import React, { useState, useEffect, useRef } from 'react';
import { Link } from 'react-router-dom';
import { useAuth } from '../../context/AuthContext';
import api from '../../utils/api';
import { Card } from '../../components/ui/card';
import { Button } from '../../components/ui/button';
import { Input } from '../../components/ui/input';
import { Label } from '../../components/ui/label';
import { Textarea } from '../../components/ui/textarea';
import { Badge } from '../../components/ui/badge';
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from '../../components/ui/select';
import { Dialog, DialogContent, DialogHeader, DialogTitle, DialogFooter } from '../../components/ui/dialog';
import { Upload, Trash2, Edit, X, ImageIcon, Calendar, MapPin, AlertCircle } from 'lucide-react';
import { toast } from 'sonner';
import moment from 'moment';

const AdminGallery = () => {
  const { hasPermission } = useAuth();
  const [events, setEvents] = useState([]);
  const [selectedEvent, setSelectedEvent] = useState(null);
  const [galleryImages, setGalleryImages] = useState([]);
  const [loading, setLoading] = useState(true);
  const [uploading, setUploading] = useState(false);
  const [editingCaption, setEditingCaption] = useState(null);
  const [newCaption, setNewCaption] = useState('');
  const [maxFileSize, setMaxFileSize] = useState(5242880); // Default 5MB
  const fileInputRef = useRef(null);

  useEffect(() => {
    fetchEvents();
    fetchConfigLimits();
  }, []);

  useEffect(() => {
    if (selectedEvent) {
      fetchGallery(selectedEvent);
    }
  }, [selectedEvent]);

  const fetchEvents = async () => {
    try {
      const response = await api.get('/admin/events');
      setEvents(response.data);
    } catch (error) {
      console.error('Failed to fetch events:', error);
      toast.error('Failed to load events');
    } finally {
      setLoading(false);
    }
  };

  const fetchGallery = async (eventId) => {
    try {
      const response = await api.get(`/events/${eventId}/gallery`);
      setGalleryImages(response.data);
    } catch (error) {
      console.error('Failed to fetch gallery:', error);
      toast.error('Failed to load gallery');
    }
  };

  const fetchConfigLimits = async () => {
    try {
      const response = await api.get('/config/limits');
      setMaxFileSize(response.data.max_file_size_bytes);
    } catch (error) {
      console.error('Failed to fetch config limits:', error);
      // Keep default value (5MB) if fetch fails
    }
  };

  const formatFileSize = (bytes) => {
    if (bytes < 1024) return bytes + ' B';
    else if (bytes < 1048576) return (bytes / 1024).toFixed(1) + ' KB';
    else return (bytes / 1048576).toFixed(1) + ' MB';
  };

  const handleFileSelect = async (e) => {
    const files = Array.from(e.target.files);
    if (files.length === 0) return;

    setUploading(true);

    try {
      for (const file of files) {
        const formData = new FormData();
        formData.append('file', file);

        await api.post(`/admin/events/${selectedEvent}/gallery`, formData, {
          headers: {
            'Content-Type': 'multipart/form-data'
          }
        });
      }

      toast.success(`${files.length} ${files.length === 1 ? 'image' : 'images'} uploaded successfully`);
      await fetchGallery(selectedEvent);
    } catch (error) {
      console.error('Failed to upload images:', error);
      toast.error(error.response?.data?.detail || 'Failed to upload images');
    } finally {
      setUploading(false);
      if (fileInputRef.current) {
        fileInputRef.current.value = '';
      }
    }
  };

  const handleDeleteImage = async (imageId) => {
    if (!window.confirm('Are you sure you want to delete this image?')) {
      return;
    }

    try {
      await api.delete(`/admin/event-gallery/${imageId}`);
      toast.success('Image deleted successfully');
      await fetchGallery(selectedEvent);
    } catch (error) {
      console.error('Failed to delete image:', error);
      toast.error('Failed to delete image');
    }
  };

  const handleUpdateCaption = async () => {
    if (!editingCaption) return;

    try {
      await api.put(`/admin/event-gallery/${editingCaption.id}`, null, {
        params: { caption: newCaption }
      });
      toast.success('Caption updated successfully');
      setEditingCaption(null);
      setNewCaption('');
      await fetchGallery(selectedEvent);
    } catch (error) {
      console.error('Failed to update caption:', error);
      toast.error('Failed to update caption');
    }
  };

  const openEditCaption = (image) => {
    setEditingCaption(image);
    setNewCaption(image.caption || '');
  };

  return (
    <div className="space-y-6">
      {/* Header */}
      <div>
        <h1 className="text-3xl font-semibold text-[#422268]" style={{ fontFamily: "'Inter', sans-serif" }}>
          Event Gallery Management
        </h1>
        <p className="text-[#664fa3] mt-2" style={{ fontFamily: "'Nunito Sans', sans-serif" }}>
          Upload and manage photos for event galleries
        </p>
      </div>

      {/* Event Selection */}
      <Card className="p-6 bg-white border-[#ddd8eb] rounded-xl">
        <div className="space-y-4">
          <div>
            <Label className="text-[#422268] mb-2" style={{ fontFamily: "'Nunito Sans', sans-serif" }}>
              Select Event
            </Label>
            <Select value={selectedEvent || ''} onValueChange={setSelectedEvent}>
              <SelectTrigger className="border-[#ddd8eb] rounded-xl">
                <SelectValue placeholder="Choose an event..." />
              </SelectTrigger>
              <SelectContent>
                {events.map((event) => (
                  <SelectItem key={event.id} value={event.id}>
                    {event.title} - {moment(event.start_at).format('MMM D, YYYY')}
                  </SelectItem>
                ))}
              </SelectContent>
            </Select>
          </div>

          {/* Empty State Message */}
          {events.length === 0 && (
            <div className="mt-4 p-4 bg-[#f1eef9] border-2 border-[#DDD8EB] rounded-xl">
              <div className="flex items-start gap-3">
                <AlertCircle className="h-5 w-5 text-[#664fa3] flex-shrink-0 mt-0.5" />
                <div className="flex-1">
                  <h4 className="text-sm font-semibold text-[#422268] mb-1" style={{ fontFamily: "'Inter', sans-serif" }}>
                    No Events Available
                  </h4>
                  <p className="text-sm text-[#664fa3] mb-3" style={{ fontFamily: "'Nunito Sans', sans-serif" }}>
                    You need to create an event before uploading gallery images. Events help organize photos by occasion.
                  </p>
                  <Link to="/admin/events">
                    <Button
                      className="bg-[#664fa3] hover:bg-[#422268] text-white rounded-xl text-sm"
                      style={{ fontFamily: "'Inter', sans-serif" }}
                    >
                      <Calendar className="h-4 w-4 mr-2" />
                      Create Your First Event
                    </Button>
                  </Link>
                </div>
              </div>
            </div>
          )}

          {selectedEvent && hasPermission('gallery.upload') && (
            <div className="pt-4">
              <input
                type="file"
                ref={fileInputRef}
                onChange={handleFileSelect}
                accept="image/*"
                multiple
                className="hidden"
              />
              <Button
                onClick={() => fileInputRef.current?.click()}
                disabled={uploading}
                className="bg-[#664fa3] hover:bg-[#422268] text-white rounded-xl"
                style={{ fontFamily: "'Inter', sans-serif" }}
              >
                {uploading ? (
                  <>
                    <Upload className="h-4 w-4 mr-2 animate-spin" />
                    Uploading...
                  </>
                ) : (
                  <>
                    <Upload className="h-4 w-4 mr-2" />
                    Upload Images
                  </>
                )}
              </Button>
              <p className="text-sm text-[#664fa3] mt-2" style={{ fontFamily: "'Nunito Sans', sans-serif" }}>
                You can select multiple images. Max {formatFileSize(maxFileSize)} per image.
              </p>
            </div>
          )}
        </div>
      </Card>

      {/* Gallery Grid */}
      {selectedEvent && (
        <Card className="p-6 bg-white border-[#ddd8eb] rounded-xl">
          <div className="flex items-center justify-between mb-6">
            <h2 className="text-xl font-semibold text-[#422268]" style={{ fontFamily: "'Inter', sans-serif" }}>
              Gallery Images
            </h2>
            <Badge className="bg-[#664fa3] text-white px-3 py-1">
              {galleryImages.length} {galleryImages.length === 1 ? 'image' : 'images'}
            </Badge>
          </div>

          {galleryImages.length > 0 ? (
            <div className="grid grid-cols-2 md:grid-cols-3 lg:grid-cols-4 gap-4">
              {galleryImages.map((image) => (
                <div key={image.id} className="relative group">
                  <div className="aspect-square rounded-xl overflow-hidden bg-[#F8F7FB]">
                    <img
                      src={image.image_url}
                      alt={image.caption || 'Gallery image'}
                      className="w-full h-full object-cover"
                    />
                  </div>

                  {/* Overlay with Actions */}
                  {(hasPermission('gallery.edit') || hasPermission('gallery.delete')) && (
                    <div className="absolute inset-0 bg-black/60 opacity-0 group-hover:opacity-100 transition-opacity rounded-xl flex flex-col items-center justify-center gap-2">
                      {hasPermission('gallery.edit') && (
                        <Button
                          onClick={() => openEditCaption(image)}
                          size="sm"
                          className="bg-white/90 hover:bg-white text-[#422268] rounded-lg"
                          style={{ fontFamily: "'Inter', sans-serif" }}
                        >
                          <Edit className="h-4 w-4 mr-1" />
                          Caption
                        </Button>
                      )}
                      {hasPermission('gallery.delete') && (
                        <Button
                          onClick={() => handleDeleteImage(image.id)}
                          size="sm"
                          className="bg-red-500 hover:bg-red-600 text-white rounded-lg"
                          style={{ fontFamily: "'Inter', sans-serif" }}
                        >
                          <Trash2 className="h-4 w-4 mr-1" />
                          Delete
                        </Button>
                      )}
                    </div>
                  )}

                  {/* Caption Preview */}
                  {image.caption && (
                    <div className="mt-2">
                      <p className="text-sm text-[#664fa3] line-clamp-2" style={{ fontFamily: "'Nunito Sans', sans-serif" }}>
                        {image.caption}
                      </p>
                    </div>
                  )}

                  {/* File Size */}
                  <div className="mt-1">
                    <p className="text-xs text-[#664fa3]" style={{ fontFamily: "'Nunito Sans', sans-serif" }}>
                      {formatFileSize(image.file_size_bytes)}
                    </p>
                  </div>
                </div>
              ))}
            </div>
          ) : (
            <div className="text-center py-16">
              <ImageIcon className="h-16 w-16 text-[#ddd8eb] mx-auto mb-4" />
              <h3 className="text-lg font-semibold text-[#422268] mb-2" style={{ fontFamily: "'Inter', sans-serif" }}>
                No Images Yet
              </h3>
              <p className="text-[#664fa3]" style={{ fontFamily: "'Nunito Sans', sans-serif" }}>
                Upload images to create a gallery for this event.
              </p>
            </div>
          )}
        </Card>
      )}

      {/* Edit Caption Dialog */}
      <Dialog open={!!editingCaption} onOpenChange={() => setEditingCaption(null)}>
        <DialogContent className="bg-white sm:max-w-[600px]">
          <DialogHeader>
            <DialogTitle className="text-[#422268]" style={{ fontFamily: "'Inter', sans-serif" }}>
              Edit Image Caption
            </DialogTitle>
          </DialogHeader>

          {editingCaption && (
            <div className="space-y-4">
              <div className="aspect-video rounded-xl overflow-hidden bg-[#F8F7FB]">
                <img
                  src={editingCaption.image_url}
                  alt="Preview"
                  className="w-full h-full object-contain"
                />
              </div>

              <div>
                <Label className="text-[#422268]" style={{ fontFamily: "'Nunito Sans', sans-serif" }}>
                  Caption
                </Label>
                <Textarea
                  value={newCaption}
                  onChange={(e) => setNewCaption(e.target.value)}
                  placeholder="Add a caption for this image..."
                  rows={3}
                  className="border-[#ddd8eb] rounded-xl mt-2"
                  style={{ fontFamily: "'Nunito Sans', sans-serif" }}
                />
              </div>
            </div>
          )}

          <DialogFooter>
            <Button
              onClick={() => setEditingCaption(null)}
              variant="outline"
              className="border-[#ddd8eb] text-[#664fa3] rounded-xl"
              style={{ fontFamily: "'Inter', sans-serif" }}
            >
              Cancel
            </Button>
            <Button
              onClick={handleUpdateCaption}
              className="bg-[#664fa3] hover:bg-[#422268] text-white rounded-xl"
              style={{ fontFamily: "'Inter', sans-serif" }}
            >
              Save Caption
            </Button>
          </DialogFooter>
        </DialogContent>
      </Dialog>
    </div>
  );
};

export default AdminGallery;