package middleware

import (
	"bytes"
	"context"
	"fmt"
	"io"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/google/uuid"
	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/trace"
	"go.uber.org/zap"

	"tyapi-server/internal/shared/tracing"
)

// RequestLoggerMiddleware 请求日志中间件
type RequestLoggerMiddleware struct {
	logger        *zap.Logger
	useColoredLog bool
	isDevelopment bool
	tracer        *tracing.Tracer
}

// NewRequestLoggerMiddleware 创建请求日志中间件
func NewRequestLoggerMiddleware(logger *zap.Logger, isDevelopment bool, tracer *tracing.Tracer) *RequestLoggerMiddleware {
	return &RequestLoggerMiddleware{
		logger:        logger,
		useColoredLog: isDevelopment, // 开发环境使用彩色日志
		isDevelopment: isDevelopment,
		tracer:        tracer,
	}
}

// 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 {
	if m.useColoredLog {
		// 开发环境：使用Gin默认的彩色日志格式
		return gin.LoggerWithFormatter(func(param gin.LogFormatterParams) string {
			var statusColor, methodColor, resetColor string
			if param.IsOutputColor() {
				statusColor = param.StatusCodeColor()
				methodColor = param.MethodColor()
				resetColor = param.ResetColor()
			}

			if param.Latency > time.Minute {
				param.Latency = param.Latency.Truncate(time.Second)
			}

			// 获取TraceID
			traceID := param.Request.Header.Get("X-Trace-ID")
			if traceID == "" && m.tracer != nil {
				traceID = m.tracer.GetTraceID(param.Request.Context())
			}

			// 检查是否为错误响应
			if param.StatusCode >= 400 && m.tracer != nil {
				span := trace.SpanFromContext(param.Request.Context())
				if span.IsRecording() {
					// 标记为错误操作，确保100%采样
					span.SetAttributes(
						attribute.String("error.operation", "true"),
						attribute.String("operation.type", "error"),
					)
				}
			}

			traceInfo := ""
			if traceID != "" {
				traceInfo = fmt.Sprintf(" | TraceID: %s", traceID)
			}

			return fmt.Sprintf("[GIN] %v |%s %3d %s| %13v | %15s |%s %-7s %s %#v%s\n%s",
				param.TimeStamp.Format("2006/01/02 - 15:04:05"),
				statusColor, param.StatusCode, resetColor,
				param.Latency,
				param.ClientIP,
				methodColor, param.Method, resetColor,
				param.Path,
				traceInfo,
				param.ErrorMessage,
			)
		})
	} else {
		// 生产环境：使用结构化JSON日志
		return gin.LoggerWithFormatter(func(param gin.LogFormatterParams) string {
			// 获取TraceID
			traceID := param.Request.Header.Get("X-Trace-ID")
			if traceID == "" && m.tracer != nil {
				traceID = m.tracer.GetTraceID(param.Request.Context())
			}

			// 检查是否为错误响应
			if param.StatusCode >= 400 && m.tracer != nil {
				span := trace.SpanFromContext(param.Request.Context())
				if span.IsRecording() {
					// 标记为错误操作，确保100%采样
					span.SetAttributes(
						attribute.String("error.operation", "true"),
						attribute.String("operation.type", "error"),
					)

					// 对于服务器错误，记录更详细的日志
					if param.StatusCode >= 500 {
						m.logger.Error("服务器错误",
							zap.Int("status_code", param.StatusCode),
							zap.String("method", param.Method),
							zap.String("path", param.Path),
							zap.Duration("latency", param.Latency),
							zap.String("client_ip", param.ClientIP),
							zap.String("trace_id", traceID),
						)
					}
				}
			}

			// 记录请求日志
			logFields := []zap.Field{
				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")),
			}

			// 添加TraceID
			if traceID != "" {
				logFields = append(logFields, zap.String("trace_id", traceID))
			}

			m.logger.Info("HTTP请求", logFields...)
			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
}

// TraceIDMiddleware 追踪ID中间件
type TraceIDMiddleware struct {
	tracer *tracing.Tracer
}

// NewTraceIDMiddleware 创建追踪ID中间件
func NewTraceIDMiddleware(tracer *tracing.Tracer) *TraceIDMiddleware {
	return &TraceIDMiddleware{
		tracer: tracer,
	}
}

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

// GetPriority 返回中间件优先级
func (m *TraceIDMiddleware) GetPriority() int {
	return 94 // 仅次于请求ID中间件
}

// Handle 返回中间件处理函数
func (m *TraceIDMiddleware) Handle() gin.HandlerFunc {
	return func(c *gin.Context) {
		// 获取或生成追踪ID
		traceID := m.tracer.GetTraceID(c.Request.Context())
		if traceID != "" {
			// 设置追踪ID到响应头
			c.Header("X-Trace-ID", traceID)
			// 添加到上下文
			c.Set("trace_id", traceID)
		}

		// 检查是否为错误请求（例如URL不存在）
		c.Next()

		// 请求完成后检查状态码
		if c.Writer.Status() >= 400 {
			// 获取当前span
			span := trace.SpanFromContext(c.Request.Context())
			if span.IsRecording() {
				// 标记为错误操作，确保100%采样
				span.SetAttributes(
					attribute.String("error.operation", "true"),
					attribute.String("operation.type", "error"),
				)

				// 设置错误上下文，以便后续span可以识别
				c.Request = c.Request.WithContext(context.WithValue(
					c.Request.Context(),
					"otel_error_request",
					true,
				))
			}
		}
	}
}

// IsGlobal 是否为全局中间件
func (m *TraceIDMiddleware) 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
	tracer *tracing.Tracer
}

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

// 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))

					// 获取追踪ID
					traceID := ""
					if m.tracer != nil {
						traceID = m.tracer.GetTraceID(c.Request.Context())
					}

					// 记录请求体（注意：生产环境中应该谨慎记录敏感信息）
					logFields := []zap.Field{
						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")),
					}

					// 添加追踪ID
					if traceID != "" {
						logFields = append(logFields, zap.String("trace_id", traceID))
					}

					m.logger.Debug("请求体", logFields...)
				}
			}
		}

		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
}

// ErrorTrackingMiddleware 错误追踪中间件
type ErrorTrackingMiddleware struct {
	logger *zap.Logger
	tracer *tracing.Tracer
}

// NewErrorTrackingMiddleware 创建错误追踪中间件
func NewErrorTrackingMiddleware(logger *zap.Logger, tracer *tracing.Tracer) *ErrorTrackingMiddleware {
	return &ErrorTrackingMiddleware{
		logger: logger,
		tracer: tracer,
	}
}

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

// GetPriority 返回中间件优先级
func (m *ErrorTrackingMiddleware) GetPriority() int {
	return 60 // 低优先级，在大多数中间件之后执行
}

// Handle 返回中间件处理函数
func (m *ErrorTrackingMiddleware) Handle() gin.HandlerFunc {
	return func(c *gin.Context) {
		c.Next()

		// 检查是否有错误
		if len(c.Errors) > 0 || c.Writer.Status() >= 400 {
			// 获取当前span
			span := trace.SpanFromContext(c.Request.Context())
			if span.IsRecording() {
				// 标记为错误操作，确保100%采样
				span.SetAttributes(
					attribute.String("error.operation", "true"),
					attribute.String("operation.type", "error"),
				)

				// 记录错误日志
				traceID := m.tracer.GetTraceID(c.Request.Context())
				spanID := m.tracer.GetSpanID(c.Request.Context())

				logFields := []zap.Field{
					zap.Int("status_code", c.Writer.Status()),
					zap.String("method", c.Request.Method),
					zap.String("path", c.FullPath()),
					zap.String("client_ip", c.ClientIP()),
				}

				// 添加追踪信息
				if traceID != "" {
					logFields = append(logFields, zap.String("trace_id", traceID))
				}
				if spanID != "" {
					logFields = append(logFields, zap.String("span_id", spanID))
				}

				// 添加错误信息
				if len(c.Errors) > 0 {
					logFields = append(logFields, zap.String("errors", c.Errors.String()))
				}

				// 根据状态码决定日志级别
				if c.Writer.Status() >= 500 {
					m.logger.Error("服务器错误", logFields...)
				} else {
					m.logger.Warn("客户端错误", logFields...)
				}
			}
		}
	}
}

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