import { useState } from 'react';
import { Download, Copy, Eye, EyeOff, Shield, AlertTriangle, CheckCircle, ExternalLink, KeyRound, QrCode } from 'lucide-react';
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card';
import { Button } from '@/components/ui/button';
import { Alert, AlertDescription } from '@/components/ui/alert';
import { QRCodeCanvas } from '@/components/ui/qrcode';
import { useCurrentUser } from '@/hooks/useCurrentUser';
import { useLocalStorage } from '@/hooks/useLocalStorage';
import { useNostrLogin } from '@nostrify/react/login';
import { toast } from '@/hooks/useToast';
import { useTranslation } from '@/contexts/language';

const sanitizeFilename = (filename: string) => filename.replace(/[^a-z0-9_.-]/gi, '_');

export function SecuritySettings() {
  const { user } = useCurrentUser();
  const { logins } = useNostrLogin();
  const { t } = useTranslation();
  const [confirmed, setConfirmed] = useLocalStorage('backup-confirmed', false);
  const [showWarning, setShowWarning] = useState(!confirmed);

  // Recovery reveal state
  const [revealed, setRevealed] = useState(false);
  const [showQr, setShowQr] = useState(false);

  // The active login. For nsec logins, the recovery code (nsec) is stored on
  // the login object itself — this is how we can reveal it later for users who
  // skipped backup at signup. For bunker/extension/Amber logins, the app never
  // held the key, so there is nothing to reveal here.
  const activeLogin = logins[0] as
    | (typeof logins[number] & { nsec?: string; data?: { nsec?: string } })
    | undefined;
  const loginType = activeLogin?.type;
  // Nostrify stores the bech32 nsec directly on the login (older builds nested
  // it under `data`), so check both to be safe.
  const recoveryCode = loginType === 'nsec'
    ? (activeLogin?.nsec ?? activeLogin?.data?.nsec)
    : undefined;

  const handleReveal = () => setRevealed(true);

  const handleCopyRecovery = () => {
    if (!recoveryCode) return;
    navigator.clipboard.writeText(recoveryCode);
    // Copying the recovery code counts as a real backup — mark confirmed so the
    // gentle reminder stops nagging a user who has genuinely saved their login.
    setConfirmed(true);
    setShowWarning(false);
    toast({ title: t('common.copied'), description: t('settingsUi.security.recoveryCopied') });
  };

  const handleDownloadRecovery = () => {
    if (!recoveryCode) return;
    try {
      const blob = new Blob([recoveryCode], { type: 'text/plain; charset=utf-8' });
      const url = globalThis.URL.createObjectURL(blob);
      const a = document.createElement('a');
      a.href = url;
      a.download = sanitizeFilename('skatespots-recovery-code.txt');
      a.style.display = 'none';
      document.body.appendChild(a);
      a.click();
      globalThis.URL.revokeObjectURL(url);
      document.body.removeChild(a);
      // A downloaded recovery file is a genuine backup — mark confirmed so the
      // reminder stops for good.
      setConfirmed(true);
      setShowWarning(false);
      toast({ title: t('settingsUi.security.savedTitle'), description: t('settingsUi.security.recoveryDownloaded') });
    } catch {
      toast({ title: t('settingsUi.security.downloadFailedTitle'), description: t('settingsUi.security.downloadFailedDesc'), variant: 'destructive' });
    }
  };

  if (!user) {
    return (
      <Card className="border-dashed">
        <CardContent className="py-12 text-center">
          <Shield className="h-12 w-12 mx-auto mb-4 text-muted-foreground/50" />
          <h3 className="text-lg font-medium mb-2">{t('settingsUi.security.loginRequired')}</h3>
          <p className="text-muted-foreground">
            {t('settingsUi.security.loginRequiredDesc')}
          </p>
        </CardContent>
      </Card>
    );
  }

  const handleConfirmBackup = () => {
    setConfirmed(true);
    setShowWarning(false);
    toast({
      title: t('settingsUi.security.backupConfirmedTitle'),
      description: t('settingsUi.security.backupConfirmedDesc'),
    });
  };

  return (
    <div className="space-y-6">
      {/* Recover / reveal recovery code — the real backup path for skaters who
          skipped it at signup. Only possible for nsec logins. */}
      <Card className="bg-black/90 border-2 border-amber-500/40">
        <CardHeader>
          <CardTitle className="flex items-center gap-2 text-amber-400">
            <KeyRound className="h-5 w-5" />
            {t('settingsUi.security.yourRecoveryCode')}
          </CardTitle>
          <CardDescription>
            {t('settingsUi.security.recoveryCodeDesc')}
          </CardDescription>
        </CardHeader>
        <CardContent className="space-y-4">
          {recoveryCode ? (
            <>
              <p className="text-sm text-gray-300">
                {t('settingsUi.security.recoveryCodeBefore')}{' '}
                <strong className="text-white">{t('settingsUi.security.only')}</strong>{' '}
                {t('settingsUi.security.recoveryCodeAfter')}
              </p>

              {!revealed ? (
                <Button
                  onClick={handleReveal}
                  className="w-full bg-amber-500 hover:bg-amber-600 text-black font-bold"
                >
                  <Eye className="h-4 w-4 mr-2" />
                  {t('settingsUi.security.revealRecovery')}
                </Button>
              ) : (
                <div className="space-y-3">
                  <div className="p-3 bg-black rounded-lg border border-amber-500/30 font-mono text-xs break-all text-white select-all">
                    {recoveryCode}
                  </div>

                  <div className="grid grid-cols-3 gap-2">
                    <Button
                      variant="outline"
                      size="sm"
                      className="border-amber-500/40 text-amber-300 hover:bg-amber-500/10"
                      onClick={handleCopyRecovery}
                    >
                      <Copy className="h-3.5 w-3.5 mr-1.5" />
                      {t('common.copy')}
                    </Button>
                    <Button
                      variant="outline"
                      size="sm"
                      className="border-amber-500/40 text-amber-300 hover:bg-amber-500/10"
                      onClick={handleDownloadRecovery}
                    >
                      <Download className="h-3.5 w-3.5 mr-1.5" />
                      {t('common.save')}
                    </Button>
                    <Button
                      variant="outline"
                      size="sm"
                      className="border-amber-500/40 text-amber-300 hover:bg-amber-500/10"
                      onClick={() => setShowQr((v) => !v)}
                    >
                      <QrCode className="h-3.5 w-3.5 mr-1.5" />
                      QR
                    </Button>
                  </div>

                  {showQr && (
                    <div className="flex flex-col items-center gap-2 pt-2">
                      <div className="bg-white p-3 rounded-xl">
                        <QRCodeCanvas value={recoveryCode} size={200} level="M" />
                      </div>
                      <p className="text-xs text-gray-500 text-center max-w-xs">
                        {t('settingsUi.security.qrHint')}
                      </p>
                    </div>
                  )}

                  <div className="flex items-center justify-between">
                    <p className="text-xs text-amber-300/80">{t('settingsUi.security.neverShareHide')}</p>
                    <Button
                      variant="ghost"
                      size="sm"
                      className="text-gray-500 hover:text-gray-300 h-auto py-1"
                      onClick={() => { setRevealed(false); setShowQr(false); }}
                    >
                      <EyeOff className="h-3.5 w-3.5 mr-1.5" />
                      {t('settingsUi.security.hide')}
                    </Button>
                  </div>
                </div>
              )}
            </>
          ) : (
            <Alert className="bg-blue-950/30 border border-blue-500/30">
              <Shield className="h-4 w-4 text-blue-400" />
              <AlertDescription className="text-sm text-gray-300">
                {loginType === 'x-amber' && (
                  <>{t('settingsUi.security.amberNoteBefore')} <strong className="text-white">Amber</strong>{t('settingsUi.security.amberNoteAfter')}</>
                )}
                {loginType === 'bunker' && (
                  <>{t('settingsUi.security.bunkerNoteBefore')} <strong className="text-white">{t('settingsUi.security.remoteSigner')}</strong>{t('settingsUi.security.bunkerNoteAfter')}</>
                )}
                {(loginType as string) === 'extension' && (
                  <>{t('settingsUi.security.extensionNoteBefore')} <strong className="text-white">{t('settingsUi.security.browserExtension')}</strong>{t('settingsUi.security.extensionNoteAfter')}</>
                )}
                {!loginType && (
                  <>{t('settingsUi.security.otherNote')}</>
                )}
              </AlertDescription>
            </Alert>
          )}
        </CardContent>
      </Card>

      {/* Backup Warning */}
      {showWarning && (
        <Alert className="bg-gradient-to-r from-amber-500/10 to-red-500/10 border-2 border-amber-500/50">
          <AlertTriangle className="h-5 w-5 text-amber-500" />
          <AlertDescription>
            <div className="space-y-3">
              <p className="font-bold text-amber-400">
                {t('settingsUi.security.backupWarningTitle')}
              </p>
              <p className="text-sm text-gray-300">
                {t('settingsUi.security.backupWarningBody')}
              </p>
              <Button
                onClick={handleConfirmBackup}
                size="sm"
                className="bg-amber-500 hover:bg-amber-600 text-black font-bold"
              >
                <CheckCircle className="h-4 w-4 mr-2" />
                {t('settingsUi.security.iveBackedUp')}
              </Button>
            </div>
          </AlertDescription>
        </Alert>
      )}

      {/* Backup Status */}
      <Card className={confirmed ? "bg-green-950/20 border-2 border-green-500/30" : "bg-red-950/20 border-2 border-red-500/30"}>
        <CardHeader>
          <CardTitle className={confirmed ? "text-green-400" : "text-red-400"}>
            {confirmed ? t('settingsUi.security.backupConfirmed') : t('settingsUi.security.backupNotConfirmed')}
          </CardTitle>
          <CardDescription>
            {confirmed 
              ? t('settingsUi.security.backupConfirmedStatusDesc')
              : t('settingsUi.security.backupNotConfirmedDesc')}
          </CardDescription>
        </CardHeader>
        {!confirmed && (
          <CardContent>
            <p className="text-sm text-gray-400 mb-4">
              {t('settingsUi.security.notSavedYetBefore')}
              <strong className="text-amber-400"> {t('settingsUi.security.yourRecoveryCode')}</strong> {t('settingsUi.security.notSavedYetAfter')}
            </p>
            <Button
              onClick={handleConfirmBackup}
              variant="outline"
              className="border-green-500/50 text-green-400 hover:bg-green-500/20"
            >
              {t('settingsUi.security.yesBackedUp')}
            </Button>
          </CardContent>
        )}
      </Card>

      {/* Security Information */}
      <Card className="bg-black/90 border-2 border-[#ccff00]/30">
        <CardHeader>
          <CardTitle className="flex items-center gap-2 text-[#ccff00]">
            <Shield className="h-5 w-5" />
            {t('settingsUi.security.bestPracticesTitle')}
          </CardTitle>
          <CardDescription>
            {t('settingsUi.security.bestPracticesDesc')}
          </CardDescription>
        </CardHeader>
        <CardContent className="space-y-4">
          <div className="space-y-3 text-sm">
            <div className="flex items-start gap-3">
              <div className="text-2xl">✍️</div>
              <div>
                <p className="font-bold text-white">{t('settingsUi.security.bp1Title')}</p>
                <p className="text-gray-400">{t('settingsUi.security.bp1Desc')}</p>
              </div>
            </div>
            
            <div className="flex items-start gap-3">
              <div className="text-2xl">💾</div>
              <div>
                <p className="font-bold text-white">{t('settingsUi.security.bp2Title')}</p>
                <p className="text-gray-400">{t('settingsUi.security.bp2Desc')}</p>
              </div>
            </div>
            
            <div className="flex items-start gap-3">
              <div className="text-2xl">🔒</div>
              <div>
                <p className="font-bold text-white">{t('settingsUi.security.bp3Title')}</p>
                <p className="text-gray-400">{t('settingsUi.security.bp3Desc')}</p>
              </div>
            </div>
            
            <div className="flex items-start gap-3">
              <div className="text-2xl">🚫</div>
              <div>
                <p className="font-bold text-white">{t('settingsUi.security.bp4Title')}</p>
                <p className="text-gray-400">{t('settingsUi.security.bp4Desc')}</p>
              </div>
            </div>
            
            <div className="flex items-start gap-3">
              <div className="text-2xl">🔐</div>
              <div>
                <p className="font-bold text-white">{t('settingsUi.security.bp5Title')}</p>
                <p className="text-gray-400">{t('settingsUi.security.bp5Desc')}</p>
              </div>
            </div>
          </div>

          <div className="pt-4 border-t border-[#ccff00]/20">
            <h4 className="font-bold text-[#ff0040] mb-2 uppercase text-sm">
              {t('settingsUi.security.importantReminders')}
            </h4>
            <ul className="text-xs text-gray-400 space-y-1">
              <li>• {t('settingsUi.security.rem1')}</li>
              <li>• {t('settingsUi.security.rem2')}</li>
              <li>• {t('settingsUi.security.rem3')}</li>
              <li>• {t('settingsUi.security.rem4')}</li>
            </ul>
          </div>
        </CardContent>
      </Card>

      {/* Browser Extension & Mobile App Recommendations */}
      <Card className="bg-black/90 border-2 border-purple-500/30">
        <CardHeader>
          <CardTitle className="text-purple-400">{t('settingsUi.security.recommendedSigners')}</CardTitle>
          <CardDescription>
            {t('settingsUi.security.recommendedSignersDesc')}
          </CardDescription>
        </CardHeader>
        <CardContent>
          <div className="space-y-3">
            {/* Amber - Android */}
            <a 
              href="https://github.com/greenart7c3/Amber" 
              target="_blank" 
              rel="noopener noreferrer"
              className="block p-4 rounded-lg bg-gradient-to-r from-[#ccff00]/10 to-green-500/10 border border-[#ccff00]/30 hover:border-[#ccff00]/60 transition-all"
            >
              <div className="flex items-start justify-between gap-3">
                <div className="flex-1">
                  <div className="font-bold text-white flex items-center gap-2">
                    Amber
                    <span className="text-xs px-2 py-0.5 bg-[#ccff00]/20 text-[#ccff00] rounded-full">Android</span>
                  </div>
                  <p className="text-xs text-gray-400 mt-1">
                    {t('settingsUi.security.amberDesc')}
                  </p>
                </div>
                <ExternalLink className="h-4 w-4 text-gray-500" />
              </div>
            </a>
            <a 
              href="https://getalby.com" 
              target="_blank" 
              rel="noopener noreferrer"
              className="block p-4 rounded-lg bg-gradient-to-r from-amber-500/10 to-yellow-500/10 border border-amber-500/30 hover:border-amber-500/60 transition-all"
            >
              <div className="flex items-start justify-between gap-3">
                <div className="flex-1">
                  <div className="font-bold text-white flex items-center gap-2">
                    Alby
                    <span className="text-xs px-2 py-0.5 bg-green-500/20 text-green-400 rounded-full">{t('settingsUi.security.recommended')}</span>
                  </div>
                  <p className="text-xs text-gray-400 mt-1">
                    {t('settingsUi.security.albyDesc')}
                  </p>
                </div>
                <ExternalLink className="h-4 w-4 text-gray-500" />
              </div>
            </a>

            <a 
              href="https://www.getflamingo.org/" 
              target="_blank" 
              rel="noopener noreferrer"
              className="block p-4 rounded-lg bg-black/50 border border-purple-500/30 hover:border-purple-500/60 transition-all"
            >
              <div className="flex items-start justify-between gap-3">
                <div className="flex-1">
                  <div className="font-bold text-white">Flamingo</div>
                  <p className="text-xs text-gray-400 mt-1">
                    {t('settingsUi.security.flamingoDesc')}
                  </p>
                </div>
                <ExternalLink className="h-4 w-4 text-gray-500" />
              </div>
            </a>

            <a 
              href="https://github.com/fiatjaf/nos2x" 
              target="_blank" 
              rel="noopener noreferrer"
              className="block p-4 rounded-lg bg-black/50 border border-purple-500/30 hover:border-purple-500/60 transition-all"
            >
              <div className="flex items-start justify-between gap-3">
                <div className="flex-1">
                  <div className="font-bold text-white">nos2x</div>
                  <p className="text-xs text-gray-400 mt-1">
                    {t('settingsUi.security.nos2xDesc')}
                  </p>
                </div>
                <ExternalLink className="h-4 w-4 text-gray-500" />
              </div>
            </a>
          </div>
        </CardContent>
      </Card>

      {/* Nostr Connect (Bunkers) */}
      <Card className="bg-black/90 border-2 border-blue-500/30">
        <CardHeader>
          <CardTitle className="text-blue-400">{t('settingsUi.security.nostrConnectTitle')}</CardTitle>
          <CardDescription>
            {t('settingsUi.security.nostrConnectDesc')}
          </CardDescription>
        </CardHeader>
        <CardContent>
          <p className="text-sm text-gray-400 mb-4">
            {t('settingsUi.security.nostrConnectBody')}
          </p>

          <div className="space-y-3">
            <a 
              href="https://nsec.app" 
              target="_blank" 
              rel="noopener noreferrer"
              className="block p-4 rounded-lg bg-gradient-to-r from-blue-500/10 to-cyan-500/10 border border-blue-500/30 hover:border-blue-500/60 transition-all"
            >
              <div className="flex items-start justify-between gap-3">
                <div className="flex-1">
                  <div className="font-bold text-white flex items-center gap-2">
                    nsec.app
                    <span className="text-xs px-2 py-0.5 bg-blue-500/20 text-blue-400 rounded-full">{t('common.popular')}</span>
                  </div>
                  <p className="text-xs text-gray-400 mt-1">
                    {t('settingsUi.security.nsecAppDesc')}
                  </p>
                </div>
                <ExternalLink className="h-4 w-4 text-gray-500" />
              </div>
            </a>

            <a 
              href="https://nostrum.social" 
              target="_blank" 
              rel="noopener noreferrer"
              className="block p-4 rounded-lg bg-black/50 border border-blue-500/30 hover:border-blue-500/60 transition-all"
            >
              <div className="flex items-start justify-between gap-3">
                <div className="flex-1">
                  <div className="font-bold text-white">Nostrum</div>
                  <p className="text-xs text-gray-400 mt-1">
                    {t('settingsUi.security.nostrumDesc')}
                  </p>
                </div>
                <ExternalLink className="h-4 w-4 text-gray-500" />
              </div>
            </a>
          </div>

          <div className="mt-4 p-3 rounded-lg bg-blue-950/30 border border-blue-500/30 text-sm text-gray-300">
            <p><strong className="text-blue-400">{t('settingsUi.security.howToUse')}</strong> {t('settingsUi.security.howToUseDesc')}</p>
          </div>
        </CardContent>
      </Card>
    </div>
  );
}