import { JOB_TIMEOUT_MS } from "../config";
import { unprocessable } from "../errors";

/**
 * ffprobe, with its own field names passed through untouched.
 *
 * `codec_name`, `r_frame_rate`, `nb_frames` and the rest reach the caller exactly as ffprobe emits
 * them. Renaming them into some house style would mean maintaining a translation table and would
 * make ffprobe's own documentation stop applying to this API, which is the opposite of the point.
 */

export type FfprobeStream = {
  index: number;
  codec_type?: string;
  codec_name?: string;
  width?: number;
  height?: number;
  [key: string]: unknown;
};

export type FfprobeResult = {
  format?: { format_name?: string; duration?: string; bit_rate?: string; [key: string]: unknown };
  streams?: FfprobeStream[];
};

export async function ffprobe(path: string): Promise<FfprobeResult> {
  // Spawned as an argv ARRAY, never a command string — there is no shell here to quote for, so a
  // filename containing shell metacharacters is inert data. See docs/SECURITY.md, Layer 1.
  //
  // `-protocol_whitelist file` is the second lock: `path` is always one this process constructed,
  // but if that ever stops being true, ffprobe still cannot be talked into speaking http.
  const proc = Bun.spawn(
    [
      "ffprobe",
      "-v", "error",
      "-protocol_whitelist", "file",
      "-print_format", "json",
      "-show_format",
      "-show_streams",
      path,
    ],
    { stdout: "pipe", stderr: "pipe", stdin: "ignore" },
  );

  const timer = setTimeout(() => proc.kill(), JOB_TIMEOUT_MS);

  try {
    const [stdout, stderr, code] = await Promise.all([
      new Response(proc.stdout).text(),
      new Response(proc.stderr).text(),
      proc.exited,
    ]);

    if (code !== 0) {
      throw unprocessable(`Could not read that file: ${stderr.trim().split("\n").at(-1) ?? "ffprobe failed"}`);
    }

    return JSON.parse(stdout) as FfprobeResult;
  } finally {
    clearTimeout(timer);
  }
}