defineProperty(object, key, desc);
            }
        }
    }
}