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;

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

    # 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;

    server {
        listen 80;
        server_name _;
        root /usr/share/nginx/html;
        index index.html;

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

        # Handle client-side routing
        location / {
            try_files $uri $uri/ /index.html;
        }

        # API proxy to backend
        location /api/ {
            proxy_pass http://turash-backend.turash.svc.cluster.local:80;
            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;

            # CORS headers
            add_header Access-Control-Allow-Origin *;
            add_header Access-Control-Allow-Methods "GET, POST, PUT, DELETE, OPTIONS";
            add_header Access-Control-Allow-Headers "DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range,Authorization";

            # Handle preflight requests
            if ($request_method = 'OPTIONS') {
                add_header Access-Control-Allow-Origin *;
                add_header Access-Control-Allow-Methods "GET, POST, PUT, DELETE, OPTIONS";
                add_header Access-Control-Allow-Headers "DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range,Authorization";
                add_header Content-Type 'text/plain charset=UTF-8';
                add_header Content-Length 0;
                return 204;
            }
        }

        # Static assets with caching
        location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg)$ {
            expires 1y;
            add_header Cache-Control "public, immutable";
        }

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