import { registerWorkerAdapter } from './Worker';

export const CHECK_FPS_WORKER_KEY = 'check_browser_max_fps';
const CHECK_FPS_WORKER_CODE = `function (exports) {
    exports.initialize = function () {};
    function now(){
        return new Date().getTime();
    }
    function checkFPS(cb) {
        if (typeof(requestAnimationFrame) === 'undefined') {
            cb(-1);
            return;
        }
        const count = 100;
        let idx = 0;
        let id;
        let startTime;
        function loop() {
            idx++;
            if (idx === count) {
                cancelAnimationFrame(id);
                const endTime = now();
                const timePerFPS = (endTime - startTime) / count;
                const fps = Math.floor(1000 / timePerFPS);
                cb(fps);
            } else {
                id = requestAnimationFrame(loop);
            }
        }
        startTime = now();
        id = requestAnimationFrame(loop);
    }
    //recive message
    exports.onmessage = function (msg, postResponse) {
        checkFPS((fps) => {
            if (fps <= -1) {
                postResponse('check fps fail');
            } else {
                postResponse(null, { fps });
            }
        })
    }
}`;

registerWorkerAdapter(CHECK_FPS_WORKER_KEY, function () { return CHECK_FPS_WORKER_CODE; });