'use client';

import React from 'react';
import Link from 'next/link';
import { getImageUrl } from '@/lib/utils';
import { requireLoginForCheckout } from '@/lib/requireLoginForCheckout';
import type { MegaMenuBadge, MegaMenuData } from '@/services/api/storefrontService';

type BadgeKind = MegaMenuBadge;

type MegaLink = {
  label: string;
  href: string;
  badge?: BadgeKind;
  accent?: boolean;
};

type MegaGroup = {
  title: string;
  links: MegaLink[];
};

const BADGE_STYLES: Record<BadgeKind, string> = {
  new: 'bg-[#e8f5e9] text-[#43a047]',
  hot: 'bg-[#ffebee] text-[#e57373]',
  trending: 'bg-[#e3f2fd] text-[#1976d2]',
  featured: 'bg-[#e0f7fa] text-[#00acc1]',
};

const BADGE_LABEL: Record<BadgeKind, string> = {
  new: 'NEW',
  hot: 'HOT',
  trending: 'TRENDING',
  featured: 'FEATURED',
};

function parseBadge(value: unknown): BadgeKind | undefined {
  const v = String(value || '')
    .toLowerCase()
    .trim();
  if (v === 'hot' || v === 'new' || v === 'trending' || v === 'featured') {
    return v;
  }
  return undefined;
}

export function hasCmsMegaGroups(menu?: MegaMenuData | null): boolean {
  return Boolean(
    menu?.groups?.some(
      (group) =>
        Array.isArray(group?.links) &&
        group.links.some((link) => link?.label && link?.href)
    )
  );
}

export function normalizeCmsMegaMenu(menu: MegaMenuData): {
  groups: MegaGroup[];
  promo: NonNullable<MegaMenuData['promo']> | null;
} {
  const groups: MegaGroup[] = (menu.groups || [])
    .map((group) => ({
      title: String(group.title || '').trim(),
      links: (group.links || [])
        .filter((link) => link?.label && link?.href)
        .map((link) => {
          const href = String(link.href).trim();
          const label = String(link.label).trim();
          return {
            label,
            href,
            badge: parseBadge(link.badge),
            accent: Boolean(link.accent),
          };
        }),
    }))
    .filter((group) => group.links.length > 0);

  const promo = menu.promo;
  const hasPromo = Boolean(
    promo && (promo.image_url || promo.title || promo.badge || promo.href)
  );

  return { groups, promo: (hasPromo && promo) ? promo : null };
}

function MegaBadge({ kind }: { kind: BadgeKind }) {
  return (
    <span
      className={`inline-flex items-center px-1.5 py-0.5 rounded text-[9px] font-bold uppercase tracking-wide leading-none ${BADGE_STYLES[kind]}`}
    >
      {BADGE_LABEL[kind]}
    </span>
  );
}

function MegaColumn({ title, links }: MegaGroup) {
  return (
    <div className="min-w-0">
      {title ? (
        <h4 className="text-[15px] font-bold text-[#2d2d2d] mb-4">{title}</h4>
      ) : null}
      <ul className="space-y-2.5">
        {links.map((item) => (
          <li key={`${title}-${item.label}-${item.href}`}>
            {item.href === '/checkout' ? (
              <button
                type="button"
                onClick={() => {
                  if (!requireLoginForCheckout('/checkout')) return;
                  window.location.assign('/checkout');
                }}
                className={`inline-flex items-center gap-2 text-[13px] leading-snug transition-colors hover:text-primary cursor-pointer bg-transparent border-0 p-0 ${
                  item.accent
                    ? 'text-primary font-medium'
                    : 'text-[#555] font-normal'
                }`}
              >
                <span>{item.label}</span>
                {item.badge ? <MegaBadge kind={item.badge} /> : null}
              </button>
            ) : (
              <Link
                href={item.href}
                className={`inline-flex items-center gap-2 text-[13px] leading-snug transition-colors hover:text-primary ${
                  item.accent
                    ? 'text-primary font-medium'
                    : 'text-[#555] font-normal'
                }`}
              >
                <span>{item.label}</span>
                {item.badge ? <MegaBadge kind={item.badge} /> : null}
              </Link>
            )}
          </li>
        ))}
      </ul>
    </div>
  );
}

function PromoCard({
  promo,
}: {
  promo: NonNullable<MegaMenuData['promo']>;
}) {
  const href = promo.href || '/shop';
  const image = getImageUrl(promo.image_url);

  return (
    <Link
      href={href}
      className="relative block min-h-[220px] lg:min-h-[260px] rounded-xl overflow-hidden group"
    >
      <div
        className="absolute inset-0 bg-cover bg-center transition-transform duration-500 group-hover:scale-105 bg-[#ecf0f5]"
        style={
          image
            ? {
                backgroundImage: `linear-gradient(105deg, rgba(236,240,245,0.92) 0%, rgba(236,240,245,0.55) 42%, rgba(236,240,245,0.15) 100%), url(${image})`,
              }
            : undefined
        }
      />
      <div className="relative z-10 p-5 md:p-6 flex flex-col justify-center h-full min-h-[220px] lg:min-h-[260px]">
        {promo.badge ? (
          <span className="inline-flex self-start bg-white text-[#222] text-[11px] font-bold tracking-wide px-2.5 py-1 rounded-sm shadow-sm mb-2">
            {promo.badge}
          </span>
        ) : null}
        {promo.title ? (
          <p className="text-[22px] md:text-[24px] font-extrabold text-[#1a1a1a] leading-tight max-w-[140px]">
            {promo.title}
          </p>
        ) : null}
      </div>
    </Link>
  );
}

export function CmsMegaMenuPanel({ menu }: { menu: MegaMenuData }) {
  const { groups, promo } = normalizeCmsMegaMenu(menu);
  if (groups.length === 0 && !promo) return null;

  const colCount = groups.length + (promo ? 1 : 0);
  const gridClass =
    colCount >= 4
      ? 'lg:grid-cols-[repeat(3,minmax(0,1fr))_minmax(200px,240px)]'
      : colCount === 3
        ? 'lg:grid-cols-3'
        : colCount === 2
          ? 'lg:grid-cols-2'
          : 'lg:grid-cols-1';

  return (
    <div className="w-full max-w-full bg-white border border-t-0 border-gray-200 shadow-[0_16px_40px_rgba(0,0,0,0.12)] rounded-b-md overflow-hidden">
      <div
        className={`grid grid-cols-1 sm:grid-cols-2 ${gridClass} gap-6 lg:gap-8 px-5 py-6 md:px-7 md:py-7`}
      >
        {groups.map((group) => (
          <MegaColumn
            key={group.title || group.links[0]?.href}
            title={group.title}
            links={group.links}
          />
        ))}
        {promo ? <PromoCard promo={promo} /> : null}
      </div>
    </div>
  );
}