using System;
using System.Linq;
using System.Net.Http;
using System.Reactive;
using System.Reactive.Disposables;
using System.Reactive.Linq;
using System.Threading;
using System.Threading.Tasks;
using Avalonia.Media;
using Avalonia.Threading;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using ReactiveUI;
using ReactiveUI.Fody.Helpers;
using Wabbajack.App.Messages;
using Wabbajack.App.ViewModels.SubViewModels;
using Wabbajack.Common;
using Wabbajack.DTOs;
using Wabbajack.DTOs.DownloadStates;
using Wabbajack.DTOs.JsonConverters;
using Wabbajack.Installer;
using Wabbajack.RateLimiter;

namespace Wabbajack.App.ViewModels
{
    public class StandardInstallationViewModel : ViewModelBase, IReceiver<StartInstallation>
    {
        private readonly IServiceProvider _provider;
        private readonly GameLocator _locator;
        private IServiceScope _scope;
        private InstallerConfiguration _config;
        private StandardInstaller _installer;
        private readonly ILogger<StandardInstallationViewModel> _logger;
        private readonly DTOSerializer _dtos;
        private SlideViewModel[] _slides = Array.Empty<SlideViewModel>();
        private readonly HttpClient _httpClient;
        private Timer _slideTimer;
        private int _currentSlideIndex;

        [Reactive]
        public SlideViewModel Slide { get; set; }
        
        [Reactive]
        public ReactiveCommand<Unit,Unit> NextCommand { get; set; }
        
        [Reactive]
        public ReactiveCommand<Unit, Unit> PrevCommand { get; set; }
        
        [Reactive]
        public ReactiveCommand<Unit, bool> PauseCommand { get; set; }
        
        [Reactive]
        public ReactiveCommand<Unit, bool> PlayCommand { get; set; }

        [Reactive] public bool IsPlaying { get; set; } = true;

        [Reactive] public string StatusText { get; set; } = "";
        [Reactive] public Percent StepsProgress { get; set; } = Percent.Zero;
        [Reactive] public Percent StepProgress { get; set; } = Percent.Zero;

        public StandardInstallationViewModel(ILogger<StandardInstallationViewModel> logger, IServiceProvider provider, GameLocator locator, DTOSerializer dtos, HttpClient httpClient)
        {
            _provider = provider;
            _locator = locator;
            _logger = logger;
            _dtos = dtos;
            _httpClient = httpClient;
            Activator = new ViewModelActivator();

            this.WhenActivated(disposables => {
                _slideTimer = new Timer(_ =>
                {
                    if (IsPlaying) NextSlide(1);
                }, null, TimeSpan.FromSeconds(0.1), TimeSpan.FromSeconds(5));
                
                _currentSlideIndex = 0;
                _slideTimer.DisposeWith(disposables);

                NextCommand = ReactiveCommand.Create(() => NextSlide(1))
                    .DisposeWith(disposables);
                PrevCommand = ReactiveCommand.Create(() => NextSlide(-1))
                    .DisposeWith(disposables);
                PauseCommand = ReactiveCommand.Create(() => IsPlaying = false,
                        this.ObservableForProperty(vm => vm.IsPlaying, skipInitial:false)
                            .Select(v => v.Value))
                    .DisposeWith(disposables);
                
                PlayCommand = ReactiveCommand.Create(() => IsPlaying = true,
                        this.ObservableForProperty(vm => vm.IsPlaying, skipInitial:false)
                            .Select(v => !v.Value))
                    .DisposeWith(disposables);
            });
        }




        private void NextSlide(int direction)
        {
            if (_slides.Length == 0) return;
            _currentSlideIndex = InSlideRange(_currentSlideIndex + direction);
            
            var thisSlide = _slides[_currentSlideIndex];
            
            if (thisSlide.Image == null)
                thisSlide.PreCache(_httpClient).FireAndForget();
            
            // Cache the next image
            _slides[InSlideRange(_currentSlideIndex + 1)].PreCache(_httpClient).FireAndForget();

            var prevSlide = _slides[InSlideRange(_currentSlideIndex - 2)];
            if (prevSlide.Image != null)
                prevSlide.Image = null;

            Dispatcher.UIThread.InvokeAsync(() =>
            {
                Slide = thisSlide;
            });
        }

        private int InSlideRange(int i)
        {
            while (!(i >= 0 && i <= _slides.Length))
            {
                if (i >= _slides.Length) i -= _slides.Length;
                if (i < 0) i += _slides.Length;
            }

            return i;
        }

        public void Receive(StartInstallation msg)
        {
            
            Install(msg).FireAndForget();
        }

        private async Task Install(StartInstallation msg)
        {
            _scope = _provider.CreateScope();
            _config = _provider.GetService<InstallerConfiguration>()!;
            _config.Downloads = msg.Download;
            _config.Install = msg.Install;
            _config.ModlistArchive = msg.ModListPath;

            _logger.LogInformation("Loading ModList Data");
            _config.ModList = await StandardInstaller.LoadFromFile(_dtos, msg.ModListPath);
            _config.Game = _config.ModList.GameType;

            _slides = _config.ModList.Archives.Select(a => a.State).OfType<IMetaState>()
                .Select(m => new SlideViewModel { MetaState = m })
                .Shuffle()
                .ToArray();

            _slides[1].PreCache(_httpClient).FireAndForget();
            Slide = _slides[1];
            
            if (_config.GameFolder == default)
            {
                if (!_locator.TryFindLocation(_config.Game, out var found))
                {
                    _logger.LogCritical("Game {game} is not installed on this system",
                        _config.Game.MetaData().HumanFriendlyGameName);
                    throw new Exception("Game not found");
                }

                _config.GameFolder = found;
            }

            _installer = _provider.GetService<StandardInstaller>()!;
            
            _installer.OnStatusUpdate += (_, update) =>
            {
                Dispatcher.UIThread.InvokeAsync(() =>
                {
                    StatusText = update.StatusText;
                    StepsProgress = update.StepsProgress;
                    StepProgress = update.StepProgress;
                });
            };
            
            _logger.LogInformation("Installer created, starting the installation process");
            await _installer.Begin(CancellationToken.None);
        }
    }
}