feat(usage): add cost trend chart with hourly/daily toggle

src/utils/usage.ts

@@ -1395,3 +1395,90 @@ export function buildDailyTokenBreakdown(usageData: unknown): TokenBreakdownSeri
 
   return { labels, dataByCategory, hasData };
 }
+
+export interface CostSeries {
+  labels: string[];
+  data: number[];
+  hasData: boolean;
+}
+
+/**
+ * 按小时构建费用时间序列
+ */
+export function buildHourlyCostSeries(
+  usageData: unknown,
+  modelPrices: Record<string, ModelPrice>,
+  hourWindow: number = 24
+): CostSeries {
+  const hourMs = 60 * 60 * 1000;
+  const resolvedHourWindow =
+    Number.isFinite(hourWindow) && hourWindow > 0
+      ? Math.min(Math.max(Math.floor(hourWindow), 1), 24 * 31)
+      : 24;
+  const now = new Date();
+  const currentHour = new Date(now);
+  currentHour.setMinutes(0, 0, 0);
+
+  const earliestBucket = new Date(currentHour);
+  earliestBucket.setHours(earliestBucket.getHours() - (resolvedHourWindow - 1));
+  const earliestTime = earliestBucket.getTime();
+
+  const labels: string[] = [];
+  for (let i = 0; i < resolvedHourWindow; i++) {
+    labels.push(formatHourLabel(new Date(earliestTime + i * hourMs)));
+  }
+
+  const data = new Array(labels.length).fill(0);
+  const details = collectUsageDetails(usageData);
+  let hasData = false;
+
+  details.forEach((detail) => {
+    const timestamp = Date.parse(detail.timestamp);
+    if (Number.isNaN(timestamp)) return;
+    const normalized = new Date(timestamp);
+    normalized.setMinutes(0, 0, 0);
+    const bucketStart = normalized.getTime();
+    const lastBucketTime = earliestTime + (labels.length - 1) * hourMs;
+    if (bucketStart < earliestTime || bucketStart > lastBucketTime) return;
+    const bucketIndex = Math.floor((bucketStart - earliestTime) / hourMs);
+    if (bucketIndex < 0 || bucketIndex >= labels.length) return;
+
+    const cost = calculateCost(detail, modelPrices);
+    if (cost > 0) {
+      data[bucketIndex] += cost;
+      hasData = true;
+    }
+  });
+
+  return { labels, data, hasData };
+}
+
+/**
+ * 按天构建费用时间序列
+ */
+export function buildDailyCostSeries(
+  usageData: unknown,
+  modelPrices: Record<string, ModelPrice>
+): CostSeries {
+  const details = collectUsageDetails(usageData);
+  const dayMap: Record<string, number> = {};
+  let hasData = false;
+
+  details.forEach((detail) => {
+    const timestamp = Date.parse(detail.timestamp);
+    if (Number.isNaN(timestamp)) return;
+    const dayLabel = formatDayLabel(new Date(timestamp));
+    if (!dayLabel) return;
+
+    const cost = calculateCost(detail, modelPrices);
+    if (cost > 0) {
+      dayMap[dayLabel] = (dayMap[dayLabel] || 0) + cost;
+      hasData = true;
+    }
+  });
+
+  const labels = Object.keys(dayMap).sort();
+  const data = labels.map((l) => dayMap[l]);
+
+  return { labels, data, hasData };
+}