import { useState, useEffect } from 'react';
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card';
import { Button } from '@/components/ui/button';
import { useToast } from '@/hooks/useToast';
import { useWallet } from '@/hooks/useWallet';
import { useNWC } from '@/hooks/useNWCContext';
import { getInvoiceFromLightningAddress } from '@/lib/lightningAddress';
import { assertInvoiceAmount } from '@/lib/verifyInvoice';
import { LISTING_FEE_SATS, PLATFORM_LIGHTNING_ADDRESS } from '@/hooks/useListingRestrictions';
import { Zap, Loader2, CheckCircle, Copy, ExternalLink, ShieldAlert, TrendingUp, MapPin } from 'lucide-react';
import { useTranslation } from '@/contexts/language';
// qrcode imported lazily in async function

interface SpamFeePaymentProps {
  feeRecipient: string;
  feeRecipientName: string;
  onPaymentSuccess: () => void;
  /** Offered as a FREE alternative to the sats fee: mine NIP-13 proof of work. */
  onPowInstead?: () => void;
  onSkip?: () => void;
}

type PaymentState = 'idle' | 'generating' | 'waiting' | 'paying' | 'success' | 'error';

export function SpamFeePayment({
  feeRecipient,
  feeRecipientName,
  onPaymentSuccess,
  onPowInstead,
}: SpamFeePaymentProps) {
  const { t } = useTranslation();
  const { toast } = useToast();
  const { webln, activeNWC } = useWallet();
  const { sendPayment } = useNWC();
  const [paymentState, setPaymentState] = useState<PaymentState>('idle');
  const [invoice, setInvoice] = useState<string | null>(null);
  const [qrCodeUrl, setQrCodeUrl] = useState<string | null>(null);
  const [error, setError] = useState<string | null>(null);

  // Auto-pay when wallet is connected and invoice is generated
  useEffect(() => {
    if (invoice && paymentState === 'waiting' && (webln || activeNWC)) {
      handleAutoPay();
    }
    // Intentionally omit handleAutoPay: it is recreated each render, so adding
    // it would re-trigger auto-pay on every render. Keyed to invoice/state.
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [invoice, paymentState, webln, activeNWC]);

  const generateInvoice = async () => {
    setPaymentState('generating');
    setError(null);

    try {
      const bolt11 = await getInvoiceFromLightningAddress({
        lightningAddress: feeRecipient,
        amountSats: LISTING_FEE_SATS,
        comment: t('marketUi.spamFee.invoiceComment'),
      });

      // SECURITY: verify the returned invoice really requests the listing fee
      // (and not an inflated amount) before it can be auto-paid.
      assertInvoiceAmount(bolt11, LISTING_FEE_SATS);

      setInvoice(bolt11);

      // Generate QR code
      const { default: QRCode } = await import('qrcode');
      const qr = await QRCode.toDataURL(bolt11.toUpperCase(), {
        width: 256,
        margin: 2,
        color: {
          dark: '#000000',
          light: '#ffffff',
        },
      });
      setQrCodeUrl(qr);

      setPaymentState('waiting');

      // If wallet is available, try auto-pay
      if (webln || activeNWC) {
        await handleAutoPay();
      }
    } catch (err) {
      console.error('Failed to generate invoice:', err);
      setError(err instanceof Error ? err.message : t('marketUi.spamFee.generateFailed'));
      setPaymentState('error');
    }
  };

  const handleAutoPay = async () => {
    if (!invoice) return;
    
    setPaymentState('paying');

    try {
      // Try NWC first
      if (activeNWC && activeNWC.isConnected) {
        await sendPayment(activeNWC, invoice);
        setPaymentState('success');
        toast({
          title: t('marketUi.spamFee.paymentSuccess'),
          description: t('marketUi.spamFee.satsSent', { amount: LISTING_FEE_SATS.toLocaleString(), name: feeRecipientName }),
        });
        setTimeout(onPaymentSuccess, 1500);
        return;
      }

      // Try WebLN
      if (webln) {
        if (webln.enable) {
          await webln.enable();
        }
        await webln.sendPayment(invoice);
        setPaymentState('success');
        toast({
          title: t('marketUi.spamFee.paymentSuccess'),
          description: t('marketUi.spamFee.satsSent', { amount: LISTING_FEE_SATS.toLocaleString(), name: feeRecipientName }),
        });
        setTimeout(onPaymentSuccess, 1500);
        return;
      }

      // No auto-pay available, stay in waiting state
      setPaymentState('waiting');
    } catch (err) {
      console.error('Auto-pay failed:', err);
      // Fall back to manual payment
      setPaymentState('waiting');
      toast({
        title: t('marketUi.spamFee.autoPayFailed'),
        description: t('marketUi.spamFee.autoPayFailedBody'),
        variant: 'destructive',
      });
    }
  };

  const copyInvoice = async () => {
    if (!invoice) return;
    try {
      await navigator.clipboard.writeText(invoice);
      toast({ title: t('marketUi.spamFee.invoiceCopied') });
    } catch {
      toast({ title: t('marketUi.spamFee.copyFailed'), variant: 'destructive' });
    }
  };

  const openInWallet = () => {
    if (!invoice) return;
    window.open(`lightning:${invoice}`, '_blank');
  };

  // Show success state
  if (paymentState === 'success') {
    return (
      <Card className="bg-green-950/30 border-2 border-green-500/50">
        <CardContent className="py-8 text-center">
          <CheckCircle className="h-12 w-12 text-green-400 mx-auto mb-4" />
          <h3 className="font-bold text-green-400 text-lg mb-2">{t('marketUi.spamFee.received')}</h3>
          <p className="text-gray-300">
            {t('marketUi.spamFee.receivedBody', { amount: LISTING_FEE_SATS.toLocaleString() })}
          </p>
        </CardContent>
      </Card>
    );
  }

  // Show payment flow
  return (
    <Card className="bg-yellow-950/30 border-2 border-yellow-500/50">
      <CardHeader>
        <CardTitle className="flex items-center gap-2 text-yellow-400">
          <ShieldAlert className="h-5 w-5" />
          {t('marketUi.spamFee.title')}
        </CardTitle>
        <CardDescription className="text-gray-300">
          {t('marketUi.spamFee.subtitle')}
        </CardDescription>
      </CardHeader>
      <CardContent className="space-y-4">
        {/* Why this fee exists */}
        <div className="bg-black/30 rounded-lg p-4 space-y-3">
          <h4 className="font-bold text-white text-sm">{t('marketUi.spamFee.whyTitle')}</h4>
          <div className="space-y-2 text-sm">
            <div className="flex items-start gap-2">
              <ShieldAlert className="h-4 w-4 text-yellow-400 mt-0.5 flex-shrink-0" />
              <p className="text-gray-300">
                <span className="text-white font-medium">{t('marketUi.spamFee.spamLabel')}</span> {t('marketUi.spamFee.spamBody')}
              </p>
            </div>
            <div className="flex items-start gap-2">
              <TrendingUp className="h-4 w-4 text-green-400 mt-0.5 flex-shrink-0" />
              <p className="text-gray-300">
                <span className="text-white font-medium">{t('marketUi.spamFee.trustLabel')}</span> {t('marketUi.spamFee.trustBody')}
              </p>
            </div>
            <div className="flex items-start gap-2">
              <MapPin className="h-4 w-4 text-[#ff6600] mt-0.5 flex-shrink-0" />
              <p className="text-gray-300">
                <span className="text-white font-medium">{t('marketUi.spamFee.supportsLabel')}</span> {t('marketUi.spamFee.supportsPrefix')}{' '}
                <span className="font-semibold text-yellow-400">{feeRecipientName}</span>
                {feeRecipient !== PLATFORM_LIGHTNING_ADDRESS && t('marketUi.spamFee.supportsSpotOwner')}
                {feeRecipient === PLATFORM_LIGHTNING_ADDRESS && t('marketUi.spamFee.supportsPlatform')}
              </p>
            </div>
          </div>
        </div>

        {/* Fee amount */}
        <div className="text-center py-3 bg-yellow-500/10 rounded-lg border border-yellow-500/30">
          <div className="text-3xl font-black text-yellow-400">
            ⚡ {LISTING_FEE_SATS.toLocaleString()} {t('common.sats')}
          </div>
          <p className="text-sm text-gray-400 mt-1">{t('marketUi.spamFee.oneTimeFee', { usd: (LISTING_FEE_SATS * 0.0006).toFixed(2) })}</p>
        </div>

        {/* Initial state — pay, or prove work instead (free) */}
        {paymentState === 'idle' && (
          <div className="space-y-3">
            <Button
              onClick={generateInvoice}
              className="w-full bg-yellow-500 hover:bg-yellow-600 text-black font-bold"
            >
              <Zap className="h-4 w-4 mr-2" />
              {t('marketUi.spamFee.payToContinue', { amount: LISTING_FEE_SATS.toLocaleString() })}
            </Button>
            {onPowInstead && (
              <>
                <p className="text-center text-xs uppercase tracking-widest text-gray-500">{t('common.or')}</p>
                <Button
                  onClick={onPowInstead}
                  variant="outline"
                  className="w-full font-bold border-[#ccff00]/40 text-[#ccff00] hover:bg-[#ccff00]/10"
                >
                  ⚡ {t('marketUi.spamFee.proveWork')}
                </Button>
                <p className="text-center text-xs text-gray-500">
                  {t('marketUi.spamFee.proveWorkBody', { amount: LISTING_FEE_SATS.toLocaleString() })}
                </p>
              </>
            )}
          </div>
        )}

        {/* Generating invoice */}
        {paymentState === 'generating' && (
          <div className="text-center py-4">
            <Loader2 className="h-8 w-8 animate-spin mx-auto text-yellow-400" />
            <p className="text-gray-400 mt-2">{t('marketUi.spamFee.generating')}</p>
          </div>
        )}

        {/* Paying */}
        {paymentState === 'paying' && (
          <div className="text-center py-4">
            <Loader2 className="h-8 w-8 animate-spin mx-auto text-yellow-400" />
            <p className="text-gray-400 mt-2">{t('marketUi.spamFee.processing')}</p>
          </div>
        )}

        {/* Waiting for payment - show QR and manual options */}
        {paymentState === 'waiting' && invoice && qrCodeUrl && (
          <div className="space-y-4">
            {/* QR Code */}
            <div className="flex justify-center">
              <div className="bg-white p-3 rounded-lg">
                <img src={qrCodeUrl} alt={t('marketUi.spamFee.qrAlt')} className="w-48 h-48" />
              </div>
            </div>

            {/* Action buttons */}
            <div className="grid grid-cols-2 gap-2">
              <Button
                variant="outline"
                onClick={copyInvoice}
                className="border-yellow-500/50 hover:bg-yellow-500/10"
              >
                <Copy className="h-4 w-4 mr-2" />
                {t('marketUi.spamFee.copyInvoice')}
              </Button>
              <Button
                variant="outline"
                onClick={openInWallet}
                className="border-yellow-500/50 hover:bg-yellow-500/10"
              >
                <ExternalLink className="h-4 w-4 mr-2" />
                {t('marketUi.spamFee.openWallet')}
              </Button>
            </div>

            {/* Try again with wallet */}
            {(webln || activeNWC) && (
              <Button
                onClick={handleAutoPay}
                className="w-full bg-yellow-500 hover:bg-yellow-600 text-black font-bold"
              >
                <Zap className="h-4 w-4 mr-2" />
                {t('marketUi.spamFee.payWithWallet')}
              </Button>
            )}

            <p className="text-xs text-gray-400 text-center">
              {t('marketUi.spamFee.scanHint')}
            </p>
          </div>
        )}

        {/* Error state */}
        {paymentState === 'error' && error && (
          <div className="space-y-4">
            <div className="text-center py-2">
              <p className="text-red-400">{error}</p>
            </div>
            <Button
              onClick={generateInvoice}
              variant="outline"
              className="w-full border-yellow-500/50 hover:bg-yellow-500/10"
            >
              {t('common.tryAgain')}
            </Button>
          </div>
        )}

        {/* How to avoid future fees */}
        <div className="bg-green-500/10 rounded-lg p-3 border border-green-500/30">
          <p className="text-green-400 font-semibold text-sm mb-2">
            ✨ {t('marketUi.spamFee.skipTitle')}
          </p>
          <ul className="text-gray-300 text-sm space-y-1">
            <li className="flex items-center gap-2">
              <span className="text-green-400">→</span>
              {t('marketUi.spamFee.skip1')}
            </li>
            <li className="flex items-center gap-2">
              <span className="text-green-400">→</span>
              {t('marketUi.spamFee.skip2')}
            </li>
            <li className="flex items-center gap-2">
              <span className="text-green-400">→</span>
              {t('marketUi.spamFee.skip3')}
            </li>
          </ul>
          <p className="text-xs text-gray-400 mt-2">
            {t('marketUi.spamFee.skipNote')}
          </p>
        </div>
      </CardContent>
    </Card>
  );
}