feat: add budget sum calculation (#290)

Author: morremeyer

pkg/controllers/budget.go

@@ -351,7 +351,7 @@ func getBudgetObject(c *gin.Context, id uuid.UUID) (Budget, error) {
 	}
 
 	return Budget{
-		resource,
+		resource.WithCalculations(),
 		getBudgetLinks(c, resource.ID),
 	}, nil
 }

pkg/models/budget.go

@@ -1,8 +1,10 @@
 package models
 
 import (
+	"fmt"
 	"time"
 
+	"github.com/envelope-zero/backend/internal/database"
 	"github.com/google/uuid"
 	"github.com/shopspring/decimal"
 )
@@ -29,3 +31,23 @@ type BudgetMonth struct {
 	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.
 	Envelopes []EnvelopeMonth `json:"envelopes"`
 }
+
+// WithCalculations computes all the calculated values.
+func (b Budget) WithCalculations() Budget {
+	// Get all OnBudget accounts for the budget
+	var accounts []Account
+	_ = database.DB.Where(&Account{
+		AccountCreate: AccountCreate{
+			BudgetID: b.ID,
+			OnBudget: true,
+		},
+	}).Find(&accounts)
+
+	// Add all their balances to the budget's balance
+	for _, account := range accounts {
+		fmt.Println(account.WithCalculations().Balance)
+		b.Balance = b.Balance.Add(account.WithCalculations().Balance)
+	}
+
+	return b
+}

pkg/models/budget_test.go

@@ -0,0 +1,130 @@
+package models_test
+
+import (
+	"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() {
+	budget := models.Budget{}
+	err := database.DB.Save(&budget).Error
+	if err != nil {
+		suite.Assert().Fail("Resource could not be saved", err)
+	}
+
+	bankAccount := models.Account{
+		AccountCreate: models.AccountCreate{
+			BudgetID: budget.ID,
+			OnBudget: true,
+			External: false,
+		},
+	}
+	err = database.DB.Save(&bankAccount).Error
+	if err != nil {
+		suite.Assert().Fail("Resource could not be saved", err)
+	}
+
+	cashAccount := models.Account{
+		AccountCreate: models.AccountCreate{
+			BudgetID: budget.ID,
+			OnBudget: true,
+			External: false,
+		},
+	}
+	err = database.DB.Save(&cashAccount).Error
+	if err != nil {
+		suite.Assert().Fail("Resource could not be saved", err)
+	}
+
+	employerAccount := models.Account{
+		AccountCreate: models.AccountCreate{
+			BudgetID: budget.ID,
+			External: true,
+		},
+	}
+	err = database.DB.Save(&employerAccount).Error
+	if err != nil {
+		suite.Assert().Fail("Resource could not be saved", err)
+	}
+
+	groceryAccount := models.Account{
+		AccountCreate: models.AccountCreate{
+			BudgetID: budget.ID,
+			External: true,
+		},
+	}
+	err = database.DB.Save(&groceryAccount).Error
+	if err != nil {
+		suite.Assert().Fail("Resource could not be saved", err)
+	}
+
+	category := models.Category{
+		CategoryCreate: models.CategoryCreate{
+			BudgetID: budget.ID,
+		},
+	}
+	err = database.DB.Save(&category).Error
+	if err != nil {
+		suite.Assert().Fail("Resource could not be saved", err)
+	}
+
+	envelope := models.Envelope{
+		EnvelopeCreate: models.EnvelopeCreate{
+			CategoryID: category.ID,
+		},
+	}
+	err = database.DB.Save(&envelope).Error
+	if err != nil {
+		suite.Assert().Fail("Resource could not be saved", err)
+	}
+
+	salaryTransaction := models.Transaction{
+		TransactionCreate: models.TransactionCreate{
+			BudgetID:             budget.ID,
+			EnvelopeID:           &envelope.ID,
+			SourceAccountID:      employerAccount.ID,
+			DestinationAccountID: bankAccount.ID,
+			Reconciled:           true,
+			Amount:               decimal.NewFromFloat(2857.51),
+		},
+	}
+	err = database.DB.Save(&salaryTransaction).Error
+	if err != nil {
+		suite.Assert().Fail("Resource could not be saved", err)
+	}
+
+	outgoingTransactionBank := models.Transaction{
+		TransactionCreate: models.TransactionCreate{
+			BudgetID:             budget.ID,
+			EnvelopeID:           &envelope.ID,
+			SourceAccountID:      bankAccount.ID,
+			DestinationAccountID: groceryAccount.ID,
+			Amount:               decimal.NewFromFloat(87.45),
+		},
+	}
+	err = database.DB.Save(&outgoingTransactionBank).Error
+	if err != nil {
+		suite.Assert().Fail("Resource could not be saved", err)
+	}
+
+	outgoingTransactionCash := models.Transaction{
+		TransactionCreate: models.TransactionCreate{
+			BudgetID:             budget.ID,
+			EnvelopeID:           &envelope.ID,
+			SourceAccountID:      cashAccount.ID,
+			DestinationAccountID: groceryAccount.ID,
+			Amount:               decimal.NewFromFloat(23.17),
+		},
+	}
+	err = database.DB.Save(&outgoingTransactionCash).Error
+	if err != nil {
+		suite.Assert().Fail("Resource could not be saved", err)
+	}
+
+	budget = budget.WithCalculations()
+
+	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)
+}