import Link from "next/link";
import { Plus } from "lucide-react";
import { redirect } from "next/navigation";
import { BackgroundBlobs } from "@/components/background-blobs";
import { Badge } from "@/components/ui/badge";
import { Button } from "@/components/ui/button";
import { getSessionUser } from "@/lib/auth";
import { EXAM_TYPE_LABEL, listPapers } from "@/lib/exam";

// xuchao: 试卷管理列表——与孩子端考试中心同分组(月份),点击进入编辑
const MONTH_LABEL: Record<number, string> = {
  0: "入学 · 分班考",
  9: "9 月 · 有理数",
  10: "10 月 · 整式的加减",
  11: "11 月 · 一元一次方程",
  12: "12 月 · 几何图形初步",
  1: "1 月 · 期末全册",
};
const MONTH_ORDER = [0, 9, 10, 11, 12, 1];

function countQuestions(qs: string): number {
  try {
    const arr = JSON.parse(qs) as unknown[];
    return Array.isArray(arr) ? arr.length : 0;
  } catch {
    return 0;
  }
}

export default async function ExamsAdmin() {
  const parent = await getSessionUser();
  if (!parent) redirect("/login");
  if (parent.role !== "parent") redirect("/kid");

  const papers = await listPapers("g7", "s1");

  return (
    <main className="relative mx-auto max-w-2xl space-y-5 p-4 pb-10">
      <BackgroundBlobs />
      <header className="flex items-center justify-between">
        <Link href="/parent" className="text-sm font-medium text-indigo-600">
          ← 返回家长中心
        </Link>
        <h1 className="text-xl font-extrabold text-slate-900">考试试卷管理</h1>
        <Link href="/parent/exams/new">
          <Button size="sm">
            <Plus className="size-4" /> 新建试卷
          </Button>
        </Link>
      </header>
      <p className="rounded-lg border-l-4 border-indigo-400 bg-indigo-50 px-3 py-2 text-sm text-indigo-800">
        点击试卷可编辑元信息与题目,保存后孩子端考试中心立即生效。
      </p>

      {papers.length === 0 && (
        <div className="rounded-2xl border border-slate-100 bg-white p-8 text-center shadow-soft">
          <p className="text-sm text-muted-foreground">还没有试卷,点右上角新建</p>
        </div>
      )}

      {MONTH_ORDER.map((m) => {
        const group = papers.filter((p) => p.month === m);
        if (group.length === 0) return null;
        return (
          <section key={m} className="rounded-xl border border-slate-100 bg-white p-4 shadow-soft">
            <h2 className="mb-2 text-sm font-extrabold text-slate-900">{MONTH_LABEL[m]}</h2>
            <div className="space-y-1.5">
              {group.map((p) => (
                <Link
                  key={p.paperId}
                  href={`/parent/exams/${p.paperId}`}
                  className="flex items-center gap-2 rounded-lg border border-slate-200 px-3 py-2 text-sm text-slate-700 transition-colors hover:border-indigo-300"
                >
                  <span className="truncate font-medium text-slate-800">{p.title}</span>
                  <Badge className="shrink-0 bg-indigo-100 text-indigo-700 hover:bg-indigo-100">
                    {EXAM_TYPE_LABEL[p.examType] ?? p.examType}
                  </Badge>
                  <span className="ml-auto shrink-0 text-xs text-muted-foreground">{p.seq} 号卷</span>
                </Link>
              ))}
            </div>
          </section>
        );
      })}
    </main>
  );
}