upstream backend {
    server backend:5000;
}

upstream frontend {
    server frontend:5173;
}

server {
    listen 80;
    server_name localhost;
    client_max_body_size 100M;

    # 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;

    # API requests → Flask backend
    location /api/ {
        proxy_pass http://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;

        # Timeout for large file uploads
        proxy_read_timeout 300s;
        proxy_send_timeout 300s;
        proxy_connect_timeout 60s;
    }

    # Frontend (Vite dev server in dev, static in prod)
    location / {
        proxy_pass http://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 Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
    }

    # Health check
    location /health {
        proxy_pass http://backend/api/health;
    }
}