KoogleApp/src/Koogle.Web/Components/Game/ParticipantSelector.razor

@using Koogle.Application.DTOs
@using Koogle.Domain.Enums
@using MudBlazor

<MudPaper Class="pa-4" Elevation="0">
    <MudStack Row="true" Justify="Justify.SpaceBetween" AlignItems="AlignItems.Center" Class="mb-3">
        <MudText Typo="Typo.subtitle1">Teilnehmer auswählen</MudText>
        <MudStack Row="true" Spacing="1">
            <MudButton Size="Size.Small"
                       Variant="Variant.Text"
                       OnClick="SelectAll"
                       Disabled="@(_availableParticipants.Count == 0)">
                Alle
            </MudButton>
            <MudButton Size="Size.Small"
                       Variant="Variant.Text"
                       OnClick="SelectNone"
                       Disabled="@(_selectedIds.Count == 0)">
                Keine
            </MudButton>
        </MudStack>
    </MudStack>

    @if (_availableParticipants.Count == 0)
    {
        <MudAlert Severity="Severity.Info" Dense="true">
            Keine Teilnehmer verfügbar. Füge zuerst Teilnehmer zum Spieltag hinzu.
        </MudAlert>
    }
    else
    {
        <MudGrid Spacing="2">
            @foreach (var participant in _availableParticipants)
            {
                var isSelected = _selectedIds.Contains(participant.PersonId);
                <MudItem xs="12" sm="6" md="4">
                    <MudPaper Class="@GetParticipantClass(isSelected)"
                              Style="cursor: pointer;"
                              Elevation="@(isSelected ? 2 : 0)"
                              @onclick="() => ToggleParticipant(participant.PersonId)">
                        <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="2" Class="pa-2">
                            <MudCheckBox T="bool"
                                         Value="@isSelected"
                                         ValueChanged="@((bool _) => ToggleParticipant(participant.PersonId))"
                                         Color="Color.Primary"
                                         Dense="true"
                                         DisableRipple="true" />
                            <MudStack Spacing="0">
                                <MudText Typo="Typo.body2" Style="font-weight: 500;">
                                    @participant.PersonName
                                </MudText>
                                <MudText Typo="Typo.caption" Color="Color.Secondary">
                                    @GetStatusLabel(participant.PersonStatus)
                                </MudText>
                            </MudStack>
                        </MudStack>
                    </MudPaper>
                </MudItem>
            }
        </MudGrid>
    }

    <MudText Typo="Typo.caption" Color="Color.Secondary" Class="mt-3">
        @_selectedIds.Count von @_availableParticipants.Count Teilnehmer ausgewählt
    </MudText>
</MudPaper>

@code {
    /// <summary>
    /// List of available participants from the day.
    /// </summary>
    [Parameter]
    public IReadOnlyList<DayParticipantDto> AvailableParticipants { get; set; } = [];

    /// <summary>
    /// Currently selected participant IDs.
    /// </summary>
    [Parameter]
    public IReadOnlyList<Guid> SelectedParticipantIds { get; set; } = [];

    /// <summary>
    /// Callback when selected participants change.
    /// </summary>
    [Parameter]
    public EventCallback<IReadOnlyList<Guid>> SelectedParticipantIdsChanged { get; set; }

    /// <summary>
    /// Minimum number of participants required.
    /// </summary>
    [Parameter]
    public int MinimumParticipants { get; set; } = 1;

    private List<DayParticipantDto> _availableParticipants = [];
    private HashSet<Guid> _selectedIds = new();

    
    protected override async Task OnParametersSetAsync()
    {
        _availableParticipants = AvailableParticipants.ToList();
        _selectedIds = new HashSet<Guid>(SelectedParticipantIds);

        // Auto-select all if none selected
        if (_selectedIds.Count == 0 && _availableParticipants.Count > 0)
        {
            await SelectAll();
        }
    }

    private async Task ToggleParticipant(Guid personId)
    {
        if (_selectedIds.Contains(personId))
        {
            _selectedIds.Remove(personId);
        }
        else
        {
            _selectedIds.Add(personId);
        }

        await NotifySelectionChanged();
    }

    private async Task SelectAll()
    {
        _selectedIds = _availableParticipants.Select(p => p.PersonId).ToHashSet();
        await NotifySelectionChanged();
    }

    private async Task SelectNone()
    {
        _selectedIds.Clear();
        await NotifySelectionChanged();
    }

    private async Task NotifySelectionChanged()
    {
        await SelectedParticipantIdsChanged.InvokeAsync(_selectedIds.ToList());
    }

    private string GetParticipantClass(bool isSelected) =>
        isSelected
            ? "mud-theme-primary pa-1"
            : "mud-paper-outlined pa-1";

    private string GetStatusLabel(PersonStatus status) => status switch
    {
        PersonStatus.Member => "Mitglied",
        PersonStatus.Guest => "Gast",
        _ => status.ToString()
    };

    /// <summary>
    /// Gets the currently selected participant IDs.
    /// </summary>
    public IReadOnlyList<Guid> GetSelectedIds() => _selectedIds.ToList();

    /// <summary>
    /// Validates that minimum participants are selected.
    /// </summary>
    public bool IsValid() => _selectedIds.Count >= MinimumParticipants;
}