ShrlAlgoToolkit/WPFluent/Controls/BreadcrumbBar/BreadcrumbBar.xaml.cs

/* Based on Windows UI Library
   Copyright(c) Microsoft Corporation.All rights reserved. */


using System.Collections.Specialized;

using System.Windows.Controls.Primitives;
using System.Windows.Input;

using WPFluent.Input;


// ReSharper disable once CheckNamespace
namespace WPFluent.Controls;

/// <summary>
/// The <see cref="BreadcrumbBar"/> control provides the direct path of pages or folders to the current location.
/// </summary>
/// <example>
/// <code lang="xml"> /// &lt;ui:BreadcrumbBar x:Name="BreadcrumbBar" /&gt; ///</code>
/// </example>
[StyleTypedProperty(Property = nameof(ItemContainerStyle), StyleTargetType = typeof(BreadcrumbBarItem))]
public class BreadcrumbBar : System.Windows.Controls.ItemsControl
{
    /// <summary>
    /// Identifies the <see cref="Command"/> dependency property.
    /// </summary>
    public static readonly DependencyProperty CommandProperty = DependencyProperty.Register(
        nameof(Command),
        typeof(ICommand),
        typeof(BreadcrumbBar),
        new PropertyMetadata(null));

    /// <summary>
    /// Identifies the <see cref="ItemClicked"/> routed event.
    /// </summary>
    public static readonly RoutedEvent ItemClickedEvent = EventManager.RegisterRoutedEvent(
        nameof(ItemClicked),
        RoutingStrategy.Bubble,
        typeof(TypedEventHandler<BreadcrumbBar, BreadcrumbBarItemClickedEventArgs>),
        typeof(BreadcrumbBar));

    /// <summary>
    /// Identifies the <see cref="TemplateButtonCommand"/> dependency property.
    /// </summary>
    public static readonly DependencyProperty TemplateButtonCommandProperty = DependencyProperty.Register(
        nameof(TemplateButtonCommand),
        typeof(IRelayCommand),
        typeof(BreadcrumbBar),
        new PropertyMetadata(null));

    /// <summary>
    /// Initializes a new instance of the <see cref="BreadcrumbBar"/> class.
    /// </summary>
    public BreadcrumbBar()
    {
        SetValue(TemplateButtonCommandProperty, new RelayCommand<object>(OnTemplateButtonClick));

        Loaded += OnLoaded;
        Unloaded += OnUnloaded;
    }

    /// <summary>
    /// Occurs when an item is clicked in the <see cref="BreadcrumbBar"/>.
    /// </summary>
    public event TypedEventHandler<BreadcrumbBar, BreadcrumbBarItemClickedEventArgs> ItemClicked
    {
        add => AddHandler(ItemClickedEvent, value);
        remove => RemoveHandler(ItemClickedEvent, value);
    }

    private void InteractWithItemContainer(int offsetFromEnd, Action<BreadcrumbBarItem> action)
    {
        if (ItemContainerGenerator.Items.Count <= 0)
        {
            return;
        }

        var item = ItemContainerGenerator.Items[^offsetFromEnd];
        var container = (BreadcrumbBarItem)ItemContainerGenerator.ContainerFromItem(item);

        action.Invoke(container);
    }

    private void ItemContainerGeneratorOnItemsChanged(object sender, ItemsChangedEventArgs e)
    {
        if (e.Action != NotifyCollectionChangedAction.Remove)
        {
            return;
        }

        UpdateLastContainer();
    }

    private void ItemContainerGeneratorOnStatusChanged(object sender, EventArgs e)
    {
        if (ItemContainerGenerator.Status != GeneratorStatus.ContainersGenerated)
        {
            return;
        }

        if (ItemContainerGenerator.Items.Count <= 1)
        {
            UpdateLastContainer();

            return;
        }

        InteractWithItemContainer(2, static item => item.SetCurrentValue(BreadcrumbBarItem.IsLastProperty, false));
        UpdateLastContainer();
    }

    private void OnLoaded(object sender, RoutedEventArgs e)
    {
        ItemContainerGenerator.ItemsChanged += ItemContainerGeneratorOnItemsChanged;
        ItemContainerGenerator.StatusChanged += ItemContainerGeneratorOnStatusChanged;

        UpdateLastContainer();
    }

    private void OnTemplateButtonClick(object obj)
    {
        if (obj is null)
        {
            throw new ArgumentNullException("Item content is null");
        }

        var container = ItemContainerGenerator.ContainerFromItem(obj);
        var index = ItemContainerGenerator.IndexFromContainer(container);

        OnItemClicked(obj, index);
    }

    private void OnUnloaded(object sender, RoutedEventArgs e)
    {
        Loaded -= OnLoaded;
        Unloaded -= OnUnloaded;

        ItemContainerGenerator.ItemsChanged -= ItemContainerGeneratorOnItemsChanged;
        ItemContainerGenerator.StatusChanged -= ItemContainerGeneratorOnStatusChanged;
    }

    private void UpdateLastContainer() => InteractWithItemContainer(
        1,
        static item => item.SetCurrentValue(BreadcrumbBarItem.IsLastProperty, true));

    protected override DependencyObject GetContainerForItemOverride() { return new BreadcrumbBarItem(); }

    protected override bool IsItemItsOwnContainerOverride(object item) { return item is BreadcrumbBarItem; }

    protected virtual void OnItemClicked(object item, int index)
    {
        var args = new BreadcrumbBarItemClickedEventArgs(ItemClickedEvent, this, item, index);
        RaiseEvent(args);

        if (Command?.CanExecute(item) ?? false)
        {
            Command.Execute(item);
        }

        if (Command?.CanExecute(null) ?? false)
        {
            Command.Execute(null);
        }
    }

    /// <summary>
    /// Gets or sets custom command executed after selecting the item.
    /// </summary>
    [Bindable(true)]
    [Category("Action")]
    [Localizability(LocalizationCategory.NeverLocalize)]
    public ICommand Command { get => (ICommand)GetValue(CommandProperty); set => SetValue(CommandProperty, value); }

    /// <summary>
    /// Gets the <see cref="RelayCommand{T}"/> triggered after clicking
    /// </summary>
    public IRelayCommand TemplateButtonCommand => (IRelayCommand)GetValue(TemplateButtonCommandProperty);
}