package logging

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"net"
	"net/http"
	"net/url"
	"os"
	"path/filepath"
	"strings"
	"sync"
	"time"
	"tyc-server/app/main/api/internal/config"

	"github.com/zeromicro/go-zero/core/logx"
)

// userOperation 用户操作记录
type userOperation struct {
	Timestamp    string                 `json:"timestamp"`       // 操作时间戳
	RequestID    string                 `json:"requestId"`       // 请求ID
	UserID       string                 `json:"userId"`          // 用户ID
	Username     string                 `json:"username"`        // 用户名
	IP           string                 `json:"ip"`              // 客户端IP
	UserAgent    string                 `json:"userAgent"`       // 用户代理
	Method       string                 `json:"method"`          // HTTP方法
	Path         string                 `json:"path"`            // 请求路径
	QueryParams  map[string]string      `json:"queryParams"`     // 查询参数
	StatusCode   int                    `json:"statusCode"`      // 响应状态码
	ResponseTime int64                  `json:"responseTime"`    // 响应时间(毫秒)
	RequestSize  int64                  `json:"requestSize"`     // 请求大小
	ResponseSize int64                  `json:"responseSize"`    // 响应大小
	Operation    string                 `json:"operation"`       // 操作类型
	Details      map[string]interface{} `json:"details"`         // 详细信息
	Error        string                 `json:"error,omitempty"` // 错误信息
}

// UserOperationMiddleware 用户操作日志中间件
type UserOperationMiddleware struct {
	config       *config.LoggingConfig
	logDir       string
	maxFileSize  int64 // 单个日志文件最大大小(字节)
	maxDays      int   // 日志保留天数
	jwtExtractor *jwtExtractor
	mu           sync.Mutex
	currentFile  *os.File
	currentSize  int64
	currentDate  string
}

// NewUserOperationMiddleware 创建用户操作日志中间件
func NewUserOperationMiddleware(config *config.LoggingConfig, jwtSecret string) *UserOperationMiddleware {
	middleware := &UserOperationMiddleware{
		config:       config,
		logDir:       config.UserOperationLogDir,
		maxFileSize:  config.MaxFileSize,
		maxDays:      180, // 6个月
		jwtExtractor: newJWTExtractor(jwtSecret),
	}

	// 确保日志目录存在
	if err := os.MkdirAll(middleware.logDir, 0755); err != nil {
		logx.Errorf("创建用户操作日志目录失败: %v", err)
	}

	// 启动日志清理协程
	go middleware.startLogCleanup()

	return middleware
}

// Handle 处理HTTP请求并记录用户操作
func (m *UserOperationMiddleware) Handle(next http.HandlerFunc) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		startTime := time.Now()

		// 创建响应记录器
		responseRecorder := &responseWriter{
			ResponseWriter: w,
			body:           &bytes.Buffer{},
			statusCode:     http.StatusOK,
		}

		// 读取请求体
		var requestBody []byte
		if r.Body != nil {
			requestBody, _ = io.ReadAll(r.Body)
			r.Body = io.NopCloser(bytes.NewBuffer(requestBody))
		}

		// 执行下一个处理器
		next(responseRecorder, r)

		// 计算响应时间
		responseTime := time.Since(startTime).Milliseconds()

		// 记录用户操作
		m.recordUserOperation(r, responseRecorder, requestBody, responseTime)
	}
}

// recordUserOperation 记录用户操作
func (m *UserOperationMiddleware) recordUserOperation(r *http.Request, w *responseWriter, requestBody []byte, responseTime int64) {
	// 获取用户信息
	userID, username := m.extractUserInfo(r)

	// 获取客户端IP
	clientIP := m.getClientIP(r)

	// 确定操作类型
	operationType := m.determineOperation(r.Method, r.URL.Path)

	// 创建操作记录
	operation := &userOperation{
		Timestamp:    time.Now().Format("2006-01-02 15:04:05.000"),
		RequestID:    m.generateRequestID(),
		UserID:       userID,
		Username:     username,
		IP:           clientIP,
		UserAgent:    r.UserAgent(),
		Method:       r.Method,
		Path:         r.URL.Path,
		QueryParams:  m.parseQueryParams(r.URL.RawQuery),
		StatusCode:   w.statusCode,
		ResponseTime: responseTime,
		RequestSize:  int64(len(requestBody)),
		ResponseSize: int64(w.body.Len()),
		Operation:    operationType,
		Details:      m.extractOperationDetails(r, w),
	}

	// 如果有错误，记录错误信息
	if w.statusCode >= 400 {
		operation.Error = w.body.String()
	}

	// 写入日志
	m.writeLog(operation)
}

// extractUserInfo 提取用户信息
func (m *UserOperationMiddleware) extractUserInfo(r *http.Request) (userID, username string) {
	// 从JWT Token中提取用户信息
	if token := r.Header.Get("Authorization"); token != "" {
		userID, username = m.jwtExtractor.ExtractUserInfo(token)
	}

	// 如果没有Token，尝试从其他头部获取
	if userID == "" {
		userID = r.Header.Get("X-User-ID")
	}
	if username == "" {
		username = r.Header.Get("X-Username")
	}

	// 如果都没有，使用默认值
	if userID == "" {
		userID = "anonymous"
	}
	if username == "" {
		username = "anonymous"
	}

	return userID, username
}

// getClientIP 获取客户端真实IP
func (m *UserOperationMiddleware) getClientIP(r *http.Request) string {
	// 优先级: X-Forwarded-For > X-Real-IP > RemoteAddr
	if forwardedFor := r.Header.Get("X-Forwarded-For"); forwardedFor != "" {
		if ips := strings.Split(forwardedFor, ","); len(ips) > 0 {
			return strings.TrimSpace(ips[0])
		}
	}

	if realIP := r.Header.Get("X-Real-IP"); realIP != "" {
		return realIP
	}

	if r.RemoteAddr != "" {
		if host, _, err := net.SplitHostPort(r.RemoteAddr); err == nil {
			return host
		}
		return r.RemoteAddr
	}

	return "unknown"
}

// determineOperation 确定操作类型
func (m *UserOperationMiddleware) determineOperation(method, path string) string {
	// 根据HTTP方法和路径确定操作类型
	switch {
	case strings.Contains(path, "/login"):
		return "用户登录"
	case strings.Contains(path, "/logout"):
		return "用户退出"
	case strings.Contains(path, "/register"):
		return "用户注册"
	case strings.Contains(path, "/password"):
		return "密码操作"
	case strings.Contains(path, "/profile"):
		return "个人信息"
	case strings.Contains(path, "/admin"):
		return "管理操作"
	case method == "GET":
		return "查询操作"
	case method == "POST":
		return "创建操作"
	case method == "PUT", method == "PATCH":
		return "更新操作"
	case method == "DELETE":
		return "删除操作"
	default:
		return "其他操作"
	}
}

// parseQueryParams 解析查询参数
func (m *UserOperationMiddleware) parseQueryParams(rawQuery string) map[string]string {
	params := make(map[string]string)
	if rawQuery == "" {
		return params
	}

	for _, pair := range strings.Split(rawQuery, "&") {
		if kv := strings.SplitN(pair, "=", 2); len(kv) == 2 {
			key, _ := url.QueryUnescape(kv[0])
			value, _ := url.QueryUnescape(kv[1])
			params[key] = value
		}
	}

	return params
}

// extractOperationDetails 提取操作详细信息
func (m *UserOperationMiddleware) extractOperationDetails(r *http.Request, w *responseWriter) map[string]interface{} {
	details := make(map[string]interface{})

	// 记录请求头信息（排除敏感信息）
	headers := make(map[string]string)
	for key, values := range r.Header {
		lowerKey := strings.ToLower(key)
		// 排除敏感头部
		if !strings.Contains(lowerKey, "authorization") &&
			!strings.Contains(lowerKey, "cookie") &&
			!strings.Contains(lowerKey, "password") {
			headers[key] = values[0]
		}
	}
	details["headers"] = headers

	// 记录响应头信息
	responseHeaders := make(map[string]string)
	for key, values := range w.Header() {
		responseHeaders[key] = values[0]
	}
	details["responseHeaders"] = responseHeaders

	// 记录其他有用信息
	details["referer"] = r.Referer()
	details["origin"] = r.Header.Get("Origin")
	details["contentType"] = r.Header.Get("Content-Type")

	return details
}

// generateRequestID 生成请求ID
func (m *UserOperationMiddleware) generateRequestID() string {
	return fmt.Sprintf("req_%d_%d", time.Now().UnixNano(), os.Getpid())
}

// writeLog 写入日志
func (m *UserOperationMiddleware) writeLog(operation *userOperation) {
	m.mu.Lock()
	defer m.mu.Unlock()

	// 检查是否需要切换日志文件
	m.checkAndSwitchLogFile()

	// 序列化操作记录
	data, err := json.Marshal(operation)
	if err != nil {
		logx.Errorf("序列化用户操作记录失败: %v", err)
		return
	}

	// 添加换行符
	data = append(data, '\n')

	// 写入日志文件
	if m.currentFile != nil {
		if _, err := m.currentFile.Write(data); err != nil {
			logx.Errorf("写入用户操作日志失败: %v", err)
			return
		}

		// 更新当前文件大小
		m.currentSize += int64(len(data))

		// 强制刷新到磁盘
		m.currentFile.Sync()
	}
}

// checkAndSwitchLogFile 检查并切换日志文件
func (m *UserOperationMiddleware) checkAndSwitchLogFile() {
	now := time.Now()
	currentDate := now.Format("2006-01-02")

	// 检查日期是否变化
	if m.currentDate != currentDate {
		m.closeCurrentFile()
		m.currentDate = currentDate
	}

	// 检查文件大小是否超过限制
	if m.currentFile != nil && m.currentSize >= m.maxFileSize {
		m.closeCurrentFile()
	}

	// 如果当前没有文件，创建新文件
	if m.currentFile == nil {
		m.createNewLogFile()
	}
}

// createNewLogFile 创建新的日志文件
func (m *UserOperationMiddleware) createNewLogFile() {
	// 生成文件名
	timestamp := time.Now().Format("2006-01-02_15-04-05")
	filename := fmt.Sprintf("user_operation_%s_%s.log", m.currentDate, timestamp)
	filePath := filepath.Join(m.logDir, m.currentDate, filename)

	// 确保日期目录存在
	dateDir := filepath.Join(m.logDir, m.currentDate)
	if err := os.MkdirAll(dateDir, 0755); err != nil {
		logx.Errorf("创建日期目录失败: %v", err)
		return
	}

	// 创建日志文件
	file, err := os.OpenFile(filePath, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0644)
	if err != nil {
		logx.Errorf("创建日志文件失败: %v", err)
		return
	}

	m.currentFile = file
	m.currentSize = 0

	logx.Infof("创建新的用户操作日志文件: %s", filePath)
}

// closeCurrentFile 关闭当前日志文件
func (m *UserOperationMiddleware) closeCurrentFile() {
	if m.currentFile != nil {
		m.currentFile.Close()
		m.currentFile = nil
		m.currentSize = 0
	}
}

// startLogCleanup 启动日志清理协程
func (m *UserOperationMiddleware) startLogCleanup() {
	ticker := time.NewTicker(24 * time.Hour) // 每天检查一次
	defer ticker.Stop()

	for range ticker.C {
		m.cleanupOldLogs()
	}
}

// cleanupOldLogs 清理旧日志
func (m *UserOperationMiddleware) cleanupOldLogs() {
	cutoffDate := time.Now().AddDate(0, 0, -m.maxDays)

	// 遍历日志目录
	err := filepath.Walk(m.logDir, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}

		// 只处理目录
		if !info.IsDir() {
			return nil
		}

		// 检查是否是日期目录
		if date, err := time.Parse("2006-01-02", info.Name()); err == nil {
			if date.Before(cutoffDate) {
				// 删除超过保留期的日志目录
				if err := os.RemoveAll(path); err != nil {
					logx.Errorf("删除过期日志目录失败: %s, %v", path, err)
				} else {
					logx.Infof("删除过期日志目录: %s", path)
				}
			}
		}

		return nil
	})

	if err != nil {
		logx.Errorf("清理旧日志失败: %v", err)
	}
}

// Close 关闭中间件
func (m *UserOperationMiddleware) Close() error {
	m.mu.Lock()
	defer m.mu.Unlock()

	if m.currentFile != nil {
		return m.currentFile.Close()
	}
	return nil
}

// responseWriter 响应记录器
type responseWriter struct {
	http.ResponseWriter
	body       *bytes.Buffer
	statusCode int
}

func (w *responseWriter) WriteHeader(statusCode int) {
	w.statusCode = statusCode
	w.ResponseWriter.WriteHeader(statusCode)
}

func (w *responseWriter) Write(data []byte) (int, error) {
	w.body.Write(data)
	return w.ResponseWriter.Write(data)
}

func (w *responseWriter) Header() http.Header {
	return w.ResponseWriter.Header()
}