// Sub2API Performance Thresholds
// 性能阈值定义

// ============= HTTP 请求阈值 =============

export const httpThresholds = {
  // 全局 HTTP 请求阈值
  httpReqFailed: ['rate<0.01'],           // 错误率 < 1%
  httpReqDuration: ['p(95)<1000'],        // P95 < 1s
  httpReqDurationP99: ['p(99)<3000'],     // P99 < 3s

  // 按路径的阈值
  'http_req_duration{path:/health}': ['p(95)<100'],           // 健康检查 P95 < 100ms
  'http_req_duration{path:/api/v1/auth/login}': ['p(95)<500'], // 登录 P95 < 500ms
  'http_req_duration{path:/api/v1/keys}': ['p(95)<300'],       // API Key 列表 P95 < 300ms
};

// ============= Gateway 请求阈值 =============

export const gatewayThresholds = {
  // Gateway 请求整体阈值
  'gateway_req_duration{p(95)}': ['<2000'],    // P95 < 2s
  'gateway_req_duration{p(99)}': ['<5000'],   // P99 < 5s
  'gateway_req_failed': ['rate<0.05'],         // 错误率 < 5%

  // TTFT (Time To First Token)
  'gateway_ttft{p(95)}': ['<3000'],            // TTFT P95 < 3s
  'gateway_ttft{p(99)}': ['<5000'],            // TTFT P99 < 5s

  // 按平台/模型分类
  'gateway_latency_openai{p(95)}': ['<1500'], // OpenAI P95 < 1.5s
  'gateway_latency_claude{p(95)}': ['<2000'], // Claude P95 < 2s
  'gateway_latency_gemini{p(95)}': ['<1500'], // Gemini P95 < 1.5s
};

// ============= 数据库连接池阈值 =============

export const dbConnectionThresholds = {
  // 连接数不应超过配置的 80%
  dbConnectionsActive: ['value<0.8*max'],      // 活跃连接 < 80%
  dbConnectionsIdle: ['value>5'],              // 空闲连接 > 5
};

// ============= Redis 连接池阈值 =============

export const redisConnectionThresholds = {
  redisConnectionsTotal: ['value<0.8*pool_size'], // 总连接 < 80%
  redisConnectionsIdle: ['value>3'],              // 空闲连接 > 3
};

// ============= 速率限制阈值 =============

export const rateLimitThresholds = {
  rateLimitHits: ['rate<0.1'],  // 速率限制命中率应 < 10%
};

// ============= 缓存命中率 =============

export const cacheHitThresholds = {
  cacheHitRate: ['rate>0.8'],   // 缓存命中率 > 80%
  cacheMissRate: ['rate<0.2'],   // 缓存未命中率 < 20%
};

// ============= SLA 级别定义 =============

export const slaLevels = {
  // 黄金 SLA: 最严格的要求
  gold: {
    availability: 0.9995,      // 99.95%
    latencyP95: 500,           // ms
    latencyP99: 1500,          // ms
    errorRate: 0.001,          // 0.1%
    ttftP99: 3000,             // ms
  },

  // 白银 SLA: 标准要求
  silver: {
    availability: 0.99,         // 99%
    latencyP95: 1000,          // ms
    latencyP99: 3000,          // ms
    errorRate: 0.01,           // 1%
    ttftP99: 5000,             // ms
  },

  // 青铜 SLA: 最低要求
  bronze: {
    availability: 0.95,         // 95%
    latencyP95: 2000,           // ms
    latencyP99: 5000,          // ms
    errorRate: 0.05,           // 5%
    ttftP99: 10000,            // ms
  },
};

// ============= 导出便捷函数 =============

/**
 * 获取指定 SLA 级别的阈值配置
 */
export function getThresholdsForSLA(level = 'silver') {
  const sla = slaLevels[level];
  if (!sla) {
    console.warn(`Unknown SLA level: ${level}, using silver`);
    return slaLevels.silver;
  }

  return {
    httpReqFailed: [`rate<${sla.errorRate}`],
    httpReqDuration: [`p(95)<${sla.latencyP95}`],
    httpReqDurationP99: [`p(99)<${sla.latencyP99}`],
  };
}

/**
 * 检查指标是否满足指定 SLA 级别
 */
export function meetsSLA(metrics, level = 'silver') {
  const sla = slaLevels[level];

  const checks = [
    {
      name: '可用性',
      value: metrics.availability,
      threshold: sla.availability,
      pass: metrics.availability >= sla.availability,
    },
    {
      name: 'P95 延迟',
      value: metrics.latencyP95,
      threshold: sla.latencyP95,
      unit: 'ms',
      pass: metrics.latencyP95 <= sla.latencyP95,
    },
    {
      name: 'P99 延迟',
      value: metrics.latencyP99,
      threshold: sla.latencyP99,
      unit: 'ms',
      pass: metrics.latencyP99 <= sla.latencyP99,
    },
    {
      name: '错误率',
      value: metrics.errorRate,
      threshold: sla.errorRate,
      pass: metrics.errorRate <= sla.errorRate,
    },
  ];

  return {
    level,
    sla,
    checks,
    allPassed: checks.every(c => c.pass),
    summary: checks.map(c => ({
      name: c.name,
      value: c.value,
      threshold: c.threshold,
      unit: c.unit || '%',
      passed: c.pass,
    })),
  };
}