import { execFile } from "child_process";
import { promisify } from "util";
import { writeFile, unlink } from "fs/promises";
import { tmpdir } from "os";
import { join } from "path";
import { randomBytes } from "crypto";

const execFileAsync = promisify(execFile);

const WHISPER_CLI = "/opt/homebrew/Cellar/whisper-cpp/1.8.3/bin/whisper-cli";
const WHISPER_MODEL = "/opt/homebrew/share/whisper-cpp/models/ggml-base.en.bin";
const FFMPEG = "/opt/homebrew/bin/ffmpeg";

const WHISPER_NATIVE = new Set(["wav", "flac", "mp3", "ogg"]);

export const AUDIO_TYPES = new Set([
  "audio/mpeg",
  "audio/mp4",
  "audio/ogg",
  "audio/wav",
  "audio/webm",
  "audio/flac",
  "audio/x-m4a",
  "audio/m4a",
  "audio/mp3",
  "audio/aac",
  "audio/amr",
  "audio/3gpp",
  "audio/x-caf",
  "audio/caf",
]);

export function isAudioFile(f: { mimetype?: string }): boolean {
  if (!f.mimetype) return false;
  return AUDIO_TYPES.has(f.mimetype) || f.mimetype.startsWith("audio/");
}

export async function transcribeBuffer(
  buf: Buffer,
  filename: string,
  _mimeType: string
): Promise<string> {
  const ext = (filename.split(".").pop() || "mp3").toLowerCase();
  const id = randomBytes(8).toString("hex");
  const tmpInput = join(tmpdir(), `whisper-in-${id}.${ext}`);
  const needsConvert = !WHISPER_NATIVE.has(ext);
  const tmpWav = needsConvert ? join(tmpdir(), `whisper-wav-${id}.wav`) : tmpInput;

  try {
    await writeFile(tmpInput, buf);

    if (needsConvert) {
      await execFileAsync(FFMPEG, [
        "-y", "-i", tmpInput,
        "-ar", "16000", "-ac", "1", "-f", "wav",
        tmpWav,
      ]);
    }

    const { stdout } = await execFileAsync(WHISPER_CLI, [
      "--model", WHISPER_MODEL,
      "--no-prints",
      "--no-timestamps",
      "--file", tmpWav,
    ]);
    
    const transcript = stdout.replace(/\s+/g, " ").trim();
    return transcript;
  } finally {
    await unlink(tmpInput).catch((err) => console.warn(`[whisper] cleanup failed: ${tmpInput}`, err.message));
    if (needsConvert) await unlink(tmpWav).catch((err) => console.warn(`[whisper] cleanup failed: ${tmpWav}`, err.message));
  }
}