feat: animate month swipe feedback

apps/web/src/styles.css

@@ -327,7 +327,20 @@ input:focus-visible {
   box-shadow: 0 2px 6px rgba(32, 57, 51, 0.04);
 }
 
-.list-toolbar > .list-toolbar-copy {
+.list-toolbar-content {
+  width: 100%;
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  transform: translateX(var(--month-swipe-offset, 0px));
+  transition: transform 220ms cubic-bezier(.2,.8,.2,1);
+}
+
+.list-toolbar-content.dragging { transition: none; }
+.month-swipe-hint { position:absolute; top:50%; left:50%; display:flex; align-items:center; gap:3px; transform:translate(-50%,-50%); border:1px solid #cfe0db; border-radius:999px; padding:4px 8px; background:rgba(255,255,255,.96); color:#087f72; box-shadow:0 4px 12px rgba(26,60,52,.12); font-size:11px; font-weight:700; pointer-events:none; }
+.month-swipe-hint.next { color:#3478e5; }
+
+.list-toolbar-copy {
   min-width: 0;
   display: grid;
   gap: 3px;

apps/web/src/views/LedgerView.vue

@@ -2,7 +2,9 @@
 import { formatCurrencyAmount, type LedgerEntry } from "@cents/domain";
 import {
   BookOpen,
+  ChevronLeft,
   ChevronDown,
+  ChevronRight,
   CircleUserRound,
   CloudOff,
   Copy,
@@ -40,6 +42,8 @@ const loadMoreTrigger = ref<HTMLElement | null>(null);
 const monthInput = ref<HTMLInputElement | null>(null);
 const selectedMonth = ref(toMonthValue(new Date()));
 const monthSwipeStart = ref<{ x: number; y: number } | null>(null);
+const monthSwipeDelta = ref(0);
+const monthSwipeDragging = ref(false);
 let loadMoreObserver: IntersectionObserver | null = null;
 
 const selectedMonthParts = computed(() => {
@@ -158,7 +162,26 @@ function openMonthPicker() {
 
 function startMonthSwipe(event: TouchEvent) {
   const touch = event.touches[0];
-  if (touch) monthSwipeStart.value = { x: touch.clientX, y: touch.clientY };
+  if (touch) {
+    monthSwipeStart.value = { x: touch.clientX, y: touch.clientY };
+    monthSwipeDelta.value = 0;
+    monthSwipeDragging.value = false;
+  }
+}
+
+function moveMonthSwipe(event: TouchEvent) {
+  const start = monthSwipeStart.value;
+  const touch = event.touches[0];
+  if (!start || !touch) return;
+  const deltaX = touch.clientX - start.x;
+  const deltaY = touch.clientY - start.y;
+  if (Math.abs(deltaY) > Math.abs(deltaX) && Math.abs(deltaY) > 8) {
+    monthSwipeDelta.value = 0;
+    monthSwipeDragging.value = false;
+    return;
+  }
+  monthSwipeDelta.value = Math.max(-96, Math.min(96, deltaX));
+  monthSwipeDragging.value = Math.abs(deltaX) > 8;
 }
 
 function finishMonthSwipe(event: TouchEvent) {
@@ -168,8 +191,20 @@ function finishMonthSwipe(event: TouchEvent) {
   if (!start || !touch) return;
   const deltaX = touch.clientX - start.x;
   const deltaY = touch.clientY - start.y;
-  if (Math.abs(deltaX) < 48 || Math.abs(deltaX) <= Math.abs(deltaY)) return;
+  if (Math.abs(deltaX) < 48 || Math.abs(deltaX) <= Math.abs(deltaY)) {
+    monthSwipeDelta.value = 0;
+    monthSwipeDragging.value = false;
+    return;
+  }
   shiftMonth(deltaX < 0 ? 1 : -1);
+  monthSwipeDelta.value = 0;
+  monthSwipeDragging.value = false;
+}
+
+function cancelMonthSwipe() {
+  monthSwipeStart.value = null;
+  monthSwipeDelta.value = 0;
+  monthSwipeDragging.value = false;
 }
 
 function shiftMonth(offset: number) {
@@ -178,6 +213,13 @@ function shiftMonth(offset: number) {
   selectedMonth.value = toMonthValue(new Date(selected.year, selected.month + offset, 1));
 }
 
+const monthSwipePreview = computed(() => {
+  const selected = selectedMonthParts.value;
+  if (!selected || !monthSwipeDelta.value) return "";
+  const date = new Date(selected.year, selected.month + (monthSwipeDelta.value < 0 ? 1 : -1), 1);
+  return `${date.getFullYear()}年${date.getMonth() + 1}月`;
+});
+
 function dateHeading(value: string) {
   const date = new Date(`${value}T00:00:00`);
   const today = new Date();
@@ -344,24 +386,31 @@ async function shareLedger() {
           <span><Clock3 :size="15" />{{ pendingConversionCount }} 条外币账目等待换算</span>
         </div>
       </div>
-      <div class="list-toolbar" @touchstart.passive="startMonthSwipe" @touchend="finishMonthSwipe">
-        <div class="list-toolbar-copy">
-          <div class="list-toolbar-heading">
-            <button class="list-month-switcher" type="button" @click="openMonthPicker">
-              <strong>{{ monthTitle }}</strong>
-              <ChevronDown :size="14" />
-            </button>
-            <input ref="monthInput" v-model="selectedMonth" class="native-month-input" type="month" aria-label="选择流水月份" tabindex="-1" />
-            <span>{{ monthlyEntries.length }} 笔</span>
-          </div>
-          <div class="list-toolbar-totals">
-            <span class="income">收入 {{ formatMoney(totals.income) }}</span>
-            <span class="expense">支出 {{ formatMoney(totals.expense) }}</span>
+      <div class="list-toolbar" @touchstart.passive="startMonthSwipe" @touchmove.passive="moveMonthSwipe" @touchend="finishMonthSwipe" @touchcancel="cancelMonthSwipe">
+        <div class="list-toolbar-content" :class="{ dragging: monthSwipeDragging }" :style="{ '--month-swipe-offset': `${monthSwipeDelta * 0.22}px` }">
+          <div class="list-toolbar-copy">
+            <div class="list-toolbar-heading">
+              <button class="list-month-switcher" type="button" @click="openMonthPicker">
+                <strong>{{ monthTitle }}</strong>
+                <ChevronDown :size="14" />
+              </button>
+              <input ref="monthInput" v-model="selectedMonth" class="native-month-input" type="month" aria-label="选择流水月份" tabindex="-1" />
+              <span>{{ monthlyEntries.length }} 笔</span>
+            </div>
+            <div class="list-toolbar-totals">
+              <span class="income">收入 {{ formatMoney(totals.income) }}</span>
+              <span class="expense">支出 {{ formatMoney(totals.expense) }}</span>
+            </div>
           </div>
+          <button class="icon-button list-action" type="button" aria-label="搜索流水" title="搜索流水">
+            <Search :size="19" />
+          </button>
+        </div>
+        <div v-if="monthSwipeDragging" class="month-swipe-hint" :class="{ next: monthSwipeDelta < 0 }" aria-hidden="true">
+          <ChevronRight v-if="monthSwipeDelta < 0" :size="14" />
+          <ChevronLeft v-else :size="14" />
+          <span>{{ monthSwipePreview }}</span>
         </div>
-        <button class="icon-button list-action" type="button" aria-label="搜索流水" title="搜索流水">
-          <Search :size="19" />
-        </button>
       </div>
 
       <section v-for="group in groupedEntries" :key="group.date" class="day-group">