import React, { useState, useMemo, useEffect } from 'react';
import { Download, Grid, Square, LogOut, Calendar, Clock, Search, SortAsc } from 'lucide-react';
import { format, differenceInDays, parseISO } from 'date-fns';
import { useQuery } from '@tanstack/react-query';

import { Button, Input, SkeletonGalleryGrid, Skeleton } from '../common';
import { useGalleryAuth, useTheme } from '../../contexts';
import { useGalleryPhotos, useDownloadAllPhotos } from '../../hooks/useGallery';
import { PhotoGrid } from './PhotoGrid';
import { ExpirationBanner } from './ExpirationBanner';
import { CountdownTimer } from './CountdownTimer';
import { analyticsService } from '../../services/analytics.service';
import { api } from '../../config/api';

interface GalleryViewProps {
  slug: string;
  event: {
    id: number;
    event_name: string;
    event_type: string;
    event_date: string;
    welcome_message?: string;
    color_theme?: string;
    expires_at: string;
  };
}

export const GalleryView: React.FC<GalleryViewProps> = ({ slug, event }) => {
  const { logout } = useGalleryAuth();
  const { setTheme } = useTheme();
  const [viewMode, setViewMode] = useState<'all' | 'collages' | 'individual'>('all');
  const [searchTerm, setSearchTerm] = useState('');
  const [sortBy, setSortBy] = useState<'date' | 'name' | 'size'>('date');
  const [showSortMenu, setShowSortMenu] = useState(false);
  const [brandingSettings, setBrandingSettings] = useState<any>(null);
  
  // Fetch photos
  const { data, isLoading, error } = useGalleryPhotos(slug);
  const downloadAllMutation = useDownloadAllPhotos();

  // Fetch branding settings
  const { data: settingsData } = useQuery({
    queryKey: ['gallery-settings'],
    queryFn: async () => {
      const response = await api.get('/api/public/settings');
      return response.data;
    },
    staleTime: 5 * 60 * 1000, // Cache for 5 minutes
  });

  // Apply theme and branding settings
  useEffect(() => {
    if (settingsData) {
      // Apply branding settings
      setBrandingSettings({
        company_name: settingsData.branding_company_name || '',
        company_tagline: settingsData.branding_company_tagline || '',
        support_email: settingsData.branding_support_email || '',
        footer_text: settingsData.branding_footer_text || '© 2024 Your Company. All rights reserved.',
        watermark_enabled: settingsData.branding_watermark_enabled || false,
      });

      // Apply theme settings
      if (settingsData.theme_config) {
        setTheme(settingsData.theme_config);
      }
    }
  }, [settingsData, setTheme]);

  // Apply event-specific theme if available
  useEffect(() => {
    if (event.color_theme) {
      try {
        const eventTheme = JSON.parse(event.color_theme);
        console.log('Applying event-specific theme:', eventTheme);
        setTheme(eventTheme);
      } catch (e) {
        console.error('Failed to parse event theme:', e);
      }
    } else if (settingsData?.theme_config) {
      // Fall back to global theme if no event-specific theme
      console.log('No event theme, using global theme');
    }
  }, [event.color_theme, setTheme, settingsData]);

  // Calculate days until expiration
  const daysUntilExpiration = differenceInDays(parseISO(event.expires_at), new Date());
  const showUrgentWarning = daysUntilExpiration <= 7;

  // Filter and sort photos
  const filteredPhotos = useMemo(() => {
    if (!data?.photos) return [];
    
    let photos = [...data.photos];
    
    // Apply view mode filter
    if (viewMode === 'collages') {
      photos = photos.filter(photo => photo.type === 'collage');
    } else if (viewMode === 'individual') {
      photos = photos.filter(photo => photo.type === 'individual');
    }
    
    // Apply search filter
    if (searchTerm) {
      const term = searchTerm.toLowerCase();
      photos = photos.filter(photo => 
        photo.filename.toLowerCase().includes(term)
      );
    }
    
    // Apply sorting
    photos.sort((a, b) => {
      switch (sortBy) {
        case 'name':
          return a.filename.localeCompare(b.filename);
        case 'size':
          return b.size - a.size;
        case 'date':
        default:
          return new Date(b.uploaded_at).getTime() - new Date(a.uploaded_at).getTime();
      }
    });
    
    return photos;
  }, [data?.photos, viewMode, searchTerm, sortBy]);

  const handleDownloadAll = () => {
    downloadAllMutation.mutate(slug);
    
    // Track download all action
    analyticsService.trackGalleryEvent('bulk_download', {
      gallery: slug,
      photo_count: data?.photos.length || 0,
      is_download_all: true
    });
  };

  // Track search usage with debouncing
  useEffect(() => {
    if (searchTerm.length > 0) {
      const timer = setTimeout(() => {
        analyticsService.trackSearch(searchTerm, filteredPhotos.length, 'gallery');
      }, 1000); // Debounce for 1 second

      return () => clearTimeout(timer);
    }
  }, [searchTerm, filteredPhotos.length]);

  // Track expiration warning views
  useEffect(() => {
    if (showUrgentWarning && daysUntilExpiration > 0) {
      analyticsService.trackExpirationWarning(slug, daysUntilExpiration);
    }
  }, [showUrgentWarning, daysUntilExpiration, slug]);

  if (isLoading) {
    return (
      <div className="min-h-screen bg-neutral-50">
        {/* Header Skeleton */}
        <header className="bg-white border-b border-neutral-200 sticky top-0 z-40">
          <div className="container py-4">
            <div className="flex items-center justify-between">
              <div>
                <Skeleton height={32} width={200} className="mb-2" />
                <Skeleton height={20} width={300} />
              </div>
              <div className="flex items-center gap-2">
                <Skeleton height={40} width={120} />
                <Skeleton height={40} width={100} />
              </div>
            </div>
          </div>
        </header>
        
        {/* Content Skeleton */}
        <div className="container mt-6">
          <Skeleton height={80} className="mb-6" />
          <SkeletonGalleryGrid count={12} />
        </div>
      </div>
    );
  }

  if (error || !data) {
    return (
      <div className="min-h-screen bg-neutral-50 flex items-center justify-center">
        <div className="text-center">
          <p className="text-lg text-neutral-600">Failed to load photos</p>
          <Button onClick={() => window.location.reload()} className="mt-4">
            Try Again
          </Button>
        </div>
      </div>
    );
  }

  return (
    <div className="min-h-screen bg-neutral-50">
      {/* Expiration Banner */}
      {showUrgentWarning && (
        <ExpirationBanner daysRemaining={daysUntilExpiration} expiresAt={event.expires_at} />
      )}

      {/* Header */}
      <header className="bg-white border-b border-neutral-200 sticky top-0 z-40">
        <div className="container py-4">
          <div className="flex items-center justify-between">
            <div className="flex items-center gap-4">
              {/* Company branding */}
              {brandingSettings?.company_name && (
                <div className="pr-4 border-r border-neutral-200">
                  <h2 className="text-lg font-semibold text-neutral-800">{brandingSettings.company_name}</h2>
                  {brandingSettings.company_tagline && (
                    <p className="text-xs text-neutral-600">{brandingSettings.company_tagline}</p>
                  )}
                </div>
              )}
              <div>
                <h1 className="text-2xl font-bold text-neutral-900">{event.event_name}</h1>
                <div className="flex items-center gap-4 mt-1 text-sm text-neutral-600">
                  <span className="flex items-center">
                    <Calendar className="w-4 h-4 mr-1" />
                    {format(parseISO(event.event_date), 'MMMM d, yyyy')}
                  </span>
                  <span className="flex items-center">
                    <Clock className="w-4 h-4 mr-1" />
                    Expires {format(parseISO(event.expires_at), 'MMM d')}
                  </span>
                </div>
              </div>
            </div>
            
            <div className="flex items-center gap-2">
              {daysUntilExpiration <= 1 && daysUntilExpiration > 0 && (
                <CountdownTimer expiresAt={event.expires_at} className="mr-4" />
              )}
              <Button
                variant="primary"
                size="md"
                leftIcon={<Download className="w-4 h-4" />}
                onClick={handleDownloadAll}
                isLoading={downloadAllMutation.isPending}
                className={showUrgentWarning ? 'animate-pulse' : ''}
              >
                Download All
              </Button>
              <Button
                variant="outline"
                size="md"
                leftIcon={<LogOut className="w-4 h-4" />}
                onClick={logout}
              >
                Logout
              </Button>
            </div>
          </div>
        </div>
      </header>

      {/* Welcome Message */}
      {event.welcome_message && (
        <div className="container mt-6">
          <div className="bg-primary-50 border border-primary-200 rounded-lg p-4">
            <p className="text-primary-900">{event.welcome_message}</p>
          </div>
        </div>
      )}

      {/* Search and Filters */}
      <div className="container mt-6">
        <div className="flex flex-col lg:flex-row gap-4 mb-6">
          {/* Search Bar */}
          <div className="flex-1">
            <Input
              type="text"
              placeholder="Search photos by filename..."
              leftIcon={<Search className="w-5 h-5 text-neutral-400" />}
              value={searchTerm}
              onChange={(e) => setSearchTerm(e.target.value)}
            />
          </div>
          
          {/* Sort Dropdown */}
          <div className="relative">
            <Button
              variant="outline"
              size="md"
              leftIcon={<SortAsc className="w-4 h-4" />}
              onClick={() => setShowSortMenu(!showSortMenu)}
            >
              Sort by {sortBy === 'date' ? 'Date' : sortBy === 'name' ? 'Name' : 'Size'}
            </Button>
            
            {showSortMenu && (
              <div className="absolute right-0 mt-2 w-48 bg-white rounded-lg shadow-lg border border-neutral-200 py-1 z-10">
                <button
                  onClick={() => {
                    setSortBy('date');
                    setShowSortMenu(false);
                  }}
                  className={`w-full text-left px-4 py-2 text-sm hover:bg-neutral-50 ${sortBy === 'date' ? 'text-primary-600 bg-primary-50' : 'text-neutral-700'}`}
                >
                  Sort by Date
                </button>
                <button
                  onClick={() => {
                    setSortBy('name');
                    setShowSortMenu(false);
                  }}
                  className={`w-full text-left px-4 py-2 text-sm hover:bg-neutral-50 ${sortBy === 'name' ? 'text-primary-600 bg-primary-50' : 'text-neutral-700'}`}
                >
                  Sort by Name
                </button>
                <button
                  onClick={() => {
                    setSortBy('size');
                    setShowSortMenu(false);
                  }}
                  className={`w-full text-left px-4 py-2 text-sm hover:bg-neutral-50 ${sortBy === 'size' ? 'text-primary-600 bg-primary-50' : 'text-neutral-700'}`}
                >
                  Sort by Size
                </button>
              </div>
            )}
          </div>
        </div>

        {/* View Mode Toggle */}
        <div className="flex items-center justify-between mb-6">
          <div className="flex items-center gap-2">
            <Button
              variant={viewMode === 'all' ? 'primary' : 'outline'}
              size="sm"
              onClick={() => setViewMode('all')}
              leftIcon={<Grid className="w-4 h-4" />}
            >
              All Photos ({data.photos.length})
            </Button>
            <Button
              variant={viewMode === 'collages' ? 'primary' : 'outline'}
              size="sm"
              onClick={() => setViewMode('collages')}
              leftIcon={<Square className="w-4 h-4" />}
            >
              Collages ({data.photos.filter(p => p.type === 'collage').length})
            </Button>
            <Button
              variant={viewMode === 'individual' ? 'primary' : 'outline'}
              size="sm"
              onClick={() => setViewMode('individual')}
            >
              Individual ({data.photos.filter(p => p.type === 'individual').length})
            </Button>
          </div>

          <p className="text-sm text-neutral-600">
            {filteredPhotos.length} {filteredPhotos.length === 1 ? 'photo' : 'photos'}
          </p>
        </div>

        {/* Photo Grid */}
        <PhotoGrid photos={filteredPhotos} slug={slug} />
      </div>

      {/* Footer */}
      <footer className="mt-12 py-8 border-t border-neutral-200">
        <div className="container text-center">
          {brandingSettings?.support_email && (
            <p className="text-sm text-neutral-600 mb-2">
              Need help? Contact us at{' '}
              <a 
                href={`mailto:${brandingSettings.support_email}`}
                className="text-primary-600 hover:text-primary-700"
              >
                {brandingSettings.support_email}
              </a>
            </p>
          )}
          <p className="text-sm text-neutral-500">
            {brandingSettings?.footer_text || '© 2024 Your Company. All rights reserved.'}
          </p>
          {brandingSettings?.company_name && brandingSettings?.company_tagline && (
            <p className="text-xs text-neutral-400 mt-2">
              {brandingSettings.company_name} - {brandingSettings.company_tagline}
            </p>
          )}
        </div>
      </footer>
    </div>
  );
};