package middleware

import (
	"bytes"
	"io"
	"strings"
	"time"

	"carrot_bbs/internal/model"
	"carrot_bbs/internal/pkg/sanitizer"

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

// AccessLogConfig 访问日志配置
type AccessLogConfig struct {
	Enable     bool
	SkipPaths  []string
	ServerIP   string
	ServerPort int
}

// AccessLogMiddleware 访问日志中间件
func AccessLogMiddleware(logService OperationLogRecorder, config *AccessLogConfig) gin.HandlerFunc {
	return func(c *gin.Context) {
		if !config.Enable {
			c.Next()
			return
		}

		// 跳过指定路径
		for _, path := range config.SkipPaths {
			if strings.HasPrefix(c.Request.URL.Path, path) {
				c.Next()
				return
			}
		}

		start := time.Now()
		path := c.Request.URL.Path
		method := c.Request.Method

		// 读取请求体（用于记录）
		var requestBody string
		if c.Request.Body != nil {
			bodyBytes, _ := io.ReadAll(c.Request.Body)
			c.Request.Body = io.NopCloser(bytes.NewBuffer(bodyBytes))
			requestBody = string(bodyBytes)
		}

		c.Next()

		// 记录日志
		latency := time.Since(start)
		statusCode := c.Writer.Status()

		userID := ""
		if userIDVal, exists := c.Get("user_id"); exists {
			if uid, ok := userIDVal.(string); ok {
				userID = uid
			}
		}

		userName := ""
		if userNameVal, exists := c.Get("user_name"); exists {
			if name, ok := userNameVal.(string); ok {
				userName = name
			}
		}

		ip := c.ClientIP()
		userAgent := c.Request.UserAgent()
		referer := c.Request.Referer()

		// 确定操作类型
		operation := determineOperation(method, path, c)

		// 脱敏处理
		requestBody = sanitizeRequestBody(requestBody)

		// 构造日志对象
		log := &model.OperationLog{
			UserID:       userID,
			UserName:     sanitizer.MaskValue("username", userName),
			Operation:    operation,
			Module:       determineModule(path),
			Method:       method,
			Path:         path,
			QueryParams:  c.Request.URL.RawQuery,
			RequestBody:  requestBody,
			ResponseCode: statusCode,
			IP:           ip,
			UserAgent:    userAgent,
			Duration:     latency.Milliseconds(),
			Referer:      referer,
			Protocol:     c.Request.Proto,
			ServerIP:     config.ServerIP,
			ServerPort:   config.ServerPort,
			Status:       determineStatus(statusCode),
			OccurredAt:   start,
		}

		// 异步记录日志
		logService.RecordOperation(log)
	}
}

// OperationLogRecorder 操作日志记录器接口
type OperationLogRecorder interface {
	RecordOperation(log *model.OperationLog)
}

// determineOperation 确定操作类型
func determineOperation(method, path string, c *gin.Context) string {
	if method == "GET" {
		return string(model.OpUserLogin)
	}

	pathLower := strings.ToLower(path)

	switch {
	case strings.Contains(pathLower, "/posts"):
		if method == "POST" {
			return string(model.OpPostCreate)
		} else if method == "PUT" || method == "PATCH" {
			return string(model.OpPostUpdate)
		} else if method == "DELETE" {
			return string(model.OpPostDelete)
		}
	case strings.Contains(pathLower, "/comments"):
		if method == "POST" {
			return string(model.OpCommentCreate)
		} else if method == "DELETE" {
			return string(model.OpCommentDelete)
		}
	case strings.Contains(pathLower, "/users/me") || strings.Contains(pathLower, "/users/"):
		if strings.Contains(pathLower, "/avatar") {
			return string(model.OpAvatarUpload)
		}
		return string(model.OpProfileUpdate)
	case strings.Contains(pathLower, "/auth/register"):
		return string(model.OpUserRegister)
	case strings.Contains(pathLower, "/auth/login"):
		return string(model.OpUserLogin)
	case strings.Contains(pathLower, "/auth/logout"):
		return string(model.OpUserLogout)
	}

	return method + ":" + path
}

// determineModule 确定业务模块
func determineModule(path string) string {
	pathLower := strings.ToLower(path)

	switch {
	case strings.Contains(pathLower, "/posts"):
		return "post"
	case strings.Contains(pathLower, "/comments"):
		return "comment"
	case strings.Contains(pathLower, "/users"):
		return "user"
	case strings.Contains(pathLower, "/auth"):
		return "auth"
	case strings.Contains(pathLower, "/groups"):
		return "group"
	case strings.Contains(pathLower, "/admin"):
		return "admin"
	default:
		return "other"
	}
}

// determineStatus 确定状态
func determineStatus(statusCode int) string {
	if statusCode >= 400 {
		return "fail"
	}
	return "success"
}

// sanitizeRequestBody 脱敏请求体
func sanitizeRequestBody(body string) string {
	lines := strings.Split(body, "\n")
	sanitizedLines := make([]string, 0, len(lines))

	for _, line := range lines {
		sanitizedLine := line
		parts := strings.Split(line, ":")
		if len(parts) >= 2 {
			field := strings.TrimSpace(strings.Trim(parts[0], `"'`))
			if sanitizer.IsSensitiveField(field) {
				sanitizedLine = parts[0] + ": ***"
			}
		}
		sanitizedLines = append(sanitizedLines, sanitizedLine)
	}

	return strings.Join(sanitizedLines, "\n")
}