import { useState, useEffect } from 'react';
import { useNavigate } from 'react-router-dom';
import { AlertTriangle, X, Download, CheckCircle } from 'lucide-react';
import { Button } from '@/components/ui/button';
import { useCurrentUser } from '@/hooks/useCurrentUser';
import { useLocalStorage } from '@/hooks/useLocalStorage';
import { useTranslation } from '@/contexts/language';
import {
  Sheet,
  SheetContent,
  SheetDescription,
  SheetHeader,
  SheetTitle,
} from '@/components/ui/sheet';

const BACKUP_CONFIRMED_KEY = 'backup-confirmed';
// Session-scoped snooze key. "Remind me later" used to set a PERMANENT
// localStorage flag, which silently turned into "never remind again" — a real
// safety hole. We now snooze only for the current browser session, so the
// reminder returns on the next visit until the user actually saves their login.
// Only `backup-confirmed` (set when they back up) stops it for good.
const BACKUP_SNOOZE_KEY = 'backup-reminder-snoozed-session';

/**
 * Gently-persistent backup reminder shown after signup.
 * Encourages users to save their recovery code (nsec) so they never lose access.
 * Non-blocking: one tap to back up, one tap to say "already done", or snooze for
 * this session. It keeps coming back each session until backup is confirmed.
 * Uses a bottom sheet for a good experience on both phone and desktop.
 */
export function BackupReminder() {
  const { user } = useCurrentUser();
  const [confirmed, setConfirmed] = useLocalStorage(BACKUP_CONFIRMED_KEY, false);
  const [showReminder, setShowReminder] = useState(false);
  const { t } = useTranslation();
  const navigate = useNavigate();

  useEffect(() => {
    if (!user) {
      setShowReminder(false);
      return;
    }

    // Show reminder if:
    // 1. User is logged in
    // 2. Not snoozed for THIS session (resets when they come back)
    // 3. Not confirmed they backed up (the only permanent stop)
    // Add a small delay so it doesn't immediately pop up on login.
    const timer = setTimeout(() => {
      const snoozed = sessionStorage.getItem(BACKUP_SNOOZE_KEY) === 'true';
      const shouldShow = !snoozed && !confirmed;
      setShowReminder(shouldShow);
    }, 2000);

    return () => clearTimeout(timer);
  }, [user, confirmed]);

  const handleDismiss = () => {
    // Snooze for this session only — it returns next visit until backup is done.
    try {
      sessionStorage.setItem(BACKUP_SNOOZE_KEY, 'true');
    } catch {
      // sessionStorage can throw in strict privacy modes — safe to ignore.
    }
    setShowReminder(false);
  };

  const handleConfirmBackup = () => {
    setConfirmed(true);
    setShowReminder(false);
  };

  const handleBackupNow = () => {
    // Client-side nav (HashRouter). window.location.href forced a full reload to
    // a non-hash path the router couldn't match — it dropped the user on a blank
    // page instead of the security settings. navigate() keeps it in-app.
    setShowReminder(false);
    // SettingsPage deep-links via ?section=… (NOT ?tab=…) — using the wrong
    // param silently dropped the user on the settings root instead of Security.
    navigate('/settings?section=security');
  };

  if (!showReminder) return null;

  return (
    <Sheet open={showReminder} onOpenChange={setShowReminder}>
      <SheetContent 
        side="bottom" 
        className="rounded-t-2xl border-t-4 border-amber-500 bg-gradient-to-b from-amber-950/90 to-black/95 backdrop-blur-lg"
        onInteractOutside={(e) => e.preventDefault()}
      >
        <SheetHeader className="text-left">
          <div className="flex items-start justify-between">
            <div className="flex items-center gap-3">
              <div className="flex-shrink-0 w-10 h-10 sm:w-12 sm:h-12 rounded-full bg-amber-500/20 flex items-center justify-center">
                <AlertTriangle className="h-5 w-5 sm:h-6 sm:w-6 text-amber-500" />
              </div>
              <div className="flex-1">
                <SheetTitle className="text-lg sm:text-xl font-bold text-amber-400">
                  {t('backup.title')}
                </SheetTitle>
                <SheetDescription className="text-xs sm:text-sm text-gray-400">
                  {t('backup.subtitle')}
                </SheetDescription>
              </div>
            </div>
            <Button
              variant="ghost"
              size="icon"
              onClick={handleDismiss}
              className="ml-2 -mt-1 text-gray-500 hover:text-gray-300"
            >
              <X className="h-5 w-5" />
            </Button>
          </div>
        </SheetHeader>

        <div className="mt-4 sm:mt-6 space-y-4">
          {/* Warning message */}
          <div className="p-3 sm:p-4 rounded-xl bg-amber-500/10 border border-amber-500/30">
            <p className="text-sm sm:text-base text-gray-200 leading-relaxed">
              {t('backup.message')}
            </p>
            <p className="text-sm sm:text-base text-gray-300 mt-2">
              ⚠️ {t('backup.warning')}
            </p>
          </div>

          {/* Action buttons - stacked on mobile */}
          <div className="flex flex-col sm:flex-row gap-3">
            <Button
              onClick={handleBackupNow}
              className="flex-1 h-12 sm:h-11 text-sm sm:text-base font-semibold bg-amber-500 hover:bg-amber-600 text-black"
              size="lg"
            >
              <Download className="mr-2 h-5 w-5" />
              {t('backup.backupNow')}
            </Button>
            
            <Button
              onClick={handleConfirmBackup}
              variant="outline"
              className="flex-1 h-12 sm:h-11 text-sm sm:text-base border-amber-500/50 text-amber-400 hover:bg-amber-500/20"
              size="lg"
            >
              <CheckCircle className="mr-2 h-5 w-5" />
              {t('backup.confirmed')}
            </Button>
          </div>

          {/* Dismiss link */}
          <div className="text-center pt-1">
            <button 
              onClick={handleDismiss}
              className="text-xs text-gray-500 hover:text-gray-400 underline"
            >
              {t('backup.remindLater')}
            </button>
          </div>
        </div>
      </SheetContent>
    </Sheet>
  );
}