package middleware

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

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

// TestCORS_Headers 测试CORS中间件设置的响应头
func TestCORS_Headers(t *testing.T) {
	gin.SetMode(gin.TestMode)

	router := gin.New()
	router.Use(CORS())
	router.GET("/test", func(c *gin.Context) {
		c.JSON(http.StatusOK, gin.H{"message": "success"})
	})

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

	router.ServeHTTP(w, req)

	// 验证CORS响应头
	// 注意：当 Access-Control-Allow-Origin 为 "*" 时，根据CORS规范，
	// 不应该设置 Access-Control-Allow-Credentials 为 "true"
	expectedHeaders := map[string]string{
		"Access-Control-Allow-Origin":  "*",
		"Access-Control-Allow-Methods": "POST, OPTIONS, GET, PUT, DELETE",
	}

	for header, expectedValue := range expectedHeaders {
		actualValue := w.Header().Get(header)
		if actualValue != expectedValue {
			t.Errorf("Header %s = %q, want %q", header, actualValue, expectedValue)
		}
	}

	// 验证在通配符模式下不设置Credentials（这是正确的安全行为）
	if credentials := w.Header().Get("Access-Control-Allow-Credentials"); credentials != "" {
		t.Errorf("通配符origin模式下不应设置 Access-Control-Allow-Credentials, got %q", credentials)
	}

	// 验证Access-Control-Allow-Headers包含必要字段
	allowHeaders := w.Header().Get("Access-Control-Allow-Headers")
	if allowHeaders == "" {
		t.Error("Access-Control-Allow-Headers 不应为空")
	}
}

// TestCORS_OPTIONS 测试OPTIONS请求处理
func TestCORS_OPTIONS(t *testing.T) {
	gin.SetMode(gin.TestMode)

	router := gin.New()
	router.Use(CORS())
	router.GET("/test", func(c *gin.Context) {
		c.JSON(http.StatusOK, gin.H{"message": "success"})
	})

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

	router.ServeHTTP(w, req)

	// OPTIONS请求应该返回204状态码
	if w.Code != http.StatusNoContent {
		t.Errorf("OPTIONS请求状态码 = %d, want %d", w.Code, http.StatusNoContent)
	}
}

// TestCORS_AllowMethods 测试允许的HTTP方法
func TestCORS_AllowMethods(t *testing.T) {
	gin.SetMode(gin.TestMode)

	router := gin.New()
	router.Use(CORS())
	router.GET("/test", func(c *gin.Context) {
		c.JSON(http.StatusOK, gin.H{"message": "success"})
	})

	methods := []string{"GET", "POST", "PUT", "DELETE"}
	for _, method := range methods {
		t.Run(method, func(t *testing.T) {
			req, _ := http.NewRequest(method, "/test", nil)
			w := httptest.NewRecorder()

			router.ServeHTTP(w, req)

			// 验证允许的方法头包含该方法
			allowMethods := w.Header().Get("Access-Control-Allow-Methods")
			if allowMethods == "" {
				t.Error("Access-Control-Allow-Methods 不应为空")
			}
		})
	}
}

// TestCORS_AllowHeaders 测试允许的请求头
func TestCORS_AllowHeaders(t *testing.T) {
	gin.SetMode(gin.TestMode)

	router := gin.New()
	router.Use(CORS())
	router.GET("/test", func(c *gin.Context) {
		c.JSON(http.StatusOK, gin.H{"message": "success"})
	})

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

	router.ServeHTTP(w, req)

	allowHeaders := w.Header().Get("Access-Control-Allow-Headers")
	expectedHeaders := []string{"Content-Type", "Authorization", "Accept"}

	for _, expectedHeader := range expectedHeaders {
		if !contains(allowHeaders, expectedHeader) {
			t.Errorf("Access-Control-Allow-Headers 应包含 %s", expectedHeader)
		}
	}
}

// TestCORS_WithSpecificOrigin 测试配置了具体origin时的CORS行为
func TestCORS_WithSpecificOrigin(t *testing.T) {
	gin.SetMode(gin.TestMode)

	// 注意：此测试验证的是在配置了具体allowed origins时的行为
	// 在没有配置初始化的情况下，默认使用通配符模式
	router := gin.New()
	router.Use(CORS())
	router.GET("/test", func(c *gin.Context) {
		c.JSON(http.StatusOK, gin.H{"message": "success"})
	})

	req, _ := http.NewRequest("GET", "/test", nil)
	req.Header.Set("Origin", "http://example.com")
	w := httptest.NewRecorder()

	router.ServeHTTP(w, req)

	// 默认配置下使用通配符，所以不应该设置credentials
	if credentials := w.Header().Get("Access-Control-Allow-Credentials"); credentials != "" {
		t.Logf("当前模式下 Access-Control-Allow-Credentials = %q (通配符模式不设置)", credentials)
	}
}

// 辅助函数：检查字符串是否包含子字符串（简单实现）
func contains(s, substr string) bool {
	if len(substr) == 0 {
		return true
	}
	if len(s) < len(substr) {
		return false
	}
	for i := 0; i <= len(s)-len(substr); i++ {
		if s[i:i+len(substr)] == substr {
			return true
		}
	}
	return false
}