# ========================================
# PROMETHEUS ALERTING RULES
# Enterprise Grade Monitoring
# ========================================

groups:
  # ========================================
  # Backend API Alerts
  # ========================================
  - name: backend_alerts
    interval: 30s
    rules:
      - alert: BackendDown
        expr: up{job="backend"} == 0
        for: 1m
        labels:
          severity: critical
        annotations:
          summary: "Backend API is down"
          description: "Backend API has been down for more than 1 minute"

      - alert: BackendHighErrorRate
        expr: rate(http_requests_total{job="backend", status=~"5.."}[5m]) > 0.05
        for: 2m
        labels:
          severity: warning
        annotations:
          summary: "Backend high error rate"
          description: "Backend error rate is {{ $value | humanizePercentage }}"

      - alert: BackendHighResponseTime
        expr: histogram_quantile(0.95, rate(http_request_duration_seconds_bucket{job="backend"}[5m])) > 2
        for: 3m
        labels:
          severity: warning
        annotations:
          summary: "Backend high response time"
          description: "95th percentile response time is {{ $value }}s"

      - alert: BackendLowSuccessRate
        expr: rate(http_requests_total{job="backend", status=~"2.."}[5m]) / rate(http_requests_total{job="backend"}[5m]) < 0.95
        for: 5m
        labels:
          severity: critical
        annotations:
          summary: "Backend low success rate"
          description: "Success rate is {{ $value | humanizePercentage }}"

  # ========================================
  # Database Alerts
  # ========================================
  - name: database_alerts
    interval: 30s
    rules:
      - alert: PostgreSQLDown
        expr: up{job="postgres"} == 0
        for: 1m
        labels:
          severity: critical
        annotations:
          summary: "PostgreSQL is down"
          description: "PostgreSQL database has been down for more than 1 minute"

      - alert: PostgreSQLHighConnections
        expr: pg_stat_activity_count > 150
        for: 5m
        labels:
          severity: warning
        annotations:
          summary: "PostgreSQL high connection count"
          description: "PostgreSQL has {{ $value }} connections (> 150)"

      - alert: PostgreSQLReplicationLag
        expr: pg_replication_lag_seconds > 30
        for: 5m
        labels:
          severity: warning
        annotations:
          summary: "PostgreSQL replication lag"
          description: "Replication lag is {{ $value }}s"

      - alert: PostgreSQLSlowQueries
        expr: rate(pg_stat_statements_seconds_total[5m]) > 1
        for: 5m
        labels:
          severity: warning
        annotations:
          summary: "PostgreSQL slow queries detected"
          description: "Slow query rate is {{ $value }}s/s"

  # ========================================
  # Redis Alerts
  # ========================================
  - name: redis_alerts
    interval: 30s
    rules:
      - alert: RedisDown
        expr: up{job="redis"} == 0
        for: 1m
        labels:
          severity: critical
        annotations:
          summary: "Redis is down"
          description: "Redis has been down for more than 1 minute"

      - alert: RedisHighMemoryUsage
        expr: redis_memory_used_bytes / redis_memory_max_bytes > 0.9
        for: 5m
        labels:
          severity: warning
        annotations:
          summary: "Redis high memory usage"
          description: "Redis memory usage is {{ $value | humanizePercentage }}"

      - alert: RedisRejectedConnections
        expr: rate(redis_rejected_connections_total[5m]) > 0
        for: 1m
        labels:
          severity: warning
        annotations:
          summary: "Redis rejected connections"
          description: "Redis is rejecting connections"

  # ========================================
  # Worker Alerts
  # ========================================
  - name: worker_alerts
    interval: 30s
    rules:
      - alert: PDFWorkerDown
        expr: up{job="pdf-worker"} == 0
        for: 2m
        labels:
          severity: warning
        annotations:
          summary: "PDF Worker is down"

      - alert: ExerciseWorkerDown
        expr: up{job="exercise-worker"} == 0
        for: 2m
        labels:
          severity: warning
        annotations:
          summary: "Exercise Worker is down"

      - alert: NotificationWorkerDown
        expr: up{job="notification-worker"} == 0
        for: 2m
        labels:
          severity: warning
        annotations:
          summary: "Notification Worker is down"

      - alert: WorkerHighCPUUsage
        expr: 100 - (avg by (instance) (irate(node_cpu_seconds_total{mode="idle"}[5m])) * 100) > 80
        for: 10m
        labels:
          severity: warning
        annotations:
          summary: "Worker high CPU usage"
          description: "CPU usage is {{ $value }}%"

  # ========================================
  # Infrastructure Alerts
  # ========================================
  - name: infrastructure_alerts
    interval: 30s
    rules:
      - alert: NodeHighMemoryUsage
        expr: (node_memory_MemTotal_bytes - node_memory_MemAvailable_bytes) / node_memory_MemTotal_bytes > 0.9
        for: 5m
        labels:
          severity: critical
        annotations:
          summary: "Node high memory usage"
          description: "Memory usage is {{ $value | humanizePercentage }}"

      - alert: NodeDiskFull
        expr: (node_filesystem_avail_bytes / node_filesystem_size_bytes) < 0.1
        for: 5m
        labels:
          severity: critical
        annotations:
          summary: "Node disk is filling up"
          description: "Disk has {{ $value | humanizePercentage }} available"

      - alert: NodeHighLoad
        expr: node_load1 > 4
        for: 5m
        labels:
          severity: warning
        annotations:
          summary: "Node high load average"
          description: "Load average is {{ $value }}"

      - alert: ContainerHighRestartRate
        expr: rate(container_start_count_total[15m]) > 0
        for: 5m
        labels:
          severity: warning
        annotations:
          summary: "Container restarting frequently"
          description: "Container {{ $labels.name }} is restarting"