import fs from "node:fs/promises";
import path from "node:path";
import { afterEach, describe, expect, it } from "vitest";
import { createTrackedTempDirs } from "../test-utils/tracked-temp-dirs.js";
import {
  SafeOpenError,
  openFileWithinRoot,
  readLocalFileSafely,
  writeFileWithinRoot,
} from "./fs-safe.js";

const tempDirs = createTrackedTempDirs();

afterEach(async () => {
  await tempDirs.cleanup();
});

describe("fs-safe", () => {
  it("reads a local file safely", async () => {
    const dir = await tempDirs.make("openclaw-fs-safe-");
    const file = path.join(dir, "payload.txt");
    await fs.writeFile(file, "hello");

    const result = await readLocalFileSafely({ filePath: file });
    expect(result.buffer.toString("utf8")).toBe("hello");
    expect(result.stat.size).toBe(5);
    expect(result.realPath).toContain("payload.txt");
  });

  it("rejects directories", async () => {
    const dir = await tempDirs.make("openclaw-fs-safe-");
    await expect(readLocalFileSafely({ filePath: dir })).rejects.toMatchObject({
      code: "not-file",
    });
  });

  it("enforces maxBytes", async () => {
    const dir = await tempDirs.make("openclaw-fs-safe-");
    const file = path.join(dir, "big.bin");
    await fs.writeFile(file, Buffer.alloc(8));

    await expect(readLocalFileSafely({ filePath: file, maxBytes: 4 })).rejects.toMatchObject({
      code: "too-large",
    });
  });

  it.runIf(process.platform !== "win32")("rejects symlinks", async () => {
    const dir = await tempDirs.make("openclaw-fs-safe-");
    const target = path.join(dir, "target.txt");
    const link = path.join(dir, "link.txt");
    await fs.writeFile(target, "target");
    await fs.symlink(target, link);

    await expect(readLocalFileSafely({ filePath: link })).rejects.toMatchObject({
      code: "symlink",
    });
  });

  it("blocks traversal outside root", async () => {
    const root = await tempDirs.make("openclaw-fs-safe-root-");
    const outside = await tempDirs.make("openclaw-fs-safe-outside-");
    const file = path.join(outside, "outside.txt");
    await fs.writeFile(file, "outside");

    await expect(
      openFileWithinRoot({
        rootDir: root,
        relativePath: path.join("..", path.basename(outside), "outside.txt"),
      }),
    ).rejects.toMatchObject({ code: "invalid-path" });
  });

  it.runIf(process.platform !== "win32")("blocks symlink escapes under root", async () => {
    const root = await tempDirs.make("openclaw-fs-safe-root-");
    const outside = await tempDirs.make("openclaw-fs-safe-outside-");
    const target = path.join(outside, "outside.txt");
    const link = path.join(root, "link.txt");
    await fs.writeFile(target, "outside");
    await fs.symlink(target, link);

    await expect(
      openFileWithinRoot({
        rootDir: root,
        relativePath: "link.txt",
      }),
    ).rejects.toMatchObject({ code: "invalid-path" });
  });

  it.runIf(process.platform !== "win32")("blocks hardlink aliases under root", async () => {
    const root = await tempDirs.make("openclaw-fs-safe-root-");
    const outside = await tempDirs.make("openclaw-fs-safe-outside-");
    const outsideFile = path.join(outside, "outside.txt");
    const hardlinkPath = path.join(root, "link.txt");
    await fs.writeFile(outsideFile, "outside");
    try {
      try {
        await fs.link(outsideFile, hardlinkPath);
      } catch (err) {
        if ((err as NodeJS.ErrnoException).code === "EXDEV") {
          return;
        }
        throw err;
      }
      await expect(
        openFileWithinRoot({
          rootDir: root,
          relativePath: "link.txt",
        }),
      ).rejects.toMatchObject({ code: "invalid-path" });
    } finally {
      await fs.rm(hardlinkPath, { force: true });
      await fs.rm(outsideFile, { force: true });
    }
  });

  it("writes a file within root safely", async () => {
    const root = await tempDirs.make("openclaw-fs-safe-root-");
    await writeFileWithinRoot({
      rootDir: root,
      relativePath: "nested/out.txt",
      data: "hello",
    });
    await expect(fs.readFile(path.join(root, "nested", "out.txt"), "utf8")).resolves.toBe("hello");
  });

  it("rejects write traversal outside root", async () => {
    const root = await tempDirs.make("openclaw-fs-safe-root-");
    await expect(
      writeFileWithinRoot({
        rootDir: root,
        relativePath: "../escape.txt",
        data: "x",
      }),
    ).rejects.toMatchObject({ code: "invalid-path" });
  });

  it.runIf(process.platform !== "win32")("rejects writing through hardlink aliases", async () => {
    const root = await tempDirs.make("openclaw-fs-safe-root-");
    const outside = await tempDirs.make("openclaw-fs-safe-outside-");
    const outsideFile = path.join(outside, "outside.txt");
    const hardlinkPath = path.join(root, "alias.txt");
    await fs.writeFile(outsideFile, "outside");
    try {
      try {
        await fs.link(outsideFile, hardlinkPath);
      } catch (err) {
        if ((err as NodeJS.ErrnoException).code === "EXDEV") {
          return;
        }
        throw err;
      }
      await expect(
        writeFileWithinRoot({
          rootDir: root,
          relativePath: "alias.txt",
          data: "pwned",
        }),
      ).rejects.toMatchObject({ code: "invalid-path" });
      await expect(fs.readFile(outsideFile, "utf8")).resolves.toBe("outside");
    } finally {
      await fs.rm(hardlinkPath, { force: true });
      await fs.rm(outsideFile, { force: true });
    }
  });

  it("returns not-found for missing files", async () => {
    const dir = await tempDirs.make("openclaw-fs-safe-");
    const missing = path.join(dir, "missing.txt");

    await expect(readLocalFileSafely({ filePath: missing })).rejects.toBeInstanceOf(SafeOpenError);
    await expect(readLocalFileSafely({ filePath: missing })).rejects.toMatchObject({
      code: "not-found",
    });
  });
});
