import EventEmitter from "./events.js";
import HookEvent from "./hook.js";

class Workers extends EventEmitter {
    constructor(ctx) {
        super();
        this.ctx = ctx;
        this.window = ctx.window;
        this.Worker = this.window.Worker || {};
        this.Worklet = this.window.Worklet || {};
        this.workletProto = this.Worklet.prototype || {};
        this.workerProto = this.Worker.prototype || {};
        this.postMessage = this.workerProto.postMessage;
        this.terminate = this.workerProto.terminate;
        this.addModule = this.workletProto.addModule;
    };
    overrideWorker() {
        this.ctx.override(this.window, 'Worker', (target, that, args) => {
            if (!args.length) return new target(...args);
            let [ url, options = {} ] = args;

            const event = new HookEvent({ url, options }, target, that);
            this.emit('worker', event);

            if (event.intercepted) return event.returnValue;
            return new event.target(...[ event.data.url, event.data.options ]);
        }, true);
    };
    overrideAddModule() {
        this.ctx.override(this.workletProto, 'addModule', (target, that, args) => {
            if (!args.length) return target.apply(that, args);
            let [ url, options = {} ] = args;

            const event = new HookEvent({ url, options }, target, that);
            this.emit('addModule', event);

            if (event.intercepted) return event.returnValue;
            return event.target.call(event.that, event.data.url, event.data.options);
        });
    };
    overridePostMessage() {
        this.ctx.override(this.workerProto, 'postMessage', (target, that, args) => {
            if (!args.length) return target.apply(that, args);
            let [ message, transfer = [] ] = args;

            const event = new HookEvent({ message, transfer }, target, that);
            this.emit('postMessage', event);

            if (event.intercepted) return event.returnValue;
            return event.target.call(event.that, event.data.message, event.data.transfer);
        });
    };
    overrideImportScripts() {
        this.ctx.override(this.window, 'importScripts', (target, that, scripts) => {
            if (!scripts.length) return target.apply(that, scripts);

            const event = new HookEvent({ scripts }, target, that);
            this.emit('importScripts', event);

            if (event.intercepted) return event.returnValue;
            return event.target.apply(event.that, event.data.scripts);
        });
    };
};

export default Workers;