/**
 * Integration test: end-to-end pipeline round-trip via testcontainers.
 *
 * Spins up Redis 7 and TimescaleDB-HA (timescale/timescaledb-ha:pg16.6-ts2.17.2-all,
 * matching the deploy stack image) containers, runs the Processor migration,
 * starts the consumer pipeline, publishes synthetic Position records, and asserts
 * the resulting rows in `positions`. The `-all` image variant ships PostGIS too,
 * so the migration's `CREATE EXTENSION IF NOT EXISTS postgis` succeeds.
 *
 * If Docker is unavailable (CI runner without Docker, local dev without Docker
 * Desktop), the suite skips — it does not fail the build. Docker availability is
 * determined by a container start attempt in beforeAll; the skip flag is set once,
 * and each `it` block early-returns when `!dockerAvailable`.
 *
 * WARNING: Do NOT replace the early-return skip pattern with a try/catch alone.
 * A hang does not throw; only an explicit `!dockerAvailable` check per test
 * guarantees that unavailable Docker exits cleanly (see tcp-ingestion history).
 */

import { describe, it, expect, beforeAll, afterAll } from 'vitest';
import { GenericContainer, type StartedTestContainer, Wait } from 'testcontainers';
import type { Redis } from 'ioredis';
import type pg from 'pg';
import type { ConsumedRecord } from '../src/core/consumer.js';
import { createConsumer, connectRedis, ensureConsumerGroup } from '../src/core/consumer.js';
import { createWriter } from '../src/core/writer.js';
import { createDeviceStateStore } from '../src/core/state.js';
import { createPool, connectWithRetry } from '../src/db/pool.js';
import { runMigrations } from '../src/db/migrate.js';
import { createMetrics } from '../src/observability/metrics.js';
import type { Config } from '../src/config/load.js';
import type { Position } from '../src/core/types.js';
import { vi } from 'vitest';
import type { Logger } from 'pino';

// ---------------------------------------------------------------------------
// Helpers
// ---------------------------------------------------------------------------

function makeSilentLogger(): Logger {
  return {
    debug: vi.fn(),
    info: vi.fn(),
    warn: vi.fn(),
    error: vi.fn(),
    fatal: vi.fn(),
    trace: vi.fn(),
    child: vi.fn().mockReturnThis(),
    level: 'silent',
    silent: vi.fn(),
  } as unknown as Logger;
}

function makeConfig(overrides: Partial<Config> = {}): Config {
  return {
    NODE_ENV: 'test',
    INSTANCE_ID: 'test-integration',
    LOG_LEVEL: 'silent',
    REDIS_URL: 'redis://localhost:6379', // overridden below with mapped port
    POSTGRES_URL: 'postgres://postgres:postgres@localhost:5432/trm', // overridden below
    REDIS_TELEMETRY_STREAM: 'telemetry:t',
    REDIS_CONSUMER_GROUP: 'processor',
    REDIS_CONSUMER_NAME: 'test-consumer',
    METRICS_PORT: 0,
    BATCH_SIZE: 100,
    BATCH_BLOCK_MS: 500,
    WRITE_BATCH_SIZE: 50,
    DEVICE_STATE_LRU_CAP: 10_000,
    ...overrides,
  };
}

/**
 * Serializes a Position into the flat field map that XADD expects.
 * Mirrors tcp-ingestion's serializePosition format exactly: bigint → __bigint
 * sentinel, Buffer → __buffer_b64 sentinel, Date → ISO string.
 */
function buildXaddFields(position: Position, codec: string): string[] {
  function jsonReplacer(_key: string, value: unknown): unknown {
    if (typeof value === 'bigint') return { __bigint: value.toString() };
    if (value instanceof Uint8Array) {
      return { __buffer_b64: Buffer.from(value).toString('base64') };
    }
    if (value instanceof Date) return value.toISOString();
    return value;
  }

  const payload = JSON.stringify(position, jsonReplacer);
  return [
    'ts', position.timestamp.toISOString(),
    'device_id', position.device_id,
    'codec', codec,
    'payload', payload,
  ];
}

/**
 * Polls `fn` up to `timeoutMs` with `intervalMs` gaps until it returns a
 * truthy result. Returns null if the timeout expires.
 */
async function pollUntil<T>(
  fn: () => Promise<T | null | undefined>,
  timeoutMs: number,
  intervalMs = 200,
): Promise<T | null> {
  const deadline = Date.now() + timeoutMs;
  while (Date.now() < deadline) {
    const result = await fn();
    if (result !== null && result !== undefined) return result as T;
    await new Promise<void>((resolve) => setTimeout(resolve, intervalMs));
  }
  return null;
}

// ---------------------------------------------------------------------------
// Container and pipeline lifecycle
// ---------------------------------------------------------------------------

let redisContainer: StartedTestContainer | null = null;
let pgContainer: StartedTestContainer | null = null;
let redisClient: Redis | null = null;
let pgPool: pg.Pool | null = null;
let consumer: { start: () => Promise<void>; stop: () => Promise<void> } | null = null;
let dockerAvailable = true;

const STREAM = 'telemetry:t';
const GROUP = 'processor';

beforeAll(async () => {
  // --- Step 1: start Redis container -----------------------------------------
  try {
    redisContainer = await new GenericContainer('redis:7-alpine')
      .withExposedPorts(6379)
      .withWaitStrategy(Wait.forLogMessage('Ready to accept connections'))
      .start();
  } catch {
    console.warn(
      '[pipeline.integration.test] Docker not available — skipping integration tests',
    );
    dockerAvailable = false;
    return;
  }

  // --- Step 2: start TimescaleDB-HA container (same image as deploy stack) ---
  try {
    pgContainer = await new GenericContainer('timescale/timescaledb-ha:pg16.6-ts2.17.2-all')
      .withExposedPorts(5432)
      .withEnvironment({
        POSTGRES_USER: 'postgres',
        POSTGRES_PASSWORD: 'postgres',
        POSTGRES_DB: 'trm',
      })
      .withWaitStrategy(Wait.forLogMessage('database system is ready to accept connections', 2))
      .start();
  } catch (err) {
    console.warn(
      `[pipeline.integration.test] Failed to start TimescaleDB-HA container: ${String(err)} — skipping`,
    );
    dockerAvailable = false;
    await redisContainer?.stop().catch(() => {});
    redisContainer = null;
    return;
  }

  const redisHost = redisContainer.getHost();
  const redisPort = redisContainer.getMappedPort(6379);
  const pgHost = pgContainer.getHost();
  const pgPort = pgContainer.getMappedPort(5432);

  const redisUrl = `redis://${redisHost}:${redisPort}`;
  const postgresUrl = `postgres://postgres:postgres@${pgHost}:${pgPort}/trm`;

  const config = makeConfig({ REDIS_URL: redisUrl, POSTGRES_URL: postgresUrl });
  const logger = makeSilentLogger();

  // --- Step 3: connect Redis --------------------------------------------------
  const { default: Redis } = await import('ioredis');
  const client = new Redis(redisUrl, {
    enableOfflineQueue: false,
    lazyConnect: true,
    maxRetriesPerRequest: 0,
  });
  await client.connect();
  redisClient = client;

  // --- Step 4: connect Postgres and run migrations ---------------------------
  pgPool = createPool(postgresUrl);
  await connectWithRetry(pgPool, logger);
  await runMigrations(pgPool, logger);

  // --- Step 5: wire and start the consumer pipeline -------------------------
  const metrics = createMetrics();
  const state = createDeviceStateStore(config, logger);
  const writer = createWriter(pgPool, config, logger, metrics);

  await ensureConsumerGroup(client, STREAM, GROUP, logger);

  const sink = async (records: ConsumedRecord[]): Promise<string[]> => {
    for (const record of records) {
      state.update(record.position);
    }
    const results = await writer.write(records);
    return results
      .filter((r) => r.status === 'inserted' || r.status === 'duplicate')
      .map((r) => r.id);
  };

  // Use connectRedis for the consumer's own connection (separate from the
  // redisClient used for XADD in tests) so we mirror production topology.
  const consumerRedis = await connectRedis(redisUrl, logger);
  consumer = createConsumer(consumerRedis, config, logger, metrics, sink);
  await consumer.start();
}, 120_000);

afterAll(async () => {
  await consumer?.stop().catch(() => {});
  await redisClient?.quit().catch(() => {});
  await pgPool?.end().catch(() => {});
  await redisContainer?.stop().catch(() => {});
  await pgContainer?.stop().catch(() => {});
}, 30_000);

// ---------------------------------------------------------------------------
// Integration tests
// ---------------------------------------------------------------------------

describe('pipeline integration — full round-trip', () => {
  // Test 1: happy-path with bigint + Buffer attributes
  it('publishes a Position with bigint and Buffer attributes and verifies the row in positions', async () => {
    if (!dockerAvailable || !redisClient || !pgPool) {
      console.warn('[pipeline.integration.test] skipping test 1: Docker not available');
      return;
    }

    const position: Position = {
      device_id: '356307042441013',
      timestamp: new Date('2024-06-15T12:00:00.000Z'),
      latitude: 54.687157,
      longitude: 25.279652,
      altitude: 130,
      angle: 90,
      speed: 45,
      satellites: 12,
      priority: 0,
      attributes: {
        num_attr: 255,
        big_attr: BigInt('18446744073709551615'), // u64 max
        buf_attr: Buffer.from([0xde, 0xad, 0xbe, 0xef]),
      },
    };

    const fields = buildXaddFields(position, '8E');
    await redisClient.xadd(STREAM, '*', ...fields);

    // Poll until the row appears in positions (up to 10 s).
    type Row = {
      device_id: string;
      ts: Date;
      latitude: number;
      longitude: number;
      attributes: Record<string, unknown>;
    };

    const row = await pollUntil<Row>(async () => {
      const result = await pgPool!.query<Row>(
        'SELECT device_id, ts, latitude, longitude, attributes FROM positions WHERE device_id = $1 AND ts = $2',
        [position.device_id, position.timestamp],
      );
      return result.rows[0] ?? null;
    }, 10_000);

    expect(row).not.toBeNull();
    expect(row!.device_id).toBe(position.device_id);
    expect(row!.latitude).toBeCloseTo(position.latitude, 4);
    expect(row!.longitude).toBeCloseTo(position.longitude, 4);

    // attributes JSONB: bigint stored as decimal string, Buffer as base64 string.
    expect(typeof row!.attributes['big_attr']).toBe('string');
    expect(row!.attributes['big_attr']).toBe('18446744073709551615');

    expect(typeof row!.attributes['buf_attr']).toBe('string');
    const decoded = Buffer.from(row!.attributes['buf_attr'] as string, 'base64');
    expect(decoded).toEqual(Buffer.from([0xde, 0xad, 0xbe, 0xef]));

    expect(row!.attributes['num_attr']).toBe(255);
  }, 30_000);

  // Test 2: idempotency — duplicate (device_id, ts) must not create a second row
  it('does not create a duplicate row when the same (device_id, ts) is published twice', async () => {
    if (!dockerAvailable || !redisClient || !pgPool) {
      console.warn('[pipeline.integration.test] skipping test 2: Docker not available');
      return;
    }

    const position: Position = {
      device_id: 'DUP-DEVICE-001',
      timestamp: new Date('2024-06-15T13:00:00.000Z'),
      latitude: 1.0,
      longitude: 2.0,
      altitude: 10,
      angle: 0,
      speed: 0,
      satellites: 4,
      priority: 0,
      attributes: {},
    };

    const fields = buildXaddFields(position, '8');

    // Publish the same position twice.
    await redisClient.xadd(STREAM, '*', ...fields);
    await redisClient.xadd(STREAM, '*', ...fields);

    // Wait long enough for both entries to be processed.
    await new Promise<void>((resolve) => setTimeout(resolve, 3_000));

    const result = await pgPool.query<{ count: string }>(
      'SELECT COUNT(*) AS count FROM positions WHERE device_id = $1 AND ts = $2',
      [position.device_id, position.timestamp],
    );
    const count = parseInt(result.rows[0]?.count ?? '0', 10);
    expect(count).toBe(1);
  }, 30_000);

  // Test 3: malformed payload — decode error counter increments, entry not ACKed
  it('increments decode error counter and leaves malformed entry pending (not ACKed)', async () => {
    if (!dockerAvailable || !redisClient || !pgPool) {
      console.warn('[pipeline.integration.test] skipping test 3: Docker not available');
      return;
    }

    // Push a stream entry with a broken payload (not valid JSON).
    const badEntryId = await redisClient.xadd(
      STREAM,
      '*',
      'ts', new Date().toISOString(),
      'device_id', 'BAD-DEVICE',
      'codec', '8',
      'payload', 'NOT_VALID_JSON {{{',
    );

    // Wait for the consumer to attempt processing.
    await new Promise<void>((resolve) => setTimeout(resolve, 2_000));

    // The entry should remain in the Pending Entry List (PEL) — it was not ACKed.
    const pendingResult = await redisClient.xpending(
      STREAM,
      GROUP,
      '-',
      '+',
      '100',
    ) as Array<[string, string, number, number]>;

    // Find the bad entry in the PEL.
    const pendingIds = pendingResult.map(([id]) => id);
    expect(pendingIds).toContain(badEntryId);
  }, 30_000);

  // Test 4: writer failure → retry — stop Postgres before publish, restart, verify row lands
  it('retries and writes the row after Postgres recovers from a stopped state', async () => {
    if (!dockerAvailable || !redisClient || !pgPool || !pgContainer) {
      console.warn('[pipeline.integration.test] skipping test 4: Docker not available');
      return;
    }

    const position: Position = {
      device_id: 'RETRY-DEVICE-001',
      timestamp: new Date('2024-06-15T14:00:00.000Z'),
      latitude: 3.0,
      longitude: 4.0,
      altitude: 20,
      angle: 45,
      speed: 10,
      satellites: 8,
      priority: 1,
      attributes: {},
    };

    // Stop Postgres before publishing so the first write attempt fails.
    await pgContainer.stop();

    const fields = buildXaddFields(position, '8');
    await redisClient.xadd(STREAM, '*', ...fields);

    // Wait briefly — the write should fail while Postgres is down.
    await new Promise<void>((resolve) => setTimeout(resolve, 1_500));

    // Restart Postgres.
    pgContainer = await pgContainer.restart();

    // Wait a bit to ensure the new container is accepting connections before
    // reconnecting. The pool will get fresh connections once the TCP stack
    // accepts again.
    await new Promise<void>((resolve) => setTimeout(resolve, 3_000));

    // The entry is still pending in the consumer's PEL; the next XREADGROUP
    // poll will re-deliver it. The pipeline should eventually write it.
    type Row = { device_id: string };
    const row = await pollUntil<Row>(async () => {
      try {
        const result = await pgPool!.query<Row>(
          'SELECT device_id FROM positions WHERE device_id = $1 AND ts = $2',
          [position.device_id, position.timestamp],
        );
        return result.rows[0] ?? null;
      } catch {
        // Pool may throw transiently while connections re-establish.
        return null;
      }
    }, 20_000);

    expect(row).not.toBeNull();
    expect(row!.device_id).toBe(position.device_id);
  }, 60_000);
});