fix: add md & fix dateformat & add note

app/Http/Controllers/Api/DashboardController.php

@@ -15,21 +15,42 @@ class DashboardController extends Controller
         $userId = Auth::id();
         $now    = Carbon::now();
 
+        $latestMonth = $now->copy();
+        $latestYear = $latestMonth->year;
+
         // 1. 本月基礎統計 (用一個查詢同時撈出「總金額」與「總筆數」)
         $monthStats = Expense::where('user_id', $userId)
-            ->whereYear('date',  $now->year)
-            ->whereMonth('date', $now->month)
+            ->whereYear('date',  $latestYear)
+            ->whereMonth('date', $latestMonth)
             ->selectRaw('SUM(amount) as total_amount, COUNT(id) as total_count')
             ->first();
 
+        if (!$monthStats || $monthStats->total_amount == 0) {
+            // 改用 first() 確保能抓到單筆資料
+            $latestExpense = Expense::where('user_id', $userId)->latest('date')->first();
+
+            if ($latestExpense) {
+                $targetDate = Carbon::parse($latestExpense->date);
+                $latestYear = $targetDate->year;
+                $latestMonth = $targetDate->month;
+
+                // 重新撈取該月份的統計資料
+                $monthStats = Expense::where('user_id', $userId)
+                    ->whereYear('date', $latestYear)
+                    ->whereMonth('date', $latestMonth)
+                    ->selectRaw('SUM(amount) as total_amount, COUNT(id) as total_count')
+                    ->first();
+            }
+        }
+
         $monthlyTotal = (float) ($monthStats->total_amount ?? 0);
         $monthlyCount = (int) ($monthStats->total_count ?? 0);
 
         // 2. 本月分類統計（圓餅圖）- 保持集合操作即可
         $categoryStats = Expense::with('category')
             ->where('user_id', $userId)
-            ->whereYear('date',  $now->year)
-            ->whereMonth('date', $now->month)
+            ->whereYear('date',  $latestYear)
+            ->whereMonth('date', $latestMonth)
             ->get()
             ->groupBy(fn($e) => $e->category?->name ?? '未分類')
             ->map(fn($group, $name) => [
@@ -86,12 +107,12 @@ class DashboardController extends Controller
             $monthlyShare = (float) $expense->amount / $totalMonths;
 
             // 跑這 6 個月的迴圈，看有沒有落在這筆費用的歸屬區間內
-            foreach ($monthlyTrendData as $monthStr => $currentTotal) {
+            foreach ($monthlyTrendData as $monthStr => &$currentTotal) {
                 $currentMonthObj = Carbon::createFromFormat('Y/m', $monthStr)->startOfMonth();
 
                 // 如果圖表上的這個月份，剛好在費用的歸屬起訖之內，就把每月平均金額灌進去！
                 if ($currentMonthObj->betweenIncluded($start, $end)) {
-                    $monthlyTrendData[$monthStr] += $monthlyShare;
+                    $currentTotal += $monthlyShare;
                 }
             }
         }