@namespace LANCommander.UI.Components
@typeparam TItem

<div class="data-list">
    <CascadingValue Value="_radio" Name="Radio">
        <CascadingValue Value="_checkbox" Name="Checkbox">
            <Flex Direction="FlexDirection.Vertical" Gap="Gap">
                @foreach (var item in DataSource)
                {
                    <CascadingValue Value="@(Value?.Equals(item) ?? Values?.Contains(item) ?? false)" Name="Selected">
                        <DataListItem
                            TItem="TItem"
                            Item="item"
                            OnSelectedChanged="(selected) => SelectionChanged(item, selected)"
                            ItemTemplate="ChildContent"/>
                    </CascadingValue>
                }
            </Flex>
        </CascadingValue>
    </CascadingValue>
</div>

@code {
    [Parameter] public IEnumerable<TItem> DataSource { get; set; }
    [Parameter] public TItem Value { get; set; } = default!;
    [Parameter] public EventCallback<TItem> ValueChanged { get; set; }
    [Parameter] public IEnumerable<TItem> Values { get; set; } = null!;
    [Parameter] public EventCallback<IEnumerable<TItem>> ValuesChanged { get; set; }
    [Parameter] public RenderFragment<TItem> ChildContent { get; set; }
    [Parameter] public RenderFragment<TItem> ItemTemplate { get; set; }
    [Parameter] public FlexGap Gap { get; set; } = FlexGap.Middle;

    bool _radio;
    bool _checkbox;

    List<TItem> _selectedValues = new();

    protected override void OnInitialized()
    {
        if (ValueChanged.HasDelegate)
            _radio = true;
        else if (ValuesChanged.HasDelegate)
            _checkbox = true;

        if (ChildContent == null && ItemTemplate != null)
            ChildContent = ItemTemplate;
    }

    async Task SelectionChanged(TItem item, bool selected)
    {
        if (_radio && selected)
        {
            Value = item;

            await ValueChanged.InvokeAsync(Value);
        }
        else if (_checkbox)
        {
            _selectedValues.Remove(item);
            
            if (selected)
                _selectedValues.Add(item);

            Values = _selectedValues;
            
            await ValuesChanged.InvokeAsync(Values);
        }
    }
}