Swimlanes

Group by

use Illuminate\Database\Eloquent\Builder;
use Illuminate\Support\Facades\DB;
use Relaticle\Flowforge\Grouping;
use Relaticle\Flowforge\Lane;

->groupings([
    Grouping::attribute('priority'),

    Grouping::make('assignee')
        ->label('Assignee')
        ->lanes(fn (Builder $boardQuery): array => User::query()
            ->whereIn('id', DB::table('task_user')
                ->whereIn('task_id', (clone $boardQuery)->select('tasks.id'))
                ->select('user_id'))
            ->orderBy('name')
            ->get()
            ->map(fn (User $user): Lane => Lane::make($user->id)
                ->label($user->name)
                ->avatar($user->avatar_url)
                ->query(fn (Builder $query): Builder => $query->whereHas(
                    'assignees',
                    fn (Builder $assignees): Builder => $assignees->whereKey($user->id),
                )))
            ->all())
        ->emptyLane('Unassigned', fn (Builder $query): Builder => $query->whereDoesntHave('assignees'))
        ->moveUsing(function (Task $card, Lane $from, Lane $to): void {
            if ($from->getName() !== Grouping::EMPTY_LANE) {
                $card->assignees()->detach($from->getName());
            }

            if ($to->getName() !== Grouping::EMPTY_LANE) {
                $card->assignees()->syncWithoutDetaching([$to->getName()]);
            }
        }),
])

Defining groupings adds a "Group by" button to the board. It names the active grouping and opens a menu of every grouping. It sits above the board under the filters. With headerToolbar() it moves into the page header, next to the filters and search. A standalone board has no page header, so with headerToolbar() it shows no picker, the same as its filters.

The choice lives in the URL as ?groupBy=assignee, so a grouped view can be shared. Choosing "None" returns to the plain board.

A click on a lane's header collapses that lane, and another click opens it again. The chevron in front of the label is the keyboard control for the same toggle. Collapsed lanes stay collapsed while the board updates and open again on a reload.

Lanes

• lanes() receives the board query with filters and search applied. Name the parameter $boardQuery, or type it as the Eloquent builder. Return the lanes in the order to show them.
• A Lane takes a name, which must be unique within the grouping, and a query() closure that narrows the board query to that lane. It also takes label(), avatar(), color() and icon().
• emptyLane() adds a last lane for cards that match none of the others. The name Grouping::EMPTY_LANE identifies it in moveUsing().
• Grouping::attribute('priority') builds one lane per distinct value, busiest first, plus an empty lane for null. A backed enum cast supplies the labels and colors when it implements Filament's HasLabel and HasColor.
• A card that matches two lanes appears in both. The move callback receives the lane the card left, so only that link changes.
• A lane with no cards in view is not shown.
• Ten lanes render at first, and "Show more lanes" loads ten more. Change the page size with ->lanesPerPage(). Each cell shows cardsPerColumn() cards, then "Show N more".
• Each rendered lane loads its cards in one query, using window functions.

The paging state ($visibleLaneCount, $cellCardLimits and $columnCardLimits) is #[Locked], so the browser cannot write it. loadMoreItems() clamps the count it loads into a lane cell to between 1 and cardsPerColumn().

Creating cards in lane mode

The header + from createCardAction() creates a card without knowing the lane. The card lands in whichever lane its data matches. A custom grouping without emptyLane() hides a card that matches no lane, so add emptyLane() to every custom grouping. Lane cells have no add row.

Moving between lanes

• With moveUsing(), a drop into another lane runs the callback in the same transaction as the column move. Throw CardMoveRejectedException::because('...') to refuse. Both writes roll back, the user sees the message, and the card returns.
• The callback receives the card as $card or $record, or typed by its model class, plus the lane it left as $from and the lane it entered as $to.
• Grouping::attribute() writes the attribute itself, and writes null for the empty lane. An attribute qualified with another table's name, such as 'details.priority', is read-only.
• Without moveUsing(), the lanes are read-only. Cards move between columns inside their lane, the browser blocks a drop into another lane, and the server refuses it with a message.
• The server checks that the card sits in the lane it left, and refuses the move when the board has changed underneath the user.

Limits and collapsed columns

• A column limit counts the whole column across every lane, and the header is shared.
• collapseEmptyColumns() applies to the plain board only. In lanes every column keeps its width, so every cell stays a drop target.