using AvParser.Core.Collecting;
using AvParser.Infrastructure.Storage;
using AvParser.UI.Navigation;
using Microsoft.Extensions.DependencyInjection;
using ReactiveUI;
using ReactiveUI.Primitives;

namespace AvParser.UI.ViewModels;

/// <summary>Landing page: what is registered, where data lives, and shortcuts into the app.</summary>
public sealed class DashboardViewModel : PageViewModel
{
    private readonly IServiceProvider _services;

    /// <summary>Creates the dashboard.</summary>
    /// <param name="catalog">Registered media sources, shown as cards.</param>
    /// <param name="paths">Where the app writes settings and logs.</param>
    /// <param name="services">
    /// Used to resolve <see cref="INavigationService"/> at click time rather than at construction
    /// time. Injecting it directly would be a cycle: the navigation service is built from every
    /// page, so a page cannot also depend on it up front.
    /// </param>
    public DashboardViewModel(IMediaSourceCatalog catalog, IAppPaths paths, IServiceProvider services)
    {
        ArgumentNullException.ThrowIfNull(catalog);
        ArgumentNullException.ThrowIfNull(paths);

        _services = services ?? throw new ArgumentNullException(nameof(services));

        Sources = [.. catalog.Sources.Select(source => new MediaSourceViewModel(source))];
        DataDirectory = paths.DataDirectory;
        MediaDirectory = paths.MediaDirectory;

        GoToCollectCommand = ReactiveCommand.Create(() => Navigate<CollectViewModel>());
        GoToSettingsCommand = ReactiveCommand.Create(() => Navigate<SettingsViewModel>());
    }

    /// <inheritdoc />
    public override string TitleKey => "Page.Dashboard";

    /// <inheritdoc />
    public override string IconKey => "IconHome";

    /// <summary>Registered media sources, shown as cards.</summary>
    public IReadOnlyList<MediaSourceViewModel> Sources { get; }

    /// <summary>Where settings and logs are written.</summary>
    public string DataDirectory { get; }

    /// <summary>Where collected media is written.</summary>
    public string MediaDirectory { get; }

    /// <summary>Jumps to the Collect page.</summary>
    public ReactiveCommand<RxVoid, RxVoid> GoToCollectCommand { get; }

    /// <summary>Jumps to the Settings page.</summary>
    public ReactiveCommand<RxVoid, RxVoid> GoToSettingsCommand { get; }

    private void Navigate<TPage>()
        where TPage : PageViewModel => _services.GetRequiredService<INavigationService>().NavigateTo<TPage>();
}