import type { Metadata } from "next";
import Link from "next/link";
import { BlogCoverImage } from "@/components/BlogCoverImage";
import { ContentPageShell } from "@/components/ContentPageShell";
import { Pagination } from "@/components/Pagination";
import {
  findInstructionCategory,
  getDescendantInstructionCategoryIds,
  getRootInstructionCategories,
  instructionCategoryHref,
  instructionCategoryLabelFa,
  topInstructionCategories,
  type InstructionCategory,
} from "@/data/instructionCategories";
import {
  getInstructionCategories,
  getInstructionCoverImage,
  getInstructions,
  getInstructionsByCategory,
} from "@/lib/api";

export const metadata: Metadata = {
  title: "آموزش‌ها",
  description: "راهنماها و آموزش‌های کاربردی تیم مشکی.",
  alternates: { canonical: "/instruction" },
};

const PAGE_SIZE = 12;

type InstructionPageProps = {
  searchParams: Promise<{ page?: string; category?: string }>;
};

function mapApiCategories(
  items: Awaited<ReturnType<typeof getInstructionCategories>>,
): InstructionCategory[] {
  return items.map((item) => ({
    id: String(item.id),
    slug: item.slug,
    nameEn: item.name,
    nameFa: item.nameFa || item.name,
    parentId: item.parentId,
    sortOrder: item.sortOrder ?? 0,
  }));
}

export default async function InstructionListPage({
  searchParams,
}: InstructionPageProps) {
  const { page: pageParam, category: categoryParam } = await searchParams;
  const page = Math.max(1, Number(pageParam) || 1);

  let allCategories: InstructionCategory[] = topInstructionCategories;
  try {
    allCategories = mapApiCategories(await getInstructionCategories());
  } catch {
    allCategories = topInstructionCategories;
  }

  const rootCategories = getRootInstructionCategories(allCategories);
  const activeCategory =
    findInstructionCategory(categoryParam, allCategories) ??
    findInstructionCategory(categoryParam, rootCategories);

  let items: Awaited<ReturnType<typeof getInstructions>>["items"] = [];
  let total = 0;

  try {
    if (activeCategory) {
      const data = await getInstructionsByCategory({
        categoryId: activeCategory.id,
        categoryIds: getDescendantInstructionCategoryIds(
          allCategories,
          activeCategory.id,
        ),
        page,
        pageSize: PAGE_SIZE,
      });
      items = data.items;
      total = data.total;
    } else {
      const data = await getInstructions({ page, pageSize: PAGE_SIZE });
      items = data.items;
      total = data.total;
    }
  } catch {
    items = [];
    total = 0;
  }

  const paginationQuery = activeCategory
    ? { category: activeCategory.slug }
    : undefined;

  const filterCategories =
    rootCategories.length > 0 ? rootCategories : topInstructionCategories;

  return (
    <ContentPageShell flushTop>
      <section className="pb-20 lg:pb-28">
        <div className="page-title-band mb-8 md:mb-10">
          <div className="relative mx-auto max-w-7xl px-5 pb-9 pt-[calc(var(--header-height)+0.15rem)] lg:px-8 lg:pb-12 lg:pt-[calc(var(--header-height)+0.3rem)]">
            <p
              aria-hidden
              className="latin pointer-events-none absolute inset-x-5 top-[calc(var(--header-height)+0.5rem)] z-0 text-[clamp(1.75rem,5.5vw,3.75rem)] font-light uppercase leading-none tracking-[0.05em] text-ink/[0.07] lg:inset-x-8 lg:top-[calc(var(--header-height)+0.65rem)]"
            >
              Instructions
            </p>
            <div className="reveal relative z-10 max-w-2xl">
              <h1 className="whitespace-normal text-[clamp(1.35rem,3.6vw,2.75rem)] font-normal leading-tight tracking-tight text-ink">
                آموزش‌ها
              </h1>
              <p className="mt-1 text-sm leading-6 text-muted md:text-base">
                راهنماها و آموزش‌های کاربردی برای استفاده از خدمات مشکی.
              </p>
            </div>
          </div>
        </div>

        <div className="mx-auto max-w-7xl px-5 lg:px-8">
          <div className="reveal mb-10 flex flex-wrap gap-2 md:mb-12">
            <Link
              href="/instruction"
              className={`rounded-full border px-4 py-2 text-sm transition ${
                !activeCategory
                  ? "border-ink bg-ink text-surface"
                  : "border-line/70 text-ink-soft hover:border-ink/30 hover:text-ink"
              }`}
            >
              همه
            </Link>
            {filterCategories.map((category) => {
              const active = activeCategory?.id === category.id;
              return (
                <Link
                  key={category.id}
                  href={instructionCategoryHref(category.slug)}
                  className={`rounded-full border px-4 py-2 text-sm transition ${
                    active
                      ? "border-ink bg-ink text-surface"
                      : "border-line/70 text-ink-soft hover:border-ink/30 hover:text-ink"
                  }`}
                >
                  {category.nameFa}
                </Link>
              );
            })}
          </div>

          {items.length === 0 ? (
            <p className="text-sm text-muted">
              آموزشی برای نمایش وجود ندارد.
            </p>
          ) : (
            <div
              key={`${activeCategory?.slug ?? "all"}-${page}`}
              className="grid gap-8 sm:grid-cols-2 lg:grid-cols-3"
            >
              {items.map((item, index) => {
                const image = getInstructionCoverImage(item);
                const categoryFa = instructionCategoryLabelFa(
                  item.categoryName,
                  allCategories,
                );
                const titleFa = item.titleFa || item.title;
                const titleEn =
                  item.titleEn ??
                  (item.titleFa && item.title !== item.titleFa
                    ? item.title
                    : null);

                return (
                  <article
                    key={item.id}
                    className={`reveal group overflow-hidden rounded-2xl border border-line/70 ${
                      index % 3 === 1
                        ? "reveal-delay-1"
                        : index % 3 === 2
                          ? "reveal-delay-2"
                          : ""
                    }`}
                  >
                    <Link href={`/instruction/${item.slug}`} className="block">
                      <div className="relative overflow-hidden bg-paper-deep">
                        {image ? (
                          <BlogCoverImage src={image} alt={titleFa} />
                        ) : null}
                      </div>
                      <div className="px-4 py-4">
                        {categoryFa ? (
                          <p className="mb-2 text-[11px] text-muted">
                            {categoryFa}
                          </p>
                        ) : null}
                        <h2 className="group-text-hover line-clamp-2 whitespace-normal text-lg font-normal leading-7 text-ink">
                          {titleFa}
                        </h2>
                        {titleEn ? (
                          <p className="latin text-[12px] font-light uppercase tracking-[0.22em] text-ink-soft/70">
                            {titleEn}
                          </p>
                        ) : null}
                        {item.abstract ? (
                          <p className="mt-2 line-clamp-3 text-sm leading-6 text-muted">
                            {item.abstract}
                          </p>
                        ) : null}
                      </div>
                    </Link>
                  </article>
                );
              })}
            </div>
          )}

          <Pagination
            page={page}
            pageSize={PAGE_SIZE}
            total={total}
            basePath="/instruction"
            query={paginationQuery}
          />
        </div>
      </section>
    </ContentPageShell>
  );
}