package middleware

import (
	"net/http"
	"net/http/httptest"
	"testing"

	"github.com/gin-gonic/gin"
)

func init() {
	gin.SetMode(gin.TestMode)
}

func TestRequestIDMiddleware_GeneratesID(t *testing.T) {
	r := gin.New()
	r.Use(RequestIDMiddleware())
	r.GET("/test", func(c *gin.Context) {
		c.Status(http.StatusOK)
	})

	w := httptest.NewRecorder()
	req, _ := http.NewRequest(http.MethodGet, "/test", nil)
	r.ServeHTTP(w, req)

	gotID := w.Header().Get("X-Request-ID")
	if gotID == "" {
		t.Error("expected X-Request-ID to be generated, got empty string")
	}
	if len(gotID) != 16 {
		t.Errorf("expected 16-char hex ID, got %d chars: %q", len(gotID), gotID)
	}
}

func TestRequestIDMiddleware_PreservesExisting(t *testing.T) {
	r := gin.New()
	r.Use(RequestIDMiddleware())
	r.GET("/test", func(c *gin.Context) {
		c.Status(http.StatusOK)
	})

	w := httptest.NewRecorder()
	req, _ := http.NewRequest(http.MethodGet, "/test", nil)
	req.Header.Set("X-Request-ID", "my-custom-id")
	r.ServeHTTP(w, req)

	gotID := w.Header().Get("X-Request-ID")
	if gotID != "my-custom-id" {
		t.Errorf("expected X-Request-ID to be preserved as %q, got %q", "my-custom-id", gotID)
	}
}