{#
================================================================================
TRACK LIST — LMS Card Grid over site.data.tracks (Kida-Native)
================================================================================

Catalog of every learning track defined in `site/data/tracks.yaml`. Each track
becomes an LMS-style card: title, lesson count, description, a chip preview of
the first lessons, and a "Start learning" CTA pointing at the track's pillar
page (or its first lesson as a fallback).

DOM contract (CSS wave #141):
  .chirp-theme-tracks-index                 page root
  .chirp-theme-track-grid                   the card grid
  .chirp-theme-track-card                    one track card
    .chirp-theme-track-card__head / __icon / __title / __count
    .chirp-theme-track-card__lede
    .chirp-theme-track-card__chips / __chip / __chip-num / __chip(--more)
    .chirp-theme-track-card__cta
  .chirp-theme-tracks-empty                  empty state

USAGE: set `template: tracks/list.html` on the tracks landing page.
================================================================================
#}
{% extends "base.html" %}

{% from "chirpui/badge.html" import badge %}
{% from "chirpui/button.html" import btn %}
{% from "chirpui/hero.html" import page_hero %}
{% from "chirpui/layout.html" import container, grid, stack %}
{% from "partials/learning-pages.html" import rendered_body %}

{# =============================================================================
   TRACK CARD — one LMS card. `track_page` is the resolved pillar page (or none).
   ============================================================================= #}
{% def track_card(id, track, track_page) %}
{% let card_title = track?.title ?? id %}
{% let card_lede = track?.description ?? 'Start your learning journey with this curated track.' %}
{% let card_items = track?.items ?? [] %}
{% let count = card_items | length %}
{% let preview_limit = 3 %}
{% let start_href = track_page?.href ?? none %}

<article class="chirp-theme-track-card" data-track-id="{{ id }}">
  <header class="chirp-theme-track-card__head">
    <span class="chirp-theme-track-card__icon" aria-hidden="true">{{ icon('graduation-cap', size=20) }}</span>
    <h2 class="chirp-theme-track-card__title">
      {% if start_href %}
      <a href="{{ start_href }}"{{ route_link_attrs(start_href) | html_attrs }}>{{ card_title }}</a>
      {% else %}
      {{ card_title }}
      {% end %}
    </h2>
    {{ badge(count ~ ' lesson' ~ ('s' if count != 1 else ''), variant='muted', cls='chirp-theme-track-card__count') }}
  </header>

  <p class="chirp-theme-track-card__lede">{{ card_lede }}</p>

  {% if count > 0 %}
  <ol class="chirp-theme-track-card__chips">
    {% for item_slug in card_items[:preview_limit] %}
    {% let item_page = get_page(item_slug) %}
    <li class="chirp-theme-track-card__chip">
      <span class="chirp-theme-track-card__chip-num" aria-hidden="true">{{ loop.index }}</span>
      <span class="chirp-theme-track-card__chip-label">{{ item_page?.title ?? item_slug }}</span>
    </li>
    {% end %}
    {% if count > preview_limit %}
    <li class="chirp-theme-track-card__chip chirp-theme-track-card__chip--more">
      +{{ count - preview_limit }} more
    </li>
    {% end %}
  </ol>
  {% end %}

  <div class="chirp-theme-track-card__cta">
    {% if start_href %}
    {{ btn('Start learning', href=start_href, variant='primary', size='sm', icon='arrow-right') }}
    {% elif count > 0 %}
    {% let first_page = get_page(card_items[0]) %}
    {% if first_page %}
    {{ btn('Start learning', href=first_page.href, variant='primary', size='sm', icon='arrow-right') }}
    {% else %}
    {{ badge('Unavailable', variant='muted') }}
    {% end %}
    {% else %}
    {{ badge('No lessons yet', variant='muted') }}
    {% end %}
  </div>
</article>
{% end %}

{% block content %}
{% let page_title = page?.title ?? section?.title ?? 'Learning tracks' %}
{% let page_desc = page?.description ?? section?.description ?? 'Follow curated, self-paced learning paths.' %}
{% let tracks_data = site?.data?.tracks ?? {} %}
{% let track_count = tracks_data | length %}

{# Pre-compute track_id → pillar page map ONCE. #}
{% let track_page_map = {} %}
{% for p in (site?.pages ?? []) %}
{% let tid = p?.metadata?.track_id ?? '' %}
{% if tid %}
{% let track_page_map = track_page_map | merge({tid: p}) %}
{% end %}
{% end %}

{% call container(cls="chirp-theme-tracks-index") %}
  {% call stack(gap="lg") %}
    {% call page_hero(title=page_title, subtitle=page_desc, variant='editorial', background='solid', cls='chirp-theme-tracks-index__hero') %}
      {% slot eyebrow %}{{ badge('Tracks', variant='primary', icon='graduation-cap') }}{% end %}
      {% slot metadata %}
      <span>{{ track_count }} track{{ 's' if track_count != 1 else '' }}</span>
      {% end %}
    {% end %}

    {{ rendered_body(content) }}

    {% if track_count > 0 %}
    {% call grid(cols=3, gap="md", cls="chirp-theme-track-grid") %}
      {% for id, track in tracks_data | items %}
      {% let track_page = track_page_map[id] if id in track_page_map else none %}
      {{ track_card(id, track, track_page) }}
      {% end %}
    {% end %}
    {% else %}
    <div class="chirp-theme-tracks-empty">
      <span class="chirp-theme-tracks-empty__icon" aria-hidden="true">{{ icon('graduation-cap', size=48) }}</span>
      <h2>No tracks yet</h2>
      <p>Define learning tracks in <code>site/data/tracks.yaml</code> and they will appear here.</p>
    </div>
    {% end %}
  {% end %}
{% end %}
{% end %}