import { randomUUID } from 'node:crypto';
import { INestApplication } from '@nestjs/common';
import request from 'supertest';
import { App } from 'supertest/types';
import { PrismaThrottlerStorage } from '../src/common/throttler/prisma-throttler.storage';
import { PrismaService } from '../src/prisma/prisma.service';
import { createTestApp } from './utils/create-test-app';

// Public batches allow 30 requests per minute and client network.
const PUBLIC_BATCH_LIMIT = 30;
const PARALLEL_REQUESTS = 40;

describe('Database-backed throttler (e2e)', () => {
  const suffix = randomUUID();
  const path = `/api/v1/public/batches/NONE-${suffix}`;
  const namespaces: string[] = [];
  const apps: INestApplication<App>[] = [];
  let prisma: PrismaService;

  const newApp = async (
    throttlerNamespace: string,
  ): Promise<INestApplication<App>> => {
    namespaces.push(throttlerNamespace);
    const app = await createTestApp({ throttlerNamespace });
    apps.push(app);
    prisma = app.get(PrismaService);
    return app;
  };

  const status = async (app: INestApplication<App>): Promise<number> =>
    (await request(app.getHttpServer()).get(path)).status;

  afterAll(async () => {
    for (const ns of namespaces) {
      await prisma.throttlerHit.deleteMany({
        where: { key: { startsWith: `${ns}:` } },
      });
    }
    for (const app of apps) await app.close();
  });

  it('counts across two app instances sharing one namespace', async () => {
    const ns = randomUUID();
    const [a, b] = [await newApp(ns), await newApp(ns)];

    for (let i = 0; i < PUBLIC_BATCH_LIMIT; i += 1) {
      await request((i % 2 ? a : b).getHttpServer())
        .get(path)
        .expect(404);
    }

    await request(a.getHttpServer()).get(path).expect(429);
    await request(b.getHttpServer()).get(path).expect(429);
  });

  it('40 parallel requests over two instances yield exactly 10 × 429', async () => {
    const ns = randomUUID();
    const [a, b] = [await newApp(ns), await newApp(ns)];

    const statuses = await Promise.all(
      Array.from({ length: PARALLEL_REQUESTS }, (_, i) =>
        status(i % 2 ? a : b),
      ),
    );

    expect(statuses.filter((s) => s === 429)).toHaveLength(
      PARALLEL_REQUESTS - PUBLIC_BATCH_LIMIT,
    );
    expect(statuses.filter((s) => s === 404)).toHaveLength(PUBLIC_BATCH_LIMIT);
  });

  it('separate namespaces never share counters', async () => {
    const [a, b] = [await newApp(randomUUID()), await newApp(randomUUID())];

    for (let i = 0; i < PUBLIC_BATCH_LIMIT; i += 1) {
      await request(a.getHttpServer()).get(path).expect(404);
    }
    await request(a.getHttpServer()).get(path).expect(429);

    await request(b.getHttpServer()).get(path).expect(404);
  });

  it('an expired window starts again at 1', async () => {
    const ns = randomUUID();
    await newApp(ns);
    const storage = apps[apps.length - 1].get(PrismaThrottlerStorage);

    for (let i = 0; i < 3; i += 1) {
      await storage.increment('window', 60000, 10, 60000, 'default');
    }
    // The window ends in the past, decided by the database clock.
    await prisma.$executeRaw`
      UPDATE "ThrottlerHit"
      SET "expiresAt" = now() - interval '1 second'
      WHERE "key" = ${`${ns}:window`}`;

    const record = await storage.increment(
      'window',
      60000,
      10,
      60000,
      'default',
    );

    expect(record.totalHits).toBe(1);
    expect(record.isBlocked).toBe(false);
    expect(record.timeToExpire).toBeGreaterThan(0);
    expect(record.timeToExpire).toBeLessThanOrEqual(60);
  });

  it('never reports more seconds than the ttl or the block duration (sub-ms rounding)', async () => {
    const ns = randomUUID();
    await newApp(ns);
    const storage = apps[apps.length - 1].get(PrismaThrottlerStorage);

    // The column keeps milliseconds while now() has microseconds; rounding
    // up by < 1 ms used to turn 60.0004 s into 61. About half of all
    // timestamps round up, so 60 fresh keys catch it reliably.
    for (let i = 0; i < 60; i += 1) {
      const record = await storage.increment(`ms-${i}`, 60000, 0, 60000, 'd');
      expect(record.timeToExpire).toBeGreaterThanOrEqual(59);
      expect(record.timeToExpire).toBeLessThanOrEqual(60);
      expect(record.isBlocked).toBe(true);
      expect(record.timeToBlockExpire).toBeGreaterThanOrEqual(59);
      expect(record.timeToBlockExpire).toBeLessThanOrEqual(60);
    }
  });

  it('keeps the same bounds when a window restarts or a block starts on an existing row', async () => {
    const ns = randomUUID();
    await newApp(ns);
    const storage = apps[apps.length - 1].get(PrismaThrottlerStorage);
    const sleep = (ms: number): Promise<void> =>
      new Promise((resolve) => setTimeout(resolve, ms));

    for (let i = 0; i < 60; i += 1) {
      // Restart branch: the 1 ms window is over, the row starts again at 1.
      await storage.increment(`re-${i}`, 1, 10, 60000, 'd');
      await sleep(5);
      const restarted = await storage.increment(
        `re-${i}`,
        60000,
        10,
        60000,
        'd',
      );
      expect(restarted.totalHits).toBe(1);
      expect(restarted.timeToExpire).toBeGreaterThanOrEqual(59);
      expect(restarted.timeToExpire).toBeLessThanOrEqual(60);

      // Block branch: hits + 1 > limit on an open window sets blockedUntil.
      await storage.increment(`bl-${i}`, 60000, 1, 60000, 'd');
      const blocked = await storage.increment(`bl-${i}`, 60000, 1, 60000, 'd');
      expect(blocked.isBlocked).toBe(true);
      expect(blocked.timeToBlockExpire).toBeGreaterThanOrEqual(59);
      expect(blocked.timeToBlockExpire).toBeLessThanOrEqual(60);
    }
  });

  it('keeps hits while blocked and releases the block after it expired', async () => {
    const ns = randomUUID();
    await newApp(ns);
    const storage = apps[apps.length - 1].get(PrismaThrottlerStorage);

    await storage.increment('block', 60000, 1, 60000, 'default');
    const blocked = await storage.increment(
      'block',
      60000,
      1,
      60000,
      'default',
    );
    expect(blocked.isBlocked).toBe(true);
    expect(blocked.totalHits).toBe(2);
    expect(blocked.timeToBlockExpire).toBeGreaterThan(0);

    const stillBlocked = await storage.increment(
      'block',
      60000,
      1,
      60000,
      'default',
    );
    expect(stillBlocked.isBlocked).toBe(true);
    expect(stillBlocked.totalHits).toBe(2);

    await prisma.$executeRaw`
      UPDATE "ThrottlerHit"
      SET "blockedUntil" = now() - interval '1 second'
      WHERE "key" = ${`${ns}:block`}`;

    const released = await storage.increment(
      'block',
      60000,
      1,
      60000,
      'default',
    );
    expect(released.isBlocked).toBe(false);
    expect(released.totalHits).toBe(1);
    expect(released.timeToBlockExpire).toBe(0);
  });

  it('blocks the first hit when the limit is 0', async () => {
    const ns = randomUUID();
    await newApp(ns);
    const storage = apps[apps.length - 1].get(PrismaThrottlerStorage);

    const first = await storage.increment('zero', 60000, 0, 60000, 'default');
    expect(first.isBlocked).toBe(true);
    expect(first.totalHits).toBe(1);

    // Same after a window or block has expired.
    await prisma.$executeRaw`
      UPDATE "ThrottlerHit"
      SET "expiresAt" = now() - interval '1 second',
          "blockedUntil" = now() - interval '1 second'
      WHERE "key" = ${`${ns}:zero`}`;
    const again = await storage.increment('zero', 60000, 0, 60000, 'default');
    expect(again.isBlocked).toBe(true);
    expect(again.totalHits).toBe(1);
  });
});