From 5e18d51b5d5cac4ead39603bf0cf36926922d151 Mon Sep 17 00:00:00 2001
From: Jan Bader <jan@javil.eu>
Date: Wed, 8 Dec 2021 15:21:10 +0000
Subject: [PATCH] Only show last month's overflow

---
 http/budgeting.go               |  7 ++++---
 postgres/categories.sql.go      | 35 +++++++++++++++++++++++++--------
 postgres/queries/categories.sql | 19 +++++++++++++++---
 web/budgeting.html              |  2 ++
 4 files changed, 49 insertions(+), 14 deletions(-)

diff --git a/http/budgeting.go b/http/budgeting.go
index 7e95332..c13b31e 100644
--- a/http/budgeting.go
+++ b/http/budgeting.go
@@ -64,9 +64,10 @@ func (h *Handler) budgeting(c *gin.Context) {
 	firstOfPreviousMonth := firstOfMonth.AddDate(0, -1, 0)
 
 	params := postgres.GetCategoriesWithBalanceParams{
-		BudgetID: budgetUUID,
-		FromDate: firstOfMonth,
-		ToDate:   firstOfNextMonth,
+		BudgetID:     budgetUUID,
+		FromDate:     firstOfMonth,
+		ToDate:       firstOfNextMonth,
+		PrevFromDate: firstOfMonth.AddDate(0, -1, 0),
 	}
 	categories, err := h.Service.DB.GetCategoriesWithBalance(c.Request.Context(), params)
 	if err != nil {
diff --git a/postgres/categories.sql.go b/postgres/categories.sql.go
index 3377752..2b5d2ce 100644
--- a/postgres/categories.sql.go
+++ b/postgres/categories.sql.go
@@ -133,14 +133,27 @@ SELECT categories.id, categories.name, category_groups.name as group,
             WHERE categories.id = t_hist.category_id AND t_hist.date < $1
         ), 0)
     )::decimal(12,2) as available,
-    (
-        COALESCE((
+    (               COALESCE((
             SELECT SUM(a_hist.amount) FROM assignments a_hist
             WHERE categories.id = a_hist.category_id AND a_hist.date < $2
         ), 0)+COALESCE((
             SELECT SUM(t_hist.amount) FROM transactions t_hist
             WHERE categories.id = t_hist.category_id AND t_hist.date < $2
-        ), 0)
+        ), 0)-CASE WHEN (COALESCE((
+            SELECT SUM(a_hist.amount) FROM assignments a_hist
+            WHERE categories.id = a_hist.category_id AND a_hist.date < $3
+        ), 0)+COALESCE((
+            SELECT SUM(t_hist.amount) FROM transactions t_hist
+            WHERE categories.id = t_hist.category_id AND t_hist.date < $3
+        ), 0)) < 0 THEN (COALESCE((
+            SELECT SUM(a_hist.amount) FROM assignments a_hist
+            WHERE categories.id = a_hist.category_id AND a_hist.date < $3
+        ), 0)+COALESCE((
+            SELECT SUM(t_hist.amount) FROM transactions t_hist
+            WHERE categories.id = t_hist.category_id AND t_hist.date < $3
+        ), 0)) ELSE 0 END
+
+
     )::decimal(12,2) as available_last_month, 
     COALESCE((
             SELECT SUM(t_this.amount) FROM transactions t_this
@@ -153,15 +166,16 @@ SELECT categories.id, categories.name, category_groups.name as group,
 
 FROM categories
 INNER JOIN category_groups ON categories.category_group_id = category_groups.id
-WHERE category_groups.budget_id = $3
+WHERE category_groups.budget_id = $4
 GROUP BY categories.id, categories.name, category_groups.name
 ORDER BY category_groups.name, categories.name
 `
 
 type GetCategoriesWithBalanceParams struct {
-	ToDate   time.Time
-	FromDate time.Time
-	BudgetID uuid.UUID
+	ToDate       time.Time
+	FromDate     time.Time
+	PrevFromDate time.Time
+	BudgetID     uuid.UUID
 }
 
 type GetCategoriesWithBalanceRow struct {
@@ -175,7 +189,12 @@ type GetCategoriesWithBalanceRow struct {
 }
 
 func (q *Queries) GetCategoriesWithBalance(ctx context.Context, arg GetCategoriesWithBalanceParams) ([]GetCategoriesWithBalanceRow, error) {
-	rows, err := q.db.QueryContext(ctx, getCategoriesWithBalance, arg.ToDate, arg.FromDate, arg.BudgetID)
+	rows, err := q.db.QueryContext(ctx, getCategoriesWithBalance,
+		arg.ToDate,
+		arg.FromDate,
+		arg.PrevFromDate,
+		arg.BudgetID,
+	)
 	if err != nil {
 		return nil, err
 	}
diff --git a/postgres/queries/categories.sql b/postgres/queries/categories.sql
index a322f22..22c4470 100644
--- a/postgres/queries/categories.sql
+++ b/postgres/queries/categories.sql
@@ -30,14 +30,27 @@ SELECT categories.id, categories.name, category_groups.name as group,
             WHERE categories.id = t_hist.category_id AND t_hist.date < @to_date
         ), 0)
     )::decimal(12,2) as available,
-    (
-        COALESCE((
+    (               COALESCE((
             SELECT SUM(a_hist.amount) FROM assignments a_hist
             WHERE categories.id = a_hist.category_id AND a_hist.date < @from_date
         ), 0)+COALESCE((
             SELECT SUM(t_hist.amount) FROM transactions t_hist
             WHERE categories.id = t_hist.category_id AND t_hist.date < @from_date
-        ), 0)
+        ), 0)-CASE WHEN (COALESCE((
+            SELECT SUM(a_hist.amount) FROM assignments a_hist
+            WHERE categories.id = a_hist.category_id AND a_hist.date < @prev_from_date
+        ), 0)+COALESCE((
+            SELECT SUM(t_hist.amount) FROM transactions t_hist
+            WHERE categories.id = t_hist.category_id AND t_hist.date < @prev_from_date
+        ), 0)) < 0 THEN (COALESCE((
+            SELECT SUM(a_hist.amount) FROM assignments a_hist
+            WHERE categories.id = a_hist.category_id AND a_hist.date < @prev_from_date
+        ), 0)+COALESCE((
+            SELECT SUM(t_hist.amount) FROM transactions t_hist
+            WHERE categories.id = t_hist.category_id AND t_hist.date < @prev_from_date
+        ), 0)) ELSE 0 END
+
+
     )::decimal(12,2) as available_last_month, 
     COALESCE((
             SELECT SUM(t_this.amount) FROM transactions t_this
diff --git a/web/budgeting.html b/web/budgeting.html
index d424499..d3901e6 100644
--- a/web/budgeting.html
+++ b/web/budgeting.html
@@ -28,6 +28,7 @@
         <th>Category</th>
         <th></th>
         <th></th>
+        <th>Leftover</th>
         <th>Assigned</th>
         <th>Activity</th>
         <th>Available</th>
@@ -40,6 +41,7 @@
         </td>
         <td>
         </td>
+        {{template "amount-cell" .AvailableLastMonth}}
         {{template "amount-cell" .Assigned}}
         {{template "amount-cell" .Activity}}
         {{template "amount-cell" .Available}}