第二期:企业信任风 UI + 打卡科目分类 + 英语语法学习模块

- 全站按 Corporate Trust 设计规范重做:靛蓝/紫罗兰渐变、Plus Jakarta Sans
  自托管字体、带色阴影、卡片悬浮、氛围光斑
- 打卡任务增加科目分类(语文/数学/英语/运动/其他),孩子端按科目分组
- 英语语法自学模块:线性解锁课程 + 课后/周/月测验引擎,测验达标
  自动联动当日英语打卡;家长概览显示语法进度
- 课程内容:A1→B1 完整大纲,9 周 54 课 + 9 周测 + 2 月测,讲解/例句/
  练习/测验均原创,仅参考两份语法书的主题编排

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/lib/grammar.ts

@@ -0,0 +1,89 @@
+import { and, eq, sql } from "drizzle-orm";
+import { db } from "@/db";
+import { grammarProgress, taskInstances } from "@/db/schema";
+import { todayStr } from "@/lib/dates";
+import { SYLLABUS, TOTAL, entryBySeq } from "@/content/grammar";
+
+// 已通过的课程序列集合
+export async function passedSet(childId: number): Promise<Set<number>> {
+  const rows = await db
+    .select({ seq: grammarProgress.seq })
+    .from(grammarProgress)
+    .where(and(eq(grammarProgress.childUserId, childId), eq(grammarProgress.passed, true)));
+  return new Set(rows.map((r) => r.seq));
+}
+
+// 下一个该学的序列(第一个未通过的);全部完成返回 TOTAL+1
+export async function nextSeq(childId: number): Promise<number> {
+  const passed = await passedSet(childId);
+  for (const e of SYLLABUS) if (!passed.has(e.seq)) return e.seq;
+  return TOTAL + 1;
+}
+
+// 解锁规则:第 1 课永远开放;其余需前一课已通过
+export function isUnlocked(seq: number, passed: Set<number>): boolean {
+  return seq === 1 || passed.has(seq - 1);
+}
+
+// 记录某课结果;通过则同步完成当天的英语打卡
+export async function completeSeq(
+  childId: number,
+  seq: number,
+  score: number,
+  passed: boolean,
+) {
+  await db
+    .insert(grammarProgress)
+    .values({ childUserId: childId, seq, score, passed })
+    .onDuplicateKeyUpdate({ set: { score, passed, completedAt: sql`CURRENT_TIMESTAMP` } });
+
+  if (!passed) return;
+
+  const entry = entryBySeq(seq);
+  if (!entry) return;
+  const title = entry.type === "lesson" ? `英语语法 · ${entry.title}` : entry.title;
+  const today = todayStr();
+
+  const [existing] = await db
+    .select({ id: taskInstances.id, status: taskInstances.status })
+    .from(taskInstances)
+    .where(
+      and(
+        eq(taskInstances.childUserId, childId),
+        eq(taskInstances.date, today),
+        eq(taskInstances.title, title),
+      ),
+    )
+    .limit(1);
+
+  if (existing) {
+    if (existing.status !== "done") {
+      await db
+        .update(taskInstances)
+        .set({ status: "done", doneAt: sql`CURRENT_TIMESTAMP` })
+        .where(eq(taskInstances.id, existing.id));
+    }
+  } else {
+    await db.insert(taskInstances).values({
+      childUserId: childId,
+      date: today,
+      title,
+      subject: "english",
+      status: "done",
+      doneAt: new Date(),
+      sortOrder: 99,
+    });
+  }
+}
+
+// 服务端计分:对比提交的答案,返回得分与每题对错,防作弊
+export function grade(entryQuiz: { answer: number }[], answers: number[]) {
+  let correct = 0;
+  const detail = entryQuiz.map((q, i) => {
+    const right = answers[i] === q.answer;
+    if (right) correct++;
+    return right;
+  });
+  const score = entryQuiz.length ? Math.round((correct / entryQuiz.length) * 100) : 0;
+  return { score, passed: score >= 80, correct, total: entryQuiz.length, detail };
+}