refactor period (rolling/calender) to periodType

src/components/Dashboard/Dashboard.models.ts

@@ -1,11 +1,11 @@
 import * as React from "react";
 
 export type DashboardMode = "expense" | "income";
-export type DashboardPeriod = "rolling" | "calendar";
+export type DashboardPeriodType = "rolling" | "calendar";
 
 export interface DashboardState {
   mode: DashboardMode;
-  period: DashboardPeriod;
+  periodType: DashboardPeriodType;
   comparison: boolean;
 }
 

src/components/Dashboard/Dashboard.tsx

@@ -5,7 +5,7 @@ import { DashboardProps, DashboardState } from "./Dashboard.models";
 export default function Dashboard(props: DashboardProps) {
   const [state, setState] = React.useState<DashboardState>({
     mode: "expense",
-    period: "rolling",
+    periodType: "rolling",
     comparison: false,
   });
 

src/components/Dashboard/Dashboard.view.tsx

@@ -25,7 +25,7 @@ export default function DashboardView({
 }: ViewProps) {
   const theme = useTheme();
   const themeMode = theme.palette.mode;
-  const { mode, period, comparison } = state;
+  const { mode, periodType, comparison } = state;
 
   // Resolve colors with fallbacks
   const colors = React.useMemo(() => {
@@ -139,8 +139,8 @@ export default function DashboardView({
                   title={section.title}
                   accentColor={colors.primary}
                   colorScheme={colors}
-                  period={period}
-                  onPeriodChange={(p: any) => setState(prev => ({ ...prev, period: p }))}
+                  periodType={periodType}
+                  onPeriodTypeChange={(p: any) => setState(prev => ({ ...prev, periodType: p }))}
                   comparison={comparison}
                   setComparison={(c: any) => setState(prev => ({ ...prev, comparison: c }))}
                 />

src/components/HistoryChart/HistoryChart.models.ts

@@ -25,8 +25,8 @@ export interface HistoryChartProps {
   summary?: string;
   tabs: string[];
   data: ChartData;
-  period: "rolling" | "calendar";
-  onPeriodChange: (p: "rolling" | "calendar") => void;
+  periodType: "rolling" | "calendar";
+  onPeriodTypeChange: (p: "rolling" | "calendar") => void;
   comparison: boolean;
   setComparison: (v: boolean) => void;
   colorScheme: {

src/components/HistoryChart/HistoryChart.tsx

@@ -3,7 +3,7 @@ import { ChartDataPoint, HistoryChartProps, ChartData } from "./HistoryChart.mod
 import HistoryChartView from "./HistoryChart.view";
 
 export default function HistoryChart(props: HistoryChartProps) {
-  const { tabs, data, period, comparison } = props;
+  const { tabs, data, periodType, comparison } = props;
 
   const [activeTab, setActiveTab] = React.useState<string>(tabs[0] || "");
   const [startIndex, setStartIndex] = React.useState(0);
@@ -16,7 +16,7 @@ export default function HistoryChart(props: HistoryChartProps) {
     rawData = data.daily || [];
   } else {
     const section = data[activeDataKey];
-    rawData = section?.[period] || [];
+    rawData = section?.[periodType] || [];
   }
 
   const currentData = rawData;

src/components/HistoryChart/HistoryChart.view.tsx

@@ -33,8 +33,8 @@ export default function HistoryChartView(props: ViewProps) {
     header,
     summary,
     tabs,
-    period,
-    onPeriodChange,
+    periodType,
+    onPeriodTypeChange,
     comparison,
     setComparison,
     colorScheme,
@@ -99,7 +99,7 @@ export default function HistoryChartView(props: ViewProps) {
       </ToggleButtonGroup>
 
       <Box sx={{ display: "flex", alignItems: "center", justifyContent: "space-between", mb: 3 }}>
-        <ToggleButtonGroup value={period} exclusive onChange={(_, v) => v && onPeriodChange(v)} size="small">
+        <ToggleButtonGroup value={periodType} exclusive onChange={(_, v) => v && onPeriodTypeChange(v)} size="small">
           <ToggleButton value="rolling">Rolling</ToggleButton>
           <ToggleButton value="calendar" disabled={activeDataKey === "daily"}>
             Calendar

src/features/report/report.mapper.ts

@@ -25,14 +25,57 @@ const toLabel = (start: string, end: string, type: "weekly" | "monthly") => {
   })}`;
 };
 
+const getWeekOfMonth = (date: Date) => {
+  const firstDay = new Date(date.getFullYear(), date.getMonth(), 1);
+  return Math.ceil((date.getDate() + firstDay.getDay()) / 7);
+};
+
+const findCompareBucket = (
+  current: ReportBucket,
+  buckets: ReportBucket[],
+  type: "weekly" | "monthly"
+): ReportBucket | undefined => {
+  const start = new Date(current.start);
+
+  if (type === "monthly") {
+    const targetYear = start.getFullYear() - 1;
+    const targetMonth = start.getMonth();
+
+    return buckets.find(b => {
+      const d = new Date(b.start);
+      return (
+        d.getFullYear() === targetYear &&
+        d.getMonth() === targetMonth
+      );
+    });
+  }
+
+  if (type === "weekly") {
+    const weekIndex = getWeekOfMonth(start); // you must define this
+    const target = new Date(start);
+    target.setMonth(target.getMonth() - 1);
+
+    return buckets.find(b => {
+      const d = new Date(b.start);
+      return (
+        d.getFullYear() === target.getFullYear() &&
+        d.getMonth() === target.getMonth() &&
+        getWeekOfMonth(d) === weekIndex
+      );
+    });
+  }
+
+  return undefined;
+};
+
 const toPoints = (
   buckets: ReportBucket[],
   type: "weekly" | "monthly",
   flow: "expenses" | "incomes"
 ): ChartDataPoint[] => {
-  return buckets.map((b, i) => {
+  return buckets.map((b) => {
     const amount = sumBucket(b, flow);
-    const prev = buckets[i - 1];
+    const prev = findCompareBucket(b, buckets, type);
 
     return {
       id: toLabel(b.start, b.end, type),