using BS.Shared;
using BS.Shared.Interface;
using DevExpress.Mvvm;
using DevExpress.XtraPrinting;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace BeWo.ViewModel.Controls.AI
{
	public class AiChatButtonWithHistoryViewModel : AiChatButtonViewModel
	{
		private readonly ITextProvider _provider;
		private readonly string _key;
		private int _currentIndex;

		public List<string> History { get; set; }

		public string CurrentValue
		{
			get => _provider.GetText(_key);
			set => _provider.SetText(_key, value);
		}

		public int CurrentIndex
		{
			get => _currentIndex;
			set { 
				if(SetProperty(ref _currentIndex, value, nameof(CurrentIndex)))
				{
					FirePropertyChanged(nameof(IsUndoButtonVisible));
					FirePropertyChanged(nameof(IsRedoButtonVisible));
				}
			}
		}

		public override bool IsHistoryEnabled => true;
		public override bool IsHistoryVisible => History.Count > 1;

		public bool IsUndoButtonVisible => CurrentIndex > 0;
		public bool IsRedoButtonVisible => CurrentIndex < History.Count - 1;

		public DelegateCommand UndoAiActionCommand { get; protected set; }
		public DelegateCommand RedoAiActionCommand { get; protected set; }

		public AiChatButtonWithHistoryViewModel(AiActionType aiActionType, ITextProvider provider, string key) : base(aiActionType)
		{
			History = new List<string>();
			CurrentIndex = 0;
			AssistentCommands = new List<AiMenuItemTemplate>()
			{
				new AiMenuItemTemplate()
				{
					Command = new DelegateCommand<AiConversationMessageVM>(x => AddValue(x.Message)),
					Icon = null,
					Name = "Anfügen"
				},
				new AiMenuItemTemplate()
				{
					Command = new DelegateCommand<AiConversationMessageVM>(x => ReplaceValue(x.Message)),
					Icon = null,
					Name = "Ersetzen"
				},
			};
			UndoAiActionCommand = new DelegateCommand(UndoAiAction);
			RedoAiActionCommand = new DelegateCommand(RedoAiAction);

			_provider = provider;
			_key = key;
		}

		public override bool CanSendNewMessage => base.CanSendNewMessage && !string.IsNullOrEmpty(CurrentValue);

		public void ClearHistory()
		{
			History.Clear();
			History.Add(CurrentValue);
			CurrentIndex = 0;

			FirePropertyChanged(nameof(IsHistoryVisible));
		}

		public void UndoAiAction()
		{
			if (CurrentIndex <= 0)
				return;

			CurrentIndex--;
			CurrentValue = History[CurrentIndex];
		}

		public void RedoAiAction()
		{
			if (CurrentIndex >= History.Count - 1)
				return;

			CurrentIndex++;
			CurrentValue = History[CurrentIndex];
		}

		public void AddValue(string s)
		{
			var sb = new StringBuilder();
			sb.AppendLine("Antwort:");
			sb.AppendLine(s);

			sb.AppendLine();
			sb.AppendLine("Original:");
			sb.AppendLine(CurrentValue);
			
			var str = sb.ToString();

			accept(str);
		}

		public void ReplaceValue(string str)
		{
			accept(str);
		}

		private void accept(string str)
		{
			var idx = CurrentIndex;
			var count = History.Count;

			var last_idx = count - 1;

			if (last_idx > idx)
			{
				History.RemoveRange(idx + 1, last_idx - idx);
			}

			if (History.Count == 0)
			{
				History.Add(CurrentValue);
			}
			else if (CurrentValue != History[CurrentIndex])
			{
				History.Add(CurrentValue);
				CurrentIndex++;
			}

			History.Add(str);
			CurrentIndex++;

			CurrentValue = str;

			FirePropertyChanged(nameof(IsHistoryVisible));
		}
	}
}