// 本项目新增:ffprobe 封装与 statfs 磁盘用量(REQ §8.2、§8.4.1);失败一律返回 unknown。
import { execFile } from "node:child_process";
import { statfs } from "node:fs/promises";
import { errnoOf } from "./errors.ts";

export interface ProbeVideo {
  codec?: string;
  profile?: string;
  width?: number;
  height?: number;
  pixFmt?: string;
  /** 仅在流信息明确时给出;未知不补值 */
  hdr?: "HDR10" | "HLG" | "DV";
  frameRate?: string;
}
export interface ProbeAudio {
  codec?: string;
  profile?: string;
  channels?: number;
  channelLayout?: string;
  language?: string;
  title?: string;
}
export interface ProbeSubtitle {
  codec?: string;
  language?: string;
  title?: string;
  forced?: boolean;
}

export type ProbeResult =
  | {
      status: "ok";
      container?: string;
      durationSec?: number;
      bitRate?: number;
      sizeBytes?: number;
      video: ProbeVideo[];
      audio: ProbeAudio[];
      subtitles: ProbeSubtitle[];
    }
  | {
      status: "unknown";
      reason: "ffprobe_unavailable" | "timeout" | "probe_failed" | "parse_failed";
      message?: string;
    };

export interface ProbeOptions {
  /** ffprobe 可执行文件,默认 "ffprobe"(PATH 查找) */
  bin?: string;
  timeoutMs?: number;
  /** 输入前的附加参数(远端直链用 -rw_timeout 等) */
  inputArgs?: string[];
}

const optNum = (v: unknown): number | undefined => {
  const n = typeof v === "string" ? Number(v) : v;
  return typeof n === "number" && Number.isFinite(n) ? n : undefined;
};
const optStr = (v: unknown): string | undefined => (typeof v === "string" && v !== "" ? v : undefined);

type Stream = Record<string, unknown> & {
  tags?: Record<string, string>;
  side_data_list?: { side_data_type?: string }[];
};

function hdrOf(s: Stream): ProbeVideo["hdr"] {
  if (s.side_data_list?.some((d) => /dovi|dolby vision/i.test(d.side_data_type ?? ""))) return "DV";
  if (s.color_transfer === "smpte2084") return "HDR10";
  if (s.color_transfer === "arib-std-b67") return "HLG";
  return undefined;
}

function clean<T extends object>(o: T): T {
  return Object.fromEntries(Object.entries(o).filter(([, v]) => v !== undefined)) as T;
}

/** ffprobe 封装:任何失败(含本机无 ffprobe)返回 { status: "unknown" },不抛。 */
export function ffprobe(path: string, opts: ProbeOptions = {}): Promise<ProbeResult> {
  return new Promise((resolve) => {
    execFile(
      opts.bin ?? "ffprobe",
      ["-v", "error", ...(opts.inputArgs ?? []), "-print_format", "json", "-show_format", "-show_streams", "--", path],
      { timeout: opts.timeoutMs ?? 30_000, maxBuffer: 16 * 1024 * 1024 },
      (err, stdout, stderr) => {
        if (err) {
          const e = err as NodeJS.ErrnoException & { killed?: boolean; signal?: string };
          if (errnoOf(e) === "ENOENT" || errnoOf(e) === "EACCES")
            return resolve({ status: "unknown", reason: "ffprobe_unavailable" });
          if (e.killed || e.signal === "SIGTERM") return resolve({ status: "unknown", reason: "timeout" });
          return resolve({ status: "unknown", reason: "probe_failed", message: String(stderr).slice(0, 500) });
        }
        try {
          const j = JSON.parse(stdout) as { format?: Record<string, unknown>; streams?: Stream[] };
          const streams = j.streams ?? [];
          const f = j.format ?? {};
          resolve(
            clean({
              status: "ok" as const,
              container: optStr(f.format_name),
              durationSec: optNum(f.duration),
              bitRate: optNum(f.bit_rate),
              sizeBytes: optNum(f.size),
              video: streams
                .filter((s) => s.codec_type === "video" && !(s.disposition as { attached_pic?: number })?.attached_pic)
                .map((s) =>
                  clean({
                    codec: optStr(s.codec_name),
                    profile: optStr(s.profile),
                    width: optNum(s.width),
                    height: optNum(s.height),
                    pixFmt: optStr(s.pix_fmt),
                    hdr: hdrOf(s),
                    frameRate: optStr(s.avg_frame_rate) === "0/0" ? undefined : optStr(s.avg_frame_rate),
                  }),
                ),
              audio: streams
                .filter((s) => s.codec_type === "audio")
                .map((s) =>
                  clean({
                    codec: optStr(s.codec_name),
                    profile: optStr(s.profile),
                    channels: optNum(s.channels),
                    channelLayout: optStr(s.channel_layout),
                    language: optStr(s.tags?.language),
                    title: optStr(s.tags?.title),
                  }),
                ),
              subtitles: streams
                .filter((s) => s.codec_type === "subtitle")
                .map((s) =>
                  clean({
                    codec: optStr(s.codec_name),
                    language: optStr(s.tags?.language),
                    title: optStr(s.tags?.title),
                    forced: (s.disposition as { forced?: number } | undefined)?.forced === 1 ? true : undefined,
                  }),
                ),
            }),
          );
        } catch (e) {
          resolve({ status: "unknown", reason: "parse_failed", message: (e as Error).message });
        }
      },
    );
  });
}

export type DiskUsage =
  | {
      status: "ok";
      path: string;
      totalBytes: number;
      freeBytes: number;
      /** 非 root 可用空间 */
      availableBytes: number;
      usedBytes: number;
      /** used / (used + available),与 df 的 Use% 一致 */
      usedRatio: number;
    }
  /** 无法读取:调用方应保守阻止新增分配并告警(REQ §8.4.1) */
  | { status: "unknown"; path: string; code: string; message: string };

export async function diskUsage(path: string): Promise<DiskUsage> {
  try {
    const s = await statfs(path);
    const total = s.blocks * s.bsize;
    const free = s.bfree * s.bsize;
    const avail = s.bavail * s.bsize;
    const used = total - free;
    return {
      status: "ok",
      path,
      totalBytes: total,
      freeBytes: free,
      availableBytes: avail,
      usedBytes: used,
      usedRatio: used + avail > 0 ? used / (used + avail) : 0,
    };
  } catch (e) {
    return { status: "unknown", path, code: errnoOf(e) ?? "UNKNOWN", message: (e as Error)?.message ?? String(e) };
  }
}