events {
    worker_connections 1024;
}

http {
    include /etc/nginx/mime.types;
    default_type application/octet-stream;

    # Logging
    access_log /var/log/nginx/access.log;
    error_log /var/log/nginx/error.log;

    # Gzip compression
    gzip on;
    gzip_vary on;
    gzip_min_length 1024;
    gzip_types text/plain text/css text/xml text/javascript application/x-javascript application/xml+rss application/javascript application/json;

    # Rate limiting
    limit_req_zone $binary_remote_addr zone=general:10m rate=10r/s;
    limit_req_zone $binary_remote_addr zone=auth:10m rate=5r/m;

    # Upstream backend
    upstream books_backend {
        server books-library:3001;
    }

    # HTTP server - redirect to HTTPS
    server {
        listen 80;
        server_name yourdomain.com www.yourdomain.com;

        # Let's Encrypt challenge
        location /.well-known/acme-challenge/ {
            root /var/www/certbot;
        }

        # Redirect all HTTP to HTTPS
        location / {
            return 301 https://$server_name$request_uri;
        }
    }

    # HTTPS server
    server {
        listen 443 ssl http2;
        server_name yourdomain.com www.yourdomain.com;

        # SSL certificates (use Let's Encrypt)
        ssl_certificate /etc/nginx/ssl/fullchain.pem;
        ssl_certificate_key /etc/nginx/ssl/privkey.pem;

        # SSL configuration
        ssl_protocols TLSv1.2 TLSv1.3;
        ssl_ciphers HIGH:!aNULL:!MD5;
        ssl_prefer_server_ciphers on;
        ssl_session_cache shared:SSL:10m;
        ssl_session_timeout 10m;

        # Security headers
        add_header X-Frame-Options "SAMEORIGIN" always;
        add_header X-Content-Type-Options "nosniff" always;
        add_header X-XSS-Protection "1; mode=block" always;
        add_header Referrer-Policy "no-referrer-when-downgrade" always;
        add_header Content-Security-Policy "default-src 'self' https: data: 'unsafe-inline' 'unsafe-eval';" always;

        # Client max body size (for file uploads if implemented)
        client_max_body_size 100M;

        # Proxy settings
        location / {
            proxy_pass http://books_backend;
            proxy_http_version 1.1;
            
            # Headers
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
            proxy_set_header X-Forwarded-Host $host;
            proxy_set_header X-Forwarded-Port $server_port;
            
            # WebSocket support (if needed in future)
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection "upgrade";
            
            # Timeouts
            proxy_connect_timeout 60s;
            proxy_send_timeout 60s;
            proxy_read_timeout 60s;
            
            # Buffering
            proxy_buffering on;
            proxy_buffer_size 4k;
            proxy_buffers 8 4k;
            proxy_busy_buffers_size 8k;
            
            # Rate limiting (general)
            limit_req zone=general burst=20 nodelay;
        }

        # Rate limiting for auth endpoints
        location /api/auth/ {
            proxy_pass http://books_backend;
            proxy_http_version 1.1;
            
            # Headers
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
            
            # Strict rate limiting for auth
            limit_req zone=auth burst=3 nodelay;
        }

        # Cache static assets
        location ~* \.(jpg|jpeg|png|gif|ico|css|js|svg|woff|woff2|ttf|eot)$ {
            proxy_pass http://books_backend;
            proxy_http_version 1.1;
            proxy_set_header Host $host;
            
            # Cache for 1 year
            expires 1y;
            add_header Cache-Control "public, immutable";
        }

        # Health check endpoint (no rate limiting)
        location /api/auth/status {
            proxy_pass http://books_backend;
            proxy_http_version 1.1;
            proxy_set_header Host $host;
            
            # No rate limiting for health checks
            access_log off;
        }
    }
}