import React, { useEffect, useRef } from 'react';
import { useParams, Link } from 'react-router-dom';
import { useQuery } from '@tanstack/react-query';
import { api } from '@/lib/api';
import { formatMoney } from '@/lib/currency';
import { ArrowLeft, Printer } from 'lucide-react';
import { Button } from '@/components/ui/button';
import { InlineLoadingState } from '@/components/LoadingState';
import { ErrorCard } from '@/components/ErrorCard';
import { getPageLoadErrorMessage } from '@/lib/errorHandling';
import { __ } from '@/lib/i18n';

function Money({ value, currency, symbol }: { value?: number; currency?: string; symbol?: string }) {
    return <>{formatMoney(value, { currency, symbol })}</>;
}

export default function Invoice() {
    const { id } = useParams<{ id: string }>();
    const siteTitle = (window as any).wnw?.siteTitle || 'WooNooW';
    const qrRef = useRef<HTMLCanvasElement | null>(null);

    const q = useQuery({
        queryKey: ['order', id],
        enabled: !!id,
        queryFn: () => api.get(`/orders/${id}`),
    });

    const order = q.data;

    // Check if all items are virtual
    const isVirtualOnly = React.useMemo(() => {
        if (!order?.items || order.items.length === 0) return false;
        return order.items.every((item: any) => item.virtual || item.downloadable);
    }, [order?.items]);

    // Generate QR code
    useEffect(() => {
        if (!qrRef.current || !order) return;
        (async () => {
            try {
                const mod = await import('qrcode');
                const QR = (mod as any).default || (mod as any);
                const text = `ORDER:${order.number || id}`;
                await QR.toCanvas(qrRef.current, text, { width: 96, margin: 1 });
            } catch (_) {
                // QR library not available
            }
        })();
    }, [order, id]);

    const handlePrint = () => {
        window.print();
    };

    if (q.isLoading) {
        return <InlineLoadingState message={__('Loading invoice...')} />;
    }

    if (q.isError) {
        return (
            <ErrorCard
                title={__('Failed to load order')}
                message={getPageLoadErrorMessage(q.error)}
                onRetry={() => q.refetch()}
            />
        );
    }

    if (!order) return null;

    return (
        <div className="min-h-screen bg-gray-100">
            {/* Actions bar - hidden on print */}
            <div className="no-print bg-white border-b sticky top-0 z-10">
                <div className="max-w-4xl mx-auto px-4 py-3 flex items-center justify-between">
                    <Link to={`/orders/${id}`}>
                        <Button variant="ghost" size="sm">
                            <ArrowLeft className="w-4 h-4 mr-2" />
                            {__('Back to Order')}
                        </Button>
                    </Link>
                    <Button onClick={handlePrint} size="sm">
                        <Printer className="w-4 h-4 mr-2" />
                        {__('Print Invoice')}
                    </Button>
                </div>
            </div>

            {/* Invoice content */}
            <div className="py-8 print:py-0 print:bg-white">
                <div className="print-a4 bg-white shadow-lg print:shadow-none mx-auto max-w-3xl p-8 print:max-w-none print:p-0">
                    {/* Invoice Header */}
                    <div className="flex items-start justify-between mb-8 pb-6 border-b-2 border-gray-200">
                        <div>
                            <div className="text-3xl font-bold text-gray-900">{__('INVOICE')}</div>
                            <div className="text-sm text-gray-600 mt-1">#{order.number}</div>
                        </div>
                        <div className="text-right">
                            <div className="text-xl font-semibold text-gray-900">{siteTitle}</div>
                            <div className="text-sm text-gray-500 mt-1">{window.location.origin}</div>
                        </div>
                    </div>

                    {/* Invoice Meta */}
                    <div className="grid grid-cols-2 gap-8 mb-8">
                        <div>
                            <div className="text-xs font-semibold text-gray-500 uppercase tracking-wide mb-2">{__('Invoice Date')}</div>
                            <div className="text-sm text-gray-900">{new Date((order.date_ts || 0) * 1000).toLocaleDateString()}</div>
                            {order.payment_method && (
                                <>
                                    <div className="text-xs font-semibold text-gray-500 uppercase tracking-wide mb-2 mt-4">{__('Payment Method')}</div>
                                    <div className="text-sm text-gray-900">{order.payment_method}</div>
                                </>
                            )}
                        </div>
                        <div className="flex justify-end">
                            <canvas ref={qrRef} className="w-24 h-24" style={{ border: '1px solid #e5e7eb' }} />
                        </div>
                    </div>

                    {/* Billing & Shipping */}
                    <div className="grid grid-cols-2 gap-8 mb-8">
                        <div className="bg-gray-50 rounded-lg p-4">
                            <div className="text-xs font-semibold text-gray-500 uppercase tracking-wide mb-3">{__('Bill To')}</div>
                            <div className="text-sm text-gray-900 font-medium">{order.billing?.name || '—'}</div>
                            {order.billing?.email && <div className="text-sm text-gray-600">{order.billing.email}</div>}
                            {order.billing?.phone && <div className="text-sm text-gray-600">{order.billing.phone}</div>}
                            <div className="text-sm text-gray-600 mt-2" dangerouslySetInnerHTML={{ __html: order.billing?.address || '' }} />
                        </div>
                        {!isVirtualOnly && order.shipping?.name && (
                            <div className="bg-gray-50 rounded-lg p-4">
                                <div className="text-xs font-semibold text-gray-500 uppercase tracking-wide mb-3">{__('Ship To')}</div>
                                <div className="text-sm text-gray-900 font-medium">{order.shipping?.name || '—'}</div>
                                <div className="text-sm text-gray-600 mt-2" dangerouslySetInnerHTML={{ __html: order.shipping?.address || '' }} />
                            </div>
                        )}
                    </div>

                    {/* Items Table */}
                    <table className="w-full mb-8" style={{ borderCollapse: 'collapse' }}>
                        <thead>
                            <tr className="bg-gray-900 text-white">
                                <th className="text-left py-3 px-4 text-sm font-semibold">{__('Product')}</th>
                                <th className="text-center py-3 px-4 text-sm font-semibold w-20">{__('Qty')}</th>
                                <th className="text-right py-3 px-4 text-sm font-semibold w-32">{__('Price')}</th>
                                <th className="text-right py-3 px-4 text-sm font-semibold w-32">{__('Total')}</th>
                            </tr>
                        </thead>
                        <tbody>
                            {(order.items || []).map((it: any, idx: number) => (
                                <tr key={it.id} className={idx % 2 === 0 ? 'bg-white' : 'bg-gray-50'}>
                                    <td className="py-3 px-4 text-sm">
                                        <div className="font-medium text-gray-900">{it.name}</div>
                                        {it.sku && <div className="text-xs text-gray-500">SKU: {it.sku}</div>}
                                    </td>
                                    <td className="py-3 px-4 text-sm text-center text-gray-600">{it.qty}</td>
                                    <td className="py-3 px-4 text-sm text-right text-gray-600">
                                        <Money value={it.subtotal / it.qty} currency={order.currency} symbol={order.currency_symbol} />
                                    </td>
                                    <td className="py-3 px-4 text-sm text-right font-medium text-gray-900">
                                        <Money value={it.total} currency={order.currency} symbol={order.currency_symbol} />
                                    </td>
                                </tr>
                            ))}
                        </tbody>
                    </table>

                    {/* Totals */}
                    <div className="flex justify-end mb-8">
                        <div className="w-72">
                            <div className="flex justify-between py-2 text-sm">
                                <span className="text-gray-600">{__('Subtotal')}</span>
                                <span className="text-gray-900"><Money value={order.totals?.subtotal} currency={order.currency} symbol={order.currency_symbol} /></span>
                            </div>
                            {(order.totals?.discount || 0) > 0 && (
                                <div className="flex justify-between py-2 text-sm">
                                    <span className="text-gray-600">{__('Discount')}</span>
                                    <span className="text-green-600">-<Money value={order.totals?.discount} currency={order.currency} symbol={order.currency_symbol} /></span>
                                </div>
                            )}
                            {(order.totals?.shipping || 0) > 0 && (
                                <div className="flex justify-between py-2 text-sm">
                                    <span className="text-gray-600">{__('Shipping')}</span>
                                    <span className="text-gray-900"><Money value={order.totals?.shipping} currency={order.currency} symbol={order.currency_symbol} /></span>
                                </div>
                            )}
                            {(order.totals?.tax || 0) > 0 && (
                                <div className="flex justify-between py-2 text-sm">
                                    <span className="text-gray-600">{__('Tax')}</span>
                                    <span className="text-gray-900"><Money value={order.totals?.tax} currency={order.currency} symbol={order.currency_symbol} /></span>
                                </div>
                            )}
                            <div className="flex justify-between py-3 mt-2 border-t-2 border-gray-900">
                                <span className="text-lg font-bold text-gray-900">{__('Total')}</span>
                                <span className="text-lg font-bold text-gray-900">
                                    <Money value={order.totals?.total} currency={order.currency} symbol={order.currency_symbol} />
                                </span>
                            </div>
                        </div>
                    </div>

                    {/* Footer */}
                    <div className="mt-auto pt-8 border-t border-gray-200 text-center text-xs text-gray-500">
                        <p>{__('Thank you for your business!')}</p>
                        <p className="mt-1">{siteTitle} • {window.location.origin}</p>
                    </div>
                </div>
            </div>
        </div >
    );
}