chapter-organizer/WebApp/Components/Features/Events/Index.razor

@page "/events"
@attribute [Authorize]
@implements IAsyncDisposable
@using Microsoft.EntityFrameworkCore
@using WebApp.Models
@using WebApp.Components.Shared.Components
@inject AppDbContext Context
@inject IDialogService DialogService
@inject ISnackbar Snackbar

<PageHeader Title="Events">
    <ActionButtons>
        <MudButton StartIcon="@Icons.Material.Filled.Create" Href="events/create" Variant="Variant.Filled" Color="Color.Primary">Create New</MudButton>
        <MudButton StartIcon="@Icons.Material.Filled.Print" Href="events/printout" Variant="Variant.Outlined">Printable Descriptions</MudButton>
        <MudButton StartIcon="@Icons.Material.Filled.AccountTree" Href="events/career-mapping" Variant="Variant.Outlined">Career Mapping</MudButton>
    </ActionButtons>
</PageHeader>

<MudPaper Elevation="2" Class="pa-3 pa-md-6">
    <MudDataGrid T="EventDefinition"
                 ServerData="ServerReload"
                 @ref="_dataGrid"
                 Filterable="true"
                 RowsPerPage="50"
                 Dense="true"
                 Striped="true"
                 Hover="true"
                 Loading="@_isLoading"
                 LoadingProgressColor="Color.Primary">
        <Columns>
            <PropertyColumn Property="@(e => e.Name)" Title="Event Name" Sortable="true">
                <CellTemplate>
                    <MudStack Row="true" AlignItems="AlignItems.Center" Justify="Justify.SpaceBetween" Spacing="1">
                        <MudLink Href="@($"/events/details?id={context.Item.Id}&returnUrl=/events")"
                                 Underline="Underline.Hover"
                                 Color="Color.Primary">
                            @context.Item.Name
                        </MudLink>
                        <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="1">
                            <IconButtonWithTooltip Icon="@Icons.Material.Filled.Edit"
                                                   TooltipText="Edit"
                                                   Href="@($"/events/edit?id={context.Item.Id}&returnUrl=/events")" />
                            <IconButtonWithTooltip Icon="@Icons.Material.Outlined.Delete"
                                                   TooltipText="Delete"
                                                   HoverColor="Color.Error"
                                                   OnClick="() => DeleteEventDefinition(context.Item!)" />
                        </MudStack>
                    </MudStack>
                </CellTemplate>
            </PropertyColumn>
            <TemplateColumn Title="Attributes" Sortable="false">
                <CellTemplate>
                    <EventAttributes EventDefinition="context.Item"></EventAttributes>
                </CellTemplate>
            </TemplateColumn>

            <TemplateColumn Title="Team Size" CellStyle="white-space:nowrap">
                <CellTemplate>
                    <MudTooltip Text="@context.Item.Eligibility">
                        [@context.Item.MinTeamSize&nbsp;-&nbsp;@context.Item.MaxTeamSize]
                    </MudTooltip>
                </CellTemplate>
            </TemplateColumn>
            
            <PropertyColumn Property="@(e => e.LevelOfEffort)" Title="Level of Effort" />
            <PropertyColumn Property="@(e => e.EventFormat)" Title="Event Format" />
            
        </Columns>
        <PagerContent>
            <MudDataGridPager T="EventDefinition"></MudDataGridPager>
        </PagerContent>
    </MudDataGrid>
</MudPaper>

@code {
    MudDataGrid<EventDefinition> _dataGrid = null!;
    private bool _isLoading = true;
    private CancellationTokenSource? _cancellationTokenSource;
    private bool _isDisposed = false;

    protected override void OnInitialized()
    {
        _cancellationTokenSource = new CancellationTokenSource();
    }

    private async Task<GridData<EventDefinition>> ServerReload(GridState<EventDefinition> state)
    {
        if (_isDisposed)
        {
            return new GridData<EventDefinition> { TotalItems = 0, Items = [] };
        }

        _isLoading = true;
        try
        {
            var cancellationToken = _cancellationTokenSource?.Token ?? CancellationToken.None;

            var query = Context.Events
                .AsNoTracking()
                .OrderBy(e => e.Name).Where(state.FilterDefinitions).OrderBy(state.SortDefinitions);

            var totalItems = await query.CountAsync(cancellationToken);
            var pagedData = await query.Skip(state.Page * state.PageSize).Take(state.PageSize).ToArrayAsync(cancellationToken);

            return new GridData<EventDefinition>
            {
                TotalItems = totalItems,
                Items = pagedData
            };
        }
        catch (TaskCanceledException)
        {
            return new GridData<EventDefinition> { TotalItems = 0, Items = [] };
        }
        catch (JSDisconnectedException)
        {
            return new GridData<EventDefinition> { TotalItems = 0, Items = [] };
        }
        finally
        {
            if (!_isDisposed)
            {
                _isLoading = false;
            }
        }
    }

    private async Task DeleteEventDefinition(EventDefinition evt)
    {
        if (_isDisposed) return;

        try
        {
            var cancellationToken = _cancellationTokenSource?.Token ?? CancellationToken.None;

            var result = await DialogService
                .ShowMessageBox("Delete Event",
                    (MarkupString)$"Are you sure want to delete <b>{evt.Name}</b>? This cannot be undone.",
                    yesText:"Yes",
                    noText:"Cancel");

            if (_isDisposed) return;

            if (result == true)
            {
                // Load the event fresh from database with tracking to avoid tracking conflicts
                var eventToDelete = await Context.Events
                    .FirstOrDefaultAsync(e => e.Id == evt.Id, cancellationToken);

                if (_isDisposed) return;

                if (eventToDelete == null)
                {
                    if (!_isDisposed)
                    {
                        Snackbar.Add("Event not found or already deleted", Severity.Warning);
                    }
                    return;
                }

                Context.Events.Remove(eventToDelete);
                await Context.SaveChangesAsync(cancellationToken);
                
                if (!_isDisposed)
                {
                    Snackbar.Add($"Event {eventToDelete.Name} deleted", Severity.Info);
                }
            }

            if (!_isDisposed)
            {
                StateHasChanged();
                await _dataGrid.ReloadServerData();
            }
        }
        catch (TaskCanceledException)
        {
            // Component was disposed, ignore
        }
        catch (JSDisconnectedException)
        {
            // JS connection lost, ignore
        }
        catch (Exception ex)
        {
            if (!_isDisposed)
            {
                Snackbar.Add($"Error deleting event: {ex.Message}", Severity.Error);
            }
        }
    }

    public async ValueTask DisposeAsync()
    {
        if (!_isDisposed)
        {
            _isDisposed = true;
            _cancellationTokenSource?.Cancel();
            _cancellationTokenSource?.Dispose();
            _cancellationTokenSource = null;
        }
        await ValueTask.CompletedTask;
    }
}