upstream api_back {
        server ${VITE_API_HOST};
    }

server {
    listen 80;
    server_name localhost;

    # Root directory for static files
    root /usr/share/nginx/html;
    index index.html;

    # Proxy API requests
    location /api/ {
        # IMPORTANT: The resolver is necessary for Nginx to resolve DNS inside a Docker container
        # when using variables in proxy_pass. 127.0.0.11 is Docker's internal DNS server.
        # resolver 127.0.0.11;

        # Set headers for the proxied request
        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;

        # Inject the custom API key header
        proxy_set_header X-API-KEY '${VITE_API_KEY}';

        # Use environment variables for the proxy target and API key.
        # These will be substituted by envsubst in the entrypoint script.
        proxy_pass http://api_back${VITE_API_DIR}/api/;
    }

    # Serve static files directly
    location / {
        # Fallback to index.html for Single Page Application (SPA) routing
        try_files $uri $uri/ /index.html;
    }

    # Optional: Add error pages for better user experience
    error_page 500 502 503 504 /50x.html;
    location = /50x.html {
        root /usr/share/nginx/html;
    }
}