events {
    worker_connections 1024;
}

http {
    # Basic settings
    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 65;
    types_hash_max_size 2048;
    server_tokens off;

    # SSL settings
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers HIGH:!aNULL:!MD5;
    ssl_prefer_server_ciphers on;

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

    # Rate limiting
    limit_req_zone $binary_remote_addr zone=login_limit:10m rate=10r/m;
    limit_req_zone $binary_remote_addr zone=general_limit:10m rate=100r/m;

    # Upstream to OIDC server
    upstream oidc_backend {
        server oidc_server:5000;
    }

    # HTTP server - redirect to HTTPS
    server {
        listen 80;
        server_name _;

        # Allow Let's Encrypt ACME challenge
        location /.well-known/acme-challenge/ {
            root /var/www/certbot;
        }

        # Redirect all other traffic to HTTPS
        location / {
            return 301 https://$host$request_uri;
        }
    }

    # HTTPS server
    server {
        listen 443 ssl http2;
        server_name _;  # Replace with your domain

        # SSL certificates (use Let's Encrypt)
        # Generate with: certbot certonly --webroot -w /var/www/certbot -d yourdomain.com
        ssl_certificate /etc/nginx/ssl/fullchain.pem;
        ssl_certificate_key /etc/nginx/ssl/privkey.pem;

        # Security headers
        add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
        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;

        # Max upload size
        client_max_body_size 10M;

        # Proxy settings
        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;
        proxy_redirect off;

        # Health check endpoint (no rate limit)
        location /health {
            proxy_pass http://oidc_backend;
        }

        # Login endpoints with strict rate limiting
        location ~ ^/(login|admin/login|authorize|token) {
            limit_req zone=login_limit burst=5 nodelay;
            proxy_pass http://oidc_backend;
        }

        # All other locations
        location / {
            limit_req zone=general_limit burst=20 nodelay;
            proxy_pass http://oidc_backend;
        }
    }
}