{#
================================================================================
Track Navigation Sidebar (Kida-Native)
================================================================================

Left rail for tracks/single.html: the ordered section list for the current
track plus links to sibling tracks. Reuses the pre-computed `track_item_pages`
map that single.html builds (so we never call get_page twice for the same
slug); falls back to get_page when included standalone.

Expected context (set by tracks/single.html before include):
  track_id          — resolved id of the current track
  current_track     — the track dict (or none)
  track_item_pages  — {slug: page} map for current_track.items (optional)

DOM contract (consumed by waves #141 CSS / #142 JS):
  nav.chirp-theme-track-sidebar[data-bengal="track-nav"][data-track-id]
    .chirp-theme-track-sidebar__list
      .chirp-theme-track-sidebar__item
        a.chirp-theme-track-sidebar__link[href="#track-section-{n}"]
                                          [data-track-target="#track-section-{n}"]
          .chirp-theme-track-sidebar__number (badge)

USAGE:
  {% include 'partials/track-sidebar.html' %}
================================================================================
#}
{% from "chirpui/badge.html" import badge %}
{% from "chirpui/card.html" import card %}
{% from "chirpui/list.html" import list_group, list_item %}

{% let _track_id = track_id if (track_id is defined and track_id) else (params?.track_id ?? page?.slug ?? '') %}
{% let _all_tracks = site?.data?.tracks ?? {} %}
{% let _current_track = current_track if (current_track is defined and current_track) else (_all_tracks[_track_id] if (_track_id and _track_id in _all_tracks) else none) %}
{% let _track_items = _current_track?.items ?? [] %}

<nav class="chirpui-stack chirpui-stack--md chirp-theme-track-sidebar" aria-label="Track navigation"
     data-bengal="track-nav" data-track-id="{{ _track_id }}">
  {% if _track_items | length > 0 %}
  {% call card(title=_current_track?.title ?? t('tracks.sections', default='Sections'), cls="chirp-theme-track-sidebar__card") %}
    {% call list_group(bordered=true, cls="chirp-theme-track-sidebar__list") %}
      {% for item_slug in _track_items %}
      {% let item_page = track_item_pages[item_slug] if (track_item_pages is defined and item_slug in track_item_pages) else get_page(item_slug) %}
      {% if item_page %}
      {% call list_item(cls="chirp-theme-track-sidebar__item") %}
        <a href="#track-section-{{ loop.index }}"
           class="chirpui-list__link chirp-theme-track-sidebar__link"
           data-track-section="{{ loop.index }}"
           data-track-target="#track-section-{{ loop.index }}">
          {{ badge(loop.index | string, variant="muted", cls="chirp-theme-track-sidebar__number") }}
          <span class="chirp-theme-track-sidebar__title">{{ item_page?.title ?? item_slug }}</span>
        </a>
      {% end %}
      {% end %}
      {% end %}
    {% end %}
  {% end %}
  {% end %}

  {# Sibling tracks — only when there is more than one track defined. #}
  {% let track_count = _all_tracks | length %}
  {% if track_count > 1 %}
  {% let _track_page_map = {} %}
  {% for p in (site?.pages ?? []) %}
  {% let tid = p?.metadata?.track_id ?? '' %}
  {% if tid and tid != _track_id %}
  {% let _track_page_map = _track_page_map | merge({tid: p}) %}
  {% end %}
  {% end %}

  {% call card(title=t('tracks.other', default='Other tracks'), cls="chirp-theme-track-sidebar__card chirp-theme-track-sidebar__card--siblings") %}
    {% call list_group(bordered=true, cls="chirp-theme-track-sidebar__list") %}
      {% for id, track in _all_tracks | items %}
      {% if id != _track_id %}
      {% let track_page = _track_page_map[id] if id in _track_page_map else none %}
      {% if track_page %}
      {% call list_item(cls="chirp-theme-track-sidebar__item") %}
        <a href="{{ track_page.href }}" class="chirpui-list__link chirp-theme-track-sidebar__link"{{ route_link_attrs(track_page.href) | html_attrs }}>
          <span class="chirp-theme-track-sidebar__title">{{ track?.title ?? id }}</span>
          {% let lesson_count = (track?.items ?? []) | length %}
          {{ badge(lesson_count ~ " lesson" ~ ("s" if lesson_count != 1 else ""), variant="muted") }}
        </a>
      {% end %}
      {% end %}
      {% end %}
      {% end %}
    {% end %}
  {% end %}
  {% end %}
</nav>