{#
    PR4 (p17e) -- fragment-style base for /admin/* pages.

    Pages that extend this template render as a content fragment
    injected into the <pyc-site-shell> main slot by
    render_shell_document(content_html=...). The shell owns the
    surrounding chrome (header, sidebar, layout); this fragment
    contributes only the page-specific body, any extra CSS, and any
    extra JS. The legacy Vue + bootstrap-vue script stack has been
    retired -- no admin template mounts Vue widgets any more.

    {% block title %} is preserved so per-page templates can still
    set their <title> without altering the wrapper -- the shell
    document picks the title up from the render call.

    Legacy chrome (the old fixed header, sidebar nav, login link)
    is intentionally removed; PR4 task F-4 deletes the duplicated
    chrome since the site shell now provides it.
#}
<section class="pyc-admin-page-fragment">
    {#- The child template's title block feeds the shell document's <title>;
        the shell wrapper reads and removes this element. #}
    <meta name="pyc-page-title" content="{% block title %}{% endblock %}">
    {# Carry stylesheets the admin templates depend on, alongside any
       extra_css the child block contributes. Material Icons is the
       only stylesheet the shell document does not already provide;
       color-theme.css is repo-local. bootstrap / bootstrap-vue /
       ccai.css were dropped when the project moved to the
       webworks + mj-* component stack -- the files no longer ship
       and the legacy <link> tags returned 404. #}

    {% block extra_css %}{% endblock %}

    {% if flashes %}
        {% for category, message in flashes %}
        <div class="alert alert-{{ category }}">{{ message }}</div>
        {% endfor %}
    {% endif %}

    {% block content %}{% endblock %}

    {#
        The legacy polyfill / vue / bootstrap-vue script tags were
        removed: no admin template mounts a Vue widget any more, so
        the ~2.4 MB stack was dead weight on every /admin page.
    #}
    <script nonce="{{ csp_nonce() }}">
        // Unsaved-changes guard for the admin POST forms: warn on
        // navigation after an edit until the form is submitted.
        // GET filter forms are exempt -- losing an unsubmitted
        // filter value costs nothing.
        (function () {
            var dirty = false;

            function owning_post_form(target) {
                if (target === null || typeof target.closest !== "function") {
                    return null;
                }
                var form = target.closest("form");
                if (form === null) {
                    return null;
                }
                var method = (form.getAttribute("method") || "get").toLowerCase();
                if (method !== "post") {
                    return null;
                }
                return form;
            }

            document.addEventListener("input", function (event) {
                if (owning_post_form(event.target) !== null) {
                    dirty = true;
                }
            }, true);

            document.addEventListener("change", function (event) {
                if (owning_post_form(event.target) !== null) {
                    dirty = true;
                }
            }, true);

            document.addEventListener("submit", function () {
                dirty = false;
            }, true);

            window.addEventListener("beforeunload", function (event) {
                if (dirty === true) {
                    event.preventDefault();
                    event.returnValue = "";
                }
            });
        })();
    </script>
    {% block extra_js %}{% endblock %}
</section>