From 7b52cab180e56a08f22aad51694e1ef552b6c0e4 Mon Sep 17 00:00:00 2001
From: Ross <xkjq@ymail.com>
Date: Wed, 25 Mar 2026 22:05:19 +0000
Subject: [PATCH] Refactor SelectionTable to use per-table initializers for row
 selection controls and improve JavaScript handling in templates

---
 generic/tables.py                        | 163 ++++++++++++-----------
 rad.code-workspace                       |   4 +
 templates/base.html                      |  10 ++
 templates/django_tables2/bootstrap4.html | 100 ++++++++++++++
 4 files changed, 199 insertions(+), 78 deletions(-)
 create mode 100644 templates/django_tables2/bootstrap4.html

diff --git a/generic/tables.py b/generic/tables.py
index a8745ecc..7b7f383c 100644
--- a/generic/tables.py
+++ b/generic/tables.py
@@ -18,8 +18,6 @@ from django.contrib.auth.models import User
 # column (input name="selection") and table attrs that client-side
 # scripts can use to find selectable tables.
 class SelectionTable(tables.Table):
-    # Provide a default selection checkbox column. Subclasses that wish to
-    # customise can override this attribute.
     selection = tables.CheckBoxColumn(
         accessor="pk",
         orderable=False,
@@ -32,16 +30,9 @@ class SelectionTable(tables.Table):
     )
 
     class Meta:
-        # Defaults: add js-row-selectable class so client-side code can
-        # locate tables that support row selection.
         attrs = {"class": "table js-row-selectable", "data-selection-name": "selection"}
 
     def __init__(self, *args, **kwargs):
-        # Ensure selection column is always placed last in the column order
-        # so that table actions/controls appear to the right. We attempt to
-        # reorder columns after initialization; if django-tables2 provides
-        # `reorder_columns`, use it, otherwise fall back to setting
-        # `self.sequence`.
         super().__init__(*args, **kwargs)
         try:
             cols = list(self.columns.names())
@@ -49,19 +40,12 @@ class SelectionTable(tables.Table):
                 cols.remove('selection')
                 cols.append('selection')
                 try:
-                    # Preferred API when available
                     self.reorder_columns(cols)
                 except Exception:
-                    # Fallback: set sequence attribute
                     self.sequence = tuple(cols)
         except Exception:
-            # Defensive: don't break table rendering if introspection fails
             pass
 
-        # Expose a per-instance selection token and ensure the table has the
-        # `js-row-selectable` class so client-side scripts (or the inline
-        # initializer below) can find the correct table without extra markup
-        # in templates.
         try:
             token = format(id(self), 'x')
             attrs = getattr(self, 'attrs', None) or {}
@@ -71,77 +55,100 @@ class SelectionTable(tables.Table):
             attrs['data-selection-token'] = token
             self.attrs = attrs
         except Exception:
-            # non-fatal
             pass
 
-        # By default render the row selection controls above the table so
-        # templates don't need to include `{{ table.row_selection_controls }}`.
-        try:
-            # `row_selection_controls` is already marked safe HTML.
-            self.caption = self.row_selection_controls
-        except Exception:
-            pass
+        self.caption = self.row_selection_controls
 
     @property
     def row_selection_controls(self):
-        """Return HTML for the row-selection control bar.
+                token = (self.attrs or {}).get('data-selection-token', format(id(self), 'x'))
 
-        Usage: render in template with `{{ table.row_selection_controls|safe }}`
+                html = (
+                        f"<div class=\"d-flex justify-content-between align-items-center mb-2\">"
+                        f"  <div>"
+                        f"    <button class=\"btn btn-outline-secondary btn-sm\" id=\"toggle-row-selection-{token}\" type=\"button\">Enable row selection</button>"
+                        f"    <div id=\"selection-controls-{token}\" class=\"btn-group ms-2\" role=\"group\" style=\"display:none;\">"
+                        f"      <button type=\"button\" class=\"btn btn-sm btn-outline-primary\" id=\"select-all-{token}\">Select all</button>"
+                        f"      <button type=\"button\" class=\"btn btn-sm btn-outline-secondary\" id=\"clear-selection-{token}\">Clear</button>"
+                        f"    </div>"
+                        f"  </div>"
+                        f"  <div>"
+                        f"    <small class=\"text-muted\">Selected: <span id=\"selected-count-{token}\">0</span></small>"
+                        f"  </div>"
+                        f"</div>"
+                )
 
-        The control IDs are suffixed with a small per-instance token to
-        avoid collisions when multiple tables are present on the same page.
-        """
-        token = (self.attrs or {}).get('data-selection-token', format(id(self), 'x'))
+                script = """
+<script>
+(function(){
+    var token = '__TOKEN__';
+    window.__selection_inits = window.__selection_inits || {};
+    window.__selection_inits[token] = function(){
+        try { console.log && console.log('selection init registered', token); } catch (e) {}
+        var toggleBtn = document.getElementById('toggle-row-selection-' + token);
+        try { console.log && console.log('selection init running', token, 'table?', !!table); } catch (e) {}
+        if (!toggleBtn) return;
+        var controlsEl = document.getElementById('selection-controls-' + token);
+        var selectAllBtn = document.getElementById('select-all-' + token);
+        var clearBtn = document.getElementById('clear-selection-' + token);
+        var selectedCountSpan = document.getElementById('selected-count-' + token);
+        var table = document.querySelector('table.js-row-selectable[data-selection-token="' + token + '"]');
+        if (!table) return;
 
-        html = (
-            "<div class=\"d-flex justify-content-between align-items-center mb-2\">"
-            "  <div>"
-            "    <button class=\"btn btn-outline-secondary btn-sm\" id=\"toggle-row-selection-{}\" type=\"button\">Enable row selection</button>"
-            "    <div id=\"selection-controls-{}\" class=\"btn-group ms-2\" role=\"group\" style=\"display:none;\">"
-            "      <button type=\"button\" class=\"btn btn-sm btn-outline-primary\" id=\"select-all-{}\">Select all</button>"
-            "      <button type=\"button\" class=\"btn btn-sm btn-outline-secondary\" id=\"clear-selection-{}\">Clear</button>"
-            "    </div>"
-            "  </div>"
-            "  <div>"
-            "    <small class=\"text-muted\">Selected: <span id=\"selected-count-{}\">0</span></small>"
-            "  </div>"
-            "</div>"
-        ).format(token, token, token, token, token)
-        # Append a small inline initializer that wires the controls to the
-        # specific table instance. This moves the behaviour into the server
-        # side table class so pages don't need global wiring.
-        script = (
-            "<script>(function(){"
-            "var token='{t}';"
-            "var toggleBtn=document.getElementById('toggle-row-selection-'+token);"
-            "if(!toggleBtn) return;"
-            "var controlsEl=document.getElementById('selection-controls-'+token);"
-            "var selectAllBtn=document.getElementById('select-all-'+token);"
-            "var clearBtn=document.getElementById('clear-selection-'+token);"
-            "var selectedCountSpan=document.getElementById('selected-count-'+token);"
-            "var table=document.querySelector('table.js-row-selectable[data-selection-token=\"'+token+'\"]');"
-            "if(!table) return;"
-            "var selectionEnabled=false;"
-            "function findRowCheckboxes(){"
-            "  var checks=Array.from(table.querySelectorAll('input[type=\"checkbox\"][name=\"selection\"]'));"
-            "  if(!checks.length) checks=Array.from(table.querySelectorAll('input[type=\"checkbox\"]'));"
-            "  return checks;"
-            "}"
-            "function updateSelectedCount(){ if(!selectedCountSpan) return; var checks=findRowCheckboxes(); var count=checks.filter(function(c){return c.checked;}).length; selectedCountSpan.textContent=count; checks.forEach(function(cb){var tr=cb.closest('tr'); if(tr) tr.classList.toggle('table-active', cb.checked);}); }"
-            "function setCheckboxesDisabled(disabled){ findRowCheckboxes().forEach(function(cb){ cb.disabled=disabled; }); }"
-            "function hideSelectionColumn(){ table.querySelectorAll('th, td').forEach(function(cell){ if(cell.querySelector && cell.querySelector('input[type=\"checkbox\"][name=\"selection\"]')) cell.style.display='none'; }); }"
-            "function showSelectionColumn(){ table.querySelectorAll('th, td').forEach(function(cell){ if(cell.querySelector && cell.querySelector('input[type=\"checkbox\"][name=\"selection\"]')) cell.style.display=''; }); }"
-            "setCheckboxesDisabled(true); hideSelectionColumn();"
-            "table.addEventListener('click', function(e){ if(!selectionEnabled) return; var tag=(e.target.tagName||'').toLowerCase(); if(['input','a','button','select','textarea','label'].indexOf(tag)!==-1) return; var tr=e.target.closest('tr'); if(!tr||!table.contains(tr)) return; var cb=tr.querySelector('input[type=\"checkbox\"][name=\"selection\"]')||tr.querySelector('input[type=\"checkbox\"]'); if(cb && !cb.disabled){ cb.checked=!cb.checked; tr.classList.toggle('table-active', cb.checked); updateSelectedCount(); } }, true);"
-            "table.addEventListener('change', function(e){ if(e.target && e.target.matches && e.target.matches('input[type=\"checkbox\"]')) updateSelectedCount(); }, true);"
-            "toggleBtn.addEventListener('click', function(){ selectionEnabled=!selectionEnabled; if(selectionEnabled){ toggleBtn.textContent='Disable row selection'; if(controlsEl) controlsEl.style.display=''; setCheckboxesDisabled(false); showSelectionColumn(); } else { toggleBtn.textContent='Enable row selection'; if(controlsEl) controlsEl.style.display='none'; setCheckboxesDisabled(true); hideSelectionColumn(); findRowCheckboxes().forEach(function(cb){ cb.checked=false; }); updateSelectedCount(); } });"
-            "if(selectAllBtn) selectAllBtn.addEventListener('click', function(){ findRowCheckboxes().forEach(function(cb){ if(!cb.disabled) cb.checked=true; }); updateSelectedCount(); });"
-            "if(clearBtn) clearBtn.addEventListener('click', function(){ findRowCheckboxes().forEach(function(cb){ if(!cb.disabled) cb.checked=false; }); updateSelectedCount(); });"
-            "updateSelectedCount();"
-            "})();</script>"
-        ).format(t=token)
+        var selectionEnabled = false;
+        var lastChecked = null;
 
-        return mark_safe(html + script)
+        function findRowCheckboxes() { var checks = Array.from(table.querySelectorAll('input[type="checkbox"][name="selection"]')); if (!checks.length) checks = Array.from(table.querySelectorAll('input[type="checkbox"]')); return checks; }
+        function updateSelectedCount() { if (!selectedCountSpan) return; var checks = findRowCheckboxes(); var count = checks.filter(function(c){ return c.checked; }).length; selectedCountSpan.textContent = count; checks.forEach(function(cb){ var tr = cb.closest('tr'); if (tr) tr.classList.toggle('table-active', cb.checked); }); }
+        function setCheckboxesDisabled(disabled) { findRowCheckboxes().forEach(function(cb){ cb.disabled = disabled; }); lastChecked = null; }
+        function hideSelectionColumn() { table.querySelectorAll('th, td').forEach(function(cell){ if (cell.querySelector && cell.querySelector('input[type="checkbox"][name="selection"]')) cell.style.display = 'none'; }); }
+        function showSelectionColumn() { table.querySelectorAll('th, td').forEach(function(cell){ if (cell.querySelector && cell.querySelector('input[type="checkbox"][name="selection"]')) cell.style.display = ''; }); }
+
+        setCheckboxesDisabled(true); hideSelectionColumn();
+
+        table.addEventListener('click', function(e){
+            if (!selectionEnabled) return;
+            var tag = (e.target.tagName || '').toLowerCase();
+            if (['a','button','select','textarea','label'].indexOf(tag) !== -1) return;
+            if (e.target && e.target.matches && e.target.matches('input[type="checkbox"]')){
+                var cb = e.target;
+                if (e.shiftKey && lastChecked && lastChecked !== cb){
+                    var checks = findRowCheckboxes();
+                    var start = checks.indexOf(lastChecked);
+                    var end = checks.indexOf(cb);
+                    if (start > -1 && end > -1){
+                        if (start > end){ var tmp = start; start = end; end = tmp; }
+                        for (var i = start; i <= end; i++){ if (!checks[i].disabled) checks[i].checked = cb.checked; }
+                        updateSelectedCount();
+                    }
+                }
+                lastChecked = cb;
+                return;
+            }
+            var tr = e.target.closest('tr'); if (!tr || !table.contains(tr)) return;
+            var cb = tr.querySelector('input[type="checkbox"][name="selection"]') || tr.querySelector('input[type="checkbox"]');
+            if (cb && !cb.disabled){ cb.checked = !cb.checked; tr.classList.toggle('table-active', cb.checked); updateSelectedCount(); lastChecked = cb; }
+        }, true);
+
+        table.addEventListener('change', function(e){ if (e.target && e.target.matches && e.target.matches('input[type="checkbox"]')) updateSelectedCount(); }, true);
+
+        toggleBtn.addEventListener('click', function(){ selectionEnabled = !selectionEnabled; if (selectionEnabled){ toggleBtn.textContent = 'Disable row selection'; if (controlsEl) controlsEl.style.display = ''; setCheckboxesDisabled(false); showSelectionColumn(); } else { toggleBtn.textContent = 'Enable row selection'; if (controlsEl) controlsEl.style.display = 'none'; setCheckboxesDisabled(true); hideSelectionColumn(); findRowCheckboxes().forEach(function(cb){ cb.checked = false; }); updateSelectedCount(); lastChecked = null; } });
+
+        if (selectAllBtn) selectAllBtn.addEventListener('click', function(){ findRowCheckboxes().forEach(function(cb){ if (!cb.disabled) cb.checked = true; }); updateSelectedCount(); lastChecked = null; });
+        if (clearBtn) clearBtn.addEventListener('click', function(){ findRowCheckboxes().forEach(function(cb){ if (!cb.disabled) cb.checked = false; }); updateSelectedCount(); lastChecked = null; });
+
+        updateSelectedCount();
+    };
+})();
+</script>
+"""
+
+                # Replace the simple placeholder with the runtime token. Using
+                # a plain triple-quoted string avoids f-string brace parsing errors
+                # from the JavaScript code which contains many `{`/`}` characters.
+                script = script.replace('__TOKEN__', token)
+
+                return mark_safe(html + script)
 
 class SingleImageColumn(tables.Column):
     def render(self, value):
diff --git a/rad.code-workspace b/rad.code-workspace
index feb2c722..c0f24d9d 100644
--- a/rad.code-workspace
+++ b/rad.code-workspace
@@ -15,6 +15,10 @@
 			"/^source \\.venv/bin/activate\\.fish && python manage\\.py check$/": {
 				"approve": true,
 				"matchCommandLine": true
+			},
+			"/^python -m py_compile /home/ross/penracourses/rad/generic/tables\\.py$/": {
+				"approve": true,
+				"matchCommandLine": true
 			}
 		}
 	}
diff --git a/templates/base.html b/templates/base.html
index bf743ebb..2b0f0459 100644
--- a/templates/base.html
+++ b/templates/base.html
@@ -348,6 +348,16 @@
 
                 // Selection wiring has been moved into per-table initializers
                 // emitted by `SelectionTable.row_selection_controls`.
+                try {
+                    if (window.__selection_inits) {
+                        Object.keys(window.__selection_inits).forEach(function(k){
+                            try { window.__selection_inits[k](); } catch (e) { console.error('selection init failed', k, e); }
+                            try { delete window.__selection_inits[k]; } catch (e) {}
+                        });
+                    }
+                } catch (err) {
+                    console.error('Error running selection initializers', err);
+                }
             });
         </script>
     </body>
diff --git a/templates/django_tables2/bootstrap4.html b/templates/django_tables2/bootstrap4.html
new file mode 100644
index 00000000..ddf81751
--- /dev/null
+++ b/templates/django_tables2/bootstrap4.html
@@ -0,0 +1,100 @@
+{% load django_tables2 %}
+{% load i18n l10n %}
+{% block table-wrapper %}
+    <div class="table-container">
+        {% if table.caption %}
+            {{ table.caption|safe }}
+        {% endif %}
+        {% block table %}
+            <table {% render_attrs table.attrs class="table" %}>
+                {% block table.thead %}
+                    {% if table.show_header %}
+                        <thead {{ table.attrs.thead.as_html }}>
+                            <tr>
+                                {% for column in table.columns %}
+                                    <th {{ column.attrs.th.as_html }}>
+                                        {% if column.orderable %}
+                                            <a href="{% querystring table.prefixed_order_by_field=column.order_by_alias.next %}">{{ column.header }}</a>
+                                        {% else %}
+                                            {{ column.header }}
+                                        {% endif %}
+                                    </th>
+                                {% endfor %}
+                            </tr>
+                        </thead>
+                    {% endif %}
+                {% endblock table.thead %}
+                {% block table.tbody %}
+                    <tbody {{ table.attrs.tbody.as_html }}>
+                        {% for row in table.paginated_rows %}
+                            {% block table.tbody.row %}
+                                <tr {{ row.attrs.as_html }}>
+                                    {% for column, cell in row.items %}
+                                        <td {{ column.attrs.td.as_html }}>{% if column.localize == None %}{{ cell }}{% else %}{% if column.localize %}{{ cell|localize }}{% else %}{{ cell|unlocalize }}{% endif %}{% endif %}</td>
+                                    {% endfor %}
+                                </tr>
+                            {% endblock table.tbody.row %}
+                        {% empty %}
+                            {% if table.empty_text %}
+                                {% block table.tbody.empty_text %}
+                                    <tr><td colspan="{{ table.columns|length }}">{{ table.empty_text }}</td></tr>
+                                {% endblock table.tbody.empty_text %}
+                            {% endif %}
+                        {% endfor %}
+                    </tbody>
+                {% endblock table.tbody %}
+                {% block table.tfoot %}
+                    {% if table.has_footer %}
+                        <tfoot {{ table.attrs.tfoot.as_html }}>
+                            <tr>
+                                {% for column in table.columns %}
+                                    <td {{ column.attrs.tf.as_html }}>{{ column.footer }}</td>
+                                {% endfor %}
+                            </tr>
+                        </tfoot>
+                    {% endif %}
+                {% endblock table.tfoot %}
+            </table>
+        {% endblock table %}
+
+        {% block pagination %}
+            {% if table.page and table.paginator.num_pages > 1 %}
+                <nav aria-label="Table navigation">
+                    <ul class="pagination justify-content-center">
+                        {% if table.page.has_previous %}
+                            {% block pagination.previous %}
+                                <li class="previous page-item">
+                                    <a href="{% querystring table.prefixed_page_field=table.page.previous_page_number %}" class="page-link">
+                                        <span aria-hidden="true">&laquo;</span>
+                                        {% trans 'previous' %}
+                                    </a>
+                                </li>
+                            {% endblock pagination.previous %}
+                        {% endif %}
+                        {% if table.page.has_previous or table.page.has_next %}
+                            {% block pagination.range %}
+                                {% for p in table.page|table_page_range:table.paginator %}
+                                    <li class="page-item{% if table.page.number == p %} active{% endif %}">
+                                        <a class="page-link" {% if p != '...' %}href="{% querystring table.prefixed_page_field=p %}"{% endif %}>
+                                            {{ p }}
+                                        </a>
+                                    </li>
+                                {% endfor %}
+                            {% endblock pagination.range %}
+                        {% endif %}
+                        {% if table.page.has_next %}
+                            {% block pagination.next %}
+                                <li class="next page-item">
+                                    <a href="{% querystring table.prefixed_page_field=table.page.next_page_number %}" class="page-link">
+                                        {% trans 'next' %}
+                                        <span aria-hidden="true">&raquo;</span>
+                                    </a>
+                                </li>
+                            {% endblock pagination.next %}
+                        {% endif %}
+                    </ul>
+                </nav>
+            {% endif %}
+        {% endblock pagination %}
+    </div>
+{% endblock table-wrapper %}