{#
  nav_link: renders a menu <li><a> for the given endpoint.
#}
{% macro nav_link(endpoint, label) %}
<li><a class="dropdown-item" href="{{ url_for(endpoint) }}">{{ label }}</a></li>
{% endmacro %}

{#
  flashed_messages: the shared alert list. A macro rather than a block so the
  login page can render it inside its card -- a sign-in error banner at the
  top of the page sits 10em above the form it belongs to.
#}
{% macro flashed_messages() %}
{% with messages = get_flashed_messages(with_categories=True) %}
  {% if messages %}
    {% for category, message in messages %}
      {% set mapping = {'message': 'info', 'error': 'danger'} %}
      {% set variant = ' alert-' ~ mapping.get(category, category) if category else '' %}
      <div class="alert{{ variant }} alert-dismissible fade show">
        <button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button>
        {{ message }}
      </div>
    {% endfor %}
  {% endif %}
{% endwith %}
{% endmacro %}

{#
  utc_timestamp: renders a stored (naive UTC) datetime.
  The attribute keeps the exact instant with its offset; the text is the wall
  clock, to the second and unlabelled -- the zone is named once per page by
  tz_indicator. The tooltip leads with that same wall-clock text, verbatim,
  then the exact instant in parens -- a truncated cell's tooltip must contain
  what was cut off, not just the machine-readable value. EportalUtils.
  renderTimestamps rewrites both the text and the tooltip to match; the page
  must load eportal-js/utils.js.
#}
{% macro utc_timestamp(value) -%}
{%- if value -%}
{%- set iso = value|utc_isoformat -%}
{%- set display = value|utc_display -%}
<time class="js-timestamp" datetime="{{ iso }}" title="{{ display }} ({{ iso }})">{{ display }}</time>
{%- endif -%}
{%- endmacro %}

{#
  tz_indicator: names the zone every timestamp on the page is printed in.

  Once per page, in the navbar: the zone is one fact per page, and a column
  heading is too narrow for an IANA name. On every page, from base.html: the
  values are UTC whether or not a page happens to print one, so there is
  nothing for a page to opt into and nothing it can forget. The zone *name*,
  never an abbreviation or a fixed offset: one page shows rows either side of
  a DST boundary.
#}
{% macro tz_indicator() -%}
<li class="nav-item">
    <span class="nav-link tz-indicator">TZ: <span class="js-tz-label">UTC</span></span>
</li>
{%- endmacro %}