'use client';

import { useState, useEffect, useMemo } from 'react';
import { fetchApi } from '@/lib/utils/client';
import useAuth from '@/hooks/useAuth';
import { useConfigContext } from '@/contexts/configProvider';
import { DanalCreateOrderRequest, PaymentMethodType } from '@/types/request/payment/charge';
import { DanalCreateOrderResponse } from '@/types/response/payment/charge';
import type { PaymentForm } from '@/types/config';
import CreditCardIcon from '@/public/icons/payment/credit-card.svg';
import KakaoIcon from '@/public/icons/payment/kakao.svg';
import NaverIcon from '@/public/icons/payment/naver.svg';
import BankIcon from '@/public/icons/payment/bank.svg';
import PhoneIcon from '@/public/icons/payment/phone.svg';
import { Landmark as VBankIcon } from 'lucide-react';

type PaymentMethodOption = {
	value: PaymentMethodType;
	label: string;
	danalMethod: string;
	danalKey: string;
	Icon: React.ComponentType<React.SVGProps<SVGSVGElement>>;
	enabledKey: keyof PaymentForm;
};

const PAYMENT_METHODS: PaymentMethodOption[] = [
	{ value: 'Card',           label: '신용카드',   danalMethod: 'CARD',            danalKey: 'card',           Icon: CreditCardIcon, enabledKey: 'isCardEnabled' },
	{ value: 'KakaoPay',       label: '카카오페이', danalMethod: 'KAKAOPAY',        danalKey: 'kakaoPay',       Icon: KakaoIcon,      enabledKey: 'isKakaoPayEnabled' },
	{ value: 'NaverPay',       label: '네이버페이', danalMethod: 'NAVERPAY',        danalKey: 'naverPay',       Icon: NaverIcon,      enabledKey: 'isNaverPayEnabled' },
	{ value: 'Transfer',       label: '계좌이체',   danalMethod: 'TRANSFER',        danalKey: 'transfer',       Icon: BankIcon,       enabledKey: 'isTransferEnabled' },
	{ value: 'Mobile',         label: '휴대폰',     danalMethod: 'MOBILE',          danalKey: 'mobile',         Icon: PhoneIcon,      enabledKey: 'isMobileEnabled' },
	{ value: 'VirtualAccount', label: '가상계좌',   danalMethod: 'VIRTUAL_ACCOUNT', danalKey: 'virtualAccount', Icon: VBankIcon,      enabledKey: 'isVirtualAccountEnabled' },
];

// 결제수단별 다날 SDK methods 설정
const METHOD_CONFIGS: Record<string, object> = {
	card: {},
	kakaoPay: {},
	naverPay: {},
	payco: {},
	transfer: {},
	mobile: { itemCode: '1270000000', itemType: '1' },
	virtualAccount: { notiUrl: `${process.env.NEXT_PUBLIC_API_URL}/api/payment/noti/vaccount` }
};

const QUICK_AMOUNTS = [10000, 50000, 100000, 1000000];

export default function ChargePage()
{
	// pointInput = 사용자가 충전하려는 포인트 (VAT 제외). VAT 10%는 별도 가산.
	const [pointInput, setPointInput] = useState<number>(0);
	const [paymentMethod, setPaymentMethod] = useState<PaymentMethodType>('Card');
	const [loading, setLoading] = useState(false);
	const [isPopup, setIsPopup] = useState(false);
	const { member, loginCheck } = useAuth();
	const config = useConfigContext();
	const isDanalTestMode = config?.external?.danalPayMode === 'test';

	// 결제 수단별 활성 여부 매핑
	const methodEnabled = useMemo<Record<PaymentMethodType, boolean>>(() => {
		const payment = config?.payment;
		const map = {} as Record<PaymentMethodType, boolean>;
		for (const m of PAYMENT_METHODS) {
			map[m.value] = payment ? Boolean(payment[m.enabledKey]) : false;
		}
		return map;
	}, [config?.payment]);

	useEffect(() => {
		setIsPopup(!!window.opener);
	}, []);

	// 초기 선택된 결제 수단이 비활성이면 첫 번째 활성 수단으로 자동 전환
	useEffect(() => {
		if (!methodEnabled[paymentMethod]) {
			const firstEnabled = PAYMENT_METHODS.find(m => methodEnabled[m.value]);
			if (firstEnabled) {
				setPaymentMethod(firstEnabled.value);
			}
		}
	}, [methodEnabled, paymentMethod]);

	if (!member || !loginCheck()) {
		return null;
	}

	const handleAmountChange = (value: string) => {
		const num = parseInt(value.replace(/[^0-9]/g, ''), 10);
		setPointInput(isNaN(num) ? 0 : num);
	};

	const addAmount = (add: number) => {
		setPointInput(prev => prev + add);
	};

	// VAT 10% 별도 가산. 최종 결제 금액 = pointInput + vat.
	const vatAmount = Math.round(pointInput * 0.1);
	const totalAmount = pointInput + vatAmount;

	const handleSubmit = async () => {
		if (pointInput < 1000) {
			alert('최소 충전 금액은 1,000원입니다.');
			return;
		}

		setLoading(true);

		try {
			const res = await fetchApi<DanalCreateOrderResponse>('/api/payment/order', {
				method: 'POST',
				body: {
					amount: pointInput,
					paymentMethod
				} as DanalCreateOrderRequest
			});

			if (!res.data) {
				alert(res.message || '주문 생성에 실패했습니다.');
				return setLoading(false);
			}

			const order = res.data;
			const selected = PAYMENT_METHODS.find(m => m.value === paymentMethod)!;

			const { loadDanalPaymentsSDK } = await import('@danalpay/javascript-sdk');
			const danalPayments = await loadDanalPaymentsSDK({ clientKey: order.clientKey });

			// eslint-disable-next-line @typescript-eslint/no-explicit-any
			const paymentParams: any = {
				paymentsMethod: selected.danalMethod,
				methods: {
					[selected.danalKey]: METHOD_CONFIGS[selected.danalKey]
				},
				orderName: `DPOT ${pointInput.toLocaleString()}(P) 충전`,
				amount: order.amount,
				merchantId: order.merchantID,
				orderId: order.orderID,
				userId: member.id,
				userEmail: member.email,
				userName: member.name,
				successUrl: order.successUrl,
				failUrl: order.failUrl
			};

			danalPayments.requestPayment(paymentParams);
		} catch (e) {
			console.error('결제 요청 실패:', e);
			alert('결제 요청에 실패했습니다.');
			setLoading(false);
		}
	};

	return (
		<div className="charge-page">
			{isDanalTestMode && (
				<div className="charge-page__test-banner" role="alert">
					현재 다날 충전은 테스트 환경입니다.
				</div>
			)}
			<div className="charge-page__card">
				<div className="charge-page__header">
					<h1>포인트 충전</h1>
					{isPopup && (
						<button type="button" className="charge-page__close" onClick={() => window.close()}>×</button>
					)}
				</div>

				<div className="charge-page__body">
					<label className="charge-page__label">충전 포인트 (P)</label>
					<input
						type="text"
						className="charge-page__amount-input"
						value={pointInput > 0 ? pointInput.toLocaleString() : ''}
						onChange={e => handleAmountChange(e.target.value)}
						placeholder="0"
						inputMode="numeric"
						autoFocus
					/>

					<div className="charge-page__quick-btns">
						{QUICK_AMOUNTS.map(v => (
							<button type="button" key={v} className="charge-page__quick-btn" onClick={() => addAmount(v)}>
								+{v >= 10000 ? `${v / 10000}만` : v.toLocaleString()}
							</button>
						))}
					</div>

					<div className="charge-page__method-section">
						<label className="charge-page__label">결제 수단</label>
						<div className="charge-page__method-grid">
							{PAYMENT_METHODS.map(m => {
								const enabled = methodEnabled[m.value];
								const isActive = enabled && paymentMethod === m.value;
								const cls = [
									'charge-page__method-btn',
									isActive ? 'charge-page__method-btn--active' : '',
									!enabled ? 'charge-page__method-btn--disabled' : ''
								].filter(Boolean).join(' ');

								return (
									<button
										type="button"
										key={m.value}
										className={cls}
										onClick={() => enabled && setPaymentMethod(m.value)}
										disabled={!enabled}
										aria-disabled={!enabled}
										title={!enabled ? `${m.label} 결제는 현재 사용할 수 없습니다.` : undefined}
									>
										<span className="charge-page__method-icon">
											<m.Icon width={24} height={24} aria-label={m.label} />
										</span>
										<span>{m.label}</span>
									</button>
								);
							})}
						</div>
					</div>

					<div className="charge-page__receipt">
						<div className="charge-page__receipt-row">
							<span>충전 (P)</span>
							<span>{pointInput.toLocaleString()} P</span>
						</div>
						<div className="charge-page__receipt-row">
							<span>부가세 (10%)</span>
							<span>{vatAmount.toLocaleString()} 원</span>
						</div>
						<div className="charge-page__receipt-row charge-page__receipt-row--total">
							<span>총 결제 금액</span>
							<span>{totalAmount.toLocaleString()} 원</span>
						</div>
					</div>

					<button type="button" className="charge-page__submit" onClick={handleSubmit} disabled={loading || pointInput < 1000}>
						{loading ? '처리 중...' : '충전하기'}
					</button>
				</div>
			</div>
		</div>
	);
}