import { useEffect, useRef, useState } from 'react';
import { Link, useNavigate } from 'react-router-dom';
import BrandLogo from '@dukang/shared-ui/BrandLogo';
import { request } from '../lib/api';

type BenefitSummary = {
  totalBalance: number;
  maxRedeemAmount: number;
  activeCouponCount: number;
};

type CouponItem = {
  id: string;
  couponNo: string;
  totalAmount: number;
  usedAmount: number;
  balance: number;
  status: string;
  sourceProduct: string;
};

function formatMoney(amount: number) {
  return amount.toLocaleString('zh-CN', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
}

function formatCouponNo(no: string) {
  const tail = no.replace(/^BC/i, '').slice(-6);
  return `NO. DK${tail}`;
}

function usagePercent(coupon: CouponItem) {
  const total = Number(coupon.totalAmount);
  if (total <= 0) return 0;
  return Math.min(100, Math.round((Number(coupon.usedAmount) / total) * 100));
}

function buildRedeemUrl(coupon?: CouponItem) {
  if (!coupon) return '/redeem';
  const params = new URLSearchParams({
    couponId: coupon.id,
    amount: String(coupon.balance),
  });
  return `/redeem?${params.toString()}`;
}

export default function BenefitPage() {
  const navigate = useNavigate();
  const listRef = useRef<HTMLElement>(null);
  const [summary, setSummary] = useState<BenefitSummary | null>(null);
  const [coupons, setCoupons] = useState<CouponItem[]>([]);
  const [tab, setTab] = useState<'available' | 'history'>('available');

  useEffect(() => {
    Promise.all([
      request<BenefitSummary>('USER_H5', '/benefit/summary'),
      request<CouponItem[]>('USER_H5', '/benefit/coupons'),
    ])
      .then(([s, list]) => {
        setSummary(s);
        setCoupons(
          list.map((c) => ({
            id: String(c.id),
            couponNo: String(c.couponNo),
            totalAmount: Number(c.totalAmount),
            usedAmount: Number(c.usedAmount),
            balance: Number(c.balance),
            status: String(c.status),
            sourceProduct: String(c.sourceProduct),
          })),
        );
      })
      .catch(() => {});
  }, []);

  const available = coupons.filter((c) => c.status === 'ACTIVE' && c.balance > 0);
  const history = coupons.filter((c) => c.status === 'USED_UP' || c.status === 'VOID');
  const visible = tab === 'available' ? available : history;

  function scrollToList() {
    listRef.current?.scrollIntoView({ behavior: 'smooth', block: 'start' });
  }

  function goRedeem(coupon?: CouponItem) {
    navigate(buildRedeemUrl(coupon));
  }

  return (
    <div className="benefit-page">
      <header className="benefit-header">
        <button type="button" className="benefit-header-city">
          <span className="material-symbols-outlined">location_on</span>
          <span>郑州市</span>
        </button>
        <h1 className="app-page-title">好客权益</h1>
        <button
          type="button"
          className="benefit-header-btn"
          aria-label="通知"
          onClick={() => window.alert('preV1：消息通知即将开放')}
        >
          <span className="material-symbols-outlined">notifications</span>
        </button>
      </header>

      <main className="benefit-main">
        <section className="benefit-hero">
          <div className="benefit-hero-top">
            <div>
              <p className="benefit-hero-label">当前好客权益余额</p>
              <div className="benefit-hero-amount">
                <span className="benefit-hero-symbol">¥</span>
                <span className="benefit-hero-value">
                  {summary ? formatMoney(summary.totalBalance) : '--'}
                </span>
              </div>
            </div>
            <BrandLogo className="benefit-hero-logo" />
          </div>
          <button type="button" className="benefit-hero-link" onClick={scrollToList}>
            <span>查看权益明细</span>
            <span className="material-symbols-outlined">chevron_right</span>
          </button>
        </section>

        <section className="benefit-action">
          <button type="button" className="benefit-use-btn" onClick={() => goRedeem()}>
            <span className="material-symbols-outlined filled">qr_code_2</span>
            去使用
          </button>
        </section>

        <nav className="benefit-tabs" ref={listRef}>
          <button
            type="button"
            className={`benefit-tab${tab === 'available' ? ' active' : ''}`}
            onClick={() => setTab('available')}
          >
            待使用
          </button>
          <button
            type="button"
            className={`benefit-tab${tab === 'history' ? ' active' : ''}`}
            onClick={() => setTab('history')}
          >
            已用完/已过期
          </button>
        </nav>

        {visible.length > 0 ? (
          <div className="benefit-list">
            {visible.map((c) => (
              <article
                key={c.id}
                className={`benefit-card${tab === 'available' && c.balance > 0 ? ' benefit-card--clickable' : ''}`}
                role={tab === 'available' && c.balance > 0 ? 'button' : undefined}
                tabIndex={tab === 'available' && c.balance > 0 ? 0 : undefined}
                onClick={() => {
                  if (tab === 'available' && c.balance > 0) goRedeem(c);
                }}
                onKeyDown={(e) => {
                  if (tab === 'available' && c.balance > 0 && (e.key === 'Enter' || e.key === ' ')) {
                    e.preventDefault();
                    goRedeem(c);
                  }
                }}
              >
                <div className="benefit-card-inner">
                  <div className="benefit-card-value">
                    <span className="benefit-card-value-label">好客权益</span>
                    <div className="benefit-card-value-amount">
                      <span>¥</span>
                      <span>{Math.round(c.totalAmount)}</span>
                    </div>
                    <span className="benefit-card-notch" aria-hidden />
                  </div>
                  <div className="benefit-card-body">
                    <div className="benefit-card-main">
                      <div className="benefit-card-title-row">
                        <h3 className="benefit-card-title">{c.sourceProduct}</h3>
                        <span className="benefit-card-badge">永久有效</span>
                      </div>
                      <p className="benefit-card-desc">适用于合作酒店餐饮消费，到店核销使用</p>
                      <div className="benefit-card-progress-wrap">
                        <div className="benefit-card-progress-labels">
                          <span>已使用 ¥{formatMoney(c.usedAmount)}</span>
                          <span>未使用 ¥{formatMoney(c.balance)}</span>
                        </div>
                        <div className="benefit-card-progress">
                          <div
                            className="benefit-card-progress-bar"
                            style={{ width: `${usagePercent(c)}%` }}
                          />
                        </div>
                      </div>
                    </div>
                    <div className="benefit-card-foot">
                      <Link
                        to={`/benefit/${c.id}`}
                        className="benefit-card-no"
                        onClick={(e) => e.stopPropagation()}
                      >
                        {formatCouponNo(c.couponNo)}
                      </Link>
                      {tab === 'available' && c.balance > 0 && (
                        <button
                          type="button"
                          className="benefit-card-redeem"
                          onClick={(e) => {
                            e.stopPropagation();
                            goRedeem(c);
                          }}
                        >
                          立即核销
                        </button>
                      )}
                    </div>
                  </div>
                </div>
              </article>
            ))}
          </div>
        ) : (
          <div className="benefit-empty">
            {tab === 'available' ? (
              <>
                <span className="material-symbols-outlined">card_giftcard</span>
                <p>暂无可用权益，购酒后自动发放</p>
              </>
            ) : (
              <>
                <span className="material-symbols-outlined">history_edu</span>
                <p>暂无过期或已使用的权益记录</p>
              </>
            )}
          </div>
        )}
      </main>
    </div>
  );
}