test balances push

ledger/balances.go

@@ -9,6 +9,22 @@ type Balances map[string]Balance
 
 type Balance map[Currency]float64
 
+func (balances Balances) PushAll(other Balances) {
+	for k, v := range other {
+		if _, ok := balances[k]; !ok {
+			balances[k] = v
+		} else {
+			for k2, v2 := range v {
+				if _, ok := balances[k][k2]; !ok {
+					balances[k][k2] = v2
+				} else {
+					balances[k][k2] += v2
+				}
+			}
+		}
+	}
+}
+
 func (balances Balances) Push(d Delta) {
 	if _, ok := balances[d.Name]; !ok {
 		balances[d.Name] = make(Balance)

ledger/balances_test.go

@@ -0,0 +1,19 @@
+package ledger
+
+import "testing"
+
+func TestBalances(t *testing.T) {
+	t.Run("push", func(t *testing.T) {
+		b := make(Balances)
+		b.Push(Delta{Name: "x", Currency: "y", Value: 0.1})
+		b.Push(Delta{Name: "x", Currency: "y", Value: 1.2})
+		b.Push(Delta{Name: "x", Currency: "z", Value: 2.3})
+		ba := b["x"]
+		if ba["y"] != 1.3 {
+			t.Error(ba["y"])
+		}
+		if ba["z"] != 2.3 {
+			t.Error(ba["z"])
+		}
+	})
+}

ledger/deltas.go

@@ -1,5 +1,7 @@
 package ledger
 
+import "slices"
+
 type Deltas []Delta
 
 func (deltas Deltas) Like(like ...Like) Deltas {
@@ -12,6 +14,28 @@ func (deltas Deltas) Like(like ...Like) Deltas {
 	return result
 }
 
+func (deltas Deltas) Register() (map[string]Balances, error) {
+	dateToBalances := map[string]Balances{}
+	for _, delta := range deltas {
+		if _, ok := dateToBalances[delta.Date]; !ok {
+			dateToBalances[delta.Date] = make(Balances)
+		}
+		dateToBalances[delta.Date].Push(delta)
+	}
+	dates := make([]string, 0, len(dateToBalances)+1)
+	for k := range dateToBalances {
+		dates = append(dates, k)
+	}
+	slices.Sort(dates)
+	for i := range dates {
+		if i == 0 {
+			continue
+		}
+		dateToBalances[dates[i]].PushAll(dateToBalances[dates[i-1]])
+	}
+	return dateToBalances, nil
+}
+
 func (deltas Deltas) Balances() (Balances, error) {
 	result := make(Balances)
 	for _, delta := range deltas {

todo.yaml

@@ -1,4 +1,5 @@
 todo:
+- balances over time window
 - = VAL
 - bpi.dat
 scheduled: []