using MaddoShared;
using Microsoft.Extensions.Logging;

namespace CatalogLite;

public sealed class LiteCatalogViewModel : ViewModelBase
{
    private readonly CatalogConfigurationLoader _configurationLoader;
    private readonly PicSettings _picSettings;
    private readonly ImageCreationService _imageCreationService;
    private readonly ImageProcessingCoordinator _imageProcessingCoordinator;
    private readonly ILogger<LiteCatalogViewModel> _logger;
    private CatalogLiteConfiguration? _configuration;
    private CancellationTokenSource? _processingTokenSource;
    private string _configurationPath = string.Empty;
    private string _sourcePath = string.Empty;
    private string _destinationPath = string.Empty;
    private string _processingStatus = "Carica una configurazione XML.";
    private string _speedCounter = "-";
    private int _processedImagesCount;
    private int _totalImagesCount;
    private int _progressBarValue;
    private int _progressBarMaximum = 100;
    private bool _isProcessing;

    public LiteCatalogViewModel(
        CatalogConfigurationLoader configurationLoader,
        PicSettings picSettings,
        ImageCreationService imageCreationService,
        ImageProcessingCoordinator imageProcessingCoordinator,
        ILogger<LiteCatalogViewModel> logger)
    {
        _configurationLoader = configurationLoader;
        _picSettings = picSettings;
        _imageCreationService = imageCreationService;
        _imageProcessingCoordinator = imageProcessingCoordinator;
        _logger = logger;

        LoadConfigurationCommand = new AsyncCommand(RequestLoadConfigurationAsync, () => !IsProcessing);
        SelectSourceFolderCommand = new AsyncCommand(RequestSourceFolderAsync, () => !IsProcessing);
        SelectDestinationFolderCommand = new AsyncCommand(RequestDestinationFolderAsync, () => !IsProcessing);
        StartProcessingCommand = new AsyncCommand(StartProcessingAsync, CanStartProcessing);
        StopProcessingCommand = new AsyncCommand(StopProcessingAsync, () => IsProcessing);
    }

    public event EventHandler? LoadConfigurationRequested;
    public event EventHandler? SelectSourceFolderRequested;
    public event EventHandler? SelectDestinationFolderRequested;
    public event EventHandler<LiteMessageEventArgs>? ShowMessageRequested;

    public Action<Action>? UiInvoker { get; set; }

    public AsyncCommand LoadConfigurationCommand { get; }
    public AsyncCommand SelectSourceFolderCommand { get; }
    public AsyncCommand SelectDestinationFolderCommand { get; }
    public AsyncCommand StartProcessingCommand { get; }
    public AsyncCommand StopProcessingCommand { get; }

    public string ConfigurationPath
    {
        get => _configurationPath;
        private set
        {
            _configurationPath = value;
            NotifyPropertyChanged();
        }
    }

    public string SourcePath
    {
        get => _sourcePath;
        set
        {
            _sourcePath = NormalizeDirectoryPath(value);
            NotifyPropertyChanged();
            RaiseCommandStates();
        }
    }

    public string DestinationPath
    {
        get => _destinationPath;
        set
        {
            _destinationPath = NormalizeDirectoryPath(value);
            NotifyPropertyChanged();
            RaiseCommandStates();
        }
    }

    public string ProcessingStatus
    {
        get => _processingStatus;
        private set
        {
            _processingStatus = value;
            NotifyPropertyChanged();
        }
    }

    public string SpeedCounter
    {
        get => _speedCounter;
        private set
        {
            _speedCounter = value;
            NotifyPropertyChanged();
        }
    }

    public int ProcessedImagesCount
    {
        get => _processedImagesCount;
        private set
        {
            _processedImagesCount = value;
            NotifyPropertyChanged();
        }
    }

    public int TotalImagesCount
    {
        get => _totalImagesCount;
        private set
        {
            _totalImagesCount = value;
            NotifyPropertyChanged();
        }
    }

    public int ProgressBarValue
    {
        get => _progressBarValue;
        private set
        {
            _progressBarValue = value;
            NotifyPropertyChanged();
        }
    }

    public int ProgressBarMaximum
    {
        get => _progressBarMaximum;
        private set
        {
            _progressBarMaximum = Math.Max(1, value);
            NotifyPropertyChanged();
        }
    }

    public bool IsProcessing
    {
        get => _isProcessing;
        private set
        {
            _isProcessing = value;
            NotifyPropertyChanged();
            RaiseCommandStates();
        }
    }

    public async Task LoadConfigurationFromFileAsync(string filePath)
    {
        try
        {
            var configuration = await Task.Run(() => _configurationLoader.Load(filePath, _picSettings)).ConfigureAwait(false);

            RunOnUiThread(() =>
            {
                _configuration = configuration;
                ConfigurationPath = configuration.FilePath;
                SourcePath = configuration.SourcePath;
                DestinationPath = configuration.DestinationPath;
                ResetProgress("Configurazione caricata.");
            });
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Errore durante il caricamento della configurazione");
            ShowMessage("Configurazione", $"Impossibile caricare la configurazione: {ex.GetBaseException().Message}");
        }
    }

    public static string NormalizeDirectoryPath(string? path)
    {
        if (string.IsNullOrWhiteSpace(path))
        {
            return string.Empty;
        }

        var trimmed = path.Trim().TrimEnd(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar);
        return trimmed + Path.DirectorySeparatorChar;
    }

    private Task RequestLoadConfigurationAsync()
    {
        LoadConfigurationRequested?.Invoke(this, EventArgs.Empty);
        return Task.CompletedTask;
    }

    private Task RequestSourceFolderAsync()
    {
        SelectSourceFolderRequested?.Invoke(this, EventArgs.Empty);
        return Task.CompletedTask;
    }

    private Task RequestDestinationFolderAsync()
    {
        SelectDestinationFolderRequested?.Invoke(this, EventArgs.Empty);
        return Task.CompletedTask;
    }

    private bool CanStartProcessing()
    {
        return !IsProcessing
            && _configuration is not null
            && !string.IsNullOrWhiteSpace(SourcePath)
            && !string.IsNullOrWhiteSpace(DestinationPath);
    }

    private async Task StartProcessingAsync()
    {
        if (_configuration is null)
        {
            ShowMessage("Configurazione", "Carica prima una configurazione XML.");
            return;
        }

        if (!Directory.Exists(SourcePath))
        {
            ShowMessage("Sorgente", "La cartella sorgente non esiste.");
            return;
        }

        try
        {
            Directory.CreateDirectory(DestinationPath);
        }
        catch (Exception ex)
        {
            ShowMessage("Destinazione", $"Impossibile usare la cartella destinazione: {ex.GetBaseException().Message}");
            return;
        }

        _processingTokenSource?.Dispose();
        _processingTokenSource = new CancellationTokenSource();
        var token = _processingTokenSource.Token;

        var options = CatalogConfigurationLoader.CloneOptions(_configuration.Options, SourcePath, DestinationPath);
        _picSettings.DirectorySorgente = SourcePath;
        _picSettings.DirectoryDestinazione = DestinationPath;
        _picSettings.DestDir = new DirectoryInfo(DestinationPath);
        _picSettings.ImageCreatorProvider = "ImageSharp";

        IsProcessing = true;
        ResetProgress("Analisi immagini...");

        try
        {
            var total = await Task.Run(() => _imageCreationService.GetFilesToProcessPublic(options).Count, token).ConfigureAwait(false);
            RunOnUiThread(() =>
            {
                TotalImagesCount = total;
                ProgressBarMaximum = Math.Max(1, total);
                ProcessingStatus = total == 0 ? "Nessuna immagine trovata." : "Elaborazione in corso...";
            });

            if (total == 0)
            {
                return;
            }

            var result = await _imageProcessingCoordinator.RunAsync(
                options,
                token,
                update => RunOnUiThread(() =>
                {
                    ProcessedImagesCount = update.Processed;
                    TotalImagesCount = update.Total;
                    ProgressBarMaximum = update.Total;
                    ProgressBarValue = update.Processed;
                    ProcessingStatus = update.Status;
                }),
                speed => RunOnUiThread(() => SpeedCounter = speed)).ConfigureAwait(false);

            RunOnUiThread(() =>
            {
                SpeedCounter = result.FinalSpeedCounter;
                ProcessingStatus = "Finito.";
            });
        }
        catch (OperationCanceledException)
        {
            RunOnUiThread(() => ProcessingStatus = "Operazione annullata.");
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Errore durante l'elaborazione");
            RunOnUiThread(() => ProcessingStatus = $"Errore: {ex.GetBaseException().Message}");
        }
        finally
        {
            _processingTokenSource?.Dispose();
            _processingTokenSource = null;
            RunOnUiThread(() => IsProcessing = false);
        }
    }

    private Task StopProcessingAsync()
    {
        _processingTokenSource?.Cancel();
        ProcessingStatus = "Arresto in corso...";
        return Task.CompletedTask;
    }

    private void ResetProgress(string status)
    {
        ProcessingStatus = status;
        ProcessedImagesCount = 0;
        TotalImagesCount = 0;
        ProgressBarValue = 0;
        ProgressBarMaximum = 100;
        SpeedCounter = "-";
    }

    private void RunOnUiThread(Action action)
    {
        if (UiInvoker is null)
        {
            action();
            return;
        }

        UiInvoker(action);
    }

    private void ShowMessage(string title, string message)
    {
        RunOnUiThread(() => ShowMessageRequested?.Invoke(this, new LiteMessageEventArgs(title, message)));
    }

    private void RaiseCommandStates()
    {
        LoadConfigurationCommand.RaiseCanExecuteChanged();
        SelectSourceFolderCommand.RaiseCanExecuteChanged();
        SelectDestinationFolderCommand.RaiseCanExecuteChanged();
        StartProcessingCommand.RaiseCanExecuteChanged();
        StopProcessingCommand.RaiseCanExecuteChanged();
    }
}