# =============================================================================
# Prometheus Alert Rules for RE Workflow
# =============================================================================

groups:
  # ===========================================================================
  # Backend API Alerts
  # ===========================================================================
  - name: re-workflow-backend
    interval: 30s
    rules:
      # High Error Rate
      - alert: HighErrorRate
        expr: rate(http_request_errors_total{job="re-workflow-backend"}[5m]) > 0.1
        for: 5m
        labels:
          severity: critical
          service: backend
        annotations:
          summary: "High error rate detected in RE Workflow Backend"
          description: "Error rate is {{ $value | printf \"%.2f\" }} errors/sec for the last 5 minutes."

      # High Request Latency
      - alert: HighRequestLatency
        expr: histogram_quantile(0.95, rate(http_request_duration_seconds_bucket{job="re-workflow-backend"}[5m])) > 2
        for: 5m
        labels:
          severity: warning
          service: backend
        annotations:
          summary: "High API latency detected"
          description: "95th percentile latency is {{ $value | printf \"%.2f\" }}s"

      # API Down
      - alert: BackendDown
        expr: up{job="re-workflow-backend"} == 0
        for: 1m
        labels:
          severity: critical
          service: backend
        annotations:
          summary: "RE Workflow Backend is DOWN"
          description: "Backend API has been unreachable for more than 1 minute."

      # High Memory Usage
      - alert: HighMemoryUsage
        expr: process_resident_memory_bytes{job="re-workflow-backend"} / 1024 / 1024 > 500
        for: 10m
        labels:
          severity: warning
          service: backend
        annotations:
          summary: "High memory usage in Backend"
          description: "Memory usage is {{ $value | printf \"%.0f\" }}MB"

      # Event Loop Lag
      - alert: HighEventLoopLag
        expr: nodejs_eventloop_lag_seconds{job="re-workflow-backend"} > 0.5
        for: 5m
        labels:
          severity: warning
          service: backend
        annotations:
          summary: "High Node.js event loop lag"
          description: "Event loop lag is {{ $value | printf \"%.3f\" }}s"

  # ===========================================================================
  # TAT/Workflow Alerts
  # ===========================================================================
  - name: re-workflow-tat
    interval: 1m
    rules:
      # TAT Breach Rate
      - alert: HighTATBreachRate
        expr: increase(tat_breaches_total[1h]) > 10
        for: 5m
        labels:
          severity: warning
          service: workflow
        annotations:
          summary: "High TAT breach rate detected"
          description: "{{ $value | printf \"%.0f\" }} TAT breaches in the last hour"

      # Pending Workflows Queue
      - alert: LargePendingQueue
        expr: pending_workflows_count > 100
        for: 30m
        labels:
          severity: warning
          service: workflow
        annotations:
          summary: "Large number of pending workflows"
          description: "{{ $value | printf \"%.0f\" }} workflows pending approval"

  # ===========================================================================
  # Infrastructure Alerts
  # ===========================================================================
  - name: infrastructure
    interval: 30s
    rules:
      # High CPU Usage (Node Exporter)
      - alert: HighCPUUsage
        expr: 100 - (avg by(instance) (rate(node_cpu_seconds_total{mode="idle"}[5m])) * 100) > 80
        for: 10m
        labels:
          severity: warning
          service: infrastructure
        annotations:
          summary: "High CPU usage on {{ $labels.instance }}"
          description: "CPU usage is {{ $value | printf \"%.1f\" }}%"

      # High Disk Usage
      - alert: HighDiskUsage
        expr: (node_filesystem_size_bytes - node_filesystem_free_bytes) / node_filesystem_size_bytes * 100 > 85
        for: 10m
        labels:
          severity: warning
          service: infrastructure
        annotations:
          summary: "High disk usage on {{ $labels.instance }}"
          description: "Disk usage is {{ $value | printf \"%.1f\" }}%"

      # Low Memory
      - alert: LowMemory
        expr: (node_memory_MemAvailable_bytes / node_memory_MemTotal_bytes) * 100 < 15
        for: 5m
        labels:
          severity: critical
          service: infrastructure
        annotations:
          summary: "Low memory on {{ $labels.instance }}"
          description: "Available memory is {{ $value | printf \"%.1f\" }}%"

  # ===========================================================================
  # Loki/Logging Alerts
  # ===========================================================================
  - name: logging
    interval: 1m
    rules:
      # Loki Down
      - alert: LokiDown
        expr: up{job="loki"} == 0
        for: 2m
        labels:
          severity: critical
          service: loki
        annotations:
          summary: "Loki is DOWN"
          description: "Loki has been unreachable for more than 2 minutes."