"Backend Website NooBee v2"

1package user
2
3// domain user
4type User struct {
5  Id       int
6  Name     string
7  Balance  decimal.Decimal
8}
9
10func (u User) Validate() (err error){
11  // handle validation of user
12  return
13}
14
15// interface repository
16type readRepository interface {
17  GetAllUser()
18}
19
20type writeRepository interface {
21  CreateUser(ctx context.Context, req User) (err error)
22}
23
24// service user
25func Register(ctx context.Context, user User, repo writeRepository) (err error) {
26  if err = user.Validate(); err != nil {
27    log.Println("[Register, UserValidation] error :",err.Error())
28    return
29  }
30
31  if err = repo.CreateUser(ctx, user); err != nil {
32    log.Println("[Register, CreateUser] error :",err.Error())
33    return
34  }
35
36  return
37}

1package transaction
2
3// domain transaction
4type Transaction struct {
5  From        int // user id
6  To          int // user id
7  Amount      decimal.Decimal
8  CreatedAt   time.Time
9}
10
11func (t Transaction) Validate() (err error) {
12  if t.From == 0 {
13    return ErrorFromUserIsEmpty
14  }
15
16  if t.To == 0 {
17    return ErrorToUserIsEmpty
18  }
19
20  if t.Amount == decimal.NewFromInt(0) {
21    return ErrorAmountIsRequired
22  }
23
24  return nil
25}
26
27// repository
28type writeRepository interface {
29  UpdateSaldo(ctx context.Context, tx *sqlx.Tx, req user.User) error
30  BeginTx(ctx context.Context) (tx *sqlx.Tx)
31  Commit(tx *sqlx.Tx) error
32  Rollback(tx *sqlx.Tx) error
33}
34
35type readRepository interface {
36  GetUserById(ctx context.Context, userId int) (res user.User, err error)
37}
38
39type sendMoneyRepository interface {
40  writeRepository
41  readRepository
42}
43
44// service
45func SendMoney(ctx context.Context, req Transaction, repo sendMoneyRepository) (err error){
46  if err = req.Validate(); err != nil {
47    log.Println("[SendMoney, TransactionValidation] error : ",err.Error())
48    return
49  }
50
51  fromUser, _ := repo.GetUserById(ctx, req.From)
52  toUser, _ := repo.GetUserById(ctx, req.To)
53  
54  // business rules for process change saldo
55  // need to makesure in domain user, already implement this method
56  if err = fromUser.Send(&toUser, req.amount); err != nil {
57    log.Println("[SendMoney, SendMoneyToUser] error : ",err.Error())
58    return
59  }
60  
61  tx := repo.BeginTx(ctx)
62  
63  defer repo.Rollback(tx)
64  
65  // update saldo from user
66  if err = repo.UpdateSaldo(ctx, tx, fromUser); err != nil {
67    log.Println("[SendMoney, UpdateSaldoFromUser] error : ",err.Error())
68    return
69  }
70  
71  // update saldo to user
72  if err = repo.UpdateSaldo(ctx, tx, toUser); err != nil {
73    log.Println("[SendMoney, UpdateSaldoToUser] error : ",err.Error())
74    return
75  }
76  
77  if err = repo.Commit(tx); err != nil {
78    log.Println("[SendMoney, CommitTransaction] error : ",err.Error())
79    return
80  }
81
82  return
83}
84

1package user
2
3// domain user
4type User struct {
5  Id       int
6  Name     string
7  Balance  decimal.Decimal
8}
9
10func (u User) Validate() (err error){
11  // handle validation of user
12  return
13}
14
15func (u *User) Send(to *User, amount decimal.Decimal) (err error) {
16  if u.Balance < amount {
17    return ErrorInsufficientBalance
18  }
19
20  u.Balance = u.Balance.Sub(amount)
21  to.balance = to.Balance.Add(amount)
22
23  return nil
24}
25

1package transaction
2
3// domain transaction
4type Transaction struct {
5  From        int // user id
6  To          int // user id
7  Amount      decimal.Decimal
8  CreatedAt   time.Time
9}
10
11type User struct {
12  Id       int
13  Balance  decimal.Decimal
14}
15
16func (u *User) Send(to *User, amount decimal.Decimal) (err error) {
17  if u.Balance < amount {
18    return ErrorInsufficientBalance
19  }
20
21  u.Balance = u.Balance.Sub(amount)
22  to.balance = to.Balance.Add(amount)
23
24  return nil
25}
26
27
28func (t Transaction) Validate() (err error) {
29  if t.From == 0 {
30    return ErrorFromUserIsEmpty
31  }
32
33  if t.To == 0 {
34    return ErrorToUserIsEmpty
35  }
36
37  if t.Amount == decimal.NewFromInt(0) {
38    return ErrorAmountIsRequired
39  }
40
41  return nil
42}
43
44// repository
45type writeRepository interface {
46  UpdateSaldo(ctx context.Context, tx *sqlx.Tx, req User) error
47  BeginTx(ctx context.Context) (tx *sqlx.Tx)
48  Commit(tx *sqlx.Tx) error
49  Rollback(tx *sqlx.Tx) error
50}
51
52type readRepository interface {
53  GetUserById(ctx context.Context, userId int) (res User, err error)
54}
55
56type sendMoneyRepository interface {
57  writeRepository
58  readRepository
59}
60
61// service
62func SendMoney(ctx context.Context, req Transaction, repo sendMoneyRepository) (err error){
63  if err = req.Validate(); err != nil {
64    log.Println("[SendMoney, TransactionValidation] error : ",err.Error())
65    return
66  }
67
68  fromUser, _ := repo.GetUserById(ctx, req.From)
69  toUser, _ := repo.GetUserById(ctx, req.To)
70  
71  // business rules for process change saldo
72  if err = fromUser.Send(&toUser, req.amount); err != nil {
73    log.Println("[SendMoney, SendMoneyToUser] error : ",err.Error())
74    return
75  }
76  
77  tx := repo.BeginTx(ctx)
78  
79  defer repo.Rollback(tx)
80  
81  // update saldo from user
82  if err = repo.UpdateSaldo(ctx, tx, fromUser); err != nil {
83    log.Println("[SendMoney, UpdateSaldoFromUser] error : ",err.Error())
84    return
85  }
86  
87  // update saldo to user
88  if err = repo.UpdateSaldo(ctx, tx, toUser); err != nil {
89    log.Println("[SendMoney, UpdateSaldoToUser] error : ",err.Error())
90    return
91  }
92  
93  if err = repo.Commit(tx); err != nil {
94    log.Println("[SendMoney, CommitTransaction] error : ",err.Error())
95    return
96  }
97
98  return
99}
100