events {
    worker_connections 1024;
}

http {
    # Upstream configuration
    upstream readur {
        server readur:8080;
    }

    # Rate limiting
    limit_req_zone $binary_remote_addr zone=api:10m rate=10r/s;
    limit_req_zone $binary_remote_addr zone=auth:10m rate=5r/m;

    server {
        listen 80;
        server_name localhost;

        # Redirect HTTP to HTTPS (uncomment in production)
        # return 301 https://$server_name$request_uri;

        # For development without SSL
        location / {
            proxy_pass http://readur;
            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;
        }
    }

    # HTTPS server configuration
    server {
        listen 443 ssl http2;
        server_name localhost;

        # SSL configuration (update paths as needed)
        ssl_certificate /etc/nginx/ssl/cert.pem;
        ssl_certificate_key /etc/nginx/ssl/key.pem;
        ssl_protocols TLSv1.2 TLSv1.3;
        ssl_ciphers HIGH:!aNULL:!MD5;
        ssl_prefer_server_ciphers on;

        # Security headers
        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 100M;
        client_body_timeout 300s;

        # Main application
        location / {
            proxy_pass http://readur;
            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;
            
            # WebSocket support (if needed in future)
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection "upgrade";
            
            # Timeouts for long-running OCR operations
            proxy_connect_timeout 300s;
            proxy_send_timeout 300s;
            proxy_read_timeout 300s;
        }

        # API rate limiting
        location /api/ {
            limit_req zone=api burst=20 nodelay;
            
            proxy_pass http://readur;
            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;
        }

        # Stricter rate limiting for auth endpoints
        location /api/auth/ {
            limit_req zone=auth burst=5 nodelay;
            
            proxy_pass http://readur;
            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;
        }

        # Health check endpoint (no rate limiting)
        location /api/health {
            proxy_pass http://readur;
            proxy_set_header Host $host;
            access_log off;
        }

        # Static assets caching
        location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg|woff|woff2|ttf|eot)$ {
            proxy_pass http://readur;
            proxy_set_header Host $host;
            expires 1y;
            add_header Cache-Control "public, immutable";
        }
    }
}

# Subpath example - serving readur under /readur/
# server {
#     listen 80;
#     server_name example.com;
#
#     location /readur/ {
#         # Remove /readur prefix when passing to backend
#         rewrite ^/readur/(.*) /$1 break;
#         
#         proxy_pass http://readur;
#         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_set_header X-Forwarded-Prefix /readur;
#     }
# }

# Multiple instances example
# upstream readur_pool {
#     least_conn;
#     server readur1:8080;
#     server readur2:8080;
#     server readur3:8080;
# }
#
# server {
#     listen 80;
#     
#     location / {
#         proxy_pass http://readur_pool;
#         # ... rest of proxy configuration
#     }
# }