"use client";

import Image from "next/image";
import Link from "next/link";
import { useState } from "react";
import { MEGA_MENU_TABS } from "@/data/home";

export type MegaColumn = {
  title: string;
  href: string;
  links: readonly { label: string; href: string }[];
};

export type MegaTabData = {
  id: string;
  nameFa: string;
  nameEn: string;
  href: string;
  image: string;
  /** Second-level categories as columns, each with third-level children */
  columns?: readonly MegaColumn[];
  /** Flat fallback when columns are not provided */
  links?: readonly { label: string; href: string }[];
};

type ProductsMegaMenuProps = {
  open: boolean;
  onClose: () => void;
  tabs?: MegaTabData[];
};

function columnsForTab(tab: MegaTabData): MegaColumn[] {
  if (tab.columns?.length) return [...tab.columns];
  if (tab.links?.length) {
    return [
      {
        title: tab.nameFa,
        href: tab.href,
        links: tab.links,
      },
    ];
  }
  return [];
}

export default function ProductsMegaMenu({
  open,
  onClose,
  tabs,
}: ProductsMegaMenuProps) {
  const list = (tabs?.length ? tabs : MEGA_MENU_TABS) as MegaTabData[];
  const [activeId, setActiveId] = useState(list[0]?.id ?? "coat");
  const active = list.find((t) => t.id === activeId) ?? list[0];

  if (!open || !active) return null;

  const columns = columnsForTab(active);

  return (
    <div
      id="products-mega-menu"
      role="region"
      aria-label="منوی محصولات"
      className="pointer-events-auto absolute inset-x-0 top-full z-40 border-t border-ink/5 bg-white shadow-[0_16px_40px_rgba(0,0,0,0.1)]"
      onMouseLeave={onClose}
    >
      <div className="mx-auto max-w-[1709px] px-4 py-5 sm:px-6 lg:px-10 lg:py-6">
        <div
          role="tablist"
          aria-label="دسته‌بندی محصولات"
          className="flex flex-wrap items-end justify-start gap-x-1 gap-y-1 border-b border-ink/10"
        >
          {list.map((tab) => {
            const selected = tab.id === active.id;
            return (
              <button
                key={tab.id}
                type="button"
                role="tab"
                aria-selected={selected}
                id={`mega-tab-${tab.id}`}
                aria-controls={`mega-panel-${tab.id}`}
                onMouseEnter={() => setActiveId(tab.id)}
                onFocus={() => setActiveId(tab.id)}
                onClick={() => setActiveId(tab.id)}
                className={`-mb-px border-b-2 px-3 py-2.5 text-center transition-colors sm:px-4 ${
                  selected
                    ? "border-ink"
                    : "border-transparent hover:opacity-90"
                }`}
              >
                <span
                  className={`block font-doran text-sm font-medium sm:text-[15px] ${
                    selected ? "text-ink" : "text-ink/80"
                  }`}
                >
                  {tab.nameFa}
                </span>
                <span
                  dir="ltr"
                  className={`mt-0.5 block font-montserrat text-[9px] font-light uppercase tracking-[0.22em] sm:text-[10px] ${
                    selected ? "text-ink/70" : "text-ink/40"
                  }`}
                >
                  {tab.nameEn}
                </span>
              </button>
            );
          })}
        </div>

        <div
          role="tabpanel"
          id={`mega-panel-${active.id}`}
          aria-labelledby={`mega-tab-${active.id}`}
          className="mt-5 flex items-start justify-start gap-6 sm:gap-8 lg:gap-10"
        >
          <div className="min-w-0 flex-1 pt-1">
            <div className="grid grid-cols-2 gap-x-6 gap-y-7 sm:grid-cols-3 sm:gap-x-8 lg:grid-cols-4 xl:grid-cols-5 xl:gap-x-10">
              {columns.map((col) => (
                <div key={col.href + col.title} className="min-w-0">
                  <Link
                    href={col.href}
                    onClick={onClose}
                    className="block text-sm font-medium text-ink transition-opacity hover:opacity-70 sm:text-[15px]"
                  >
                    {col.title}
                  </Link>
                  {col.links.length > 0 ? (
                    <ul className="mt-2.5 flex flex-col gap-1.5 text-[13px] font-light text-ink/70 sm:text-sm">
                      {col.links.map((link) => (
                        <li key={link.href + link.label}>
                          <Link
                            href={link.href}
                            onClick={onClose}
                            className="transition-colors hover:text-ink"
                          >
                            {link.label}
                          </Link>
                        </li>
                      ))}
                    </ul>
                  ) : null}
                </div>
              ))}
            </div>
          </div>

          <div className="relative hidden h-[160px] w-[120px] shrink-0 overflow-hidden bg-[#f3f3f3] sm:block sm:h-[200px] sm:w-[150px] lg:h-[220px] lg:w-[160px]">
            {list.map((tab) => (
              <div
                key={tab.id}
                className={`absolute inset-0 transition-opacity duration-[400ms] ease-out ${
                  tab.id === active.id ? "opacity-100" : "opacity-0"
                }`}
                aria-hidden={tab.id !== active.id}
              >
                <Image
                  src={tab.image}
                  alt=""
                  fill
                  sizes="160px"
                  className="object-cover"
                />
              </div>
            ))}
          </div>
        </div>
      </div>
    </div>
  );
}