import { execa } from "execa";

export type ProbeMediaDurationOptions = {
  ffprobeBin: string;
  file: string;
  signal?: AbortSignal;
  onLog?: (s: string) => void;
};

// Measure a media file's container duration (seconds) via ffprobe. Returns null
// when ffprobe is missing, errors, or prints something unparseable — callers
// treat null as "couldn't measure" and skip the duration guard rather than
// failing a download. Distinct from probeAudioStream (ffmpegStreamProbe), which
// is a pass/fail corruption check and yields no duration.
export async function probeMediaDurationSec(
  opts: ProbeMediaDurationOptions,
): Promise<number | null> {
  const args = [
    "-v",
    "error",
    "-show_entries",
    "format=duration",
    "-of",
    "default=noprint_wrappers=1:nokey=1",
    opts.file,
  ];
  opts.onLog?.(`$ ${opts.ffprobeBin} ${args.join(" ")}\n`);
  try {
    const result = await execa(opts.ffprobeBin, args, {
      cancelSignal: opts.signal,
      reject: false,
    });
    if (result.exitCode !== 0) {
      opts.onLog?.(
        `ffprobe exited ${result.exitCode}; skipping duration check.\n`,
      );
      return null;
    }
    const sec = Number.parseFloat(String(result.stdout).trim());
    if (!Number.isFinite(sec) || sec <= 0) return null;
    return sec;
  } catch (err) {
    opts.onLog?.(
      `ffprobe failed (${(err as Error).message}); skipping duration check.\n`,
    );
    return null;
  }
}

// The height, in pixels, of a media file's first video stream, or null when
// ffprobe is missing, errors, times out or the file has no video. Reads the
// container header only, so it is cheap enough to answer "how tall is the file
// already on disk" on a cache hit; `timeoutMs` bounds it for a caller that
// must answer promptly (default 5 s).
export async function probeVideoHeight(opts: {
  ffprobeBin: string;
  file: string;
  timeoutMs?: number;
}): Promise<number | null> {
  try {
    const result = await execa(
      opts.ffprobeBin,
      [
        "-v",
        "error",
        "-select_streams",
        "v:0",
        "-show_entries",
        "stream=height",
        "-of",
        "default=noprint_wrappers=1:nokey=1",
        opts.file,
      ],
      { reject: false, timeout: opts.timeoutMs ?? 5000 },
    );
    if (result.exitCode !== 0) return null;
    const h = Number.parseInt(String(result.stdout).trim(), 10);
    return Number.isInteger(h) && h > 0 ? h : null;
  } catch {
    return null;
  }
}