import { createUser, get, insertDump, test, TEST_DIR } from "../helpers.ts";
import { assert, assertEquals } from "@std/assert";
import { WAVEFORM_PEAKS } from "../../../shared/waveform.ts";

async function hasFfmpeg(): Promise<boolean> {
  try {
    return (await new Deno.Command("ffmpeg", {
      args: ["-version"],
      stdout: "null",
      stderr: "null",
    }).output()).success;
  } catch {
    return false;
  }
}

/**
 * Returns a mono 16-bit WAV of a 440 Hz tone, quiet for its first `seconds`
 * and four times louder for as long again.
 */
function wav(seconds: number, rate = 8000): Uint8Array {
  const n = seconds * rate * 2;
  const bytes = new Uint8Array(44 + n * 2);
  const view = new DataView(bytes.buffer);
  const ascii = (at: number, s: string) =>
    [...s].forEach((c, i) => view.setUint8(at + i, c.charCodeAt(0)));
  ascii(0, "RIFF");
  view.setUint32(4, 36 + n * 2, true);
  ascii(8, "WAVEfmt ");
  view.setUint32(16, 16, true);
  view.setUint16(20, 1, true); // PCM
  view.setUint16(22, 1, true); // mono
  view.setUint32(24, rate, true);
  view.setUint32(28, rate * 2, true);
  view.setUint16(32, 2, true);
  view.setUint16(34, 16, true);
  ascii(36, "data");
  view.setUint32(40, n * 2, true);
  for (let i = 0; i < n; i++) {
    const gain = i < n / 2 ? 4000 : 16000;
    view.setInt16(
      44 + i * 2,
      gain * Math.sin((2 * Math.PI * 440 * i) / rate),
      true,
    );
  }
  return bytes;
}

test("GET /api/dumps/:id/waveform: an audio file's peaks, made once, with privacy", async () => {
  if (!await hasFfmpeg()) return;
  const owner = await createUser();
  const song = insertDump({
    userId: owner.id,
    fileName: "s.wav",
    fileMime: "audio/wav",
    fileData: wav(2),
  });
  const res = await get<{ peaks: number[] }>(`/api/dumps/${song.id}/waveform`);
  assertEquals(res.status, 200);
  assertEquals(res.headers.get("content-type"), "application/json");
  assertEquals(res.headers.get("cache-control"), "public, no-cache");
  const { peaks } = res.data;
  assertEquals(peaks.length, WAVEFORM_PEAKS);
  // The loud half reaches the top; the quiet half a quarter of it.
  assertEquals(Math.max(...peaks), 1);
  assert(Math.abs(peaks[10] - 0.25) < 0.02, `quiet peak ${peaks[10]}`);
  assert(peaks[140] > 0.98, `loud peak ${peaks[140]}`);
  assert(
    [...Deno.readDirSync(`${TEST_DIR}/uploads/thumbnails`)].some((e) =>
      e.name === `${song.id}.waveform.json`
    ),
  );
  // The kept file is served again, with its ETag.
  const etag = res.headers.get("etag")!;
  const again = await get(`/api/dumps/${song.id}/waveform`, {
    headers: { "If-None-Match": etag },
  });
  assertEquals(again.status, 304);

  const secret = insertDump({
    userId: owner.id,
    fileName: "p.wav",
    fileMime: "audio/wav",
    fileData: wav(1),
    isPrivate: true,
  });
  assertEquals((await get(`/api/dumps/${secret.id}/waveform`)).status, 404);
  assertEquals(
    (await get(`/api/dumps/${secret.id}/waveform?token=${owner.mediaToken}`))
      .status,
    200,
  );
});

test("GET /api/dumps/:id/waveform: 404 for anything but readable audio", async () => {
  const owner = await createUser();
  const text = insertDump({ userId: owner.id, fileName: "t.txt" });
  assertEquals((await get(`/api/dumps/${text.id}/waveform`)).status, 404);
  const noise = insertDump({
    userId: owner.id,
    fileName: "n.mp3",
    fileMime: "audio/mpeg",
    fileData: new TextEncoder().encode("not audio at all"),
  });
  assertEquals((await get(`/api/dumps/${noise.id}/waveform`)).status, 404);
  assertEquals((await get(`/api/dumps/nope/waveform`)).status, 400);
});