import {useEffect, useState} from 'react';
import {useNavigate} from 'react-router-dom';
import {useTranslation} from 'react-i18next';
import {ExternalLink, Gift, Percent} from 'lucide-react';

import {Badge} from '@/components/ui/badge';
import {Button} from '@/components/ui/button';
import {Card} from '@/components/ui/card';
import {Skeleton} from '@/components/ui/skeleton';
import GameCover from '../components/GameCover.jsx';
import LibraryTabs from '../components/LibraryTabs.jsx';
import useSessionExpired from '../hooks/useSessionExpired.js';
import PageContainer from '../components/PageContainer.jsx';

const formatAdded = (instant, locale) =>
    instant ? new Date(instant).toLocaleDateString(locale, {year: 'numeric', month: 'short', day: 'numeric'}) : null;

export default function WishlistPage() {
    const {t, i18n} = useTranslation();
    const navigate = useNavigate();
    const expireSession = useSessionExpired();
    const [games, setGames] = useState(null);
    const [error, setError] = useState(null);
    const [onlyOnSale, setOnlyOnSale] = useState(false);

    useEffect(() => {
        const token = localStorage.getItem('tbp_jwt');
        if (!token) {
            navigate('/login');
            return undefined;
        }
        let cancelled = false;
        (async () => {
            try {
                const response = await fetch(`${import.meta.env.VITE_CORE_API_URL}/api/library/wishlist`, {
                    headers: {'Authorization': `Bearer ${token}`},
                });
                if (cancelled) return;
                if (response.status === 401) {
                    expireSession();
                    return;
                }
                if (!response.ok) {
                    setError(t('WISHLIST.ERROR_LOAD'));
                    return;
                }
                const json = await response.json();
                if (!cancelled) setGames(json.games ?? []);
            } catch (err) {
                console.error('Wishlist load error:', err);
                if (!cancelled) setError(t('INFO.ERROR.NETWORK_FAILURE'));
            }
        })();
        return () => {
            cancelled = true;
        };
    }, [navigate, expireSession, t]);

    const shown = (games ?? []).filter((g) => !onlyOnSale || g.discountPct > 0);
    const onSaleCount = (games ?? []).filter((g) => g.discountPct > 0).length;

    return (
        <PageContainer className="p-4 md:p-8 space-y-6">
            <div className="flex flex-col gap-4 md:flex-row md:items-end md:justify-between">
                <div className="space-y-3">
                    <LibraryTabs/>
                    <h1 className="text-3xl font-bold tracking-tight">{t('WISHLIST.TITLE')}</h1>
                </div>
                {games?.length > 0 && (
                    <Button
                        size="sm"
                        variant={onlyOnSale ? 'default' : 'outline'}
                        aria-pressed={onlyOnSale}
                        className="self-start md:self-auto"
                        onClick={() => setOnlyOnSale((v) => !v)}
                    >
                        <Percent/>{t('WISHLIST.ONLY_ON_SALE')}
                        <span className="tabular-nums opacity-70">{onSaleCount}</span>
                    </Button>
                )}
            </div>

            {games === null && !error && (
                <Card className="gap-0 py-0 divide-y">
                    {Array.from({length: 5}, (_, i) => (
                        <div key={i} className="flex items-center gap-4 px-5 py-3">
                            <Skeleton className="h-11 w-24 rounded-md"/>
                            <Skeleton className="h-4 flex-1"/>
                            <Skeleton className="h-4 w-16"/>
                        </div>
                    ))}
                </Card>
            )}

            {error && <div className="py-12 text-center text-destructive">{error}</div>}

            {games !== null && shown.length === 0 && (
                <Card className="items-center py-16 text-center text-muted-foreground">
                    <Gift className="size-10"/>
                    <p className="max-w-sm text-sm">{games.length === 0 ? t('WISHLIST.EMPTY') : t('WISHLIST.NONE_ON_SALE')}</p>
                </Card>
            )}

            {shown.length > 0 && (
                <Card className="gap-0 py-0">
                    <ul className="divide-y">
                        {shown.map((g) => (
                            <li key={g.appid}>
                                <a
                                    href={`https://store.steampowered.com/app/${g.appid}`}
                                    target="_blank"
                                    rel="noopener noreferrer"
                                    className="group flex items-center gap-3 sm:gap-4 px-4 sm:px-5 py-3 transition-colors hover:bg-muted/50"
                                >
                                    <GameCover appid={g.appid} className="w-16 sm:w-24 shrink-0"/>
                                    <div className="min-w-0 flex-1">
                                        <div className="truncate font-medium group-hover:text-primary transition-colors">
                                            {g.name ?? `App ${g.appid}`}
                                        </div>
                                        {g.addedAt && (
                                            <div className="text-xs text-muted-foreground">
                                                {t('WISHLIST.ADDED', {date: formatAdded(g.addedAt, i18n.language)})}
                                            </div>
                                        )}
                                    </div>
                                    <div className="flex shrink-0 items-center gap-2 text-sm tabular-nums">
                                        {g.discountPct > 0 && (
                                            <Badge className="bg-emerald-500/15 text-emerald-600 dark:text-emerald-400">
                                                -{g.discountPct}%
                                            </Badge>
                                        )}
                                        {g.discountPct > 0 && g.originalPrice && (
                                            <span className="hidden text-muted-foreground line-through sm:inline">{g.originalPrice}</span>
                                        )}
                                        {g.price
                                            ? <span className="font-medium">{g.price}</span>
                                            : <span className="text-muted-foreground">{t('WISHLIST.NO_PRICE')}</span>}
                                    </div>
                                    <ExternalLink className="size-4 shrink-0 text-muted-foreground"/>
                                </a>
                            </li>
                        ))}
                    </ul>
                </Card>
            )}
        </PageContainer>
    );
}