events {
    worker_connections 2048;
    use epoll;
    multi_accept on;
}

http {
    # Required basic settings
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;

    # Logging settings
    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;

    # Connection optimization
    sendfile        on;
    tcp_nopush      on;
    tcp_nodelay     on;
    keepalive_timeout  65;

    upstream r2r_backend {
        least_conn;
        server r2r:7272 max_fails=3 fail_timeout=30s;  # Use service name instead of container names
        keepalive 32;
    }

    server {
        listen 80;
        server_name localhost;

        # Timeouts
        proxy_connect_timeout 300s;
        proxy_send_timeout 300s;
        proxy_read_timeout 300s;

        # Buffer settings
        proxy_buffers 8 16k;
        proxy_buffer_size 32k;

        location / {
            proxy_pass http://r2r_backend;
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection 'upgrade';
            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;

            # Retry settings
            proxy_next_upstream error timeout invalid_header http_500 http_502 http_503 http_504;
            proxy_next_upstream_tries 3;
            proxy_next_upstream_timeout 10s;
        }

        location /health {
            access_log off;
            add_header 'Content-Type' 'application/json';
            return 200 '{"status":"healthy"}';
        }

        # Error responses
        error_page 500 502 503 504 /50x.html;
        location = /50x.html {
            root /usr/share/nginx/html;
        }
    }
}