user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log warn;
pid /var/run/nginx.pid;

events {
    worker_connections 1024;
    use epoll;
    multi_accept on;
}

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

    # Logging
    log_format main '$remote_addr - $remote_user [$time_local] "$request" '
                    '$status $body_bytes_sent "$http_referer" '
                    '"$http_user_agent" "$http_x_forwarded_for" '
                    'rt=$request_time uct="$upstream_connect_time" '
                    'uht="$upstream_header_time" urt="$upstream_response_time"';

    access_log /var/log/nginx/access.log main;

    # Performance settings
    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 65;
    types_hash_max_size 2048;
    client_max_body_size 1G;
    server_tokens off;

    # Gzip compression
    gzip on;
    gzip_vary on;
    gzip_min_length 1024;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_types
        text/plain
        text/css
        text/xml
        text/javascript
        application/json
        application/javascript
        application/xml+rss
        application/atom+xml
        image/svg+xml;

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

    # Upstream backend
    upstream web-backend {
        server web-client:8080;
        keepalive 32;
    }

    # HTTP to HTTPS redirect
    server {
        listen 80;
        listen [::]:80;
        server_name _;

        # Health check endpoint (allow HTTP)
        location /health {
            return 200 "healthy\n";
            add_header Content-Type text/plain;
            access_log off;
        }

        # Redirect all other traffic to HTTPS
        location / {
            return 301 https://$host$request_uri;
        }
    }

    # HTTPS server
    server {
        listen 443 ssl http2;
        listen [::]:443 ssl http2;
        server_name _;

        # SSL configuration
        ssl_certificate /etc/nginx/ssl/cert.pem;
        ssl_certificate_key /etc/nginx/ssl/key.pem;
        ssl_session_timeout 1d;
        ssl_session_cache shared:SSL:50m;
        ssl_session_tickets off;

        # Modern SSL configuration
        ssl_protocols TLSv1.2 TLSv1.3;
        ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384;
        ssl_prefer_server_ciphers off;

        # HSTS (optional, uncomment if using a real domain)
        # add_header Strict-Transport-Security "max-age=63072000" always;

        # Security headers
        add_header X-Frame-Options DENY always;
        add_header X-Content-Type-Options nosniff always;
        add_header X-XSS-Protection "1; mode=block" always;
        add_header Referrer-Policy "strict-origin-when-cross-origin" always;
        add_header Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-inline'; img-src 'self' data: blob:; font-src 'self'; connect-src 'self' ws: wss:; media-src 'self' blob:;" always;

        # Main application
        location / {
            proxy_pass http://web-backend;
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection 'upgrade';
            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_cache_bypass $http_upgrade;
            proxy_read_timeout 300;
            proxy_connect_timeout 300;
            proxy_send_timeout 300;

            # Rate limiting
            limit_req zone=api burst=20 nodelay;
        }

        # Authentication endpoints with stricter rate limiting
        location ~ ^/api/auth/ {
            proxy_pass http://web-backend;
            proxy_http_version 1.1;
            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;

            # Stricter rate limiting for auth
            limit_req zone=auth burst=10 nodelay;
        }

        # Health check
        location /health {
            access_log off;
            return 200 "healthy\n";
            add_header Content-Type text/plain;
        }

        # Security: Block access to sensitive files
        location ~ /\. {
            deny all;
            access_log off;
            log_not_found off;
        }

        location ~ ^/(package\.json|Dockerfile|docker-compose\.yml)$ {
            deny all;
            access_log off;
            log_not_found off;
        }
    }
}