package token

import (
	"context"
	"crypto/md5"
	"encoding/hex"
	"io"
	"strconv"
	"time"
	"wechat-api/ent"
	"wechat-api/ent/token"
	"wechat-api/internal/utils/dberrorhandler"

	"wechat-api/internal/svc"
	"wechat-api/internal/types"

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

type CheckTokenLogic struct {
	logx.Logger
	ctx    context.Context
	svcCtx *svc.ServiceContext
}

func NewCheckTokenLogic(ctx context.Context, svcCtx *svc.ServiceContext) *CheckTokenLogic {
	return &CheckTokenLogic{
		Logger: logx.WithContext(ctx),
		ctx:    ctx,
		svcCtx: svcCtx}
}

func (l *CheckTokenLogic) CheckToken(req *types.CheckTokenReq) (resp *types.CheckTokenResp, err error) {
	var (
		valid bool
		sign  string
	)
	timestamp := time.Now().Unix()

	tokenItem, err := l.svcCtx.DB.Token.Query().Where(token.TokenEQ(*req.Token)).Limit(1).Only(l.ctx)
	if err != nil && !ent.IsNotFound(err) {
		return nil, dberrorhandler.DefaultEntError(l.Logger, err, req)
	}

	if tokenItem == nil { // 判断Token是否存在
		valid = false
	} else if tokenItem.ExpireAt.Unix() > timestamp { // 判断Token是否过期
		valid = true
		if tokenItem.MAC == "" {
			err = l.svcCtx.DB.Token.UpdateOneID(tokenItem.ID).SetNotNilMAC(req.Mac).Exec(l.ctx)
			if err != nil {
				return nil, dberrorhandler.DefaultEntError(l.Logger, err, req)
			}
		}

		sign = generateSign(*req.Token, *req.Mac, strconv.Itoa(int(timestamp)))
	}

	return &types.CheckTokenResp{
		Valid:     &valid,
		Sign:      &sign,
		Timestamp: &timestamp,
	}, nil
}

// 内部Md5方法
func generateSign(token, mac, timestamp string) string {
	md5Token := easyMd5(token)
	md5Mac := easyMd5(mac)
	md5Ts := easyMd5(timestamp)

	return easyMd5(md5Token + md5Mac + md5Ts)
}

// 简易Md5用法
func easyMd5(s string) string {
	hash := md5.New()
	_, _ = io.WriteString(hash, s)
	return hex.EncodeToString(hash.Sum(nil))
}