import { useState, useEffect } from 'react';
import { useTranslation } from 'react-i18next';
import { useAuth } from '@/lib/auth';
import { api } from '@/lib/api';
import { useToast } from '@/hooks/useToast';
import { CreditCard, Plus, X } from 'lucide-react';

export default function BillingManager() {
    const { t } = useTranslation();
    const { token } = useAuth();
    const toast = useToast();
    const [transactions, setTransactions] = useState<any[]>([]);
    const [total, setTotal] = useState(0);
    const [page, setPage] = useState(1);
    const [loading, setLoading] = useState(true);
    const [showAddCredits, setShowAddCredits] = useState(false);
    const [creditOrgId, setCreditOrgId] = useState('');
    const [creditAmount, setCreditAmount] = useState('');
    const [creditDesc, setCreditDesc] = useState('');
    const [saving, setSaving] = useState(false);

    const LIMIT = 20;

    async function load() {
        if (!token) return;
        setLoading(true);
        try {
            const data = await api.get(`/v1/super-admin/billing/transactions?page=${page}&limit=${LIMIT}`, token);
            setTransactions(data.data ?? []);
            setTotal(data.total ?? 0);
        } catch { toast.error(t('super_admin.err_load_transactions')); }
        finally { setLoading(false); }
    }

    useEffect(() => { load(); }, [page, token]);

    async function handleAddCredits() {
        if (!creditOrgId || !creditAmount) return;
        setSaving(true);
        try {
            const result = await api.post('/v1/super-admin/billing/credits', {
                orgId: creditOrgId,
                amount: parseInt(creditAmount),
                description: creditDesc || undefined,
            }, token);
            toast.success(t('super_admin.credits_added', { amount: creditAmount, balance: result.newBalance }));
            setShowAddCredits(false);
            setCreditOrgId(''); setCreditAmount(''); setCreditDesc('');
            load();
        } catch { toast.error(t('super_admin.err_add_credits')); }
        finally { setSaving(false); }
    }

    const TYPE_COLORS: Record<string, string> = {
        TOP_UP_MANUAL: 'text-emerald-400',
        TOP_UP_PAYMENT: 'text-emerald-400',
        DEBIT_AI: 'text-red-400',
    };

    return (
        <div className="space-y-4">
            <div className="flex items-center justify-between">
                <div>
                    <h1 className="text-xl font-bold text-white">{t('super_admin.billing_title')}</h1>
                    <p className="text-sm text-slate-400 mt-0.5">{t('super_admin.billing_transactions', { count: total })}</p>
                </div>
                <button
                    onClick={() => setShowAddCredits(true)}
                    className="flex items-center gap-2 bg-violet-600 hover:bg-violet-500 text-white text-sm font-medium px-4 py-2 rounded-lg transition-colors"
                >
                    <Plus className="w-4 h-4" />
                    {t('super_admin.billing_add_credits')}
                </button>
            </div>

            <div className="bg-slate-900 rounded-xl border border-slate-800 overflow-hidden">
                {loading ? (
                    <div className="p-8 text-center text-slate-500 animate-pulse">{t('super_admin.org_loading')}</div>
                ) : transactions.length === 0 ? (
                    <div className="p-12 flex flex-col items-center gap-3 text-slate-500">
                        <CreditCard className="w-8 h-8" />
                        <p>{t('super_admin.billing_no_transactions')}</p>
                    </div>
                ) : (
                    <div className="overflow-x-auto">
                        <table className="w-full text-sm">
                            <thead>
                                <tr className="border-b border-slate-800">
                                    <th className="text-left px-4 py-3 text-xs font-medium text-slate-400 uppercase tracking-wider">{t('super_admin.col_date')}</th>
                                    <th className="text-left px-4 py-3 text-xs font-medium text-slate-400 uppercase tracking-wider">{t('super_admin.col_org')}</th>
                                    <th className="text-left px-4 py-3 text-xs font-medium text-slate-400 uppercase tracking-wider">{t('super_admin.col_type')}</th>
                                    <th className="text-left px-4 py-3 text-xs font-medium text-slate-400 uppercase tracking-wider">{t('super_admin.col_description')}</th>
                                    <th className="text-right px-4 py-3 text-xs font-medium text-slate-400 uppercase tracking-wider">{t('super_admin.col_amount')}</th>
                                    <th className="text-right px-4 py-3 text-xs font-medium text-slate-400 uppercase tracking-wider">{t('super_admin.col_balance_after')}</th>
                                </tr>
                            </thead>
                            <tbody className="divide-y divide-slate-800">
                                {transactions.map(tx => (
                                    <tr key={tx.id} className="hover:bg-slate-800/50 transition-colors">
                                        <td className="px-4 py-3 text-xs text-slate-400">{new Date(tx.createdAt).toLocaleDateString()}</td>
                                        <td className="px-4 py-3 text-slate-300">{tx.organization?.name || '—'}</td>
                                        <td className="px-4 py-3">
                                            <span className={`text-xs font-medium ${TYPE_COLORS[tx.type] ?? 'text-slate-300'}`}>{tx.type}</span>
                                        </td>
                                        <td className="px-4 py-3 text-xs text-slate-400 max-w-xs truncate">{tx.description || '—'}</td>
                                        <td className={`px-4 py-3 text-right font-medium text-sm ${tx.amount > 0 ? 'text-emerald-400' : 'text-red-400'}`}>
                                            {(tx.amount ?? 0) > 0 ? '+' : ''}{(tx.amount ?? 0).toLocaleString()}
                                        </td>
                                        <td className="px-4 py-3 text-right text-slate-300">{tx.balanceAfter?.toLocaleString()}</td>
                                    </tr>
                                ))}
                            </tbody>
                        </table>
                    </div>
                )}
            </div>

            {total > LIMIT && (
                <div className="flex items-center justify-between text-sm text-slate-400">
                    <span>{t('super_admin.pagination_info', { from: ((page - 1) * LIMIT) + 1, to: Math.min(page * LIMIT, total), total })}</span>
                    <div className="flex gap-2">
                        <button onClick={() => setPage(p => Math.max(1, p - 1))} disabled={page === 1} className="px-3 py-1.5 bg-slate-900 border border-slate-700 rounded-lg disabled:opacity-40 hover:bg-slate-800 transition-colors">{t('super_admin.prev')}</button>
                        <button onClick={() => setPage(p => p + 1)} disabled={page * LIMIT >= total} className="px-3 py-1.5 bg-slate-900 border border-slate-700 rounded-lg disabled:opacity-40 hover:bg-slate-800 transition-colors">{t('super_admin.next')}</button>
                    </div>
                </div>
            )}

            {showAddCredits && (
                <div className="fixed inset-0 bg-black/60 z-50 flex items-center justify-center">
                    <div className="bg-slate-900 border border-slate-800 rounded-xl p-6 w-96 space-y-4">
                        <div className="flex items-center justify-between">
                            <h2 className="text-base font-bold text-white">{t('super_admin.modal_add_credits')}</h2>
                            <button onClick={() => setShowAddCredits(false)}><X className="w-4 h-4 text-slate-400" /></button>
                        </div>
                        <div className="space-y-3">
                            <div>
                                <label className="text-xs font-medium text-slate-400 uppercase tracking-wider">{t('super_admin.label_org_id')}</label>
                                <input value={creditOrgId} onChange={e => setCreditOrgId(e.target.value)} placeholder="org-uuid..." className="mt-1.5 w-full bg-slate-800 border border-slate-700 rounded-lg px-3 py-2 text-sm text-white placeholder-slate-500 focus:outline-none focus:border-violet-500" />
                            </div>
                            <div>
                                <label className="text-xs font-medium text-slate-400 uppercase tracking-wider">{t('super_admin.label_credits_amount')}</label>
                                <input type="number" value={creditAmount} onChange={e => setCreditAmount(e.target.value)} placeholder="100" className="mt-1.5 w-full bg-slate-800 border border-slate-700 rounded-lg px-3 py-2 text-sm text-white placeholder-slate-500 focus:outline-none focus:border-violet-500" />
                            </div>
                            <div>
                                <label className="text-xs font-medium text-slate-400 uppercase tracking-wider">{t('super_admin.label_description_optional')}</label>
                                <input value={creditDesc} onChange={e => setCreditDesc(e.target.value)} placeholder={t('super_admin.credits_desc_placeholder')} className="mt-1.5 w-full bg-slate-800 border border-slate-700 rounded-lg px-3 py-2 text-sm text-white placeholder-slate-500 focus:outline-none focus:border-violet-500" />
                            </div>
                        </div>
                        <div className="flex gap-2">
                            <button onClick={() => setShowAddCredits(false)} className="flex-1 py-2 bg-slate-800 hover:bg-slate-700 text-slate-300 text-sm rounded-lg transition-colors">{t('super_admin.cancel')}</button>
                            <button onClick={handleAddCredits} disabled={saving || !creditOrgId || !creditAmount} className="flex-1 py-2 bg-violet-600 hover:bg-violet-500 disabled:opacity-50 text-white text-sm font-medium rounded-lg transition-colors">
                                {saving ? t('super_admin.adding') : t('super_admin.add')}
                            </button>
                        </div>
                    </div>
                </div>
            )}
        </div>
    );
}