package middleware

import (
	"bytes"
	"io"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/google/uuid"
	"go.uber.org/zap"
)

// RequestLoggerMiddleware 请求日志中间件
type RequestLoggerMiddleware struct {
	logger *zap.Logger
}

// NewRequestLoggerMiddleware 创建请求日志中间件
func NewRequestLoggerMiddleware(logger *zap.Logger) *RequestLoggerMiddleware {
	return &RequestLoggerMiddleware{
		logger: logger,
	}
}

// GetName 返回中间件名称
func (m *RequestLoggerMiddleware) GetName() string {
	return "request_logger"
}

// GetPriority 返回中间件优先级
func (m *RequestLoggerMiddleware) GetPriority() int {
	return 80 // 中等优先级
}

// Handle 返回中间件处理函数
func (m *RequestLoggerMiddleware) Handle() gin.HandlerFunc {
	return gin.LoggerWithFormatter(func(param gin.LogFormatterParams) string {
		// 使用zap logger记录请求信息
		m.logger.Info("HTTP Request",
			zap.String("client_ip", param.ClientIP),
			zap.String("method", param.Method),
			zap.String("path", param.Path),
			zap.String("protocol", param.Request.Proto),
			zap.Int("status_code", param.StatusCode),
			zap.Duration("latency", param.Latency),
			zap.String("user_agent", param.Request.UserAgent()),
			zap.Int("body_size", param.BodySize),
			zap.String("referer", param.Request.Referer()),
			zap.String("request_id", param.Request.Header.Get("X-Request-ID")),
		)

		// 返回空字符串，因为我们已经用zap记录了
		return ""
	})
}

// IsGlobal 是否为全局中间件
func (m *RequestLoggerMiddleware) IsGlobal() bool {
	return true
}

// RequestIDMiddleware 请求ID中间件
type RequestIDMiddleware struct{}

// NewRequestIDMiddleware 创建请求ID中间件
func NewRequestIDMiddleware() *RequestIDMiddleware {
	return &RequestIDMiddleware{}
}

// GetName 返回中间件名称
func (m *RequestIDMiddleware) GetName() string {
	return "request_id"
}

// GetPriority 返回中间件优先级
func (m *RequestIDMiddleware) GetPriority() int {
	return 95 // 最高优先级，第一个执行
}

// Handle 返回中间件处理函数
func (m *RequestIDMiddleware) Handle() gin.HandlerFunc {
	return func(c *gin.Context) {
		// 获取或生成请求ID
		requestID := c.GetHeader("X-Request-ID")
		if requestID == "" {
			requestID = uuid.New().String()
		}

		// 设置请求ID到上下文和响应头
		c.Set("request_id", requestID)
		c.Header("X-Request-ID", requestID)

		// 添加到响应头，方便客户端追踪
		c.Writer.Header().Set("X-Request-ID", requestID)

		c.Next()
	}
}

// IsGlobal 是否为全局中间件
func (m *RequestIDMiddleware) IsGlobal() bool {
	return true
}

// SecurityHeadersMiddleware 安全头部中间件
type SecurityHeadersMiddleware struct{}

// NewSecurityHeadersMiddleware 创建安全头部中间件
func NewSecurityHeadersMiddleware() *SecurityHeadersMiddleware {
	return &SecurityHeadersMiddleware{}
}

// GetName 返回中间件名称
func (m *SecurityHeadersMiddleware) GetName() string {
	return "security_headers"
}

// GetPriority 返回中间件优先级
func (m *SecurityHeadersMiddleware) GetPriority() int {
	return 85 // 高优先级
}

// Handle 返回中间件处理函数
func (m *SecurityHeadersMiddleware) Handle() gin.HandlerFunc {
	return func(c *gin.Context) {
		// 设置安全头部
		c.Header("X-Content-Type-Options", "nosniff")
		c.Header("X-Frame-Options", "DENY")
		c.Header("X-XSS-Protection", "1; mode=block")
		c.Header("Referrer-Policy", "strict-origin-when-cross-origin")
		c.Header("Content-Security-Policy", "default-src 'self'")
		c.Header("Strict-Transport-Security", "max-age=31536000; includeSubDomains")

		c.Next()
	}
}

// IsGlobal 是否为全局中间件
func (m *SecurityHeadersMiddleware) IsGlobal() bool {
	return true
}

// ResponseTimeMiddleware 响应时间中间件
type ResponseTimeMiddleware struct{}

// NewResponseTimeMiddleware 创建响应时间中间件
func NewResponseTimeMiddleware() *ResponseTimeMiddleware {
	return &ResponseTimeMiddleware{}
}

// GetName 返回中间件名称
func (m *ResponseTimeMiddleware) GetName() string {
	return "response_time"
}

// GetPriority 返回中间件优先级
func (m *ResponseTimeMiddleware) GetPriority() int {
	return 75 // 中等优先级
}

// Handle 返回中间件处理函数
func (m *ResponseTimeMiddleware) Handle() gin.HandlerFunc {
	return func(c *gin.Context) {
		start := time.Now()

		c.Next()

		// 计算响应时间并添加到头部
		duration := time.Since(start)
		c.Header("X-Response-Time", duration.String())

		// 记录到上下文中，供其他中间件使用
		c.Set("response_time", duration)
	}
}

// IsGlobal 是否为全局中间件
func (m *ResponseTimeMiddleware) IsGlobal() bool {
	return true
}

// RequestBodyLoggerMiddleware 请求体日志中间件（用于调试）
type RequestBodyLoggerMiddleware struct {
	logger *zap.Logger
	enable bool
}

// NewRequestBodyLoggerMiddleware 创建请求体日志中间件
func NewRequestBodyLoggerMiddleware(logger *zap.Logger, enable bool) *RequestBodyLoggerMiddleware {
	return &RequestBodyLoggerMiddleware{
		logger: logger,
		enable: enable,
	}
}

// GetName 返回中间件名称
func (m *RequestBodyLoggerMiddleware) GetName() string {
	return "request_body_logger"
}

// GetPriority 返回中间件优先级
func (m *RequestBodyLoggerMiddleware) GetPriority() int {
	return 70 // 较低优先级
}

// Handle 返回中间件处理函数
func (m *RequestBodyLoggerMiddleware) Handle() gin.HandlerFunc {
	if !m.enable {
		return func(c *gin.Context) {
			c.Next()
		}
	}

	return func(c *gin.Context) {
		// 只记录POST, PUT, PATCH请求的body
		if c.Request.Method == "POST" || c.Request.Method == "PUT" || c.Request.Method == "PATCH" {
			if c.Request.Body != nil {
				bodyBytes, err := io.ReadAll(c.Request.Body)
				if err == nil {
					// 重新设置body供后续处理使用
					c.Request.Body = io.NopCloser(bytes.NewBuffer(bodyBytes))

					// 记录请求体（注意：生产环境中应该谨慎记录敏感信息）
					m.logger.Debug("Request Body",
						zap.String("method", c.Request.Method),
						zap.String("path", c.Request.URL.Path),
						zap.String("body", string(bodyBytes)),
						zap.String("request_id", c.GetString("request_id")),
					)
				}
			}
		}

		c.Next()
	}
}

// IsGlobal 是否为全局中间件
func (m *RequestBodyLoggerMiddleware) IsGlobal() bool {
	return false // 可选中间件，不是全局的
}