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{
+	cumultativeBalances, err := h.Service.DB.GetCumultativeBalances(c.Request.Context(), budgetUUID)
-		BudgetID: budgetUUID,
-		FromDate: firstOfNextMonth,
-	}
-	availableBalance, err := h.Service.DB.GetAvailableBalance(c.Request.Context(), availableParams)
 	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,

postgres/cumultative-balances.sql.go

@@ -0,0 +1,60 @@
+// Code generated by sqlc. DO NOT EDIT.
+// source: cumultative-balances.sql
+
+package postgres
+
+import (
+	"context"
+	"time"
+
+	"github.com/google/uuid"
+)
+
+const getCumultativeBalances = `-- name: GetCumultativeBalances :many
+SELECT COALESCE(ass.date, tra.date), COALESCE(ass.category_id, tra.category_id),
+       COALESCE(ass.amount, 0)::decimal(12,2) as assignments, SUM(ass.amount) OVER (PARTITION BY ass.category_id ORDER BY ass.date)::decimal(12,2) as assignments_cum,
+       COALESCE(tra.amount, 0)::decimal(12,2) as transactions, SUM(tra.amount) OVER (PARTITION BY tra.category_id ORDER BY tra.date)::decimal(12,2) as transactions_cum
+FROM assignments_by_month as ass
+FULL OUTER JOIN transactions_by_month as tra ON ass.date = tra.date AND ass.category_id = tra.category_id
+WHERE (ass.budget_id IS NULL OR ass.budget_id = $1) AND (tra.budget_id IS NULL OR tra.budget_id = $1)
+ORDER BY COALESCE(ass.date, tra.date), COALESCE(ass.category_id, tra.category_id)
+`
+
+type GetCumultativeBalancesRow struct {
+	Date            time.Time
+	CategoryID      uuid.UUID
+	Assignments     Numeric
+	AssignmentsCum  Numeric
+	Transactions    Numeric
+	TransactionsCum Numeric
+}
+
+func (q *Queries) GetCumultativeBalances(ctx context.Context, budgetID uuid.UUID) ([]GetCumultativeBalancesRow, error) {
+	rows, err := q.db.QueryContext(ctx, getCumultativeBalances, budgetID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var items []GetCumultativeBalancesRow
+	for rows.Next() {
+		var i GetCumultativeBalancesRow
+		if err := rows.Scan(
+			&i.Date,
+			&i.CategoryID,
+			&i.Assignments,
+			&i.AssignmentsCum,
+			&i.Transactions,
+			&i.TransactionsCum,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Close(); err != nil {
+		return nil, err
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}

postgres/queries/cumultative-balances.sql

@@ -0,0 +1,8 @@
+-- name: GetCumultativeBalances :many
+SELECT COALESCE(ass.date, tra.date), COALESCE(ass.category_id, tra.category_id),
+       COALESCE(ass.amount, 0)::decimal(12,2) as assignments, SUM(ass.amount) OVER (PARTITION BY ass.category_id ORDER BY ass.date)::decimal(12,2) as assignments_cum,
+       COALESCE(tra.amount, 0)::decimal(12,2) as transactions, SUM(tra.amount) OVER (PARTITION BY tra.category_id ORDER BY tra.date)::decimal(12,2) as transactions_cum
+FROM assignments_by_month as ass
+FULL OUTER JOIN transactions_by_month as tra ON ass.date = tra.date AND ass.category_id = tra.category_id
+WHERE (ass.budget_id IS NULL OR ass.budget_id = @budget_id) AND (tra.budget_id IS NULL OR tra.budget_id = @budget_id)
+ORDER BY COALESCE(ass.date, tra.date), COALESCE(ass.category_id, tra.category_id);