Selection

@* Selection in a form: each checked row posts its ItemKey, so Archive works with JavaScript off. A
   footer row shows the total. *@
<form method="post" @onsubmit="Archive" @formname="archive" style="width: 100%">
    <AntiforgeryToken />
    <Stack Gap="3">
        <Table Items="Recent" Caption="Recent orders" SelectionMode="SelectionMode.Multiple" ItemKey="o => o.Number.ToString()"
               RowLabel='o => $"order {o.Number}"' @bind-Selection="_selected">
            <PropertyColumn Property="o => o.Number" Title="Order" Align="CellAlign.Start" FooterText="Total" />
            <PropertyColumn Property="o => o.Customer" />
            <PropertyColumn Property="o => o.Total" Format="C" FooterText="@Recent.Sum(o => o.Total).ToString("C")" />
        </Table>
        <Row Gap="3" Align="Align.Center" Wrap>
            <Button Submit Variant="ButtonVariant.Outline" Accent="Accent.Neutral" StartIcon="Lucide.Archive">Archive selected</Button>
            @if (_archived is not null)
            {
                <TextBlock Size="TextSize.Sm" Color="Color.Muted">
                    Archived: @(_archived.Length == 0 ? "nothing selected" : string.Join(", ", _archived.Select(k => "#" + k)))
                </TextBlock>
            }
        </Row>
    </Stack>
</form>

@code {
    private static readonly IReadOnlyList<Order> Recent = Orders.All.Take(5).ToList();

    // Static pages: the checked rows post as "selected".
    [SupplyParameterFromForm(FormName = "archive", Name = "selected")]
    private Selection? Posted { get; set; }

    // Interactive pages: bound to the checkboxes.
    private Selection? _selected;
    private string[]? _archived;

    protected override void OnInitialized() => _selected = Posted;

    private void Archive()
    {
        var selection = Posted ?? _selected ?? Selection.None;
        _archived = [.. selection.Apply(Recent.AsQueryable(), o => o.Number.ToString()).Select(o => o.Number.ToString())];
    }
}

@* Bulk actions: select rows on any page, or, with the header checkbox, every order the filters
   match. The bar above the rows holds Archive, which posts the selection; Selection.Apply finds
   the orders it means. *@
<form method="post" @onsubmit="Archive" @formname="bulk-archive" style="width: 100%">
    <AntiforgeryToken />
    <Stack Gap="3">
        <Table Items="Orders.All" PageSize="5" Caption="Orders to archive" QueryPrefix="bulk-" Grow
               ItemKey="o => o.Number.ToString()" RowLabel='o => $"order {o.Number}"'
               SelectionMode="SelectionMode.Multiple" SelectAllMode="SelectAllMode.All" @bind-Selection="_selection">
            <SelectionActions>
                <Button Submit Size="ControlSize.Sm" Variant="ButtonVariant.Outline" Accent="Accent.Neutral" StartIcon="Lucide.Archive">Archive</Button>
            </SelectionActions>
            <ChildContent>
                <PropertyColumn Property="o => o.Number" Title="Order" Align="CellAlign.Start" />
                <PropertyColumn Property="o => o.Customer" Filterable />
                <PropertyColumn Property="o => o.Status" Filterable />
                <PropertyColumn Property="o => o.Total" Format="C" />
            </ChildContent>
        </Table>
        <TextBlock Size="TextSize.Sm" Color="Color.Muted" role="status">@_status</TextBlock>
    </Stack>
</form>

@code {
    // Static pages: the selection posts under the table's SelectionName ("{QueryPrefix}selected").
    [SupplyParameterFromForm(FormName = "bulk-archive", Name = "bulk-selected")]
    private Selection? Posted { get; set; }

    // Interactive pages: bound to the table.
    private Selection? _selection;
    private string? _status;

    protected override void OnInitialized() => _selection = Posted;

    private void Archive()
    {
        var orders = (Posted ?? _selection ?? Selection.None).Apply(Orders.All.AsQueryable(), o => o.Number.ToString()).ToList();
        _status = orders.Count switch
        {
            0 => "Select the orders to archive first.",
            1 => $"Archived order #{orders[0].Number}.",
            _ => $"Archived {orders.Count} orders.",
        };
        _selection = Selection.None;
    }
}