import { describe, it, expect, beforeEach } from 'vitest';
import os from 'node:os';
import fs from 'node:fs';
import path from 'node:path';
import { writePidfile, readPidfile, cleanPidfile, isProcessAlive } from '../pidfile.js';

describe('pidfile management', () => {
  let testDir: string;

  beforeEach(() => {
    testDir = path.join(os.tmpdir(), `visionl-pidfile-test-${Date.now()}-${Math.random().toString(36).slice(2)}`);
    // clean up before in case previous run left files
    try { fs.rmSync(testDir, { recursive: true, force: true }); } catch { /* ignore */ }
    fs.mkdirSync(testDir, { recursive: true });
  });

  it('writePidfile writes pid and port files, readPidfile reads them back', () => {
    writePidfile(12345, 9527, testDir);

    const result = readPidfile(testDir);
    expect(result).toEqual({ pid: 12345, port: 9527 });
  });

  it('readPidfile returns null when pidfile does not exist', () => {
    const result = readPidfile(testDir);
    expect(result).toBeNull();
  });

  it('readPidfile returns null when pidfile has invalid content', () => {
    writePidfile(12345, 9527, testDir);
    // overwrite with invalid data
    fs.writeFileSync(path.join(testDir, 'daemon.pid'), 'not-a-number');

    const result = readPidfile(testDir);
    expect(result).toBeNull();
  });

  it('cleanPidfile removes both pid and port files', () => {
    writePidfile(12345, 9527, testDir);

    cleanPidfile(testDir);

    expect(fs.existsSync(path.join(testDir, 'daemon.pid'))).toBe(false);
    expect(fs.existsSync(path.join(testDir, 'daemon.port'))).toBe(false);
  });

  it('cleanPidfile is safe when files do not exist', () => {
    // should not throw
    expect(() => cleanPidfile(testDir)).not.toThrow();
  });

  it('isProcessAlive returns true for the current process', () => {
    expect(isProcessAlive(process.pid)).toBe(true);
  });

  it('isProcessAlive returns false for a non-existent PID', () => {
    expect(isProcessAlive(99999999)).toBe(false);
  });
});