import { beforeEach, describe, expect, it, vi } from 'vitest';
import * as nodemailer from 'nodemailer';
import { MailService, WELCOME_HEADER_CID } from './mail.service';

/**
 * MailService.spec — NEU (260914-eym, Etappe 3c, WINDOWS #30). Der Bereich
 * `mail` hatte VOR diesem Durchlauf KEINE Testdatei. Festgenagelt wird die
 * Bauform "Transport je Versand nach Mandant des Empfaengers":
 *
 * 1. IDENTITAET FUER EINEN MANDANTEN MIT SmtpConfig: Transport aus GENAU
 *    dieser Config, `from` = deren fromAddress, `close()` gerufen.
 * 2. Mandant OHNE SmtpConfig: die bisherige Umgebungs-Kette (MAIL_* vor
 *    TESSERA_SMTP_* vor localhost:1025), `from` aus TESSERA_SMTP_FROM bzw.
 *    Vorgabe.
 * 3. ZWEI Mandanten nacheinander -> zwei verschiedene Transporte, keiner
 *    sieht die Zugangsdaten des anderen (T-GWH-03 geschlossen).
 * 4. `sendMail` wirft -> kein Throw nach aussen (T-02-12), Fehler
 *    protokolliert, `close()` trotzdem gerufen.
 *
 * `nodemailer` wird per `vi.mock` ersetzt (wie in settings.service.spec.ts)
 * — kein echter Transport, der lokale `mailhog` aus docker-compose.dev.yml
 * ist nur fuer den Browser-Check gedacht.
 *
 * Erweitert in quick-260914-m97 (Fehler-melden-Knopf): Tests 5 und 6 pinnen
 * `sendBugReport` — Anhaenge werden 1:1 an `sendMail` durchgereicht, und
 * Fehler gehen bewusst NACH AUSSEN (der Anwender soll wissen, ob sein
 * Bericht ankam), waehrend `sendPasswordResetEmail` weiterhin verschluckt
 * (T-02-12 unveraendert, Gegenprobe im selben Test).
 */

let mockSendMail = vi.fn(async (_mail: unknown) => ({}));
const mockClose = vi.fn();
vi.mock('nodemailer', () => ({
  createTransport: vi.fn(() => ({
    sendMail: (...args: unknown[]) => (mockSendMail as any)(...args),
    close: (...args: unknown[]) => (mockClose as any)(...args),
  })),
}));

interface FakeDecrypted {
  host: string;
  port: number;
  encryption: string;
  username: string | null;
  fromAddress: string;
  decryptedPassword: string | null;
}

function makeFakeSettings(configsByTenant: Record<string, FakeDecrypted>) {
  return {
    getDecryptedSmtpConfig: vi.fn(async (tenantId: string) => configsByTenant[tenantId] ?? null),
  };
}

function makeFakeConfig(values: Record<string, string | number | undefined>) {
  return {
    get: vi.fn((key: string, fallback?: unknown) => (values[key] !== undefined ? values[key] : fallback)),
  };
}

const configA: FakeDecrypted = {
  host: 'smtp-a.example.invalid',
  port: 465,
  encryption: 'ssl-tls',
  username: 'user-a',
  fromAddress: 'noreply@a.example.invalid',
  decryptedPassword: 'geheim-a',
};

const configB: FakeDecrypted = {
  host: 'smtp-b.example.invalid',
  port: 587,
  encryption: 'starttls',
  username: 'user-b',
  fromAddress: 'noreply@b.example.invalid',
  decryptedPassword: 'geheim-b',
};

beforeEach(() => {
  vi.clearAllMocks();
  mockSendMail = vi.fn(async (_mail: unknown) => ({}));
});

describe('MailService — Transport je Versand nach Mandant des Empfaengers (260914-eym, WINDOWS #30)', () => {
  it('Test 1: Mandant MIT SmtpConfig -> getDecryptedSmtpConfig genau einmal mit dieser tenantId, createTransport mit deren host/port/secure/requireTLS/auth, from = deren fromAddress, close() gerufen (Identitaet zu heute)', async () => {
    const settings = makeFakeSettings({ t1: configA });
    const config = makeFakeConfig({ MAIL_HOST: 'env-darf-nicht-greifen' });
    const service = new MailService(settings as any, config as any);

    await service.sendPasswordResetEmail('alice@a.example.invalid', 'tok-1', 't1');

    expect(settings.getDecryptedSmtpConfig).toHaveBeenCalledTimes(1);
    expect(settings.getDecryptedSmtpConfig).toHaveBeenCalledWith('t1');
    expect(vi.mocked(nodemailer.createTransport)).toHaveBeenCalledTimes(1);
    expect(vi.mocked(nodemailer.createTransport)).toHaveBeenCalledWith({
      host: 'smtp-a.example.invalid',
      port: 465,
      secure: true,
      requireTLS: false,
      auth: { user: 'user-a', pass: 'geheim-a' },
    });
    expect(mockSendMail).toHaveBeenCalledTimes(1);
    const sent = mockSendMail.mock.calls[0][0] as any;
    expect(sent.from).toBe('noreply@a.example.invalid');
    expect(sent.to).toBe('alice@a.example.invalid');
    expect(sent.text).toContain('/reset-password/tok-1');
    expect(mockClose).toHaveBeenCalledTimes(1);
  });

  it('Test 2: Mandant OHNE SmtpConfig -> Umgebungs-Kette: MAIL_* vor TESSERA_SMTP_* vor localhost:1025, from aus TESSERA_SMTP_FROM bzw. Vorgabe', async () => {
    // (a) MAIL_* gesetzt -> gewinnt vor TESSERA_SMTP_*
    const svcA = new MailService(
      makeFakeSettings({}) as any,
      makeFakeConfig({
        MAIL_HOST: 'mail.example.invalid',
        MAIL_PORT: 2525,
        MAIL_USER: 'mail-user',
        MAIL_PASS: 'mail-pass',
        TESSERA_SMTP_HOST: 'legacy.example.invalid',
        TESSERA_SMTP_FROM: 'Tessera <from@example.invalid>',
      }) as any,
    );
    await svcA.sendPasswordResetEmail('x@example.invalid', 'tok', 't-ohne');
    expect(vi.mocked(nodemailer.createTransport)).toHaveBeenLastCalledWith({
      host: 'mail.example.invalid',
      port: 2525,
      secure: false,
      auth: { user: 'mail-user', pass: 'mail-pass' },
    });
    expect((mockSendMail.mock.calls.at(-1)![0] as any).from).toBe('Tessera <from@example.invalid>');

    // (b) nur TESSERA_SMTP_* gesetzt -> zweite Stufe
    const svcB = new MailService(
      makeFakeSettings({}) as any,
      makeFakeConfig({
        TESSERA_SMTP_HOST: 'legacy.example.invalid',
        TESSERA_SMTP_PORT: 587,
        TESSERA_SMTP_USER: 'legacy-user',
        TESSERA_SMTP_PASSWORD: 'legacy-pass',
        TESSERA_SMTP_SECURE: 'true',
      }) as any,
    );
    await svcB.sendPasswordResetEmail('x@example.invalid', 'tok', 't-ohne');
    expect(vi.mocked(nodemailer.createTransport)).toHaveBeenLastCalledWith({
      host: 'legacy.example.invalid',
      port: 587,
      secure: true,
      auth: { user: 'legacy-user', pass: 'legacy-pass' },
    });
    expect((mockSendMail.mock.calls.at(-1)![0] as any).from).toBe('Tessera <tessera@tessera.local>');

    // (c) nichts gesetzt -> localhost:1025
    const svcC = new MailService(makeFakeSettings({}) as any, makeFakeConfig({}) as any);
    await svcC.sendPasswordResetEmail('x@example.invalid', 'tok', 't-ohne');
    expect(vi.mocked(nodemailer.createTransport)).toHaveBeenLastCalledWith({
      host: 'localhost',
      port: 1025,
      secure: false,
      auth: { user: '', pass: '' },
    });
    expect(mockClose).toHaveBeenCalledTimes(3);
  });

  it('Test 3: zwei Mandanten nacheinander -> zwei verschiedene Transporte, keiner sieht die Zugangsdaten des anderen (T-GWH-03 geschlossen)', async () => {
    const settings = makeFakeSettings({ t1: configA, t2: configB });
    const service = new MailService(settings as any, makeFakeConfig({}) as any);

    await service.sendPasswordResetEmail('alice@a.example.invalid', 'tok-a', 't1');
    await service.sendWelcomeMail('t2', 'bob@b.example.invalid', {
      subject: 'Willkommen bei Tessera',
      text: 'Guten Tag bob,',
      html: '<p>bob</p>',
    });

    expect(settings.getDecryptedSmtpConfig.mock.calls.map((c) => c[0])).toEqual(['t1', 't2']);
    const transports = vi.mocked(nodemailer.createTransport).mock.calls.map((c) => c[0] as any);
    expect(transports).toHaveLength(2);
    expect(transports[0].host).toBe('smtp-a.example.invalid');
    expect(transports[0].auth).toEqual({ user: 'user-a', pass: 'geheim-a' });
    expect(transports[1].host).toBe('smtp-b.example.invalid');
    expect(transports[1].requireTLS).toBe(true);
    expect(transports[1].auth).toEqual({ user: 'user-b', pass: 'geheim-b' });
    expect(JSON.stringify(transports[0])).not.toContain('geheim-b');
    expect(JSON.stringify(transports[1])).not.toContain('geheim-a');

    const sentMails = mockSendMail.mock.calls.map((c) => c[0] as any);
    expect(sentMails[0].from).toBe('noreply@a.example.invalid');
    expect(sentMails[1].from).toBe('noreply@b.example.invalid');
    expect(sentMails[1].text).toContain('bob');
    expect(mockClose).toHaveBeenCalledTimes(2);
  });

  it('Test 4: sendMail wirft -> kein Throw nach aussen (T-02-12), Fehler protokolliert ohne Kennwort, close() trotzdem gerufen', async () => {
    mockSendMail = vi.fn(async () => {
      throw new Error('ECONNREFUSED smtp-a.example.invalid');
    });
    const settings = makeFakeSettings({ t1: configA });
    const service = new MailService(settings as any, makeFakeConfig({}) as any);
    const errorSpy = vi.spyOn((service as any).logger, 'error').mockImplementation(() => undefined);

    await expect(
      service.sendPasswordResetEmail('alice@a.example.invalid', 'tok-1', 't1'),
    ).resolves.toBeUndefined();

    expect(errorSpy).toHaveBeenCalledTimes(1);
    expect(String(errorSpy.mock.calls[0][0])).toContain('Failed to send Password reset email to alice@a.example.invalid');
    expect(JSON.stringify(errorSpy.mock.calls[0])).not.toContain('geheim-a');
    expect(mockClose).toHaveBeenCalledTimes(1);
  });
  it('Test 5 (260914-m97): sendBugReport reicht to/subject/text und den PNG-Anhang unveraendert an sendMail durch, from = fromAddress des Mandanten, close() gerufen', async () => {
    const settings = makeFakeSettings({ t1: configA });
    const service = new MailService(settings as any, makeFakeConfig({}) as any);
    const png = Buffer.from([1, 2, 3]);

    await service.sendBugReport('t1', 'fehler@a.example.invalid', {
      subject: 'S',
      text: 'T',
      attachments: [{ filename: 'x.png', content: png, contentType: 'image/png' }],
    });

    expect(mockSendMail).toHaveBeenCalledTimes(1);
    const sent = mockSendMail.mock.calls[0][0] as any;
    expect(sent.from).toBe('noreply@a.example.invalid');
    expect(sent.to).toBe('fehler@a.example.invalid');
    expect(sent.subject).toBe('S');
    expect(sent.text).toBe('T');
    expect(sent.attachments).toHaveLength(1);
    expect(sent.attachments[0].filename).toBe('x.png');
    expect(sent.attachments[0].contentType).toBe('image/png');
    expect(Buffer.isBuffer(sent.attachments[0].content)).toBe(true);
    expect((sent.attachments[0].content as Buffer).equals(png)).toBe(true);
    expect(mockClose).toHaveBeenCalledTimes(1);
  });

  it('Test 6 (260914-m97): sendBugReport laesst Transportfehler DURCH (rejects), close() trotzdem; Gegenprobe: sendPasswordResetEmail verschluckt denselben Fehler weiterhin (T-02-12)', async () => {
    mockSendMail = vi.fn(async () => {
      throw new Error('ECONNREFUSED smtp-a.example.invalid');
    });
    const settings = makeFakeSettings({ t1: configA });
    const service = new MailService(settings as any, makeFakeConfig({}) as any);
    const errorSpy = vi.spyOn((service as any).logger, 'error').mockImplementation(() => undefined);

    await expect(
      service.sendBugReport('t1', 'fehler@a.example.invalid', { subject: 'S', text: 'T', attachments: [] }),
    ).rejects.toThrow('ECONNREFUSED');
    expect(mockClose).toHaveBeenCalledTimes(1);

    await expect(
      service.sendPasswordResetEmail('alice@a.example.invalid', 'tok-1', 't1'),
    ).resolves.toBeUndefined();
    expect(mockClose).toHaveBeenCalledTimes(2);
    expect(errorSpy).toHaveBeenCalled();
  });
});

describe('MailService.sendReminderEmail (quick-260929-if2, E-04/E-07, T-IF2-05)', () => {
  const dueAt = new Date('2026-10-05T12:30:00.000Z'); // 14:30 in Europe/Berlin (Sommerzeit)

  function make() {
    return new MailService(makeFakeSettings({ t1: configA }) as any, makeFakeConfig({}) as any);
  }

  it('sendet Betreff "Erinnerung: <Titel>" mit Berliner Zeit, Titel, Beschreibung und App-Adresse; true bei Erfolg', async () => {
    const ok = await make().sendReminderEmail('t1', 'alice@a.example.invalid', {
      title: 'Zahnarzt',
      description: 'Kartenlesegeraet mitnehmen',
      dueAt,
    });
    expect(ok).toBe(true);
    const sent = mockSendMail.mock.calls[0][0] as any;
    expect(sent.to).toBe('alice@a.example.invalid');
    expect(sent.from).toBe('noreply@a.example.invalid');
    expect(sent.subject).toBe('Erinnerung: Zahnarzt');
    expect(sent.html).toBeUndefined();
    expect(sent.text).toContain('14:30 Uhr');
    expect(sent.text).toContain('Zahnarzt');
    expect(sent.text).toContain('Kartenlesegeraet mitnehmen');
    expect(sent.text).toContain('http://localhost:3000');
    expect(mockClose).toHaveBeenCalledTimes(1);
  });

  it('entfernt CR/LF aus dem Betreff und kuerzt auf 150 Zeichen', async () => {
    await make().sendReminderEmail('t1', 'a@a.example.invalid', {
      title: `Zeile1\r\nBcc: boese@example.invalid ${'x'.repeat(300)}`,
      description: '',
      dueAt,
    });
    const sent = mockSendMail.mock.calls[0][0] as any;
    expect(sent.subject).not.toMatch(/[\r\n]/);
    expect(sent.subject.length).toBe(150);
    expect(sent.subject.startsWith('Erinnerung: Zeile1 Bcc:')).toBe(true);
  });

  it('laesst die Beschreibung weg, wenn sie leer ist', async () => {
    await make().sendReminderEmail('t1', 'a@a.example.invalid', { title: 'T', description: '  ', dueAt });
    const sent = mockSendMail.mock.calls[0][0] as any;
    expect(sent.text.split('\n')).toEqual([
      'Guten Tag,',
      '',
      expect.stringContaining('eine Erinnerung für'),
      '',
      'T',
      '',
      'http://localhost:3000',
    ]);
  });

  it('gibt false zurueck (wirft nicht), wenn der Transport scheitert', async () => {
    mockSendMail = vi.fn(async () => {
      throw new Error('SMTP down');
    });
    const ok = await make().sendReminderEmail('t1', 'a@a.example.invalid', {
      title: 'T',
      description: '',
      dueAt,
    });
    expect(ok).toBe(false);
    expect(mockClose).toHaveBeenCalledTimes(1);
  });
});

describe('MailService.sendWelcomeMail / hasConfiguredTransport (Willkommensmail)', () => {
  it('haengt das Kopfbild als CID-Anhang an, reicht HTML und Text durch und wirft Transportfehler nach aussen', async () => {
    const service = new MailService(makeFakeSettings({ t1: configA }) as any, makeFakeConfig({}) as any);

    await service.sendWelcomeMail('t1', 'neu@a.example.invalid', {
      subject: 'Willkommen bei Tessera',
      text: 'Text',
      html: `<img src="cid:${WELCOME_HEADER_CID}">`,
    });

    const sent = mockSendMail.mock.calls[0][0] as any;
    expect(sent.from).toBe('noreply@a.example.invalid');
    expect(sent.html).toContain(`cid:${WELCOME_HEADER_CID}`);
    expect(sent.text).toBe('Text');
    expect(sent.attachments).toHaveLength(1);
    expect(sent.attachments[0].cid).toBe(WELCOME_HEADER_CID);
    expect(sent.attachments[0].contentType).toBe('image/png');
    // PNG-Signatur: das Bild aus apps/api/assets/mail ist wirklich geladen.
    expect((sent.attachments[0].content as Buffer).subarray(1, 4).toString()).toBe('PNG');

    mockSendMail = vi.fn(async () => {
      throw new Error('ECONNREFUSED');
    });
    await expect(
      service.sendWelcomeMail('t1', 'neu@a.example.invalid', { subject: 'S', text: 'T', html: 'H' }),
    ).rejects.toThrow('ECONNREFUSED');
  });

  it('hasConfiguredTransport: SmtpConfig des Mandanten oder MAIL_HOST/TESSERA_SMTP_HOST — der Rueckfall localhost:1025 zaehlt nicht', async () => {
    expect(
      await new MailService(makeFakeSettings({ t1: configA }) as any, makeFakeConfig({}) as any).hasConfiguredTransport('t1'),
    ).toBe(true);
    expect(
      await new MailService(makeFakeSettings({}) as any, makeFakeConfig({ MAIL_HOST: 'smtp.example.invalid' }) as any).hasConfiguredTransport('t1'),
    ).toBe(true);
    expect(
      await new MailService(makeFakeSettings({}) as any, makeFakeConfig({ TESSERA_SMTP_HOST: 'legacy.example.invalid' }) as any).hasConfiguredTransport('t1'),
    ).toBe(true);
    expect(
      await new MailService(makeFakeSettings({}) as any, makeFakeConfig({}) as any).hasConfiguredTransport('t1'),
    ).toBe(false);
  });
});