Try to calculate balances locally

http/budgeting.go

@@ -1,6 +1,7 @@
 package http
 
 import (
+	"fmt"
 	"net/http"
 	"strconv"
 	"time"
@@ -71,24 +72,82 @@ func (h *Handler) budgeting(c *gin.Context) {
 	}
 	categories, err := h.Service.DB.GetCategoriesWithBalance(c.Request.Context(), params)
 	if err != nil {
-		c.AbortWithError(http.StatusInternalServerError, err)
+		c.AbortWithError(http.StatusInternalServerError, fmt.Errorf("load categories: %w", err))
 		return
 	}
 
-	availableParams := postgres.GetAvailableBalanceParams{
-		BudgetID: budgetUUID,
-		FromDate: firstOfNextMonth,
-	}
-	availableBalance, err := h.Service.DB.GetAvailableBalance(c.Request.Context(), availableParams)
+	cumultativeBalances, err := h.Service.DB.GetCumultativeBalances(c.Request.Context(), budgetUUID)
 	if err != nil {
-		c.AbortWithError(http.StatusInternalServerError, err)
+		c.AbortWithError(http.StatusInternalServerError, fmt.Errorf("load balances: %w", err))
 		return
 	}
 
+	var available float64 = 0
+	var added float64 = 0
+	var assigned float64 = 0
+	for i := range categories {
+		cat := &categories[i]
+		var balance float64 = 0
+		for _, bal := range cumultativeBalances {
+			if bal.CategoryID != cat.ID {
+				continue
+			}
+
+			// skip everything in the future
+			if !bal.Date.Before(firstOfNextMonth) {
+				continue
+			}
+
+			assigned += bal.Assignments.GetFloat64()
+			balance += bal.Assignments.GetFloat64()
+			balance += bal.Transactions.GetFloat64()
+			if balance < 0 && bal.Date.Before(firstOfMonth) {
+				added -= balance
+				balance = 0
+			}
+
+			if bal.Date.Before(firstOfMonth) {
+				available = balance
+			}
+		}
+
+		num := postgres.Numeric{}
+		num.Set(balance)
+		cat.Available = num
+
+		num2 := postgres.Numeric{}
+		num2.Set(available)
+		cat.AvailableLastMonth = num2
+	}
+
+	data := c.MustGet("data").(AlwaysNeededData)
+	var availableBalance float64 = 0
+	for _, cat := range categories {
+		if cat.ID != data.Budget.IncomeCategoryID {
+			continue
+		}
+		availableBalance = -assigned - added
+
+		for _, bal := range cumultativeBalances {
+			if bal.CategoryID != cat.ID {
+				continue
+			}
+
+			if !bal.Date.Before(firstOfNextMonth) {
+				continue
+			}
+
+			availableBalance += bal.Transactions.GetFloat64()
+		}
+	}
+
+	var availableBalanceNum postgres.Numeric
+	availableBalanceNum.Set(availableBalance)
+
 	d := BudgetingData{
 		c.MustGet("data").(AlwaysNeededData),
 		categories,
-		availableBalance,
+		availableBalanceNum,
 		firstOfMonth,
 		firstOfNextMonth,
 		firstOfPreviousMonth,