{% extends "base.html" %}

{% block content %}
  {% if page.nb_url %}
    <div class="silva-notebook-actions">
      <a href="{{ page.nb_url }}" download class="md-button md-button--primary">
        {% include ".icons/material/download.svg" %}
        Download notebook
      </a>
    </div>
  {% endif %}
  {{ super() }}
{% endblock content %}

{% block config %}
  {{ super() }}
  <script>
    (() => {
      const expectedSourceVersion = "{{ config.extra.source_release_tag }}";
      const maxSourceCacheAgeMs = 60 * 60 * 1000;
      const sourceCacheKey = "__source";
      const sourceCacheTimeKey = "__source_cached_at";

      const clearSourceCache = () => {
        try {
          sessionStorage.removeItem(`${__md_scope.pathname}.${sourceCacheKey}`);
          sessionStorage.removeItem(`${__md_scope.pathname}.${sourceCacheTimeKey}`);
        } catch (error) {
          // Storage may be unavailable in restricted browser modes.
        }
      };

      try {
        const sourceFacts = __md_get(sourceCacheKey, sessionStorage);
        const cachedAt = __md_get(sourceCacheTimeKey, sessionStorage);
        const cacheAgeMs = Number.isFinite(cachedAt) ? Date.now() - cachedAt : Infinity;
        if (
          sourceFacts &&
          (sourceFacts.version !== expectedSourceVersion || cacheAgeMs > maxSourceCacheAgeMs)
        ) {
          clearSourceCache();
        }
      } catch (error) {
        clearSourceCache();
      }

      const mdSet = window.__md_set;
      window.__md_set = (key, value, storage = localStorage, scope = __md_scope) => {
        mdSet(key, value, storage, scope);
        if (key === sourceCacheKey && storage === sessionStorage) {
          mdSet(sourceCacheTimeKey, Date.now(), sessionStorage, scope);
        }
      };
    })();
  </script>
{% endblock config %}