using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using InABox.Core;
using InABox.Mobile;
using Xamarin.Forms;

namespace PRS.Mobile
{
    public class DigitalFormMultiImage : Grid, IDigitalFormField<DFLayoutMultiImage, DFLayoutMultiImageProperties, List<Guid>, DFLayoutEmbeddedMediaValues> 
    {
        private readonly CollectionView _images;
        private readonly MobileCard _frame;
        private readonly MobileButton _camera;
        private readonly MobileButton _library;
        
        private DFLayoutMultiImage? _definition;
        public DFLayoutMultiImage? Definition
        {
            get => _definition;
            set
            {
                _definition = value;
                Initialize(value ?? new DFLayoutMultiImage());
            }
        }
        
        private DFLayoutEmbeddedMediaValues _value = new DFLayoutEmbeddedMediaValues();
        public List<Guid> Value
        {
            get => _value.Values.Select(x=>x.ID).ToList();
            set
            {
                _value.Clear();
                foreach (var val in value)
                    _value.Add(new DFLayoutEmbeddedMediaValue() { ID = val });
                DoUpdateUI();
            }
        }
        
        public bool IsEmpty => Value?.Any() != true;

        private void DoUpdateUI()
        {
            _images.ItemsSource = null;
            _images.ItemsSource = _value.ToArray();
        }

        private bool _readOnly;
        public bool ReadOnly
        {
            get => _readOnly;
            set
            {
                _readOnly = value;
                UpdateStatus();
            }
        }
        
        public void Deserialize(DFLoadStorageEntry entry)
        {
            _value = Definition?.Properties.DeserializeValue(entry) ?? new DFLayoutEmbeddedMediaValues();
            foreach (var val in _value)
            {
                if ((val.Thumbnail?.Any() != true) && (val.Data?.Any() == true))
                    val.Thumbnail = MobileUtils.ImageTools.CreateThumbnail(val.Data, 256, 256);
            }
            DoUpdateUI();
        }

        public void Serialize(DFSaveStorageEntry entry)
        {
            foreach (var val in _value)
            {
                if ((val.Data?.Any() == true) && (val.ID == Guid.Empty))
                    val.ID = DigitalFormDocumentFactory.SaveDocument(val.Data);
            }
            Definition?.Properties.SerializeValue(entry,_value);
        }
        
        public event DigitalFormViewChangedHandler ValueChanged;

        public DigitalFormMultiImage()
        {
            _value = new DFLayoutEmbeddedMediaValues();
            _value.PropertyChanged += (sender, args) => DoUpdateUI();
            
            HeightRequest = 200;
            
            ColumnDefinitions.Add(new ColumnDefinition() { Width = GridLength.Star });
            ColumnDefinitions.Add(new ColumnDefinition() { Width = GridLength.Auto });
            
            RowDefinitions.Add(new RowDefinition() { Height = GridLength.Auto });
            RowDefinitions.Add(new RowDefinition() { Height = GridLength.Auto });
            RowDefinitions.Add(new RowDefinition() { Height = GridLength.Star });

            _images = new CollectionView()
            {
                ItemsLayout = new LinearItemsLayout(ItemsLayoutOrientation.Horizontal) { ItemSpacing = 10 },
                ItemSizingStrategy = ItemSizingStrategy.MeasureAllItems,
                // IndicatorView = new IndicatorView() { IndicatorColor = Color.Red, SelectedIndicatorColor = Color.Green, HorizontalOptions = LayoutOptions.Center},
                // PeekAreaInsets = new Thickness(100),
                ItemTemplate = new DataTemplate(() =>
                {
                    var image = new Image()
                    {
                        Aspect = Aspect.AspectFit, 
                        VerticalOptions = LayoutOptions.Fill,
                        HorizontalOptions = LayoutOptions.FillAndExpand,
                        WidthRequest = 200,
                        Margin = new Thickness(10),
                    };
                    image.GestureRecognizers.Add(new TapGestureRecognizer(ImageTapped));
                    image.SetBinding(Image.SourceProperty, new Binding("Thumbnail",BindingMode.Default,new ByteArrayToImageSourceConverter()));
                    var frame = new MobileCard()
                    {
                        BorderColor = Color.White,
                        BackgroundColor = Color.White,
                        CornerRadius = 5,
                        Content = image
                    };
                    return frame;
                }),
                // Loop = false,
                // HorizontalScrollBarVisibility = ScrollBarVisibility.Default
            };
            _images.SelectionChanged += (sender, args) =>
            {

            };
            _frame = new MobileCard()
            {
                Content = _images, 
                Padding = 10
            };
            _frame.SetValue(Grid.RowProperty,0);
            _frame.SetValue(Grid.ColumnProperty,0);
            _frame.SetValue(Grid.RowSpanProperty,3);
            Children.Add(_frame);
            
            _camera = new MobileButton()
            {
                Image = ImageSource.FromFile("camera"),
                Orientation = StackOrientation.Horizontal,
                WidthRequest = 40,
                HeightRequest = 40,
                CornerRadius = 5
            };
            _camera.Clicked += async (sender, args) =>
            {
                var doc = await MobileDocument.From<MobileDocumentCameraSource>(PhotoUtils.CreateCameraOptions());
                if (doc != null)
                {
                    DFLayoutEmbeddedMediaValue val = new DFLayoutEmbeddedMediaValue()
                    {
                        Data = doc.Data,
                        Thumbnail = MobileUtils.ImageTools.CreateThumbnail(doc.Data, 256, 256)
                    };
                    _value.Add(val);
                    Device.BeginInvokeOnMainThread(DoUpdateUI);
                }
            };
            _camera.SetValue(Grid.RowProperty,0);
            _camera.SetValue(Grid.ColumnProperty,1);
            Children.Add(_camera);
            
            _library = new MobileButton()
            {
                Image = ImageSource.FromFile("photolibrary"),
                Orientation = StackOrientation.Horizontal,
                WidthRequest = 40,
                HeightRequest = 40,
                CornerRadius = 5
          
            };
            _library.Clicked += async (sender, args) =>
            {
                var doc = await MobileDocument.From<MobileDocumentPhotoLibrarySource>(PhotoUtils.CreatePhotoLibraryOptions());
                if (doc != null)
                {
                    DFLayoutEmbeddedMediaValue val = new DFLayoutEmbeddedMediaValue()
                    {
                        Data = doc.Data,
                        Thumbnail = MobileUtils.ImageTools.CreateThumbnail(doc.Data, 256, 256)
                    };
                    _value.Add(val);
                    Device.BeginInvokeOnMainThread(DoUpdateUI);
                }
            };
            _library.SetValue(Grid.RowProperty,1);
            _library.SetValue(Grid.ColumnProperty,1);
            Children.Add(_library);
        }

        private void ImageTapped(View arg1, object arg2)
        {
            if ((arg1 as Image)?.BindingContext is DFLayoutEmbeddedMediaValue value)
            {
                if (value.Data?.Any() == true)
                    Navigation.PushAsync(
                        new ImageViewerPage(
                            value.Data, 
                            () =>
                            {
                               _value.Remove(value);
                               DoUpdateUI();
                            }
                        )
                    );
                else
                {
                    if (value.ID != Guid.Empty)
                    {
                        DigitalFormDocumentFactory.LoadDocument(
                            value.ID,
                            data =>
                            {
                                Device.BeginInvokeOnMainThread(() =>
                                {
                                    value.Data = data;
                                    Navigation.PushAsync(
                                        new ImageViewerPage(
                                            data,
                                            () =>
                                            {
                                               _value.Remove(value);
                                               DoUpdateUI();
                                            }
                                        )
                                    ); 
                                });
                            }
                        );
                    }
                }
            }
        }

        private void Initialize(DFLayoutMultiImage value)
        {
            UpdateStatus();
        }
        
        protected bool DisableLibrary => Definition.Properties.DisableLibrary;
        protected bool Secure => Definition.Properties.Secure;
        protected bool Required => Definition.Properties.Required;
        
        private void UpdateStatus()
        {
            bool enabled = !_readOnly && !Secure;
            _camera.IsEnabled = enabled;
            _library.IsEnabled = enabled && !DisableLibrary;
            
            var colors = DigitalFormUtils.GetColors(!enabled, Required, false);
            _frame.BackgroundColor = colors.Background;
            _frame.BorderColor = colors.Border;
            
            colors = DigitalFormUtils.GetColors(!enabled, Required, true);
            _camera.BackgroundColor = colors.Background;
            _camera.BorderColor = colors.Border;
            
            _library.BackgroundColor = colors.Background;
            _library.BorderColor = colors.Border;
        }
    }
}