async function compress() {
	showSection("loading");

	const filesize = document.getElementById("filesize").value;
	const filesizeUnit = document.getElementById("filesize-unit").value;
	const file = document.getElementById("file-input").files[0];

	updateProgress(0);

	const ffmpeg = new FFmpegWASM.FFmpeg();
	ffmpeg.on("progress", data => {
		console.log(data);
		updateProgress(data.progress);
	});

	await ffmpeg.load({ coreURL: "/assets/scripts/core/package/dist/umd/ffmpeg-core.js" });

	await ffmpeg.writeFile(file.name, await readFromBlob(file));

	await ffmpeg.exec(["-i", file.name, "-preset", "veryfast", "-fs", filesize + filesizeUnit, "compressed.mp4"]);

	const video = await ffmpeg.readFile("compressed.mp4");

	location.href = URL.createObjectURL(new Blob([video.buffer], { type: "video/mp4" }));
}

function updateProgress(progress) {
	const percent = (progress * 100).toFixed(1) + "%";

	document.getElementById("progress-percentage").innerText = percent;
	document.getElementById("progress-indicator").style.clipPath = `rect(0 ${percent} 100% 0)`;
}

function openFileSelector() {
	document.getElementById("file-input").click();
}

function selectFile() {
	setTimeout(() => {
		const file = document.getElementById("file-input").files[0];

		document.getElementById("uploaded-video").src = URL.createObjectURL(file);
		document.getElementById("uploaded-video").load();

		hideElements("#file-drop-area", "#file-input-spacing");
		showElements("#uploaded-video", "#change-file");
	}, 200);
}

// https://github.com/ffmpegwasm/ffmpeg.wasm/blob/main/packages/util/src/index.ts
function readFromBlob(blob) {
  return new Promise((resolve, reject) => {
    const fileReader = new FileReader();
    fileReader.onload = () => {
      const { result } = fileReader;
      if (result instanceof ArrayBuffer) {
        resolve(new Uint8Array(result));
      } else {
        resolve(new Uint8Array());
      }
    };
    fileReader.onerror = (event) => {
      reject(
        Error(
          `File could not be read! Code=${event?.target?.error?.code || -1}`
        )
      );
    };
    fileReader.readAsArrayBuffer(blob);
  });
}