feat(#52): Add Daily Balance mode to ledger Statistics view

src/ledger/statistics.ts

@@ -0,0 +1,15 @@
+import type {DailyBalanceResponse} from "@/generated/mammon";
+import {isMain, type Ledger} from "./ledger";
+
+export const StatisticsModes = {
+    CashFlow: 'CASH_FLOW',
+    Margin: 'MARGIN',
+    DailyBalance: 'DAILY_BALANCE',
+} as const;
+export type StatisticsMode = typeof StatisticsModes[keyof typeof StatisticsModes];
+
+export const resolveStatisticsMode = (ledger: Ledger, mode: StatisticsMode): StatisticsMode =>
+    !isMain(ledger) && mode !== StatisticsModes.DailyBalance ? StatisticsModes.DailyBalance : mode;
+
+export const latestDailyBalanceValue = (range: DailyBalanceResponse[]): number =>
+    range.at(-1)?.averageValue ?? 0;