#!/usr/bin/env bash
# ==============================================================================
# Ghaymah Cloud SRE — Q1 Automated Health Check Monitoring Script (Bash)
# Performs HTTP /healthz checks every 30 seconds, logs latency & alerts
# ==============================================================================

TARGET_URL="${MONITOR_TARGET_URL:-http://localhost:8000/healthz}"
CHECK_INTERVAL=30
LOG_FILE="./health_monitor.log"

echo "⚡ Starting Ghaymah SRE Health Check Script"
echo "🎯 Target URL: $TARGET_URL"
echo "⏱️ Check Interval: ${CHECK_INTERVAL}s"
echo "--------------------------------------------------------"

while true; do
    TIMESTAMP=$(date -u +"%Y-%m-%dT%H:%M:%SZ")
    
    # Execute cURL measuring total time in seconds & status code
    START_TIME=$(date +%s%N)
    HTTP_RESPONSE=$(curl -s -o /dev/null -w "%{http_code}" --max-time 5 "$TARGET_URL")
    END_TIME=$(date +%s%N)
    
    # Calculate round trip time in milliseconds
    LATENCY_MS=$(( (END_TIME - START_TIME) / 1000000 ))

    if [ "$HTTP_RESPONSE" -eq 200 ]; then
        STATUS_STR="[SUCCESS] 🟢 Status: HTTP 200 OK | Latency: ${LATENCY_MS}ms"
        echo "[$TIMESTAMP] $STATUS_STR"
        echo "[$TIMESTAMP] SUCCESS status=200 latency=${LATENCY_MS}ms" >> "$LOG_FILE"
    else
        STATUS_STR="[ALERT] 🚨 CRITICAL: Service Unhealthy! Code: ${HTTP_RESPONSE} | Latency: ${LATENCY_MS}ms"
        echo "[$TIMESTAMP] $STATUS_STR"
        echo "[$TIMESTAMP] ALERT status=${HTTP_RESPONSE} latency=${LATENCY_MS}ms" >> "$LOG_FILE"
        
        # Simulated PagerDuty / Ghaymah Alert trigger
        echo "🚨 [PAGERDUTY ALERT] Service at $TARGET_URL responded with HTTP $HTTP_RESPONSE at $TIMESTAMP"
    fi

    sleep $CHECK_INTERVAL
done