using System;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using InABox.Core;
using InABox.Mobile;
using Xamarin.CommunityToolkit.Converters;
using Xamarin.Forms;

namespace PRS.Mobile
{
    public abstract class DigitalFormEmbeddedMedia<T, TProperties> : Grid, IDigitalFormField<T,TProperties, DFLayoutEmbeddedMediaValue> 
        where T : DFLayoutField<TProperties>, new()
        where TProperties : DFLayoutFieldProperties<DFLayoutEmbeddedMediaValue>, new()
    {

        protected abstract bool IsVideo { get; }
        private readonly MobileCard _card;
        private readonly Image _image;
        private readonly MobileButton _cameraButton;
        private readonly MobileButton _libraryButton;
        private readonly MobileButton _clearButton;

        private T _definition;
        public T Definition
        {
            get => _definition;
            set
            {
                _definition = value;
                Initialize(value ?? new T());
            }
        }
        
        private DFLayoutEmbeddedMediaValue _value = new();
        public DFLayoutEmbeddedMediaValue Value
        {
            get => _value;
            set
            {
                _value = value;
                UpdateUI();
            }
        }

        protected abstract byte[] CreateThumbnail(byte[] data, float maxwidth = 200, float maxheight = 200);

        private void UpdateUI()
        {
            if ((_value?.Thumbnail?.Any() != true) && (_value?.Data?.Any() == true))
                _value.Thumbnail = CreateThumbnail(_value.Data);

            _image.Source = _value?.Thumbnail?.Any() == true 
                ? ImageSource.FromStream(() => new MemoryStream(_value.Thumbnail))
                : null;
        }

        public bool IsEmpty => Value.Data?.Any() != true;

        private bool _readOnly;
        
        public bool ReadOnly
        {
            get => _readOnly;
            set
            {
                _readOnly = value;
                UpdateStatus();
            }
        }
        
        public void Deserialize(string serialized)
        {
            _value.Load(serialized);
            UpdateUI();
        }

        public string Serialize()
        {
            if (_value == null)
                return new DFLayoutEmbeddedMediaValue().ToString();
            if ((_value.Data?.Any() == true) && (_value.ID == Guid.Empty))
                _value.ID = DigitalFormDocumentFactory.SaveDocument(_value.Data);
            return _value?.ToString() ?? "";
        }

        public event DigitalFormViewChangedHandler ValueChanged;

        protected DigitalFormEmbeddedMedia()
        {

            HeightRequest = 250;

            
            ColumnDefinitions.Add(new ColumnDefinition { Width = new GridLength(1, GridUnitType.Star) });
            ColumnDefinitions.Add(new ColumnDefinition { Width = new GridLength(1, GridUnitType.Auto) });
            
            RowDefinitions.Add(new RowDefinition() { Height = new GridLength(1, GridUnitType.Auto) });
            RowDefinitions.Add(new RowDefinition() { Height = new GridLength(1, GridUnitType.Auto) });
            RowDefinitions.Add(new RowDefinition() { Height = new GridLength(1, GridUnitType.Star) });
            RowDefinitions.Add(new RowDefinition() { Height = new GridLength(1, GridUnitType.Auto) });

            _card = new MobileCard()
            {
                Padding = 5,
                IsClickable = true,
            };
            _card.Clicked += ((o,e) => Image_Tapped());
            SetRow(_card, 0);
            SetColumn(_card, 0);
            SetRowSpan(_card, 4);
            Children.Add(_card);
            
            _image = new Image()
            {
                Aspect = Aspect.AspectFit
            };
            _image.GestureRecognizers.Add(new TapGestureRecognizer() { Command = new Command(Image_Tapped) });
            _card.Content = _image;
            
            _cameraButton = new MobileButton
            {
                Image = "camera",
                ImageSize = new Size(25, 25),
                Orientation = StackOrientation.Vertical,
                CornerRadius = 5,
                WidthRequest = 40,
                HeightRequest = 40,
            };
            SetRow(_cameraButton, 0);
            SetColumn(_cameraButton, 1);
            _cameraButton.Clicked += CameraButton_Clicked;
            Children.Add(_cameraButton);
            
            _libraryButton = new MobileButton
            {
                Image = "gallery",
                ImageSize = new Size(25, 25),
                Orientation = StackOrientation.Vertical,
                CornerRadius = 5,
                WidthRequest = 40,
                HeightRequest = 40,
            };
            SetRow(_libraryButton, 1);
            SetColumn(_libraryButton, 1);
            _libraryButton.Clicked += LibraryButton_Clicked;
            Children.Add(_libraryButton);
            
            _clearButton = new MobileButton
            {
                Image = "cross",
                ImageSize = new Size(25, 25),
                Orientation = StackOrientation.Vertical,
                CornerRadius = 5,
                WidthRequest = 40,
                HeightRequest = 40,
            };
            SetRow(_clearButton, 3);
            SetColumn(_clearButton, 1);
            _clearButton.Clicked += ClearButton_Clicked;
            Children.Add(_clearButton);

        }

        private void Image_Tapped()
        {
            if (_value == null)
                return;
            
            if (_value.Data?.Any() == true)
                Navigation.PushAsync(new ImageViewerPage(_value.Data));
            else
            {
                if (_value.ID != Guid.Empty)
                {
                    DigitalFormDocumentFactory.LoadDocument(
                        _value.ID,
                        data =>
                        {
                            Device.BeginInvokeOnMainThread(() =>
                            {
                                _value.Data = data;
                                Navigation.PushAsync(new ImageViewerPage(data)); 
                            });
                        }
                    );
                }
            }
        }

        private void ClearButton_Clicked(object sender, MobileButtonClickEventArgs args)
        {
            _value.ID = Guid.Empty;
            _value.Thumbnail = null;
            _value.Data = null;
            UpdateUI();
        }

        protected abstract Task<MobileDocument> CaptureMedia();
        
        protected abstract Task<MobileDocument> SelectMedia();

        private async void CameraButton_Clicked(object sender, MobileButtonClickEventArgs args)
        {
            var doc = await CaptureMedia();
            if (doc != null)
            {
                _value.ID = Guid.Empty;
                _value.Thumbnail = CreateThumbnail(doc.Data);
                _value.Data = doc.Data;
            }
            Device.BeginInvokeOnMainThread(UpdateUI);
        }

        private async void LibraryButton_Clicked(object sender, MobileButtonClickEventArgs args)
        {
            var doc = await SelectMedia();
            if (doc != null)
            {
                _value.ID = Guid.Empty;
                _value.Thumbnail = CreateThumbnail(doc.Data);
                _value.Data = doc.Data;
            }
            Device.BeginInvokeOnMainThread(UpdateUI);
        }

        private void Initialize(T definition)
        {
            UpdateStatus();
        }

        protected abstract bool DisableLibrary { get; }
        protected abstract bool Secure { get; }
        protected abstract bool Required { get; }
        
        private void UpdateStatus()
        {
            _cameraButton.Image = IsVideo ? ImageSource.FromFile("camcorder") : ImageSource.FromFile("camera");
            _libraryButton.Image = IsVideo ? ImageSource.FromFile("videolibrary") : ImageSource.FromFile("photolibrary");
            
            _libraryButton.IsEnabled = !DisableLibrary;
            
            bool enabled = !_readOnly && !Secure;
            _cameraButton.IsEnabled = enabled;
            _libraryButton.IsEnabled = enabled && !DisableLibrary;
            
            var colors = DigitalFormUtils.GetColors(!enabled, Required, false);
            _card.BackgroundColor = colors.Background;
            _card.BorderColor = colors.Border;
            
            colors = DigitalFormUtils.GetColors(!enabled, Required, true);
            _cameraButton.BackgroundColor = colors.Background;
            _cameraButton.BorderColor = colors.Border;
            
            _libraryButton.BackgroundColor = colors.Background;
            _libraryButton.BorderColor = colors.Border;
            
            _clearButton.BackgroundColor = colors.Background;
            _clearButton.BorderColor = colors.Border;
            
        }
        
    }
}