using System.ComponentModel;
using System.Runtime.CompilerServices;
using GifResizer.Models;
using GifResizer.Service;

namespace GifResizer.ViewModels;

public sealed class MainViewModel : INotifyPropertyChanged
{
    private readonly GifService _gifService;
    public event PropertyChangedEventHandler? PropertyChanged;
    
    public MainViewModel(GifService service)
    {
        _gifService = service;
        CommonFormats = [
            new Format(112, 112), 
            new Format(500, 500), 
            new Format(1000, 1000)
        ];
        FilePath = null;
    }
    
    public string? FilePath
    {
        get;
        set => SetField(ref field, value);
    }
    
    public int? GifWidth
    {
        get;
        set => SetField(ref field, value);
    }    
    
    public int? GifHeight
    {
        get;
        set => SetField(ref field, value);
    }

    public List<Format> CommonFormats { get; }

    public void LoadGifData(string filePath)
    {
        GifData data = _gifService.GetData(filePath);
        FilePath = filePath;
        GifWidth = data.Width;
        GifHeight = data.Height;
    }
    
    public void ResizeGif()
    {
        if(FilePath == null && GifWidth == null && GifHeight == null) return;
        _gifService.ResizeGif(FilePath!, GifWidth!.Value, GifHeight!.Value);
        CommonFormats
            .Where(f => f.Checked)
            .ToList()
            .ForEach(f => _gifService.ResizeGif(FilePath!, f.Width, f.Height));
    }
    
    private bool SetField<T>(ref T field, T value, [CallerMemberName] string? propertyName = null)
    {
        if (EqualityComparer<T>.Default.Equals(field, value)) return false;
        field = value;
        OnPropertyChanged(propertyName);
        return true;
    }

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