server {
    listen 80;
    server_name _;

    root /usr/share/nginx/html;
    index index.html;

    # Gzip for text assets
    gzip on;
    gzip_types text/plain text/css application/javascript application/json image/svg+xml;
    gzip_min_length 1024;

    # SPA fallback — must be before /api/ location
    location / {
        try_files $uri $uri/ /index.html;
    }

    # API + SSE — proxy to backend container
    location /api/ {
        proxy_pass http://backend:8000;
        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;

        # SSE: disable buffering, extend timeouts for long-running streams
        proxy_buffering off;
        proxy_cache off;
        proxy_read_timeout 600s;
        proxy_send_timeout 600s;

        # WebSocket support (in case of future upgrade)
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
    }

    # Static assets (icons, uploads) served by backend
    location /static/ {
        proxy_pass http://backend:8000;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }

    # Health-check passthrough
    location = /health {
        proxy_pass http://backend:8000/api/health;
    }
}