feat: add income to budget month calculations (#305)

Author: morremeyer

api/docs.go

@@ -2673,6 +2673,10 @@ const docTemplate = `{
                     "type": "string",
                     "example": "1e777d24-3f5b-4c43-8000-04f65f895578"
                 },
+                "income": {
+                    "type": "number",
+                    "example": 2317.34
+                },
                 "month": {
                     "description": "This is always set to 00:00 UTC on the first of the month.",
                     "type": "string",

api/swagger.json

@@ -2661,6 +2661,10 @@
                     "type": "string",
                     "example": "1e777d24-3f5b-4c43-8000-04f65f895578"
                 },
+                "income": {
+                    "type": "number",
+                    "example": 2317.34
+                },
                 "month": {
                     "description": "This is always set to 00:00 UTC on the first of the month.",
                     "type": "string",

api/swagger.yaml

@@ -441,6 +441,9 @@ definitions:
         description: The ID of the Envelope
         example: 1e777d24-3f5b-4c43-8000-04f65f895578
         type: string
+      income:
+        example: 2317.34
+        type: number
       month:
         description: This is always set to 00:00 UTC on the first of the month.
         example: "2006-05-01T00:00:00.000000Z"

pkg/controllers/budget.go

@@ -351,10 +351,18 @@ func GetBudgetMonth(c *gin.Context) {
 		budgeted = budgeted.Add(allocation.Amount)
 	}
 
+	// Calculate the income
+	income, err := budget.Income(month.Month)
+	if err != nil {
+		httperrors.Handler(c, err)
+		return
+	}
+
 	c.JSON(http.StatusOK, BudgetMonthResponse{Data: models.BudgetMonth{
 		ID:        budget.ID,
 		Name:      budget.Name,
-		Month:     time.Date(month.Month.UTC().Year(), month.Month.UTC().Month(), 1, 0, 0, 0, 0, time.UTC),
+		Month:     month.Month,
+		Income:    income,
 		Budgeted:  budgeted,
 		Envelopes: envelopeMonths,
 	}})
@@ -598,7 +606,7 @@ func getBudgetResource(c *gin.Context, id uuid.UUID) (models.Budget, error) {
 		return models.Budget{}, err
 	}
 
-	return budget, nil
+	return budget.WithCalculations(), nil
 }
 
 func getBudgetObject(c *gin.Context, id uuid.UUID) (Budget, error) {

pkg/controllers/budget_test.go

@@ -264,6 +264,16 @@ func (suite *TestSuiteEnv) TestBudgetMonth() {
 		Reconciled:           true,
 	})
 
+	_ = createTestTransaction(suite.T(), models.TransactionCreate{
+		Date:                 time.Date(2022, 3, 1, 7, 38, 17, 0, time.UTC),
+		Amount:               decimal.NewFromFloat(1500),
+		Note:                 "Income for march",
+		BudgetID:             budget.Data.ID,
+		SourceAccountID:      externalAccount.Data.ID,
+		DestinationAccountID: account.Data.ID,
+		EnvelopeID:           nil,
+	})
+
 	tests := []struct {
 		path     string
 		response controllers.BudgetMonthResponse
@@ -272,7 +282,8 @@ func (suite *TestSuiteEnv) TestBudgetMonth() {
 			fmt.Sprintf("%s/2022-01", budget.Data.Links.Self),
 			controllers.BudgetMonthResponse{
 				Data: models.BudgetMonth{
-					Month: time.Date(2022, 1, 1, 0, 0, 0, 0, time.UTC),
+					Month:  time.Date(2022, 1, 1, 0, 0, 0, 0, time.UTC),
+					Income: decimal.NewFromFloat(0),
 					Envelopes: []models.EnvelopeMonth{
 						{
 							Name:       "Utilities",
@@ -289,7 +300,8 @@ func (suite *TestSuiteEnv) TestBudgetMonth() {
 			fmt.Sprintf("%s/2022-02", budget.Data.Links.Self),
 			controllers.BudgetMonthResponse{
 				Data: models.BudgetMonth{
-					Month: time.Date(2022, 2, 1, 0, 0, 0, 0, time.UTC),
+					Month:  time.Date(2022, 2, 1, 0, 0, 0, 0, time.UTC),
+					Income: decimal.NewFromFloat(0),
 					Envelopes: []models.EnvelopeMonth{
 						{
 							Name:       "Utilities",
@@ -306,7 +318,8 @@ func (suite *TestSuiteEnv) TestBudgetMonth() {
 			fmt.Sprintf("%s/2022-03", budget.Data.Links.Self),
 			controllers.BudgetMonthResponse{
 				Data: models.BudgetMonth{
-					Month: time.Date(2022, 3, 1, 0, 0, 0, 0, time.UTC),
+					Month:  time.Date(2022, 3, 1, 0, 0, 0, 0, time.UTC),
+					Income: decimal.NewFromFloat(1500),
 					Envelopes: []models.EnvelopeMonth{
 						{
 							Name:       "Utilities",
@@ -327,16 +340,18 @@ func (suite *TestSuiteEnv) TestBudgetMonth() {
 		test.AssertHTTPStatus(suite.T(), http.StatusOK, &r)
 		test.DecodeResponse(suite.T(), &r, &budgetMonth)
 
-		// assert.FailNow(suite.T(), "BudgetMonth", budgetMonth)
+		// Verify income calculation
+		assert.True(suite.T(), budgetMonth.Data.Income.Equal(tt.response.Data.Income))
 
 		if !assert.Len(suite.T(), budgetMonth.Data.Envelopes, 1) {
 			assert.FailNow(suite.T(), "Response length does not match!", "Response does not have exactly 1 item")
 		}
 
+		expected := tt.response.Data.Envelopes[0]
 		envelope := budgetMonth.Data.Envelopes[0]
-		assert.True(suite.T(), envelope.Spent.Equal(tt.response.Data.Envelopes[0].Spent), "Monthly spent calculation for %v is wrong: should be %v, but is %v: %#v", budgetMonth.Data.Month, tt.response.Data.Envelopes[0].Spent, envelope.Spent, budgetMonth.Data)
-		assert.True(suite.T(), envelope.Balance.Equal(tt.response.Data.Envelopes[0].Balance), "Monthly balance calculation for %v is wrong: should be %v, but is %v: %#v", budgetMonth.Data.Month, tt.response.Data.Envelopes[0].Balance, envelope.Balance, budgetMonth.Data)
-		assert.True(suite.T(), envelope.Allocation.Equal(tt.response.Data.Envelopes[0].Allocation), "Monthly allocation fetch for %v is wrong: should be %v, but is %v: %#v", budgetMonth.Data.Month, tt.response.Data.Envelopes[0].Allocation, envelope.Allocation, budgetMonth.Data)
+		assert.True(suite.T(), envelope.Spent.Equal(expected.Spent), "Monthly spent calculation for %v is wrong: should be %v, but is %v: %#v", budgetMonth.Data.Month, expected.Spent, envelope.Spent, budgetMonth.Data)
+		assert.True(suite.T(), envelope.Balance.Equal(expected.Balance), "Monthly balance calculation for %v is wrong: should be %v, but is %v: %#v", budgetMonth.Data.Month, expected.Balance, envelope.Balance, budgetMonth.Data)
+		assert.True(suite.T(), envelope.Allocation.Equal(expected.Allocation), "Monthly allocation fetch for %v is wrong: should be %v, but is %v: %#v", budgetMonth.Data.Month, expected.Allocation, envelope.Allocation, budgetMonth.Data)
 	}
 }
 

pkg/models/budget.go

@@ -30,6 +30,7 @@ type BudgetMonth struct {
 	Name      string          `json:"name" example:"Groceries"`                          // The name of the Envelope
 	Month     time.Time       `json:"month" example:"2006-05-01T00:00:00.000000Z"`       // This is always set to 00:00 UTC on the first of the month.
 	Budgeted  decimal.Decimal `json:"budgeted" example:"2100"`
+	Income    decimal.Decimal `json:"income" example:"2317.34"`
 	Envelopes []EnvelopeMonth `json:"envelopes"`
 }
 
@@ -52,3 +53,31 @@ func (b Budget) WithCalculations() Budget {
 
 	return b
 }
+
+// Income returns the income for a budget in a given month.
+func (b Budget) Income(t time.Time) (decimal.Decimal, error) {
+	var income decimal.NullDecimal
+
+	err := database.DB.
+		Select("SUM(amount)").
+		Joins("JOIN accounts source_account ON transactions.source_account_id = source_account.id AND source_account.deleted_at IS NULL").
+		Joins("JOIN accounts destination_account ON transactions.destination_account_id = destination_account.id AND destination_account.deleted_at IS NULL").
+		Where("source_account.external = 1").
+		Where("destination_account.external = 0").
+		Where("transactions.envelope_id IS NULL").
+		Where("strftime('%m', transactions.date) = ?", fmt.Sprintf("%02d", t.Month())).
+		Where("strftime('%Y', transactions.date) = ?", fmt.Sprintf("%d", t.Year())).
+		Table("transactions").
+		Find(&income).
+		Error
+	if err != nil {
+		return decimal.Zero, err
+	}
+
+	// If no transactions are found, the value is nil
+	if !income.Valid {
+		return decimal.NewFromFloat(0), nil
+	}
+
+	return income.Decimal, nil
+}

pkg/models/budget_test.go

@@ -1,13 +1,17 @@
 package models_test
 
 import (
+	"time"
+
 	"github.com/envelope-zero/backend/internal/database"
 	"github.com/envelope-zero/backend/pkg/models"
 	"github.com/shopspring/decimal"
 	"github.com/stretchr/testify/assert"
 )
 
 func (suite *TestSuiteEnv) TestBudgetCalculations() {
+	marchFifteenthTwentyTwentyTwo := time.Date(2022, 3, 15, 0, 0, 0, 0, time.UTC)
+
 	budget := models.Budget{}
 	err := database.DB.Save(&budget).Error
 	if err != nil {
@@ -82,8 +86,9 @@ func (suite *TestSuiteEnv) TestBudgetCalculations() {
 
 	salaryTransaction := models.Transaction{
 		TransactionCreate: models.TransactionCreate{
+			Date:                 marchFifteenthTwentyTwentyTwo,
 			BudgetID:             budget.ID,
-			EnvelopeID:           &envelope.ID,
+			EnvelopeID:           nil,
 			SourceAccountID:      employerAccount.ID,
 			DestinationAccountID: bankAccount.ID,
 			Reconciled:           true,
@@ -127,4 +132,9 @@ func (suite *TestSuiteEnv) TestBudgetCalculations() {
 
 	shouldBalance := decimal.NewFromFloat(2746.89)
 	assert.True(suite.T(), budget.Balance.Equal(shouldBalance), "Balance for budget is not correct. Should be %s, is %s", shouldBalance, budget.Balance)
+
+	shouldIncome := decimal.NewFromFloat(2857.51)
+	income, err := budget.Income(marchFifteenthTwentyTwentyTwo)
+	assert.Nil(suite.T(), err)
+	assert.True(suite.T(), income.Equal(shouldIncome), "Income is %s, should be %s", income, shouldIncome)
 }