using System.Windows.Controls;

using WPFluent.Controls;

namespace WPFluent;

/// <summary>
/// Represents a contract with the service that creates <see cref="ContentDialog"/>.
/// </summary>
/// <example>
/// <code lang="xml"> &lt;ContentPresenter x:Name="RootContentDialogPresenter" Grid.Row="0" /&gt;</code> <code
/// lang="csharp"> IContentDialogService contentDialogService = new ContentDialogService();
/// contentDialogService.SetContentPresenter(RootContentDialogPresenter);  await _contentDialogService.ShowAsync( new
/// ContentDialog(){ Title = "The cake?", Content = "IS A LIE!", PrimaryButtonText = "Save", SecondaryButtonText =
/// "Don't Save", CloseButtonText = "Cancel" } );</code>
/// </example>
public class ContentDialogService
{
    private ContentPresenter? _dialogHost;

    /// <summary>
    /// 提供对 <see cref="ContentPresenter"/> 的直接访问。
    /// </summary>
    /// <returns>引用当前选定的 <see cref="ContentPresenter"/> 显示 <see cref="ContentDialog"/> 的内容。</returns>
    public ContentPresenter? GetDialogHost() { return _dialogHost; }


    /// <summary>
    /// Sets the <see cref="ContentPresenter"/>
    /// </summary>
    /// <param name="dialogHost">
    /// <see cref="ContentPresenter"/> inside of which the dialogue will be placed. The new <see cref="ContentDialog"/> will
    /// replace the current <see cref="ContentPresenter.Content"/>.
    /// </param>
    public void SetDialogHost(ContentPresenter contentPresenter) { _dialogHost = contentPresenter; }

    /// <summary>
    /// Asynchronously shows the specified dialog.
    /// </summary>
    /// <param name="dialog">The dialog to be displayed.</param>
    /// <param name="cancellationToken">A cancellation token that can be used to cancel the operation.</param>
    /// <returns>A task that represents the asynchronous operation. The task result contains the dialog result.</returns>
    public Task<ContentDialogResult> ShowAsync(ContentDialog dialog, CancellationToken cancellationToken)
    {
        if (_dialogHost == null)
        {
            throw new InvalidOperationException("The DialogHost was never set.");
        }

        if (dialog.DialogHost != null && _dialogHost != dialog.DialogHost)
        {
            throw new InvalidOperationException("The DialogHost is not the same as the one that was previously set.");
        }

        dialog.DialogHost = _dialogHost;

        return dialog.ShowAsync(cancellationToken);
    }
}