/**
 * DC-097: notification-manager `_loadConfig` write-back.
 * _canonicalizeLegacyKeys (DC-092) fixed legacy spellings in memory only;
 * the on-disk notifications.json kept `email.user`/`email.pass`, camelCase
 * event keys, and string `secure` until the next explicit UI save. These
 * tests pin the new behavior: the canonical form is persisted right after
 * load, the write is idempotent, and a failed write never blocks startup.
 */

jest.mock('fs', () => ({
  existsSync: jest.fn().mockReturnValue(false),
  readFileSync: jest.fn().mockReturnValue('{}'),
  writeFileSync: jest.fn(),
  mkdirSync: jest.fn(),
  // DC-099 atomic write path (open tmp → write → fsync → close → rename).
  openSync: jest.fn().mockReturnValue(3),
  writeSync: jest.fn(),
  fsyncSync: jest.fn(),
  closeSync: jest.fn(),
  renameSync: jest.fn(),
  unlinkSync: jest.fn(),
}));

jest.mock('nodemailer', () => ({
  createTransport: jest.fn(() => ({
    sendMail: jest.fn().mockResolvedValue({ messageId: 'mock' }),
  })),
}));

const fs = require('fs');
const NotificationManager = require('../src/managers/notification-manager');

const NOTIF_FILE = '/tmp/dc097-notif-test.json';

function makeCtx(log) {
  return {
    NOTIFICATIONS_FILE: NOTIF_FILE,
    log,
  };
}

// Serializes exactly like the manager does (2-space indent).
const ser = (obj) => JSON.stringify(obj, null, 2);

function loadWithFile(contents, log) {
  fs.existsSync.mockReturnValue(true);
  fs.readFileSync.mockReturnValue(contents);
  return new NotificationManager(makeCtx(log));
}

describe('DC-097 notification config canonicalization write-back', () => {
  let log;

  beforeEach(() => {
    jest.clearAllMocks();
    fs.existsSync.mockReturnValue(false);
    fs.readFileSync.mockReturnValue('{}');
    fs.writeFileSync.mockClear();
    log = { error: jest.fn(), info: jest.fn(), warn: jest.fn() };
  });

  afterEach(() => {
    try { NotificationManager.prototype.stopHealthDaemon && undefined; } catch (_) {}
    jest.clearAllMocks();
  });

  test('legacy file (user/pass, camelCase events, string secure) is rewritten on disk in canonical form', () => {
    const legacy = {
      enabled: true,
      providers: {
        email: {
          enabled: true,
          host: 'smtp.test',
          port: 465,
          secure: 'false',
          to: 'me@test',
          from: 'from@test',
          user: 'legacy-user',
          pass: 'legacy-pass',
        },
      },
      events: {
        containerDown: false,
        deploymentSuccess: false,
      },
    };
    const nm = loadWithFile(ser(legacy), log);

    // In-memory: canonical (pinned by DC-092 tests, re-pinned here).
    expect(nm.config.providers.email.username).toBe('legacy-user');
    expect(nm.config.providers.email.password).toBe('legacy-pass');
    expect(nm.config.providers.email.secure).toBe(false);
    expect(nm.config.events['container-down']).toBe(false);
    expect(nm.config.events['deploy-success']).toBe(false);

    // On-disk write-back: exactly one atomic write (DC-099: write tmp → fsync → rename).
    expect(fs.renameSync).toHaveBeenCalledTimes(1);
    expect(fs.renameSync.mock.calls[0][1]).toBe(NOTIF_FILE);
    const contentsArg = fs.writeSync.mock.calls[0][1];
    const written = JSON.parse(contentsArg);
    expect(written.providers.email.username).toBe('legacy-user');
    expect(written.providers.email.password).toBe('legacy-pass');
    expect(written.providers.email.user).toBeUndefined();
    expect(written.providers.email.pass).toBeUndefined();
    expect(written.providers.email.secure).toBe(false);
    expect(written.events['container-down']).toBe(false);
    written.events && expect(Object.keys(written.events)).not.toContain('containerDown');
    nm.stopHealthDaemon && nm.stopHealthDaemon();
  });

  test('write-back is idempotent: an already-canonical file is not rewritten', () => {
    // First load performs the write-back; capture what it wrote.
    const legacy = ser({
      providers: { email: { user: 'u', pass: 'p', secure: 'false' } },
      events: { containerDown: true },
    });
    const first = loadWithFile(legacy, log);
    expect(fs.renameSync).toHaveBeenCalledTimes(1);
    const canonicalContents = fs.writeSync.mock.calls[0][1];
    first.stopHealthDaemon && first.stopHealthDaemon();
    fs.renameSync.mockClear();
    fs.writeSync.mockClear();

    // Second load against the canonical bytes: no write.
    const second = loadWithFile(canonicalContents, log);
    expect(fs.renameSync).not.toHaveBeenCalled();
    expect(second.config.providers.email.username).toBe('u');
    second.stopHealthDaemon && second.stopHealthDaemon();
  });

  test('legacy keys absent → no write at all (clean file untouched)', () => {
    // Fully canonical: matches the merged config after serialization.
    // Build it by round-tripping: write-back from a minimal legacy file
    // produces the canonical full shape; feed those exact bytes back.
    const nm = loadWithFile(ser({ enabled: true }), log); // 1 write (defaults fill-in)
    const canonicalContents = fs.writeSync.mock.calls[0][1];
    nm.stopHealthDaemon && nm.stopHealthDaemon();
    fs.renameSync.mockClear();
    fs.writeSync.mockClear();
    const again = loadWithFile(canonicalContents, log);
    expect(fs.renameSync).not.toHaveBeenCalled();
    again.stopHealthDaemon && again.stopHealthDaemon();
  });

  test('write failure (EACCES) does not throw out of the constructor and in-memory config stays correct', () => {
    const legacy = ser({
      providers: { email: { user: 'u2', pass: 'p2' } },
      events: { workflowDone: true },
    });
    fs.openSync.mockImplementation(() => { throw new Error('EACCES: permission denied'); });
    let nm;
    expect(() => { nm = loadWithFile(legacy, log); }).not.toThrow();
    expect(nm.config.providers.email.username).toBe('u2');
    expect(nm.config.events['workflow']).toBe(true);
    // Warn surfaced, no error-level log (load itself succeeded).
    expect(log.warn).toHaveBeenCalled();
    expect(log.error).not.toHaveBeenCalled();
    nm.stopHealthDaemon && nm.stopHealthDaemon();
  });

  test('no file on disk → no read, no write (fresh install untouched)', () => {
    fs.existsSync.mockReturnValue(false);
    const nm = new NotificationManager(makeCtx(log));
    expect(fs.readFileSync).not.toHaveBeenCalled();
    expect(fs.renameSync).not.toHaveBeenCalled();
    nm.stopHealthDaemon && nm.stopHealthDaemon();
  });
});