package Middleware

import (
	"bytes"
	"dsBaseWeb/Model"
	"dsBaseWeb/Utils/CommonUtil"
	"encoding/json"
	"github.com/gin-gonic/gin"
	"strings"
)

//需要移除字段的map,key--->接口名称,value--->数组，描述有哪些列名
var removeFieldMap = make(map[string][]string, 0)

//初始化哪些接口需要进行字段的精减
func init() {
	jsonBody := CommonUtil.ReadSwaggerJson()
	m := jsonBody.(map[string]interface{})
	n := m["paths"].(map[string]interface{})
	for k, v := range n {
		var removeList []interface{}
		//遍历所有接口
		t := v.(map[string]interface{})
		httpType := "post"
		//非空检查器
		if t["get"] != nil {
			httpType = "get"
		}
		//接口
		r1 := t[httpType].(map[string]interface{})
		if r1["x-removeswaggerfield"] != nil {
			removeList = r1["x-removeswaggerfield"].([]interface{})
		}
		//移除指定的字段
		var arr []string
		for t := 0; t < len(removeList); t++ {
			arr = append(arr, removeList[t].(string))
		}
		if len(arr) > 0 {
			removeFieldMap[k] = arr
		}
	}
}

// bodyWriter是为了记录返回数据进行了重写
type bodyWriter struct {
	gin.ResponseWriter
	body   *bytes.Buffer
	ReqUri string
}

// 后置拦截器
// 用例地址：
// http://127.0.0.1:8002/base/area/PageGovArea
func (w bodyWriter) Write(b []byte) (int, error) {
	//1、还原成json对象
	var model Model.Res
	json.Unmarshal(b, &model)
	//2、去掉指定的列
	var reqUri = w.ReqUri
	if model.List != nil {
		list := model.List.([]interface{})
		for i := 0; i < len(list); i++ {
			_m := list[i].(map[string]interface{})
			//去掉接口名称map中所有需要干掉的列
			for j := 0; j < len(removeFieldMap[reqUri]); j++ {
				delete(_m, removeFieldMap[reqUri][j])
			}
		}
		//序列化后重新输出
		b, _ = json.Marshal(model)
	}
	w.body.Write(b)
	return w.ResponseWriter.Write(b)
}

//后置拦截器
func AfterHandler() gin.HandlerFunc {
	return func(c *gin.Context) {
		//这里用来后置拦截
		reqUri := strings.Split(c.Request.RequestURI, "?")[0]
		//如果需要进行处理
		_, exist := removeFieldMap[reqUri]
		if exist {
			//复制返回器，准备去除多余的列
			c.Writer = &bodyWriter{body: bytes.NewBufferString(""), ResponseWriter: c.Writer, ReqUri: reqUri}
		}
		// 处理请求
		c.Next()
	}
}