#!/bin/bash

# Script to check nginx status and restore it if needed
# This script can be run manually or via cron
# Usage: ./check-and-restore-nginx.sh

set -e

SERVER_IP="147.45.152.129"
SERVER_USER="root"

echo "🔍 Checking nginx status and restoring if needed..."
echo "Server: $SERVER_IP"
echo ""

ssh "$SERVER_USER@$SERVER_IP" << 'ENDSSH'
    set -e
    
    NGINX_STATUS=0
    
    # Check if nginx is running
    if systemctl is-active --quiet nginx; then
        echo "✅ Nginx is running"
        
        # Additional check: can nginx respond?
        if curl -f -s http://localhost/health > /dev/null 2>&1 || \
           curl -f -s http://localhost > /dev/null 2>&1; then
            echo "✅ Nginx is responding to requests"
        else
            echo "⚠️  Nginx process is running but not responding to requests"
            NGINX_STATUS=1
        fi
    else
        echo "❌ Nginx is not running!"
        NGINX_STATUS=1
    fi
    
    # If nginx is not working, try to restore it
    if [ $NGINX_STATUS -ne 0 ]; then
        echo ""
        echo "🔧 Attempting to restore nginx..."
        
        # Check nginx configuration
        echo "🧪 Testing nginx configuration..."
        if nginx -t 2>&1; then
            echo "✅ Nginx configuration is valid"
        else
            echo "❌ Nginx configuration has errors!"
            echo "📋 Recent nginx errors:"
            journalctl -u nginx --since "10min ago" --no-pager -n 20 || true
            exit 1
        fi
        
        # Try to start nginx
        echo ""
        echo "🚀 Starting nginx..."
        if systemctl start nginx; then
            sleep 2
            
            if systemctl is-active --quiet nginx; then
                echo "✅ Nginx started successfully"
                
                # Verify it's responding
                sleep 1
                if curl -f -s http://localhost > /dev/null 2>&1; then
                    echo "✅ Nginx is responding to requests"
                else
                    echo "⚠️  Nginx started but not responding yet (may need a moment)"
                fi
            else
                echo "❌ Failed to start nginx!"
                echo "📋 Recent nginx errors:"
                journalctl -u nginx --since "10min ago" --no-pager -n 30 || true
                exit 1
            fi
        else
            echo "❌ Failed to start nginx service!"
            echo "📋 Recent nginx errors:"
            journalctl -u nginx --since "10min ago" --no-pager -n 30 || true
            exit 1
        fi
    fi
    
    # Check for OOM kills in system logs
    echo ""
    echo "🔍 Checking for OOM kills in system logs..."
    if dmesg | grep -i "oom\|killed process.*nginx" | tail -5; then
        echo "⚠️  Found OOM kill events related to nginx!"
        echo "💡 Consider checking system memory usage: free -h"
    else
        echo "✅ No recent OOM kill events for nginx"
    fi
    
    # Show current memory usage
    echo ""
    echo "📊 Current system memory usage:"
    free -h || true
    
    # Show nginx process info
    echo ""
    echo "📊 Nginx process information:"
    if pgrep -f 'nginx: master' > /dev/null; then
        MASTER_PID=$(pgrep -f 'nginx: master' | head -1)
        echo "   Master PID: $MASTER_PID"
        
        # Check OOM score
        if [ -f "/proc/$MASTER_PID/oom_score_adj" ]; then
            OOM_SCORE=$(cat "/proc/$MASTER_PID/oom_score_adj")
            echo "   OOM Score Adjust: $OOM_SCORE"
            if [ "$OOM_SCORE" = "-1000" ]; then
                echo "   ✅ Nginx is protected from OOM killer"
            else
                echo "   ⚠️  Nginx OOM protection may not be configured correctly"
            fi
        fi
        
        # Show memory usage of nginx processes
        echo "   Memory usage:"
        ps aux | grep -E 'nginx: (master|worker)' | grep -v grep || true
    else
        echo "   ⚠️  Nginx master process not found"
    fi
    
    echo ""
    echo "✅ Nginx check completed"
ENDSSH

echo ""
echo "✅ Nginx status check completed!"