import { headers } from "next/headers";
import { auth } from "@/lib/auth";
import { redirect } from "next/navigation";
import { prisma } from "@/lib/prisma";
import Link from "next/link";

export default async function StudentDashboard() {
  const session = await auth.api.getSession({ headers: await headers() });
  if (!session) redirect("/login");

  const enrollments = await prisma.courseEnrollment.findMany({
    where: { userId: session.user.id },
    include: {
      course: {
        include: {
          modules: {
            include: {
              lessons: {
                where: { published: true },
                select: { id: true },
              },
            },
          },
          _count: { select: { modules: true } },
        },
      },
    },
    orderBy: { enrolledAt: "desc" },
  });

  const now = new Date();
  const active = enrollments.filter((e) => !e.expiresAt || e.expiresAt > now);
  const expired = enrollments.filter((e) => e.expiresAt && e.expiresAt <= now);

  // Fetch progress for all lessons in active courses
  const allLessonIds = active.flatMap((e) =>
    e.course.modules.flatMap((m) => m.lessons.map((l) => l.id))
  );
  const progressRecords = allLessonIds.length > 0
    ? await prisma.lessonProgress.findMany({
        where: { userId: session.user.id, lessonId: { in: allLessonIds } },
        select: { lessonId: true },
      })
    : [];
  const completedSet = new Set(progressRecords.map((p) => p.lessonId));

  return (
    <main className="max-w-4xl mx-auto px-6 py-10 w-full">
      <h1 className="text-2xl font-bold mb-1">Мои курсы</h1>
      <p className="text-sm mb-8" style={{ color: "var(--muted-foreground)" }}>
        {active.length} активных курсов
      </p>

      {active.length === 0 ? (
        <div className="card-aubade p-12 text-center">
          <p className="text-4xl mb-3">📚</p>
          <p className="font-medium">Доступных курсов пока нет</p>
          <p className="text-sm mt-1" style={{ color: "var(--muted-foreground)" }}>
            Обратитесь к администратору за доступом
          </p>
        </div>
      ) : (
        <div className="grid gap-4 sm:grid-cols-2">
          {active.map(({ course, expiresAt }) => {
            const totalLessons = course.modules.reduce((s, m) => s + m.lessons.length, 0);
            const completedLessons = course.modules
              .flatMap((m) => m.lessons)
              .filter((l) => completedSet.has(l.id)).length;
            const progressPct = totalLessons > 0
              ? Math.round((completedLessons / totalLessons) * 100)
              : 0;

            return (
              <Link
                key={course.id}
                href={`/courses/${course.slug}`}
                className="card-aubade p-0 overflow-hidden flex flex-col"
              >
                {course.coverImage ? (
                  // eslint-disable-next-line @next/next/no-img-element
                  <img src={course.coverImage} alt={course.title} className="w-full aspect-video object-cover" />
                ) : (
                  <div className="w-full aspect-video flex items-center justify-center text-4xl" style={{ backgroundColor: "var(--color-surface)" }}>
                    📚
                  </div>
                )}
                <div className="p-4 flex-1 flex flex-col gap-2">
                  <h2 className="font-bold text-base leading-tight">{course.title}</h2>
                  {course.description && (
                    <p className="text-xs line-clamp-2" style={{ color: "var(--muted-foreground)" }}>
                      {course.description}
                    </p>
                  )}

                  {/* Progress bar */}
                  {totalLessons > 0 && (
                    <div className="mt-auto">
                      <div className="flex items-center justify-between mb-1">
                        <span className="text-xs" style={{ color: "var(--muted-foreground)" }}>
                          {completedLessons} из {totalLessons} уроков
                        </span>
                        <span
                          className="text-xs font-bold"
                          style={{ color: progressPct === 100 ? "var(--foreground)" : "var(--muted-foreground)" }}
                        >
                          {progressPct === 100 ? "✓ Завершён" : `${progressPct}%`}
                        </span>
                      </div>
                      <div className="h-1.5 w-full" style={{ background: "var(--border)" }}>
                        <div
                          className="h-full transition-all"
                          style={{
                            width: `${progressPct}%`,
                            background: progressPct === 100 ? "var(--foreground)" : "var(--accent)",
                            border: progressPct > 0 ? "1px solid var(--foreground)" : "none",
                          }}
                        />
                      </div>
                    </div>
                  )}

                  {expiresAt && (
                    <p className="text-xs" style={{ color: "var(--muted-foreground)" }}>
                      Доступ до {new Date(expiresAt).toLocaleDateString("ru-RU")}
                    </p>
                  )}
                </div>
              </Link>
            );
          })}
        </div>
      )}

      {expired.length > 0 && (
        <div className="mt-10">
          <p className="text-xs font-bold uppercase tracking-widest mb-3" style={{ color: "var(--muted-foreground)" }}>
            Доступ истёк
          </p>
          <div className="space-y-2">
            {expired.map(({ course, expiresAt }) => (
              <div key={course.id} className="flex items-center justify-between px-4 py-3 opacity-50" style={{ border: "2px solid var(--border)" }}>
                <span className="text-sm font-medium">{course.title}</span>
                <span className="text-xs" style={{ color: "oklch(0.577 0.245 27.325)" }}>
                  Истёк {new Date(expiresAt!).toLocaleDateString("ru-RU")}
                </span>
              </div>
            ))}
          </div>
        </div>
      )}
    </main>
  );
}
