'use client';

import { useState, type CSSProperties } from 'react';
import { FontAwesomeIcon } from '@fortawesome/react-fontawesome';
import { faPlay } from '@fortawesome/free-solid-svg-icons';
import {
	DONATION_AMOUNT_MIN, DONATION_AMOUNT_MAX, DONATION_AMOUNT_STEP, DONATION_AMOUNT_DEFAULT,
	ALERT_NAME_MAX_LENGTH, PREVIEW_DEFAULT_NAME
} from '@/constants/donation';
import type { FormState } from '../types';
import { MOCK_RANKING } from '../constants';

type Props = {
	form: FormState;
};

type SimulatedDonation = {
	name: string;
	totalAmount: number;
	donationCount: number;
};

/** 순위별 폰트 스타일 반환 (1~3등은 커스텀, 나머지는 기본) */
const getRankStyle = (rank: number, form: FormState): CSSProperties => {
	if (rank === 1) {
		return {
			'--row-font-family': form.rank1FontFamily || 'inherit',
			'--row-font-size': `${form.rank1FontSizePx}px`,
			'--row-font-color': form.rank1FontColor
		} as CSSProperties;
	}
	if (rank === 2) {
		return {
			'--row-font-family': form.rank2FontFamily || 'inherit',
			'--row-font-size': `${form.rank2FontSizePx}px`,
			'--row-font-color': form.rank2FontColor
		} as CSSProperties;
	}
	if (rank === 3) {
		return {
			'--row-font-family': form.rank3FontFamily || 'inherit',
			'--row-font-size': `${form.rank3FontSizePx}px`,
			'--row-font-color': form.rank3FontColor
		} as CSSProperties;
	}
	return {};
};

export default function RankPreviewPanel({ form }: Props) {
	const [previewName, setPreviewName] = useState(PREVIEW_DEFAULT_NAME);
	const [previewAmount, setPreviewAmount] = useState(DONATION_AMOUNT_DEFAULT);
	const [simulatedDonations, setSimulatedDonations] = useState<SimulatedDonation[]>([]);

	// 시뮬레이션 데이터 있으면 그것 사용, 없으면 mock 데이터
	const visibleRanking = simulatedDonations.length > 0
		? simulatedDonations
			.slice()
			.sort((a, b) => b.totalAmount - a.totalAmount)
			.slice(0, form.maxRankCount)
			.map((d, i) => ({
				rank: i + 1,
				sponsorName: d.name,
				totalAmount: d.totalAmount,
				donationCount: d.donationCount
			}))
		: MOCK_RANKING.slice(0, form.maxRankCount);

	const titleStyle = {
		'--preview-title-font': form.titleFontFamily || 'inherit',
		'--preview-title-size': `${form.titleFontSizePx}px`,
		'--preview-title-color': form.titleFontColor
	} as CSSProperties;

	const handlePreview = () => {
		const name = (previewName || PREVIEW_DEFAULT_NAME).trim();
		const amount = previewAmount || DONATION_AMOUNT_DEFAULT;

		setSimulatedDonations(prev => {
			const existing = prev.find(d => d.name === name);
			if (existing) {
				return prev.map(d => d.name === name
					? { ...d, totalAmount: d.totalAmount + amount, donationCount: d.donationCount + 1 }
					: d
				);
			}
			return [...prev, { name, totalAmount: amount, donationCount: 1 }];
		});
	};

	const handleReset = () => {
		setSimulatedDonations([]);
	};

	const totalSimulatedAmount = simulatedDonations.reduce((sum, d) => sum + d.totalAmount, 0);

	return (
		<aside className="rank-config__preview-panel">
			<div className="rank-config__widget">
				<div className="rank-config__widget-label">미리보기</div>
				<div className={`rank-config__widget-body rank-config__widget-body--${['basic', 'dark', 'minimal'][form.theme] ?? 'basic'}`}>
					<div className="rank-preview">
						<div className="rank-preview__title" style={titleStyle}>
							{form.title || '후원 순위'}
						</div>
						<div className="rank-preview__list">
							{visibleRanking.map(item => {
								const badgeClass = item.rank <= 3 ? `rank-preview__badge--${item.rank}` : 'rank-preview__badge--default';
								const itemStyle = getRankStyle(item.rank, form);
								return (
									<div key={item.rank} className={`rank-preview__item rank-preview__item--${item.rank}`} style={itemStyle}>
										<div className={`rank-preview__badge ${badgeClass}`}>{item.rank}</div>
										{form.isShowMemberIcon && (
											<div className="rank-preview__member-icon" />
										)}
										{form.isShowGradeIcon && (
											<div className="rank-preview__grade-icon" />
										)}
										<div className="rank-preview__name">
											{item.sponsorName}
										</div>
										<div className="rank-preview__meta">
											{form.isShowAmount && (
												<span className="rank-preview__amount">
													{item.totalAmount.toLocaleString()}원
												</span>
											)}
											{form.isShowDonationCount && (
												<span className="rank-preview__count">
													{item.donationCount}회
												</span>
											)}
										</div>
									</div>
								);
							})}
							{visibleRanking.length === 0 && (
								<div className="rank-preview__empty">순위 데이터 없음</div>
							)}
						</div>
					</div>
				</div>
			</div>

			<fieldset className="rank-config__fieldset">
				<legend className="rank-config__legend">미리보기</legend>
				<div className="rank-config__preview-form">
					<div className="rank-config__field">
						<label htmlFor="rank-preview-amount" className="rank-config__field-label">후원 금액 (원)</label>
						<input
							id="rank-preview-amount"
							type="number"
							className="rank-config__input"
							min={DONATION_AMOUNT_MIN}
							max={DONATION_AMOUNT_MAX}
							step={DONATION_AMOUNT_STEP}
							value={previewAmount}
							onChange={e => setPreviewAmount(parseInt(e.target.value) || DONATION_AMOUNT_DEFAULT)}
						/>
					</div>
					<div className="rank-config__field">
						<label htmlFor="rank-preview-name" className="rank-config__field-label">이름</label>
						<input
							id="rank-preview-name"
							type="text"
							className="rank-config__input"
							maxLength={ALERT_NAME_MAX_LENGTH}
							value={previewName}
							onChange={e => setPreviewName(e.target.value)}
							placeholder="후원자 이름"
						/>
					</div>
					<div className="rank-config__preview-actions">
						<button
							type="button"
							className="rank-config__btn rank-config__btn--primary rank-config__preview-btn"
							onClick={handlePreview}
						>
							<FontAwesomeIcon icon={faPlay} />
							미리보기
						</button>
						<button
							type="button"
							className="rank-config__btn"
							onClick={handleReset}
							disabled={simulatedDonations.length === 0}
						>
							초기화
						</button>
					</div>
					{simulatedDonations.length > 0 && (
						<p className="rank-config__field-hint">
							후원자 {simulatedDonations.length}명 (총 {totalSimulatedAmount.toLocaleString()}원)
						</p>
					)}
				</div>
			</fieldset>
		</aside>
	);
}