// fsproxy 的操作表:主进程(in-process 回退)与执行子进程(fsworker.ts)共用同一份实现。
// 迁移来源:MoviePilot app/adapters/system/fsworker.py 的请求/响应模型(e6820a8),只借语义不借代码。

import { unlink } from "node:fs/promises";
import { type CopyOptions, copyWithVerify, filesMatchSha256, sha256Full, sweepStalePartials } from "./copy.ts";
import { FsError, toFsError } from "./errors.ts";
import { type CrossMoveOptions, crossDeviceMove, moveSafe } from "./move.ts";
import { checkRoot, statSafe } from "./stat.ts";

/** 可序列化的复制选项(去掉信号与回调) */
export type WireCopyOptions = Omit<CopyOptions, "signal" | "onProgress" | "onVerifyProgress">;
export type WireCrossMoveOptions = Omit<CrossMoveOptions, "signal" | "onProgress" | "onVerifyProgress">;

/** 测试开关:执行子进程在累计进度达到 hangAfterBytes 后阻塞 JS 线程(模拟卡死的系统调用);ignoreTerm 屏蔽 SIGTERM */
export interface FsTestHook {
  hangAfterBytes?: number;
  ignoreTerm?: boolean;
}

export type FsOpRequest = (
  | { op: "copy"; src: string; dst: string; opts?: WireCopyOptions }
  | { op: "crossMove"; src: string; dst: string; opts?: WireCrossMoveOptions }
  | { op: "move"; src: string; dst: string }
  | { op: "match"; a: string; b: string }
  | { op: "sha256"; path: string }
  | { op: "stat"; path: string; root?: string; sentinel?: string }
  | { op: "checkRoot"; root: string; sentinel?: string }
  | { op: "sweep"; dir: string; olderThanMs: number; suffix?: string }
  | { op: "unlink"; path: string }
) & { _test?: FsTestHook };

export type FsOpName = FsOpRequest["op"];

/** 按"进度停滞"判挂死的数据类操作;其余是快操作,按总时长判超时 */
export const DATA_OPS: ReadonlySet<FsOpName> = new Set(["copy", "crossMove", "match", "sha256"]);

export interface FsProgress {
  phase: string;
  bytes: number;
  total: number;
}

export interface FsOpContext {
  signal: AbortSignal;
  progress: (p: FsProgress) => void;
}

export async function runFsOp(req: FsOpRequest, ctx: FsOpContext): Promise<unknown> {
  const { signal, progress } = ctx;
  const at = (phase: string) => (bytes: number, total: number) => progress({ phase, bytes, total });
  switch (req.op) {
    case "copy":
      return copyWithVerify(req.src, req.dst, {
        ...req.opts,
        signal,
        onProgress: at("copy"),
        onVerifyProgress: at("verify"),
      });
    case "crossMove":
      return crossDeviceMove(req.src, req.dst, {
        ...req.opts,
        signal,
        onProgress: at("copy"),
        onVerifyProgress: at("verify"),
      });
    case "move":
      return moveSafe(req.src, req.dst);
    case "match":
      return filesMatchSha256(req.a, req.b, { signal, onProgress: at("hash") });
    case "sha256":
      return sha256Full(req.path, signal, at("hash"));
    case "stat":
      return statSafe(req.path, {
        ...(req.root ? { root: req.root } : {}),
        ...(req.sentinel ? { sentinel: req.sentinel } : {}),
      });
    case "checkRoot":
      return checkRoot(req.root, req.sentinel);
    case "sweep":
      return sweepStalePartials(req.dir, req.olderThanMs, req.suffix);
    case "unlink":
      try {
        await unlink(req.path);
        return null;
      } catch (e) {
        throw toFsError(e, req.path);
      }
    default:
      throw new FsError("IO", `unknown fs op: ${(req as { op: string }).op}`);
  }
}