package middleware

import (
	"bytes"
	"encoding/json"
	"io"
	"net/http"
	"net/url"
	"strconv"
	"strings"
	"sync"
	"time"

	"kra/pkg/utils"

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

var respPool sync.Pool
var bufferSize = 1024

func init() {
	respPool.New = func() interface{} {
		return make([]byte, bufferSize)
	}
}

// SysOperationRecord 操作记录结构
type SysOperationRecord struct {
	IP           string        `json:"ip"`
	Method       string        `json:"method"`
	Path         string        `json:"path"`
	Status       int           `json:"status"`
	Latency      time.Duration `json:"latency"`
	Agent        string        `json:"agent"`
	ErrorMessage string        `json:"error_message"`
	Body         string        `json:"body"`
	Resp         string        `json:"resp"`
	UserID       int           `json:"user_id"`
}

// OperationRecordCreator 操作记录创建接口
type OperationRecordCreator interface {
	CreateOperationRecord(record *SysOperationRecord) error
}

// 全局操作记录创建器
var operationRecordCreator OperationRecordCreator
var operationLogger *zap.Logger

// SetOperationRecordCreator 设置操作记录创建器
func SetOperationRecordCreator(creator OperationRecordCreator) {
	operationRecordCreator = creator
}

// SetOperationLogger 设置操作记录日志
func SetOperationLogger(logger *zap.Logger) {
	operationLogger = logger
}

// OperationRecord 操作记录中间件（与 kra 保持一致的命名）
// 别名函数，保持与 KRA 的兼容性
func OperationRecord() gin.HandlerFunc {
	return OperationRecordMiddleware()
}

// OperationRecordMiddleware 操作记录中间件（与 kra 保持一致）
func OperationRecordMiddleware() gin.HandlerFunc {
	return func(c *gin.Context) {
		var body []byte
		var userId int

		if c.Request.Method != http.MethodGet {
			var err error
			body, err = io.ReadAll(c.Request.Body)
			if err != nil {
				if operationLogger != nil {
					operationLogger.Error("read body from request error:", zap.Error(err))
				}
			} else {
				c.Request.Body = io.NopCloser(bytes.NewBuffer(body))
			}
		} else {
			query := c.Request.URL.RawQuery
			query, _ = url.QueryUnescape(query)
			split := strings.Split(query, "&")
			m := make(map[string]string)
			for _, v := range split {
				kv := strings.Split(v, "=")
				if len(kv) == 2 {
					m[kv[0]] = kv[1]
				}
			}
			body, _ = json.Marshal(&m)
		}

		claims, _ := utils.GetClaims(c)
		if claims != nil && claims.BaseClaims.ID != 0 {
			userId = int(claims.BaseClaims.ID)
		} else {
			id, err := strconv.Atoi(c.Request.Header.Get("x-user-id"))
			if err != nil {
				userId = 0
			}
			userId = id
		}

		record := SysOperationRecord{
			IP:     c.ClientIP(),
			Method: c.Request.Method,
			Path:   c.Request.URL.Path,
			Agent:  c.Request.UserAgent(),
			Body:   "",
			UserID: userId,
		}

		// 上传文件时候 中间件日志进行裁断操作
		if strings.Contains(c.GetHeader("Content-Type"), "multipart/form-data") {
			record.Body = "[文件]"
		} else {
			if len(body) > bufferSize {
				record.Body = "[超出记录长度]"
			} else {
				record.Body = string(body)
			}
		}

		writer := responseBodyWriter{
			ResponseWriter: c.Writer,
			body:           &bytes.Buffer{},
		}
		c.Writer = writer
		now := time.Now()

		c.Next()

		latency := time.Since(now)
		record.ErrorMessage = c.Errors.ByType(gin.ErrorTypePrivate).String()
		record.Status = c.Writer.Status()
		record.Latency = latency
		record.Resp = writer.body.String()

		// 检查是否为下载响应，如果是则截断
		if strings.Contains(c.Writer.Header().Get("Pragma"), "public") ||
			strings.Contains(c.Writer.Header().Get("Expires"), "0") ||
			strings.Contains(c.Writer.Header().Get("Cache-Control"), "must-revalidate, post-check=0, pre-check=0") ||
			strings.Contains(c.Writer.Header().Get("Content-Type"), "application/force-download") ||
			strings.Contains(c.Writer.Header().Get("Content-Type"), "application/octet-stream") ||
			strings.Contains(c.Writer.Header().Get("Content-Type"), "application/vnd.ms-excel") ||
			strings.Contains(c.Writer.Header().Get("Content-Type"), "application/download") ||
			strings.Contains(c.Writer.Header().Get("Content-Disposition"), "attachment") ||
			strings.Contains(c.Writer.Header().Get("Content-Transfer-Encoding"), "binary") {
			if len(record.Resp) > bufferSize {
				record.Resp = "[超出记录长度]"
			}
		}

		// 保存操作记录
		if operationRecordCreator != nil {
			if err := operationRecordCreator.CreateOperationRecord(&record); err != nil {
				if operationLogger != nil {
					operationLogger.Error("create operation record error:", zap.Error(err))
				}
			}
		}
	}
}

type responseBodyWriter struct {
	gin.ResponseWriter
	body *bytes.Buffer
}

func (r responseBodyWriter) Write(b []byte) (int, error) {
	r.body.Write(b)
	return r.ResponseWriter.Write(b)
}