import { useEffect, useState, useRef, useCallback } from 'react';
import { useLocalStorage } from '@/hooks/useLocalStorage';
import { useTranslation } from '@/contexts/language';
import {
  Sheet,
  SheetContent,
  SheetDescription,
  SheetHeader,
  SheetTitle,
} from '@/components/ui/sheet';
import { Button } from '@/components/ui/button';
import { Download, X, Share, Plus, Smartphone } from 'lucide-react';

interface BeforeInstallPromptEvent extends Event {
  prompt: () => Promise<void>;
  userChoice: Promise<{ outcome: 'accepted' | 'dismissed' }>;
}

// Detect iOS
const isIOS = () => {
  if (typeof navigator === 'undefined') return false;
  return /iPad|iPhone|iPod/.test(navigator.userAgent) || 
    (navigator.platform === 'MacIntel' && navigator.maxTouchPoints > 1);
};

// Detect if running in standalone mode (PWA)
const isStandalone = () => {
  if (typeof window === 'undefined') return false;
  return window.matchMedia('(display-mode: standalone)').matches ||
    // iOS Safari specific check
    ('standalone' in window.navigator && (window.navigator as Navigator & { standalone: boolean }).standalone);
};

// Detect mobile/tablet
const isMobileOrTablet = () => {
  if (typeof navigator === 'undefined') return false;
  return /Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent) ||
    (navigator.platform === 'MacIntel' && navigator.maxTouchPoints > 1); // iPad
};

export function PWAInstallPrompt() {
  const [deferredPrompt, setDeferredPrompt] = useState<BeforeInstallPromptEvent | null>(null);
  const [showPrompt, setShowPrompt] = useState(false);
  const [showManualPrompt, setShowManualPrompt] = useState(false);
  const [dismissed, setDismissed] = useLocalStorage('pwa-install-dismissed', false);
  const [installed, setInstalled] = useLocalStorage('pwa-installed', false);
  const [isIOSDevice] = useState(isIOS());
  const hasPromptFiredRef = useRef(false);
  const { t } = useTranslation();

  // Handler for beforeinstallprompt
  const handleBeforeInstallPrompt = useCallback((e: Event) => {
    e.preventDefault();
    hasPromptFiredRef.current = true;
    setDeferredPrompt(e as BeforeInstallPromptEvent);
  }, []);

  // Handler for app installed
  const handleAppInstalled = useCallback(() => {
    setInstalled(true);
    setShowPrompt(false);
    setShowManualPrompt(false);
    setDeferredPrompt(null);
  }, [setInstalled]);

  useEffect(() => {
    // Don't show if already dismissed or installed
    if (dismissed || installed) return;

    // Check if running in standalone mode (already installed)
    if (isStandalone()) {
      setInstalled(true);
      return;
    }

    // Check if mobile/tablet - only show on mobile devices
    if (!isMobileOrTablet()) return;

    // Add event listeners
    window.addEventListener('beforeinstallprompt', handleBeforeInstallPrompt);
    window.addEventListener('appinstalled', handleAppInstalled);

    // For iOS, we can't use beforeinstallprompt - show manual instructions after delay
    if (isIOSDevice) {
      const timer = setTimeout(() => {
        setShowManualPrompt(true);
      }, 5000);
      return () => {
        clearTimeout(timer);
        window.removeEventListener('beforeinstallprompt', handleBeforeInstallPrompt);
        window.removeEventListener('appinstalled', handleAppInstalled);
      };
    }

    return () => {
      window.removeEventListener('beforeinstallprompt', handleBeforeInstallPrompt);
      window.removeEventListener('appinstalled', handleAppInstalled);
    };
  }, [dismissed, installed, setInstalled, isIOSDevice, handleBeforeInstallPrompt, handleAppInstalled]);

  // Separate effect to handle showing prompts based on deferredPrompt state
  useEffect(() => {
    if (dismissed || installed) return;
    if (!isMobileOrTablet() || isIOSDevice) return;

    // If we have a deferred prompt, show native install after delay
    if (deferredPrompt) {
      const timer = setTimeout(() => {
        setShowPrompt(true);
      }, 5000);
      return () => clearTimeout(timer);
    }

    // Fallback: If beforeinstallprompt doesn't fire within 7 seconds on Android, show manual prompt
    const fallbackTimer = setTimeout(() => {
      if (!hasPromptFiredRef.current && !deferredPrompt) {
        setShowManualPrompt(true);
      }
    }, 7000);

    return () => clearTimeout(fallbackTimer);
  }, [deferredPrompt, dismissed, installed, isIOSDevice]);

  const handleInstall = async () => {
    if (!deferredPrompt) return;

    // Show the install prompt
    await deferredPrompt.prompt();

    // Wait for the user's response
    const { outcome } = await deferredPrompt.userChoice;

    if (outcome === 'accepted') {
      setInstalled(true);
    }

    // Clear the deferred prompt
    setDeferredPrompt(null);
    setShowPrompt(false);
  };

  const handleDismiss = () => {
    setShowPrompt(false);
    setShowManualPrompt(false);
    setDismissed(true);
  };

  // Native install prompt (Android Chrome)
  if (showPrompt && deferredPrompt) {
    return (
      <Sheet open={showPrompt} onOpenChange={setShowPrompt}>
        <SheetContent 
          side="bottom" 
          className="rounded-t-2xl border-t-4 border-[#ff0040] bg-gradient-to-b from-[#ff0040]/10 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-12 h-12 sm:w-14 sm:h-14 rounded-xl bg-gradient-to-br from-[#ff0040] to-[#cc0033] flex items-center justify-center shadow-lg shadow-[#ff0040]/30">
                  <Smartphone className="h-6 w-6 sm:h-7 sm:w-7 text-white" />
                </div>
                <div className="flex-1">
                  <SheetTitle className="text-lg sm:text-xl font-bold">
                    {t('pwa.installTitle')}
                  </SheetTitle>
                  <SheetDescription className="text-xs sm:text-sm text-gray-400">
                    {t('pwa.installSubtitle')}
                  </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">
            {/* Benefits list */}
            <div className="grid grid-cols-3 gap-2 mb-5">
              <div className="text-center p-2 rounded-lg bg-[#ff0040]/10 border border-[#ff0040]/30">
                <p className="text-lg">⚡</p>
                <p className="text-[10px] sm:text-xs text-gray-400">{t('pwa.benefits.fast')}</p>
              </div>
              <div className="text-center p-2 rounded-lg bg-[#ff0040]/10 border border-[#ff0040]/30">
                <p className="text-lg">📴</p>
                <p className="text-[10px] sm:text-xs text-gray-400">{t('pwa.benefits.offline')}</p>
              </div>
              <div className="text-center p-2 rounded-lg bg-[#ff0040]/10 border border-[#ff0040]/30">
                <p className="text-lg">🛹</p>
                <p className="text-[10px] sm:text-xs text-gray-400">{t('pwa.benefits.fullAccess')}</p>
              </div>
            </div>

            <div className="space-y-3">
              <Button
                onClick={handleInstall}
                className="w-full h-12 sm:h-14 text-sm sm:text-base font-bold bg-[#ff0040] hover:bg-[#ff0040]/90 shadow-lg shadow-[#ff0040]/30"
                size="lg"
              >
                <Download className="mr-2 h-5 w-5" />
                {t('pwa.installApp')}
              </Button>

              <button
                onClick={handleDismiss}
                className="w-full text-center text-xs text-gray-500 hover:text-gray-400 py-2"
              >
                {t('pwa.maybeLater')}
              </button>
            </div>
          </div>
        </SheetContent>
      </Sheet>
    );
  }

  // Manual install instructions (iOS and fallback for other browsers)
  if (showManualPrompt) {
    return (
      <Sheet open={showManualPrompt} onOpenChange={setShowManualPrompt}>
        <SheetContent 
          side="bottom" 
          className="rounded-t-2xl border-t-4 border-[#ccff00] bg-gradient-to-b from-[#ccff00]/10 to-black/95 backdrop-blur-lg max-h-[85vh] overflow-y-auto"
          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-12 h-12 sm:w-14 sm:h-14 rounded-xl bg-gradient-to-br from-[#ccff00] to-[#99cc00] flex items-center justify-center shadow-lg shadow-[#ccff00]/30">
                  <Smartphone className="h-6 w-6 sm:h-7 sm:w-7 text-black" />
                </div>
                <div className="flex-1">
                  <SheetTitle className="text-lg sm:text-xl font-bold text-[#ccff00]">
                    {t('pwa.addToHomeScreen')}
                  </SheetTitle>
                  <SheetDescription className="text-xs sm:text-sm text-gray-400">
                    {isIOSDevice ? t('pwa.iosStep1Hint') : t('pwa.androidStep1Hint')}
                  </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">
            {isIOSDevice ? (
              // iOS Instructions
              <div className="space-y-3">
                <div className="flex items-center gap-3 p-3 sm:p-4 rounded-xl bg-[#ccff00]/10 border border-[#ccff00]/30">
                  <div className="flex-shrink-0 w-9 h-9 sm:w-10 sm:h-10 rounded-full bg-[#ccff00] text-black flex items-center justify-center font-bold text-sm sm:text-base shadow-md">
                    1
                  </div>
                  <div className="flex-1 min-w-0">
                    <p className="text-sm sm:text-base font-medium text-white">{t('pwa.iosStep1')}</p>
                    <p className="text-xs sm:text-sm text-gray-400 flex items-center gap-1 mt-0.5">
                      <Share className="h-3 w-3 sm:h-4 sm:w-4" /> {t('pwa.iosStep1Hint')}
                    </p>
                  </div>
                </div>
                
                <div className="flex items-center gap-3 p-3 sm:p-4 rounded-xl bg-[#ccff00]/10 border border-[#ccff00]/30">
                  <div className="flex-shrink-0 w-9 h-9 sm:w-10 sm:h-10 rounded-full bg-[#ccff00] text-black flex items-center justify-center font-bold text-sm sm:text-base shadow-md">
                    2
                  </div>
                  <div className="flex-1 min-w-0">
                    <p className="text-sm sm:text-base font-medium text-white">{t('pwa.iosStep2')}</p>
                    <p className="text-xs sm:text-sm text-gray-400 flex items-center gap-1 mt-0.5">
                      <Plus className="h-3 w-3 sm:h-4 sm:w-4" /> {t('pwa.iosStep2Hint')}
                    </p>
                  </div>
                </div>
                
                <div className="flex items-center gap-3 p-3 sm:p-4 rounded-xl bg-[#ccff00]/10 border border-[#ccff00]/30">
                  <div className="flex-shrink-0 w-9 h-9 sm:w-10 sm:h-10 rounded-full bg-[#ccff00] text-black flex items-center justify-center font-bold text-sm sm:text-base shadow-md">
                    3
                  </div>
                  <div className="flex-1 min-w-0">
                    <p className="text-sm sm:text-base font-medium text-white">{t('pwa.iosStep3')}</p>
                    <p className="text-xs sm:text-sm text-gray-400 mt-0.5">{t('pwa.iosStep3Hint')}</p>
                  </div>
                </div>
              </div>
            ) : (
              // Android/Other Instructions
              <div className="space-y-3">
                <div className="flex items-center gap-3 p-3 sm:p-4 rounded-xl bg-[#ccff00]/10 border border-[#ccff00]/30">
                  <div className="flex-shrink-0 w-9 h-9 sm:w-10 sm:h-10 rounded-full bg-[#ccff00] text-black flex items-center justify-center font-bold text-sm sm:text-base shadow-md">
                    1
                  </div>
                  <div className="flex-1 min-w-0">
                    <p className="text-sm sm:text-base font-medium text-white">{t('pwa.androidStep1')}</p>
                    <p className="text-xs sm:text-sm text-gray-400 mt-0.5">{t('pwa.androidStep1Hint')}</p>
                  </div>
                </div>
                
                <div className="flex items-center gap-3 p-3 sm:p-4 rounded-xl bg-[#ccff00]/10 border border-[#ccff00]/30">
                  <div className="flex-shrink-0 w-9 h-9 sm:w-10 sm:h-10 rounded-full bg-[#ccff00] text-black flex items-center justify-center font-bold text-sm sm:text-base shadow-md">
                    2
                  </div>
                  <div className="flex-1 min-w-0">
                    <p className="text-sm sm:text-base font-medium text-white">{t('pwa.androidStep2')}</p>
                    <p className="text-xs sm:text-sm text-gray-400 mt-0.5">{t('pwa.androidStep2Hint')}</p>
                  </div>
                </div>
                
                <div className="flex items-center gap-3 p-3 sm:p-4 rounded-xl bg-[#ccff00]/10 border border-[#ccff00]/30">
                  <div className="flex-shrink-0 w-9 h-9 sm:w-10 sm:h-10 rounded-full bg-[#ccff00] text-black flex items-center justify-center font-bold text-sm sm:text-base shadow-md">
                    3
                  </div>
                  <div className="flex-1 min-w-0">
                    <p className="text-sm sm:text-base font-medium text-white">{t('pwa.androidStep3')}</p>
                    <p className="text-xs sm:text-sm text-gray-400 mt-0.5">{t('pwa.androidStep3Hint')}</p>
                  </div>
                </div>
              </div>
            )}

            <Button
              onClick={handleDismiss}
              className="w-full h-12 text-sm sm:text-base font-semibold bg-[#ccff00] text-black hover:bg-[#ccff00]/90"
              size="lg"
            >
              {t('pwa.gotIt')}
            </Button>
          </div>

          <div className="mt-3 text-center">
            <p className="text-xs text-muted-foreground">
              {t('pwa.tagline')}
            </p>
          </div>
        </SheetContent>
      </Sheet>
    );
  }

  return null;
}