package logic

import (
	"context"
	"crypto/rand"
	"fmt"
	"math/big"
	"member/gen_result/pb/member"
	"member/internal/domain"
	ers "member/internal/lib/error"
	"member/internal/lib/required"
	"member/internal/svc"
	"strconv"

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

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

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

type generateRefreshCodeReq struct {
	Account string `json:"account" validate:"account"`
	// CodeType 1 email 2 phone
	CodeType int32 `json:"code_type" validate:"required,oneof=1 2 3"`
}

var codeMap = map[int32]string{
	1: "email",
	2: "phone",
}

func getCodeNameByCode(code int32) (string, bool) {
	res, ok := codeMap[code]
	if !ok {
		return "", false
	}

	return res, true
}

func generateVerifyCode(digits int) (string, error) {
	if digits <= 0 {
		// 預設為六位數
		digits = 6
	}

	// 計算最大值 (10^digits - 1)
	exp := new(big.Int).Exp(big.NewInt(10), big.NewInt(int64(digits)), nil)
	// 生成隨機數
	randomNumber, err := rand.Int(rand.Reader, exp)
	if err != nil {
		return "", err
	}

	// 將隨機數轉換為 string
	verifyCode := strconv.Itoa(int(randomNumber.Int64()))
	// 如果隨機數的位數少於指定的位數，則補 0
	if len(verifyCode) < digits {
		verifyCode = fmt.Sprintf("%0*d", digits, randomNumber)
	}

	return verifyCode, nil
}

// GenerateRefreshCode 這個帳號驗證碼（十分鐘），通用的
func (l *GenerateRefreshCodeLogic) GenerateRefreshCode(in *member.GenerateRefreshCodeReq) (*member.GenerateRefreshCodeResp, error) {
	err := required.ValidateAll(l.svcCtx.Validate, &generateRefreshCodeReq{
		Account:  in.GetAccount(),
		CodeType: in.GetCodeType(),
	})
	if err != nil {
		return nil, ers.InvalidFormat(err.Error())
	}

	checkType, status := getCodeNameByCode(in.GetCodeType())
	if !status {
		return nil, ers.InvalidFormat(fmt.Errorf("failed to get correct code type").Error())
	}
	rk := fmt.Sprintf("verify:%s:%s", checkType, in.GetAccount())
	// 拿過就不要再拿了
	get, err := l.svcCtx.Redis.Get(rk)
	if err != nil {
		return nil, ers.DBError("failed to connect to redis", err.Error())
	}
	if get != "" {
		return &member.GenerateRefreshCodeResp{
			Status: &member.BaseResp{
				Code:    domain.CodeOk.ToString(),
				Message: "success",
				Error:   "",
			},
			Data: &member.VerifyCode{
				VerifyCode: get,
			},
		}, nil
	}

	code, err := generateVerifyCode(6)
	if !status {
		return nil, ers.ArkInternal(err.Error())
	}

	err = l.svcCtx.Redis.Setex(rk, code, 600)
	if err != nil {
		return nil, ers.ArkInternal(err.Error())
	}

	return &member.GenerateRefreshCodeResp{
		Status: &member.BaseResp{
			Code:    domain.CodeOk.ToString(),
			Message: "success",
			Error:   "",
		},
		Data: &member.VerifyCode{
			VerifyCode: code,
		},
	}, nil
}