User service for all user related functions

lib/service/user.go

@@ -0,0 +1,78 @@
+package service
+
+import (
+	"context"
+	"database/sql"
+	"math/rand"
+
+	"github.com/getAlby/lndhub.go/db/models"
+	"github.com/getAlby/lndhub.go/lib/security"
+	"github.com/uptrace/bun"
+)
+
+func (svc *LndhubService) CreateUser() (user *models.User, err error) {
+
+	user = &models.User{}
+
+	// generate user login/password (TODO: allow the user to choose a login/password?)
+	user.Login = randStringBytes(8)
+	password := randStringBytes(15)
+	// we only store the hashed password but return the initial plain text password in the HTTP response
+	hashedPassword := security.HashPassword(password)
+	user.Password = hashedPassword
+
+	// Create user and the user's accounts
+	// We use double-entry bookkeeping so we use 4 accounts: incoming, current, outgoing and fees
+	// Wrapping this in a transaction in case something fails
+	err = svc.DB.RunInTx(context.TODO(), &sql.TxOptions{}, func(ctx context.Context, tx bun.Tx) error {
+		if _, err := tx.NewInsert().Model(user).Exec(ctx); err != nil {
+			return err
+		}
+		accountTypes := []string{"incoming", "current", "outgoing", "fees"}
+		for _, accountType := range accountTypes {
+			account := models.Account{UserID: user.ID, Type: accountType}
+			if _, err := tx.NewInsert().Model(&account).Exec(ctx); err != nil {
+				return err
+			}
+		}
+		return nil
+	})
+	//return actual password in the response, not the hashed one
+	user.Password = password
+	return user, err
+}
+
+func (svc *LndhubService) FindUser(ctx context.Context, userId int64) (*models.User, error) {
+	var user models.User
+
+	err := svc.DB.NewSelect().Model(&user).Where("id = ?", userId).Limit(1).Scan(ctx)
+	if err != nil {
+		return &user, err
+	}
+	return &user, nil
+}
+
+func (svc *LndhubService) CurrentUserBalance(ctx context.Context, userId int64) (int64, error) {
+	var balance int64
+
+	account, err := svc.AccountFor(ctx, "current", userId)
+	if err != nil {
+		return balance, err
+	}
+	err = svc.DB.NewSelect().Table("account_ledgers").ColumnExpr("sum(account_ledgers.amount) as balance").Where("account_ledgers.account_id = ?", account.ID).Scan(context.TODO(), &balance)
+	return balance, err
+}
+
+func (svc *LndhubService) AccountFor(ctx context.Context, accountType string, userId int64) (models.Account, error) {
+	account := models.Account{}
+	err := svc.DB.NewSelect().Model(&account).Where("user_id = ? AND type= ?", userId, accountType).Limit(1).Scan(ctx)
+	return account, err
+}
+
+func randStringBytes(n int) string {
+	b := make([]byte, n)
+	for i := range b {
+		b[i] = alphaNumBytes[rand.Intn(len(alphaNumBytes))]
+	}
+	return string(b)
+}