import crypto from 'node:crypto';
import { describe, expect, it, vi } from 'vitest';
import { newUlid } from '../../src/core/ids.js';
import {
  createVapidAuthorizationHeader,
  encryptPushPayload,
  generateVapidKeys,
  resolveVapidKeys,
  sendWebPush,
} from '../../src/domain/notification/web-push.js';
import { PushDispatcher } from '../../src/domain/notification/push-dispatcher.js';

function createTestRecipient() {
  const ecdh = crypto.createECDH('prime256v1');
  ecdh.generateKeys();
  const auth = crypto.randomBytes(16);
  return {
    ecdh,
    publicKey: ecdh.getPublicKey(), // 65 bytes
    auth,
    keys: {
      p256dh: ecdh.getPublicKey().toString('base64url'),
      auth: auth.toString('base64url'),
    },
  };
}

function decryptPushPayload(
  encrypted: Buffer,
  recipient: ReturnType<typeof createTestRecipient>,
): string {
  const salt = encrypted.subarray(0, 16);
  const idlen = encrypted[20]!;
  const senderPublicKey = encrypted.subarray(21, 21 + idlen);
  const ciphertextAndTag = encrypted.subarray(21 + idlen);
  const ciphertext = ciphertextAndTag.subarray(0, ciphertextAndTag.length - 16);
  const tag = ciphertextAndTag.subarray(ciphertextAndTag.length - 16);

  const sharedSecret = recipient.ecdh.computeSecret(senderPublicKey);
  const keyInfo = Buffer.concat([
    Buffer.from('WebPush: info\0', 'utf8'),
    recipient.publicKey,
    senderPublicKey,
  ]);
  const prk = Buffer.from(
    crypto.hkdfSync('sha256', sharedSecret, recipient.auth, keyInfo, 32),
  );

  const cekInfo = Buffer.from('Content-Encoding: aes128gcm\0', 'utf8');
  const cek = Buffer.from(crypto.hkdfSync('sha256', prk, salt, cekInfo, 16));

  const nonceInfo = Buffer.from('Content-Encoding: nonce\0', 'utf8');
  const nonce = Buffer.from(crypto.hkdfSync('sha256', prk, salt, nonceInfo, 12));

  const decipher = crypto.createDecipheriv('aes-128-gcm', cek, nonce);
  decipher.setAuthTag(tag);
  const decryptedRecord = Buffer.concat([decipher.update(ciphertext), decipher.final()]);

  // Strip trailing delimiter byte (0x02)
  expect(decryptedRecord[decryptedRecord.length - 1]).toBe(0x02);
  return decryptedRecord.subarray(0, decryptedRecord.length - 1).toString('utf8');
}

describe('WebPush VAPID key management', () => {
  it('generates valid uncompressed P-256 public keys and scalar private keys', () => {
    const keys = generateVapidKeys('mailto:test@krona.local');
    const pubBuf = Buffer.from(keys.publicKey, 'base64url');
    expect(pubBuf).toHaveLength(65);
    expect(pubBuf[0]).toBe(0x04);
    expect(keys.subject).toBe('mailto:test@krona.local');
    expect(keys.privateKey.length).toBeGreaterThanOrEqual(40);
  });

  it('provides safe ephemeral fallback keys in development/test when env keys are absent', () => {
    const keys1 = resolveVapidKeys({});
    const keys2 = resolveVapidKeys({});
    expect(keys1.publicKey).toBe(keys2.publicKey);
    expect(keys1.privateKey).toBe(keys2.privateKey);
  });

  it('rejects mismatched VAPID configuration when only one key is set', () => {
    expect(() =>
      resolveVapidKeys({ VAPID_PUBLIC_KEY: 'only-pub' }),
    ).toThrow(/must be configured together/);
    expect(() =>
      resolveVapidKeys({ VAPID_PRIVATE_KEY: 'only-priv' }),
    ).toThrow(/must be configured together/);
  });
});

describe('WebPush RFC 8292 VAPID Authorization', () => {
  it('signs an ES256 JWT with audience matching the push service origin', () => {
    const vapidKeys = generateVapidKeys('mailto:admin@krona.local');
    const endpoint = 'https://fcm.googleapis.com/fcm/send/sub-123';
    const authHeader = createVapidAuthorizationHeader(endpoint, vapidKeys);

    expect(authHeader).toMatch(/^vapid t=[a-zA-Z0-9_-]+\.[a-zA-Z0-9_-]+\.[a-zA-Z0-9_-]+, k=/);

    const match = authHeader.match(/^vapid t=([^,]+), k=(.+)$/);
    expect(match).not.toBeNull();
    const jwt = match?.[1];
    const pubKey = match?.[2];
    expect(pubKey).toBe(vapidKeys.publicKey);
    if (!jwt) {
      throw new Error('jwt missing');
    }

    const parts = jwt.split('.');
    expect(parts).toHaveLength(3);
    const [headerB64, payloadB64, sigB64] = parts;
    if (!headerB64 || !payloadB64 || !sigB64) {
      throw new Error('jwt parts missing');
    }

    const header = JSON.parse(Buffer.from(headerB64, 'base64url').toString('utf8')) as {
      typ: string;
      alg: string;
    };
    const payload = JSON.parse(Buffer.from(payloadB64, 'base64url').toString('utf8')) as {
      aud: string;
      sub: string;
      exp: number;
    };

    expect(header).toEqual({ typ: 'JWT', alg: 'ES256' });
    expect(payload.aud).toBe('https://fcm.googleapis.com');
    expect(payload.sub).toBe('mailto:admin@krona.local');
    expect(payload.exp).toBeGreaterThan(Math.floor(Date.now() / 1000));

    // Verify ECDSA P-256 signature
    const signingInput = `${headerB64}.${payloadB64}`;
    const pubBuf = Buffer.from(vapidKeys.publicKey, 'base64url');
    const x = pubBuf.subarray(1, 33).toString('base64url');
    const y = pubBuf.subarray(33, 65).toString('base64url');
    const publicKeyObject = crypto.createPublicKey({
      key: { kty: 'EC', crv: 'P-256', x, y },
      format: 'jwk',
    });

    const isValid = crypto.verify(
      'SHA256',
      Buffer.from(signingInput, 'utf8'),
      { key: publicKeyObject, dsaEncoding: 'ieee-p1363' },
      Buffer.from(sigB64, 'base64url'),
    );
    expect(isValid).toBe(true);
  });
});

describe('WebPush RFC 8291 / RFC 8188 AES-128-GCM encryption', () => {
  it('encrypts and successfully decrypts payload with recipient keys', () => {
    const recipient = createTestRecipient();
    const originalText = JSON.stringify({
      title: 'Krona Staff',
      body: 'Отметка рабочего времени зарегистрирована',
    });

    const encrypted = encryptPushPayload(originalText, recipient.keys);
    expect(encrypted.length).toBeGreaterThan(originalText.length);

    // Verify RFC 8188 header structure
    const salt = encrypted.subarray(0, 16);
    expect(salt).toHaveLength(16);
    const rs = encrypted.readUInt32BE(16);
    expect(rs).toBe(4096);
    const idlen = encrypted[20];
    expect(idlen).toBe(65);

    // Decrypt and verify roundtrip
    const decrypted = decryptPushPayload(encrypted, recipient);
    expect(decrypted).toBe(originalText);
  });

  it('rejects invalid recipient keys with clear error', () => {
    expect(() =>
      encryptPushPayload('test', { p256dh: 'invalid', auth: 'invalid' }),
    ).toThrow(/Invalid recipient/);
  });
});

describe('Push notification privacy (Requirement 2)', () => {
  it('guarantees push notification body contains only neutral text without PII', () => {
    const payload = {
      title: 'Krona Staff',
      body: 'Отметка рабочего времени зарегистрирована',
      icon: '/staff/icon-192.svg',
      badge: '/staff/icon-192.svg',
      tag: 'attendance',
      data: { url: '/staff', event_type: 'attendance.clock.in' },
    };

    const serialized = JSON.stringify(payload);
    // Neutral text check
    expect(payload.body).toBe('Отметка рабочего времени зарегистрирована');
    // Ensure no name, salary, personal identifiers, or money values
    expect(serialized).not.toMatch(/Иван|Петр|Сидор|зарплат|руб|₽|amount|salary|minor/i);
  });
});

describe('sendWebPush delivery handling', () => {
  it('enforces HTTPS on subscription endpoints', async () => {
    const vapidKeys = generateVapidKeys();
    const recipient = createTestRecipient();
    await expect(
      sendWebPush(
        { endpoint: 'http://insecure.example.com/push', keys: recipient.keys },
        'test',
        vapidKeys,
      ),
    ).rejects.toThrow(/Subscription endpoint must use HTTPS/);
  });

  it('reports successful delivery on 201 Created from push service', async () => {
    const vapidKeys = generateVapidKeys();
    const recipient = createTestRecipient();
    const mockFetch = vi.fn(async () => new Response(null, { status: 201 }));

    const result = await sendWebPush(
      { endpoint: 'https://push.example.com/sub/1', keys: recipient.keys },
      'test payload',
      vapidKeys,
      { fetchFn: mockFetch as unknown as typeof fetch },
    );

    expect(result.successful).toBe(true);
    expect(result.statusCode).toBe(201);
    expect(result.shouldRemoveSubscription).toBe(false);
  });

  it('flags 404 and 410 for expired subscription removal', async () => {
    const vapidKeys = generateVapidKeys();
    const recipient = createTestRecipient();
    const mockFetch410 = vi.fn(async () => new Response('Gone', { status: 410 }));

    const result = await sendWebPush(
      { endpoint: 'https://push.example.com/sub/expired', keys: recipient.keys },
      'test payload',
      vapidKeys,
      { fetchFn: mockFetch410 as unknown as typeof fetch },
    );

    expect(result.successful).toBe(false);
    expect(result.statusCode).toBe(410);
    expect(result.shouldRemoveSubscription).toBe(true);
  });
});

describe('PushDispatcher idempotent outbox handling', () => {
  const tenantId = '01J00000000000000000000000';
  const systemActorId = '01J00000000000000000000001';
  const employeeId = '01J00000000000000000000002';
  const outboxId = '01J00000000000000000000003';
  const vapidKeys = generateVapidKeys();

  function mockDb(responses: Array<Array<Record<string, unknown>>>) {
    const queries: Array<{ sql: string; params: readonly unknown[] | undefined }> = [];
    const database = {
      tenantTransaction: vi.fn(
        async (
          _tenant: unknown,
          _actor: unknown,
          callback: (client: { query: typeof queryFn }) => Promise<unknown>,
        ) => {
          return callback({ query: queryFn });
        },
      ),
    };

    async function queryFn(sql: string, params?: readonly unknown[]) {
      queries.push({ sql, params });
      const rows = responses.shift() ?? [];
      return { rows, rowCount: rows.length };
    }

    return { database: database as never, queries };
  }

  it('rejects saving non-HTTPS subscription endpoints', async () => {
    const { database } = mockDb([]);
    const dispatcher = new PushDispatcher({ database, vapidKeys, systemActorId });

    await expect(
      dispatcher.saveSubscription(tenantId, employeeId, {
        endpoint: 'http://plain-http.example.com/sub',
        p256dh: 'p256dh',
        auth: 'auth',
      }),
    ).rejects.toThrow(/Subscription endpoint must use HTTPS/);
  });

  it('leaves the platform outbox untouched when employee has no subscriptions', async () => {
    const { database, queries } = mockDb([
      // 1. SELECT staff_outbox
      [
        {
          id: outboxId,
          tenant_id: tenantId,
          event_type: 'attendance.clock.in',
          subject_id: employeeId,
          payload: {},
          published_at: null,
          attempts: 0,
        },
      ],
      // 2. SELECT staff_push_subscriptions (empty)
      [],
    ]);

    const dispatcher = new PushDispatcher({ database, vapidKeys, systemActorId });
    const report = await dispatcher.dispatchForOutbox(tenantId, outboxId);

    expect(report.published).toBe(true);
    expect(report.subscriptionsFound).toBe(0);
    expect(queries).toHaveLength(2);
    expect(queries.some((q) => q.sql.includes('UPDATE staff_outbox'))).toBe(false);
  });

  it('deletes only a subscription owned by the current employee', async () => {
    const endpoint = 'https://push.example.com/sub/current-device';
    const { database, queries } = mockDb([[{ id: newUlid() }]]);
    const dispatcher = new PushDispatcher({ database, vapidKeys, systemActorId });

    await dispatcher.deleteSubscription(tenantId, employeeId, endpoint);

    expect(queries[0]?.sql).toContain('employee_id = $2');
    expect(queries[0]?.params).toEqual([tenantId, employeeId, endpoint]);
  });

  it('delivers push idempotently and avoids duplicate delivery', async () => {
    const recipient = createTestRecipient();
    const endpoint = 'https://push.example.com/sub/active';
    const mockFetch = vi.fn(async () => new Response(null, { status: 201 }));

    const { database, queries } = mockDb([
      // 1. SELECT staff_outbox
      [
        {
          id: outboxId,
          tenant_id: tenantId,
          event_type: 'attendance.clock.in',
          subject_id: employeeId,
          payload: {},
          published_at: null,
          attempts: 0,
        },
      ],
      // 2. SELECT staff_push_subscriptions
      [
        {
          id: newUlid(),
          endpoint,
          p256dh: recipient.keys.p256dh,
          auth: recipient.keys.auth,
          user_agent: 'TestAgent',
        },
      ],
      // 3. INSERT staff_notification_deliveries ON CONFLICT DO NOTHING
      [],
      // 4. SELECT current delivery record
      [{ id: newUlid(), status: 'pending', attempts: 0 }],
      // 5. UPDATE delivery to delivered
      [],
    ]);

    const dispatcher = new PushDispatcher({
      database,
      vapidKeys,
      systemActorId,
      fetchFn: mockFetch,
    });

    const report = await dispatcher.dispatchForOutbox(tenantId, outboxId);

    expect(report.published).toBe(true);
    expect(report.subscriptionsFound).toBe(1);
    expect(report.deliveries[0]?.status).toBe('delivered');
    expect(mockFetch).toHaveBeenCalledTimes(1);

    // Push delivery is tracked independently from platform event publication.
    expect(queries.some((q) => q.sql.includes('staff_notification_deliveries') && q.sql.includes('delivered'))).toBe(true);
    expect(queries.some((q) => q.sql.includes('UPDATE staff_outbox'))).toBe(false);
  });

  it('skips sending if endpoint was already delivered (idempotency check)', async () => {
    const recipient = createTestRecipient();
    const endpoint = 'https://push.example.com/sub/active';
    const mockFetch = vi.fn(async () => new Response(null, { status: 201 }));

    const { database } = mockDb([
      // 1. SELECT staff_outbox
      [
        {
          id: outboxId,
          tenant_id: tenantId,
          event_type: 'attendance.clock.in',
          subject_id: employeeId,
          payload: {},
          published_at: null,
          attempts: 0,
        },
      ],
      // 2. SELECT staff_push_subscriptions
      [
        {
          id: newUlid(),
          endpoint,
          p256dh: recipient.keys.p256dh,
          auth: recipient.keys.auth,
          user_agent: 'TestAgent',
        },
      ],
      // 3. INSERT delivery ON CONFLICT DO NOTHING
      [],
      // 4. SELECT current delivery: already 'delivered'
      [{ id: newUlid(), status: 'delivered', attempts: 1 }],
      // 5. UPDATE outbox to published
      [],
    ]);

    const dispatcher = new PushDispatcher({
      database,
      vapidKeys,
      systemActorId,
      fetchFn: mockFetch,
    });

    const report = await dispatcher.dispatchForOutbox(tenantId, outboxId);

    expect(report.deliveries[0]?.status).toBe('skipped');
    expect(mockFetch).not.toHaveBeenCalled();
    expect(report.published).toBe(true);
  });

  it('deletes expired subscription from staff_push_subscriptions on 410 Gone', async () => {
    const recipient = createTestRecipient();
    const endpoint = 'https://push.example.com/sub/expired';
    const mockFetch = vi.fn(async () => new Response('Expired', { status: 410 }));

    const { database, queries } = mockDb([
      // 1. SELECT staff_outbox
      [
        {
          id: outboxId,
          tenant_id: tenantId,
          event_type: 'attendance.clock.out',
          subject_id: employeeId,
          payload: {},
          published_at: null,
          attempts: 0,
        },
      ],
      // 2. SELECT staff_push_subscriptions
      [
        {
          id: newUlid(),
          endpoint,
          p256dh: recipient.keys.p256dh,
          auth: recipient.keys.auth,
          user_agent: 'TestAgent',
        },
      ],
      // 3. INSERT delivery
      [],
      // 4. SELECT delivery
      [{ id: newUlid(), status: 'pending', attempts: 0 }],
      // 5. UPDATE delivery to failed AND DELETE subscription
      [],
      // 6. UPDATE outbox
      [],
    ]);

    const dispatcher = new PushDispatcher({
      database,
      vapidKeys,
      systemActorId,
      fetchFn: mockFetch,
    });

    const report = await dispatcher.dispatchForOutbox(tenantId, outboxId);

    expect(report.deliveries[0]?.status).toBe('failed');
    expect(queries.some((q) => q.sql.includes('DELETE FROM staff_push_subscriptions'))).toBe(true);
  });
});