feat: improve balance calculations in statistics page and charts with enhanced formatting for large values

app/statistics/page.tsx

@@ -181,7 +181,7 @@ export default function StatisticsPage() {
       .map(([month, values]) => ({
         month: new Date(month + "-01").toLocaleDateString("fr-FR", {
           month: "short",
-          year: "2-digit",
+          year: "numeric",
         }),
         revenus: Math.round(values.income),
         depenses: Math.round(values.expenses),
@@ -232,18 +232,40 @@ export default function StatisticsPage() {
       (a, b) => new Date(a.date).getTime() - new Date(b.date).getTime()
     );
 
-    // Start with sum of initial balances for filtered accounts
+    // Calculate starting balance: initialBalance + transactions before startDate
     let runningBalance = 0;
-    if (selectedAccounts.includes("all")) {
-      runningBalance = data.accounts.reduce(
-        (sum, acc) => sum + (acc.initialBalance || 0),
-        0,
-      );
-    } else {
-      runningBalance = data.accounts
-        .filter((acc) => selectedAccounts.includes(acc.id))
-        .reduce((sum, acc) => sum + (acc.initialBalance || 0), 0);
-    }
+    const accountsToUse = selectedAccounts.includes("all")
+      ? data.accounts
+      : data.accounts.filter((acc) => selectedAccounts.includes(acc.id));
+
+    // Start with initial balances
+    runningBalance = accountsToUse.reduce(
+      (sum, acc) => sum + (acc.initialBalance || 0),
+      0,
+    );
+
+    // Add all transactions before the start date for these accounts
+    const accountsToUseIds = new Set(accountsToUse.map((a) => a.id));
+    data.transactions
+      .filter((t) => {
+        // Filter by account
+        if (!accountsToUseIds.has(t.accountId)) return false;
+        // Filter by category if needed
+        if (!selectedCategories.includes("all")) {
+          if (selectedCategories.includes("uncategorized")) {
+            if (t.categoryId) return false;
+          } else {
+            if (!t.categoryId || !selectedCategories.includes(t.categoryId))
+              return false;
+          }
+        }
+        // Only transactions before startDate
+        const transactionDate = new Date(t.date);
+        return transactionDate < startDate;
+      })
+      .forEach((t) => {
+        runningBalance += t.amount;
+      });
 
     const aggregatedBalanceByDate = new Map<string, number>();
     sortedFilteredTransactions.forEach((t) => {
@@ -257,6 +279,7 @@ export default function StatisticsPage() {
       date: new Date(date).toLocaleDateString("fr-FR", {
         day: "2-digit",
         month: "short",
+        year: "numeric",
       }),
       solde: Math.round(balance),
     }));
@@ -267,10 +290,31 @@ export default function StatisticsPage() {
       accountBalances.set(account.id, new Map());
     });
 
-    // Calculate running balance per account (start with initialBalance)
+    // Calculate running balance per account
+    // Start with initialBalance + transactions before startDate
     const accountRunningBalances = new Map<string, number>();
     data.accounts.forEach((account) => {
-      accountRunningBalances.set(account.id, account.initialBalance || 0);
+      let accountBalance = account.initialBalance || 0;
+      // Add transactions before startDate for this account
+      data.transactions
+        .filter((t) => {
+          if (t.accountId !== account.id) return false;
+          // Filter by category if needed
+          if (!selectedCategories.includes("all")) {
+            if (selectedCategories.includes("uncategorized")) {
+              if (t.categoryId) return false;
+            } else {
+              if (!t.categoryId || !selectedCategories.includes(t.categoryId))
+                return false;
+            }
+          }
+          const transactionDate = new Date(t.date);
+          return transactionDate < startDate;
+        })
+        .forEach((t) => {
+          accountBalance += t.amount;
+        });
+      accountRunningBalances.set(account.id, accountBalance);
     });
 
     sortedFilteredTransactions.forEach((t) => {
@@ -292,8 +336,10 @@ export default function StatisticsPage() {
 
     const sortedDates = Array.from(allDates).sort();
     const lastBalances = new Map<string, number>();
+    // Initialize with the starting balance (initialBalance + transactions before startDate)
     data.accounts.forEach((account) => {
-      lastBalances.set(account.id, account.initialBalance || 0);
+      const startingBalance = accountRunningBalances.get(account.id) || 0;
+      lastBalances.set(account.id, startingBalance);
     });
 
     const perAccountBalanceData = sortedDates.map((date) => {
@@ -301,6 +347,7 @@ export default function StatisticsPage() {
         date: new Date(date).toLocaleDateString("fr-FR", {
           day: "2-digit",
           month: "short",
+          year: "numeric",
         }),
       };