# Nginx Configuration for Optional HTTP/2 Upgrade
# Client-facing: HTTP/2
# Backend: HTTP/1.1 (MCP server)

upstream gds_mcp_backend {
    server 127.0.0.1:3000;
    keepalive 32;
}

server {
    listen 443 ssl http2;
    server_name gds-mock-mcp.example.com;

    # SSL configuration (replace with your certificates)
    ssl_certificate /path/to/ssl/certificate.crt;
    ssl_certificate_key /path/to/ssl/private.key;
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers HIGH:!aNULL:!MD5;

    # Logging
    access_log /var/log/nginx/gds-mcp-access.log;
    error_log /var/log/nginx/gds-mcp-error.log;

    # MCP endpoint proxy
    location /mcp {
        proxy_pass http://gds_mcp_backend;
        proxy_http_version 1.1;

        # Preserve headers
        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;

        # MCP headers
        proxy_set_header MCP-Protocol-Version $http_mcp_protocol_version;
        proxy_set_header MCP-Session-Id $http_mcp_session_id;
        proxy_set_header Last-Event-ID $http_last_event_id;

        # SSE configuration
        proxy_set_header Connection '';
        proxy_buffering off;
        proxy_cache off;
        chunked_transfer_encoding off;

        # Timeouts
        proxy_connect_timeout 60s;
        proxy_send_timeout 60s;
        proxy_read_timeout 60s;
    }

    # Health check endpoint
    location /health {
        proxy_pass http://gds_mcp_backend;
        proxy_http_version 1.1;
        proxy_set_header Connection '';
        proxy_buffering off;
    }

    # Rate limiting (additional layer beyond application)
    limit_req_zone $binary_remote_addr zone=mcp_limit:10m rate=100r/m;
    limit_req zone=mcp_limit burst=20 nodelay;

    # Security headers
    add_header X-Content-Type-Options nosniff;
    add_header X-Frame-Options DENY;
    add_header X-XSS-Protection "1; mode=block";
}

# HTTP redirect to HTTPS
server {
    listen 80;
    server_name gds-mock-mcp.example.com;
    return 301 https://$server_name$request_uri;
}