using System;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Windows;
using System.Windows.Input;

namespace EmbyToolbox.ViewModels;

/// <summary>Компактный индикатор прогресса ffprobe-анализа батча файлов.</summary>
public sealed class AnalysisProgressViewModel : INotifyPropertyChanged
{
    private readonly Action _onCancel;

    private bool _isPanelVisible;
    private string _statusLine = string.Empty;
    private double _analysisPercent;
    private bool _canCancel = true;

    public AnalysisProgressViewModel(Action onCancel)
    {
        _onCancel = onCancel;
        CancelCommand = new RelayCommand(ExecuteCancel, () => _canCancel && _isPanelVisible);
    }

    public ICommand CancelCommand { get; }

    public bool IsPanelVisible
    {
        get => _isPanelVisible;
        private set
        {
            if (_isPanelVisible == value)
            {
                return;
            }

            _isPanelVisible = value;
            OnPropertyChanged();
            OnPropertyChanged(nameof(PanelVisibility));
            if (CancelCommand is RelayCommand rc)
            {
                rc.RaiseCanExecuteChanged();
            }
        }
    }

    public Visibility PanelVisibility => _isPanelVisible ? Visibility.Visible : Visibility.Collapsed;

    public string StatusLine
    {
        get => _statusLine;
        private set
        {
            if (_statusLine == value)
            {
                return;
            }

            _statusLine = value;
            OnPropertyChanged();
        }
    }

    public double AnalysisPercent
    {
        get => _analysisPercent;
        private set
        {
            if (Math.Abs(_analysisPercent - value) < 0.01)
            {
                return;
            }

            _analysisPercent = value;
            OnPropertyChanged();
        }
    }

    public void StartBatch(int total)
    {
        _canCancel = true;
        IsPanelVisible = true;
        StatusLine = total > 0 ? $"Анализ файлов: 0 из {total}" : "Анализ файлов";
        AnalysisPercent = 0;
        if (CancelCommand is RelayCommand rc)
        {
            rc.RaiseCanExecuteChanged();
        }
    }

    public void OnProgress(EmbyToolbox.Services.QueueAnalysisProgress p)
    {
        if (p.Total <= 0)
        {
            return;
        }

        StatusLine = $"Анализ файлов: {p.Processed} из {p.Total}";
        AnalysisPercent = 100.0 * p.Processed / p.Total;
    }

    public async Task FinalizeAndHideAsync(int errorCount)
    {
        _canCancel = false;
        if (CancelCommand is RelayCommand rc)
        {
            rc.RaiseCanExecuteChanged();
        }

        if (errorCount > 0)
        {
            StatusLine = $"Анализ завершен с ошибками: {errorCount}";
            AnalysisPercent = 100;
            await Task.Delay(2500).ConfigureAwait(true);
        }

        IsPanelVisible = false;
    }

    public event PropertyChangedEventHandler? PropertyChanged;

    private void ExecuteCancel() => _onCancel();

    private void OnPropertyChanged([CallerMemberName] string? propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}