import fs from 'fs';
import path from 'path';

import { afterAll, beforeAll, beforeEach, describe, expect, it } from 'vitest';
import { PythonWorkerPool } from '../../src/python/workerPool';

// Windows CI has severe filesystem delays (antivirus, etc.) - allow up to 90s
// Non-Windows CI can also have timing variance with Python IPC, so use 15s (matching windows-path.test.ts)
const TEST_TIMEOUT = process.platform === 'win32' ? 90000 : 15000;

// Skip on Windows CI due to aggressive file security policies blocking temp file IPC
// Works fine on local Windows and all other platforms
const describeOrSkip = process.platform === 'win32' && process.env.CI ? describe.skip : describe;

describeOrSkip('PythonWorkerPool', () => {
  let singleWorkerPool: PythonWorkerPool;
  let multiWorkerPool: PythonWorkerPool;
  let multiApiPool: PythonWorkerPool;
  const testScriptPath = path.join(__dirname, 'fixtures', 'counter_provider.py');
  const multiApiPath = path.join(__dirname, 'fixtures', 'pool_multi_api.py');
  const fixturesDir = path.join(__dirname, 'fixtures');

  beforeAll(async () => {
    // Create fixtures directory if it doesn't exist
    if (!fs.existsSync(fixturesDir)) {
      fs.mkdirSync(fixturesDir, { recursive: true });
    }

    // Create test fixture with global state
    fs.writeFileSync(
      testScriptPath,
      `
# Global counter - persists across calls within same worker
call_count = 0

def call_api(prompt, options, context):
    global call_count
    call_count += 1
    return {"output": f"Call #{call_count}: {prompt}", "count": call_count}

def reset_call_count():
    global call_count
    call_count = 0
    return {"count": call_count}
`,
    );

    fs.writeFileSync(
      multiApiPath,
      `
def call_api(prompt, options, context):
    return {"output": f"text: {prompt}", "type": "text"}

def call_embedding_api(prompt, options, context):
    return {"output": [0.1, 0.2], "type": "embedding"}
`,
    );

    singleWorkerPool = new PythonWorkerPool(testScriptPath, 'call_api', 1);
    multiWorkerPool = new PythonWorkerPool(testScriptPath, 'call_api', 2);
    multiApiPool = new PythonWorkerPool(multiApiPath, 'call_api', 2);

    await Promise.all([
      singleWorkerPool.initialize(),
      multiWorkerPool.initialize(),
      multiApiPool.initialize(),
    ]);
  });

  beforeEach(async () => {
    await Promise.all([
      singleWorkerPool.execute('reset_call_count', []),
      ...Array.from({ length: multiWorkerPool.getWorkerCount() }, () =>
        multiWorkerPool.execute('reset_call_count', []),
      ),
    ]);
  });

  afterAll(async () => {
    await Promise.all(
      [singleWorkerPool, multiWorkerPool, multiApiPool]
        .filter((pool): pool is PythonWorkerPool => Boolean(pool))
        .map((pool) => pool.shutdown()),
    );

    for (const fixturePath of [testScriptPath, multiApiPath]) {
      if (fs.existsSync(fixturePath)) {
        fs.unlinkSync(fixturePath);
      }
    }
  });

  it(
    'should initialize pool with specified worker count',
    async () => {
      expect(multiWorkerPool.getWorkerCount()).toBe(2);
    },
    TEST_TIMEOUT,
  );

  it('should reject invalid worker counts', async () => {
    // Test zero workers
    const zeroWorkerPool = new PythonWorkerPool(testScriptPath, 'call_api', 0);
    await expect(zeroWorkerPool.initialize()).rejects.toThrow(
      'Invalid worker count: 0. Must be at least 1.',
    );

    // Test negative workers
    const negativeWorkerPool = new PythonWorkerPool(testScriptPath, 'call_api', -1);
    await expect(negativeWorkerPool.initialize()).rejects.toThrow(
      'Invalid worker count: -1. Must be at least 1.',
    );
  });

  it(
    'should execute calls sequentially with 1 worker',
    async () => {
      const result1 = await singleWorkerPool.execute('call_api', ['First', {}, {}]);
      const result2 = await singleWorkerPool.execute('call_api', ['Second', {}, {}]);
      const result3 = await singleWorkerPool.execute('call_api', ['Third', {}, {}]);

      // Same worker, counter increments
      expect(result1.count).toBe(1);
      expect(result2.count).toBe(2);
      expect(result3.count).toBe(3);
    },
    TEST_TIMEOUT,
  );

  it(
    'should handle concurrent calls with multiple workers',
    async () => {
      // Execute 4 calls concurrently
      const promises = [
        multiWorkerPool.execute('call_api', ['Call 1', {}, {}]),
        multiWorkerPool.execute('call_api', ['Call 2', {}, {}]),
        multiWorkerPool.execute('call_api', ['Call 3', {}, {}]),
        multiWorkerPool.execute('call_api', ['Call 4', {}, {}]),
      ];

      const results = await Promise.all(promises);

      // Each worker maintains its own counter
      // With 2 workers, work should be distributed across both (not all to one worker)
      const counts = results.map((r) => r.count);
      const uniqueCounts = new Set(counts);

      // Verify multiple workers were used (at least 2 different counts)
      expect(uniqueCounts.size).toBeGreaterThan(1);

      // Verify all calls completed successfully
      expect(results.length).toBe(4);
    },
    TEST_TIMEOUT,
  );

  it(
    'should queue requests when all workers busy',
    async () => {
      // Start 3 concurrent calls with 1 worker - should queue
      const promises = [
        singleWorkerPool.execute('call_api', ['Q1', {}, {}]),
        singleWorkerPool.execute('call_api', ['Q2', {}, {}]),
        singleWorkerPool.execute('call_api', ['Q3', {}, {}]),
      ];

      const results = await Promise.all(promises);

      // All should complete (queued and executed)
      expect(results.length).toBe(3);
      expect(results[0].count).toBe(1);
      expect(results[1].count).toBe(2);
      expect(results[2].count).toBe(3);
    },
    TEST_TIMEOUT,
  );

  it(
    'should handle different function names across pool',
    async () => {
      const results = await Promise.all([
        multiApiPool.execute('call_api', ['hello', {}, {}]),
        multiApiPool.execute('call_embedding_api', ['world', {}, {}]),
        multiApiPool.execute('call_api', ['again', {}, {}]),
      ]);

      expect(results[0].type).toBe('text');
      expect(results[1].type).toBe('embedding');
      expect(results[2].type).toBe('text');
    },
    TEST_TIMEOUT,
  );

  it(
    'should process queued requests after worker becomes available',
    async () => {
      // Fire off 5 requests - should queue and process sequentially
      const promises = [];
      for (let i = 0; i < 5; i++) {
        promises.push(singleWorkerPool.execute('call_api', [`request-${i}`, {}, {}]));
      }

      const results = await Promise.all(promises);

      // All requests should complete
      expect(results.length).toBe(5);

      // Counter should increment sequentially (all in same worker)
      const counts = results.map((r) => r.count);
      expect(counts).toEqual([1, 2, 3, 4, 5]);
    },
    TEST_TIMEOUT,
  );
});