package middleware

import (
	"context"
	"net/http"

	"github.com/google/uuid"
)

// requestIDKey is the context key for request ID
type requestIDKey struct{}

// RequestIDHeader is the HTTP header for request ID
const RequestIDHeader = "X-Request-ID"

// RequestID middleware generates a unique ID for each request
func RequestID() Middleware {
	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			// Check if request already has an ID
			requestID := r.Header.Get(RequestIDHeader)
			if requestID == "" {
				// Generate a new UUID for the request if not present
				requestID = uuid.New().String()
			}

			// Add request ID to response headers
			w.Header().Set(RequestIDHeader, requestID)

			// Store request ID in context
			ctx := context.WithValue(r.Context(), requestIDKey{}, requestID)

			// Call next handler with updated context
			next.ServeHTTP(w, r.WithContext(ctx))
		})
	}
}

// GetRequestID retrieves the request ID from context
func GetRequestID(ctx context.Context) string {
	if id, ok := ctx.Value(requestIDKey{}).(string); ok {
		return id
	}
	return ""
}