"use server";

import { revalidatePath } from "next/cache";
import { getSessionUser } from "@/lib/auth";
import { entryBySeq } from "@/content/grammar";
import { completeSeq, grade, isUnlocked, passedSet } from "@/lib/grammar";

export type QuizResult =
  | {
      score: number;
      passed: boolean;
      correct: number;
      total: number;
      detail: boolean[];
    }
  | { error: string };

// 提交测验:服务端按标准答案计分(防篡改),达标即记进度并联动英语打卡
export async function submitQuiz(_prev: QuizResult | null, formData: FormData): Promise<QuizResult> {
  const user = await getSessionUser();
  if (!user || user.role !== "child") return { error: "会话无效,请重新激活设备" };

  const seq = Number(formData.get("seq"));
  const entry = entryBySeq(seq);
  if (!entry) return { error: "课程不存在" };

  const passed = await passedSet(user.id);
  if (!isUnlocked(seq, passed)) return { error: "请先完成前面的课程" };

  const answers = entry.quiz.map((_, i) => Number(formData.get(`a${i}`)));
  const g = grade(entry.quiz, answers);

  await completeSeq(user.id, seq, g.score, g.passed);
  revalidatePath("/learn");
  revalidatePath(`/learn/${seq}`);
  revalidatePath("/kid");
  revalidatePath("/parent");
  return g;
}