import fs from "node:fs/promises";
import os from "node:os";
import path from "node:path";
import { afterEach, describe, expect, it, vi } from "vitest";
import { repairSessionFileIfNeeded } from "./session-file-repair.js";

function buildSessionHeaderAndMessage() {
  const header = {
    type: "session",
    version: 7,
    id: "session-1",
    timestamp: new Date().toISOString(),
    cwd: "/tmp",
  };
  const message = {
    type: "message",
    id: "msg-1",
    parentId: null,
    timestamp: new Date().toISOString(),
    message: { role: "user", content: "hello" },
  };
  return { header, message };
}

const tempDirs: string[] = [];

async function createTempSessionPath() {
  const dir = await fs.mkdtemp(path.join(os.tmpdir(), "openclaw-session-repair-"));
  tempDirs.push(dir);
  return { dir, file: path.join(dir, "session.jsonl") };
}

afterEach(async () => {
  await Promise.all(tempDirs.splice(0).map((dir) => fs.rm(dir, { recursive: true, force: true })));
});

describe("repairSessionFileIfNeeded", () => {
  it("rewrites session files that contain malformed lines", async () => {
    const { file } = await createTempSessionPath();
    const { header, message } = buildSessionHeaderAndMessage();

    const content = `${JSON.stringify(header)}\n${JSON.stringify(message)}\n{"type":"message"`;
    await fs.writeFile(file, content, "utf-8");

    const result = await repairSessionFileIfNeeded({ sessionFile: file });
    expect(result.repaired).toBe(true);
    expect(result.droppedLines).toBe(1);
    expect(result.backupPath).toBeTruthy();

    const repaired = await fs.readFile(file, "utf-8");
    expect(repaired.trim().split("\n")).toHaveLength(2);

    if (result.backupPath) {
      const backup = await fs.readFile(result.backupPath, "utf-8");
      expect(backup).toBe(content);
    }
  });

  it("does not drop CRLF-terminated JSONL lines", async () => {
    const { file } = await createTempSessionPath();
    const { header, message } = buildSessionHeaderAndMessage();
    const content = `${JSON.stringify(header)}\r\n${JSON.stringify(message)}\r\n`;
    await fs.writeFile(file, content, "utf-8");

    const result = await repairSessionFileIfNeeded({ sessionFile: file });
    expect(result.repaired).toBe(false);
    expect(result.droppedLines).toBe(0);
  });

  it("warns and skips repair when the session header is invalid", async () => {
    const { file } = await createTempSessionPath();
    const badHeader = {
      type: "message",
      id: "msg-1",
      timestamp: new Date().toISOString(),
      message: { role: "user", content: "hello" },
    };
    const content = `${JSON.stringify(badHeader)}\n{"type":"message"`;
    await fs.writeFile(file, content, "utf-8");

    const warn = vi.fn();
    const result = await repairSessionFileIfNeeded({ sessionFile: file, warn });

    expect(result.repaired).toBe(false);
    expect(result.reason).toBe("invalid session header");
    expect(warn).toHaveBeenCalledTimes(1);
    expect(warn.mock.calls[0]?.[0]).toContain("invalid session header");
  });

  it("returns a detailed reason when read errors are not ENOENT", async () => {
    const { dir } = await createTempSessionPath();
    const warn = vi.fn();

    const result = await repairSessionFileIfNeeded({ sessionFile: dir, warn });

    expect(result.repaired).toBe(false);
    expect(result.reason).toContain("failed to read session file");
    expect(warn).toHaveBeenCalledTimes(1);
  });
});