upstream server_backend {
    server server:8000;
}

upstream client_frontend {
    server client:5000;
}

server {
    listen 80;
    server_name _;

    # Gzip compression
    gzip on;
    gzip_types text/plain text/css application/json application/javascript text/xml;
    gzip_min_length 256;

    # 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 "strict-origin-when-cross-origin" always;

    # Max upload size
    client_max_body_size 50M;

    # API requests → FastAPI server
    location /api/ {
        proxy_pass http://server_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_read_timeout 120s;
    }

    # Upload files served by server
    location /uploads/ {
        proxy_pass http://server_backend;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
    }

    # All other requests → Flask client
    location / {
        proxy_pass http://client_frontend;
        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;
    }

    # Static file caching
    location ~* \.(css|js|png|jpg|jpeg|gif|ico|svg|woff|woff2|ttf)$ {
        proxy_pass http://client_frontend;
        proxy_set_header Host $host;
        expires 7d;
        add_header Cache-Control "public, immutable";
    }

    # SSL configuration (uncomment when using Let's Encrypt)
    # listen 443 ssl;
    # ssl_certificate /etc/letsencrypt/live/yourdomain.com/fullchain.pem;
    # ssl_certificate_key /etc/letsencrypt/live/yourdomain.com/privkey.pem;
    # ssl_protocols TLSv1.2 TLSv1.3;
}