fix: total budgeted sum only until the end of the month

The total budgeted amount is used for the calculation of the sum
available to budget. Therefore, only transactions before the end
of the month in question may be added to the calculation.

Author: morremeyer

pkg/models/budget.go

@@ -117,15 +117,20 @@ func (b Budget) TotalIncome() (decimal.Decimal, error) {
 	return income.Decimal, nil
 }
 
-// TotalBudgeted calculates the total sum that has been budgeted over all time.
-func (b Budget) TotalBudgeted() (decimal.Decimal, error) {
+// TotalBudgeted calculates the total sum that has been budgeted before a specific month.
+func (b Budget) TotalBudgeted(month time.Time) (decimal.Decimal, error) {
+	// Only use the year and month values, everything else is reset to the start
+	// Add a month to also factor in all allocations in the requested month
+	month = time.Date(month.Year(), month.AddDate(0, 1, 0).Month(), 1, 0, 0, 0, 0, time.UTC)
+
 	var budgeted decimal.NullDecimal
 	err := database.DB.
 		Select("SUM(amount)").
 		Joins("JOIN envelopes ON allocations.envelope_id = envelopes.id AND envelopes.deleted_at IS NULL").
 		Joins("JOIN categories ON envelopes.category_id = categories.id AND categories.deleted_at IS NULL").
 		Joins("JOIN budgets ON categories.budget_id = budgets.id AND budgets.deleted_at IS NULL").
 		Where("budgets.id = ?", b.ID).
+		Where("allocations.month < date(?) ", month).
 		Table("allocations").
 		Find(&budgeted).
 		Error

pkg/models/budget_test.go

@@ -114,6 +114,30 @@ func (suite *TestSuiteEnv) TestBudgetCalculations() {
 		suite.Assert().Fail("Resource could not be saved", err)
 	}
 
+	allocationCurrentMonth := models.Allocation{
+		AllocationCreate: models.AllocationCreate{
+			EnvelopeID: envelope.ID,
+			Amount:     decimal.NewFromFloat(25),
+			Month:      marchFifteenthTwentyTwentyTwo,
+		},
+	}
+	err = database.DB.Save(&allocationCurrentMonth).Error
+	if err != nil {
+		suite.Assert().Fail("Resource could not be saved", err)
+	}
+
+	allocationFuture := models.Allocation{
+		AllocationCreate: models.AllocationCreate{
+			EnvelopeID: envelope.ID,
+			Amount:     decimal.NewFromFloat(24.58),
+			Month:      time.Date(2170, 2, 1, 0, 0, 0, 0, time.UTC),
+		},
+	}
+	err = database.DB.Save(&allocationFuture).Error
+	if err != nil {
+		suite.Assert().Fail("Resource could not be saved", err)
+	}
+
 	salaryTransaction := models.Transaction{
 		TransactionCreate: models.TransactionCreate{
 			Date:                 marchFifteenthTwentyTwentyTwo,
@@ -204,12 +228,12 @@ func (suite *TestSuiteEnv) TestBudgetCalculations() {
 	assert.True(suite.T(), income.IsZero(), "Income is %s, should be 0", income)
 
 	// Verify total budgeted for used budget
-	budgeted, err := budget.TotalBudgeted()
+	budgeted, err := budget.TotalBudgeted(marchFifteenthTwentyTwentyTwo)
 	assert.Nil(suite.T(), err)
-	assert.True(suite.T(), budgeted.Equal(decimal.NewFromFloat(42)), "Budgeted is %s, should be 42", budgeted)
+	assert.True(suite.T(), budgeted.Equal(decimal.NewFromFloat(67)), "Budgeted is %s, should be 67", budgeted)
 
 	// Verify total budgeted for empty budget
-	budgeted, err = emptyBudget.TotalBudgeted()
+	budgeted, err = emptyBudget.TotalBudgeted(marchFifteenthTwentyTwentyTwo)
 	assert.Nil(suite.T(), err)
 	assert.True(suite.T(), budgeted.IsZero(), "Budgeted is %s, should be 0", budgeted)
 
@@ -255,7 +279,7 @@ func (suite *TestSuiteEnv) TestTotalBudgetedNoTransactions() {
 		suite.Assert().Fail("Resource could not be saved", err)
 	}
 
-	budgeted, err := budget.TotalBudgeted()
+	budgeted, err := budget.TotalBudgeted(time.Date(1913, 8, 3, 0, 0, 0, 0, time.UTC))
 	assert.Nil(suite.T(), err)
 	assert.True(suite.T(), budgeted.IsZero(), "Income is %s, should be 0", budgeted)
 }