Add support for adding allowance to ID=0 (#106)

Closes #102

Reviewed-on: #106

backend/db.go

@@ -561,36 +561,44 @@ func (db *Db) AddAllowanceAmount(userId int, allowanceId int, request AddAllowan
 		return err
 	}
 
-	// Fetch the target and progress of the specified allowance
-	var target, progress int
-	err = tx.Query("select target, balance from allowances where id = ? and user_id = ?").
-		Bind(allowanceId, userId).ScanSingle(&target, &progress)
-	if err != nil {
-		return err
-	}
-
-	// Calculate the amount to add to the current allowance
-	toAdd := remainingAmount
-	if progress+toAdd > target {
-		toAdd = target - progress
-	}
-	remainingAmount -= toAdd
-
-	// Update the current allowance
-	if toAdd > 0 {
-		err = tx.Query("update allowances set balance = balance + ? where id = ? and user_id = ?").
-			Bind(toAdd, allowanceId, userId).Exec()
+	if allowanceId == 0 {
+		err = tx.Query("update users set balance = balance + ? where id = ?").
+			Bind(remainingAmount, userId).Exec()
 		if err != nil {
 			return err
 		}
-	}
-
-	// If there's remaining amount, distribute it to the user's allowances
-	if remainingAmount > 0 {
-		err = db.addDistributedReward(tx, userId, remainingAmount)
+	} else {
+		// Fetch the target and progress of the specified allowance
+		var target, progress int
+		err = tx.Query("select target, balance from allowances where id = ? and user_id = ?").
+			Bind(allowanceId, userId).ScanSingle(&target, &progress)
 		if err != nil {
 			return err
 		}
+
+		// Calculate the amount to add to the current allowance
+		toAdd := remainingAmount
+		if progress+toAdd > target {
+			toAdd = target - progress
+		}
+		remainingAmount -= toAdd
+
+		// Update the current allowance
+		if toAdd > 0 {
+			err = tx.Query("update allowances set balance = balance + ? where id = ? and user_id = ?").
+				Bind(toAdd, allowanceId, userId).Exec()
+			if err != nil {
+				return err
+			}
+		}
+
+		// If there's remaining amount, distribute it to the user's allowances
+		if remainingAmount > 0 {
+			err = db.addDistributedReward(tx, userId, remainingAmount)
+			if err != nil {
+				return err
+			}
+		}
 	}
 
 	return tx.Commit()