events {
    worker_connections 1024;
}

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"';

    access_log /var/log/nginx/access.log main;
    error_log /var/log/nginx/error.log warn;

    # Basic Settings
    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 65;
    types_hash_max_size 2048;
    client_max_body_size 16M;

    # Gzip Settings
    gzip on;
    gzip_vary on;
    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=20r/s;
    limit_req_zone $binary_remote_addr zone=login:10m rate=10r/m;
    limit_req_zone $binary_remote_addr zone=admin:10m rate=5r/m;

    # Cache Settings
    proxy_cache_path /var/cache/nginx levels=1:2 keys_zone=portfolio_cache:10m max_size=1g inactive=60m use_temp_path=off;

    # Upstream for load balancing
    upstream portfolio_backend {
        least_conn;
        server portfolio:3000 max_fails=3 fail_timeout=30s;
    }

    # HTTP Server (redirect to HTTPS)
    server {
        listen 80;
        server_name dk0.dev www.dk0.dev;
        return 301 https://$host$request_uri;
    }

    # HTTPS Server
    server {
        listen 443 ssl http2;
        server_name dk0.dev www.dk0.dev;

        # SSL Configuration
        ssl_certificate /etc/nginx/ssl/cert.pem;
        ssl_certificate_key /etc/nginx/ssl/key.pem;
        ssl_protocols TLSv1.2 TLSv1.3;
        ssl_ciphers ECDHE-RSA-AES256-GCM-SHA512:DHE-RSA-AES256-GCM-SHA512:ECDHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES256-GCM-SHA384;
        ssl_prefer_server_ciphers off;
        ssl_session_cache shared:SSL:10m;
        ssl_session_timeout 10m;

        # Security Headers
        add_header X-Frame-Options DENY;
        add_header X-Content-Type-Options nosniff;
        add_header X-XSS-Protection "1; mode=block";
        add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
        add_header Referrer-Policy "strict-origin-when-cross-origin";
        add_header Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval' https://analytics.dk0.dev; style-src 'self' 'unsafe-inline'; img-src 'self' data: https:; font-src 'self' data:; connect-src 'self' https://analytics.dk0.dev;";

        # Cache static assets
        location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg|woff|woff2|ttf|eot)$ {
            expires 1y;
            add_header Cache-Control "public, immutable";
            add_header X-Cache-Status "STATIC";
        }

        # Admin routes with strict rate limiting
        location /manage {
            limit_req zone=admin burst=5 nodelay;
            
            # Block common attack patterns
            if ($http_user_agent ~* (bot|crawler|spider|scraper)) {
                return 403;
            }
            
            # Add extra security headers for admin
            add_header X-Frame-Options DENY;
            add_header X-Content-Type-Options nosniff;
            add_header X-XSS-Protection "1; mode=block";
            
            proxy_pass http://portfolio_backend;
            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;
            
            # No caching for admin routes
            proxy_cache_bypass 1;
            proxy_no_cache 1;
        }

        # API routes with rate limiting
        location /api/ {
            limit_req zone=api burst=30 nodelay;
            proxy_pass http://portfolio_backend;
            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_pragma $http_authorization;
            proxy_cache_revalidate on;
            proxy_cache_min_uses 1;
            proxy_cache_use_stale error timeout updating http_500 http_502 http_503 http_504;
            proxy_cache_lock on;
        }

        # Health check endpoint
        location /api/health {
            proxy_pass http://portfolio_backend;
            proxy_set_header Host $host;
            access_log off;
        }

        # Main application
        location / {
            proxy_pass http://portfolio_backend;
            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;
            
            # Enable caching for static pages
            proxy_cache portfolio_cache;
            proxy_cache_valid 200 302 10m;
            proxy_cache_valid 404 1m;
            proxy_cache_use_stale error timeout updating http_500 http_502 http_503 http_504;
            proxy_cache_lock on;
            
            # Add cache status header
            add_header X-Cache-Status $upstream_cache_status;
        }

        # Error pages
        error_page 500 502 503 504 /50x.html;
        location = /50x.html {
            root /usr/share/nginx/html;
        }
    }
}