"use server";

import { prisma } from "@/lib/prisma";
import { headers } from "next/headers";
import { auth } from "@/lib/auth";
import { revalidatePath } from "next/cache";
import { redirect } from "next/navigation";

async function requireAdmin() {
  const session = await auth.api.getSession({ headers: await headers() });
  if (!session || session.user.role !== "admin") throw new Error("Forbidden");
}

export async function createLesson(moduleId: string, courseId: string, formData: FormData) {
  await requireAdmin();
  const title = formData.get("title") as string;
  const kinescopeId = (formData.get("kinescopeId") as string | null)?.trim() || null;
  const count = await prisma.lesson.count({ where: { moduleId } });
  const lesson = await prisma.lesson.create({
    data: { moduleId, title, kinescopeId, order: count },
  });
  revalidatePath(`/admin/courses/${courseId}/modules/${moduleId}`);
  redirect(`/admin/courses/${courseId}/modules/${moduleId}/lessons/${lesson.id}`);
}

export async function updateLesson(lessonId: string, courseId: string, moduleId: string, formData: FormData) {
  await requireAdmin();
  const title = formData.get("title") as string;
  await prisma.lesson.update({ where: { id: lessonId }, data: { title } });
  revalidatePath(`/admin/courses/${courseId}/modules/${moduleId}`);
}

export async function deleteLesson(lessonId: string, courseId: string, moduleId: string) {
  await requireAdmin();
  await prisma.lesson.delete({ where: { id: lessonId } });
  revalidatePath(`/admin/courses/${courseId}/modules/${moduleId}`);
}

export async function reorderLessons(moduleId: string, courseId: string, orderedIds: string[]) {
  await requireAdmin();
  await Promise.all(
    orderedIds.map((id, index) =>
      prisma.lesson.update({ where: { id }, data: { order: index } })
    )
  );
  revalidatePath(`/admin/courses/${courseId}/modules/${moduleId}`);
}

export async function toggleLessonPublished(
  lessonId: string,
  courseId: string,
  moduleId: string,
  currentValue: boolean
) {
  await requireAdmin();
  await prisma.lesson.update({
    where: { id: lessonId },
    data: { published: !currentValue },
  });
  revalidatePath(`/admin/courses/${courseId}/modules/${moduleId}`);
  revalidatePath(`/admin/courses/${courseId}`);
}

export async function moveLessonToModule(
  lessonId: string,
  targetModuleId: string,
  courseId: string,
  sourceModuleId: string
) {
  await requireAdmin();
  // verify target module belongs to same course
  const target = await prisma.module.findFirst({
    where: { id: targetModuleId, courseId },
  });
  if (!target) throw new Error("Module not found");

  const maxOrder = await prisma.lesson.aggregate({
    where: { moduleId: targetModuleId },
    _max: { order: true },
  });

  await prisma.lesson.update({
    where: { id: lessonId },
    data: { moduleId: targetModuleId, order: (maxOrder._max.order ?? -1) + 1 },
  });

  revalidatePath(`/admin/courses/${courseId}/modules/${sourceModuleId}`);
  revalidatePath(`/admin/courses/${courseId}/modules/${targetModuleId}`);
  revalidatePath(`/admin/courses/${courseId}`);
}