{#- chirp-ui: Drag-drop primitives
    Behavior-ready row and board variants for sortable lists and kanban layouts.
    Composes existing sortable structure; Alpine/HTMX wiring is left to the consumer.

    Row variant (ordered lists: chains, todo, setup targets):
        from "chirpui/dnd.html" import dnd_list, dnd_item, dnd_handle, dnd_drop_indicator

        call dnd_list()
          for item in items
            call dnd_item()
              call dnd_handle()
              call dnd_drop_indicator()
              ...content...
            end
          end
        end

    Board variant (kanban lanes with cross-column movement):
        from "chirpui/dnd.html" import dnd_board, dnd_column, dnd_card

        call dnd_board()
          for col in columns
            call dnd_column(title=col.name)
              for card in col.cards
                call dnd_card()
                  ...card content...
                end
              end
            end
          end
        end
-#}

{% def dnd_list(cls="", attrs="") %}
<div class="chirpui-dnd chirpui-dnd--row{{ " " ~ cls if cls else "" }}"
     role="listbox" {{ attrs | safe }}>
    {% slot %}
</div>
{% end %}

{% def dnd_item(cls="", attrs="") %}
<div class="chirpui-dnd__item chirpui-dnd__item--row{{ " " ~ cls if cls else "" }}"
     role="option" {{ attrs | safe }}>
    {% slot %}
</div>
{% end %}

{% def dnd_handle(cls="", attrs="") %}
<span class="chirpui-dnd__handle{{ " " ~ cls if cls else "" }}"
      aria-hidden="true" {{ attrs | safe }}>&#x2630;</span>
{% end %}

{% def dnd_drop_indicator(cls="", attrs="") %}
<span class="chirpui-dnd__drop-indicator{{ " " ~ cls if cls else "" }}"
      aria-hidden="true" {{ attrs | safe }}></span>
{% end %}

{% def dnd_board(cls="", attrs="") %}
<div class="chirpui-dnd chirpui-dnd--board{{ " " ~ cls if cls else "" }}"
     role="group" aria-label="Board" {{ attrs | safe }}>
    {% slot %}
</div>
{% end %}

{% def dnd_column(title=none, cls="", attrs="") %}
<div class="chirpui-dnd__column{{ " " ~ cls if cls else "" }}"
     role="group" {{ attrs | safe }}>
    {% if title %}
    <div class="chirpui-dnd__column-header">{{ title }}</div>
    {% end %}
    <div class="chirpui-dnd__column-body">
        {% slot %}
    </div>
</div>
{% end %}

{% def dnd_card(cls="", attrs="") %}
<div class="chirpui-dnd__card{{ " " ~ cls if cls else "" }}"
     role="article" {{ attrs | safe }}>
    {% slot %}
</div>
{% end %}