import { describe, it, expect, vi } from 'vitest';
import { isRetryable, withRetry, DEFAULT_RETRY_CONFIG } from './retry.js';
import type { RetryConfig } from './retry.js';

describe('isRetryable', () => {
  it('returns true for generic errors', () => {
    const error = new Error('Connection reset by peer');
    expect(isRetryable(error, DEFAULT_RETRY_CONFIG.nonRetryablePatterns)).toBe(true);
  });

  it('returns true for timeout errors (transient)', () => {
    const error = new Error('Request timed out after 20000ms');
    expect(isRetryable(error, DEFAULT_RETRY_CONFIG.nonRetryablePatterns)).toBe(true);
  });

  it('returns false for authentication errors', () => {
    const error = new Error('Invalid API key: authentication failed');
    expect(isRetryable(error, DEFAULT_RETRY_CONFIG.nonRetryablePatterns)).toBe(false);
  });

  it('returns false for invalid_api_key errors', () => {
    const error = new Error('Error: invalid_api_key');
    expect(isRetryable(error, DEFAULT_RETRY_CONFIG.nonRetryablePatterns)).toBe(false);
  });

  it('returns false for unauthorized errors', () => {
    const error = new Error('Request unauthorized');
    expect(isRetryable(error, DEFAULT_RETRY_CONFIG.nonRetryablePatterns)).toBe(false);
  });

  it('returns false for invalid_request errors', () => {
    const error = new Error('invalid_request: missing parameter');
    expect(isRetryable(error, DEFAULT_RETRY_CONFIG.nonRetryablePatterns)).toBe(false);
  });

  it('returns false for context_length_exceeded errors', () => {
    const error = new Error('context_length_exceeded: max 128k tokens');
    expect(isRetryable(error, DEFAULT_RETRY_CONFIG.nonRetryablePatterns)).toBe(false);
  });

  it('returns false for content_policy errors', () => {
    const error = new Error('content_policy violation detected');
    expect(isRetryable(error, DEFAULT_RETRY_CONFIG.nonRetryablePatterns)).toBe(false);
  });

  it('returns false for "does not support" errors', () => {
    const error = new Error('registry.ollama.ai/library/qwen2.5:latest does not support tools');
    expect(isRetryable(error, DEFAULT_RETRY_CONFIG.nonRetryablePatterns)).toBe(false);
  });

  it('is case-insensitive when matching patterns', () => {
    const error = new Error('AUTHENTICATION error');
    expect(isRetryable(error, DEFAULT_RETRY_CONFIG.nonRetryablePatterns)).toBe(false);
  });

  it('uses custom patterns when provided', () => {
    const error = new Error('quota exceeded');
    expect(isRetryable(error, ['quota'])).toBe(false);
  });
});

describe('withRetry', () => {
  // Use minimal real delays to avoid fake-timer race conditions
  const fastConfig: RetryConfig = {
    maxRetries: 3,
    initialDelayMs: 1,
    backoffMultiplier: 1,
    maxDelayMs: 5,
    nonRetryablePatterns: DEFAULT_RETRY_CONFIG.nonRetryablePatterns,
  };

  it('succeeds on first attempt without delay', async () => {
    const fn = vi.fn().mockResolvedValue('success');

    const result = await withRetry(fn, fastConfig);

    expect(result).toBe('success');
    expect(fn).toHaveBeenCalledTimes(1);
  });

  it('retries on transient failure then succeeds', async () => {
    const fn = vi.fn()
      .mockRejectedValueOnce(new Error('temporary network issue'))
      .mockRejectedValueOnce(new Error('temporary network issue'))
      .mockResolvedValueOnce('recovered');

    const result = await withRetry(fn, fastConfig, 'test-op');

    expect(result).toBe('recovered');
    expect(fn).toHaveBeenCalledTimes(3);
  });

  it('throws after maxRetries exhausted', async () => {
    const fn = vi.fn().mockRejectedValue(new Error('persistent failure'));

    await expect(withRetry(fn, fastConfig, 'test-op')).rejects.toThrow('persistent failure');
    // 1 initial + 3 retries = 4 total
    expect(fn).toHaveBeenCalledTimes(4);
  });

  it('does not retry non-retryable errors', async () => {
    const fn = vi.fn().mockRejectedValue(new Error('invalid_api_key'));

    await expect(withRetry(fn, fastConfig)).rejects.toThrow('invalid_api_key');
    expect(fn).toHaveBeenCalledTimes(1);
  });

  it('does not retry authentication errors', async () => {
    const fn = vi.fn().mockRejectedValue(new Error('Request unauthorized'));

    await expect(withRetry(fn, fastConfig)).rejects.toThrow('Request unauthorized');
    expect(fn).toHaveBeenCalledTimes(1);
  });

  it('does not retry "does not support tools" errors', async () => {
    const fn = vi.fn().mockRejectedValue(
      new Error('registry.ollama.ai/library/qwen2.5:latest does not support tools'),
    );

    await expect(withRetry(fn, fastConfig)).rejects.toThrow('does not support tools');
    expect(fn).toHaveBeenCalledTimes(1);
  });

  it('converts non-Error throws to Error objects', async () => {
    const fn = vi.fn().mockRejectedValue('string error');

    await expect(withRetry(fn, { ...fastConfig, maxRetries: 0 })).rejects.toThrow('string error');
  });

  it('respects maxDelayMs cap', async () => {
    const cappedConfig: RetryConfig = {
      maxRetries: 2,
      initialDelayMs: 1,
      backoffMultiplier: 10,
      maxDelayMs: 2,
      nonRetryablePatterns: [],
    };

    let callCount = 0;
    const fn = vi.fn().mockImplementation(() => {
      callCount++;
      if (callCount < 3) {return Promise.reject(new Error('fail'));}
      return Promise.resolve('ok');
    });

    // If maxDelayMs weren't respected, a 10x multiplier could cause very long waits.
    // With maxDelayMs=2ms, this completes quickly.
    const result = await withRetry(fn, cappedConfig, 'capped-test');
    expect(result).toBe('ok');
    expect(fn).toHaveBeenCalledTimes(3);
  });

  it('uses default config when none provided', async () => {
    const fn = vi.fn().mockResolvedValue('default-config');

    const result = await withRetry(fn);

    expect(result).toBe('default-config');
    expect(fn).toHaveBeenCalledTimes(1);
  });

  it('increases delay exponentially between retries', async () => {
    const timestamps: number[] = [];
    const config: RetryConfig = {
      maxRetries: 2,
      initialDelayMs: 20,
      backoffMultiplier: 2,
      maxDelayMs: 1000,
      nonRetryablePatterns: [],
    };

    const fn = vi.fn().mockImplementation(() => {
      timestamps.push(Date.now());
      if (timestamps.length < 3) {return Promise.reject(new Error('fail'));}
      return Promise.resolve('ok');
    });

    await withRetry(fn, config, 'backoff-test');

    expect(fn).toHaveBeenCalledTimes(3);
    // First retry delay: ~20ms (jitter 50-100% of 20 = 10-20ms)
    // Second retry delay: ~40ms (jitter 50-100% of 40 = 20-40ms)
    const firstDelay = timestamps[1] - timestamps[0];
    const secondDelay = timestamps[2] - timestamps[1];
    // Second delay should be roughly double the first (within jitter range)
    expect(secondDelay).toBeGreaterThanOrEqual(firstDelay * 0.7);
  });
});