Add study activity tracking and refresh class header UI

src/services/activityService.ts

@@ -0,0 +1,104 @@
+import { prisma } from "@/lib/db";
+import type { StudyActivityType } from "@/lib/validation/activitySchemas";
+
+const ARIZONA_OFFSET_MS = 7 * 60 * 60 * 1000;
+const WEEKS_TO_DISPLAY = 53;
+const DAYS_TO_DISPLAY = WEEKS_TO_DISPLAY * 7;
+const STREAK_THRESHOLD = 20;
+
+export interface DailyActivity {
+  date: string;
+  flashcards: number;
+  questions: number;
+  total: number;
+  level: 0 | 1 | 2 | 3 | 4;
+}
+
+export interface ActivitySummary {
+  days: DailyActivity[];
+  today: string;
+  activeDays: number;
+  flashcards: number;
+  questions: number;
+  currentStreak: number;
+}
+
+function toArizonaDateKey(date: Date): string {
+  return new Date(date.getTime() - ARIZONA_OFFSET_MS).toISOString().slice(0, 10);
+}
+
+function dateKeyToUtcDate(dateKey: string): Date {
+  return new Date(`${dateKey}T00:00:00.000Z`);
+}
+
+function addDays(dateKey: string, days: number): string {
+  const date = dateKeyToUtcDate(dateKey);
+  date.setUTCDate(date.getUTCDate() + days);
+  return date.toISOString().slice(0, 10);
+}
+
+function getLevel(total: number): 0 | 1 | 2 | 3 | 4 {
+  if (total === 0) return 0;
+  if (total < 20) return 1;
+  if (total < 50) return 2;
+  if (total < 100) return 3;
+  return 4;
+}
+
+function emptyDay(date: string): DailyActivity {
+  return { date, flashcards: 0, questions: 0, total: 0, level: 0 };
+}
+
+export async function recordActivity(type: StudyActivityType) {
+  return prisma.studyActivity.create({ data: { type } });
+}
+
+export async function getActivitySummary(now = new Date()): Promise<ActivitySummary> {
+  const today = toArizonaDateKey(now);
+  const todayDate = dateKeyToUtcDate(today);
+  const dayOfWeek = todayDate.getUTCDay();
+  const startDate = addDays(today, -(dayOfWeek + (WEEKS_TO_DISPLAY - 1) * 7));
+  const endDate = addDays(startDate, DAYS_TO_DISPLAY - 1);
+
+  const activities = await prisma.studyActivity.findMany({
+    select: { type: true, occurredAt: true },
+    orderBy: { occurredAt: "asc" },
+  });
+  const totals = new Map<string, DailyActivity>();
+
+  for (const activity of activities) {
+    const date = toArizonaDateKey(activity.occurredAt);
+    const day = totals.get(date) ?? emptyDay(date);
+    if (activity.type === "FLASHCARD") day.flashcards += 1;
+    if (activity.type === "QUIZ_QUESTION") day.questions += 1;
+    day.total += 1;
+    day.level = getLevel(day.total);
+    totals.set(date, day);
+  }
+
+  const days = Array.from({ length: DAYS_TO_DISPLAY }, (_, index) => {
+    const date = addDays(startDate, index);
+    return totals.get(date) ?? emptyDay(date);
+  });
+  const visibleDays = days.filter((day) => day.date <= today && day.date <= endDate);
+  const flashcards = visibleDays.reduce((sum, day) => sum + day.flashcards, 0);
+  const questions = visibleDays.reduce((sum, day) => sum + day.questions, 0);
+
+  let streakDate = (totals.get(today)?.total ?? 0) >= STREAK_THRESHOLD
+    ? today
+    : addDays(today, -1);
+  let currentStreak = 0;
+  while ((totals.get(streakDate)?.total ?? 0) >= STREAK_THRESHOLD) {
+    currentStreak += 1;
+    streakDate = addDays(streakDate, -1);
+  }
+
+  return {
+    days,
+    today,
+    activeDays: visibleDays.filter((day) => day.total > 0).length,
+    flashcards,
+    questions,
+    currentStreak,
+  };
+}