77 lines
1.8 KiB
Go
77 lines
1.8 KiB
Go
package usecase
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import (
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"app-cloudep-member-server/internal/domain"
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"app-cloudep-member-server/internal/domain/usecase"
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mgo "app-cloudep-member-server/internal/model/mongo"
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"context"
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"math"
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"strconv"
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"strings"
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)
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type GenerateUseCaseParam struct {
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GenerateUIDRepo mgo.AutoIdModel
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}
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type GenerateUseCase struct {
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generateUIDRepo mgo.AutoIdModel
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}
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func MustGenerateUseCase(param GenerateUseCaseParam) usecase.UIDGenerateUseCase {
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return &GenerateUseCase{
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generateUIDRepo: param.GenerateUIDRepo,
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}
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}
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// Generate 利用 mongo 創立全局唯一的 ark id
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// TODO 如果之後有效能問題，扛在同一個 mongo 資料庫，在改成雪花算法
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func (g GenerateUseCase) Generate(ctx context.Context) (string, error) {
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var data mgo.AutoId
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err := g.generateUIDRepo.Inc(ctx, &data)
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if err != nil {
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return "", err
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}
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uid := strconv.Itoa(int(domain.InitAutoId + data.Counter))
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code, err := generateReferralCode(uid)
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if err != nil {
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return "", err
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}
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return code, nil
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}
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// generateReferralCode 從 UID 生成 referralCode
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func generateReferralCode(uid string) (string, error) {
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uidInt, err := strconv.ParseInt(uid, 10, 64)
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if err != nil {
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return "", err
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}
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maxReferralUIDBoundary := int64(math.Pow(float64(len(domain.ConvertTable)), float64(domain.DefaultReferralCodeLen)))
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if uidInt > maxReferralUIDBoundary {
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return "", usecase.UIDOutOfRangeErrorCodeError("uid encode out of range")
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}
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encoded := encodeToBase(uidInt, 10, domain.DefaultReferralCodeLen)
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return encoded, nil
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}
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func encodeToBase(num int64, base int, length int) string {
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result := ""
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for num > 0 {
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index := num % int64(base)
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result = domain.ConvertTable[index] + result
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num /= int64(base)
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}
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// makes sure the length fo result feats the input length
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if len(result) < length {
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result = strings.Repeat(domain.ConvertTable[0], length-len(result)) + result
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}
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return result
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}
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