perf(admin): infinite-scroll the contenus langues/mots-clés tables

The contenus page loaded both lookup tables in full via HTMX on page load:
760 tag rows + 216 language rows, ~2.4MB of HTML including ~1960 inline
SVG icons and per-row CSRF forms. The DB queries were already fast (~6ms);
the cost was pure client-side payload and DOM.

- Add paged lookups: getTagsPage/getLanguagesPage + countTagsWithCount/
  countLanguagesWithCount, and optional limit/offset on the existing
  unpaged variants (backward compatible).
- Fragments serve 25 rows per request. A sentinel <tr> with
  hx-trigger="intersect once root:#<wrap>" appends the next page when it
  scrolls into the table's own scroll container (htmx 'revealed' only
  checks the window viewport, not nested scrollers).
- Search forms still swap the whole wrapper and reset to offset 0.
- Style the load-more row; add PagedLanguagesTagsTest coverage.

Initial DOM for the page drops from ~2.4MB to ~160KB; scrolling reaches the
full totals (736 tags, 216 languages) and stops cleanly.

app/public/admin/contenus-langues-fragment.php

@@ -4,6 +4,15 @@
  *
  * HTMX fragment: returns the langues table for the contenus page,
  * optionally filtered by a search query.
+ *
+ * Infinite scroll: rows are served in pages of PAGE_SIZE. When there are
+ * more rows, a sentinel <tr> is emitted with hx-trigger="revealed": when it
+ * scrolls into view htmx fetches the next offset and swaps itself
+ * (outerHTML) with the next chunk of rows + a new sentinel. This keeps the
+ * initial payload small instead of shipping all languages at once.
+ *
+ * When $offset > 0 the fragment returns only the <tr> rows (append mode),
+ * because the sentinel lives inside the existing <tbody>.
  */
 require_once __DIR__ . '/../../bootstrap.php';
 require_once __DIR__ . '/../../src/AdminAuth.php';
@@ -15,14 +24,83 @@ if (empty($_SESSION['csrf_token'])) {
 
 require_once __DIR__ . '/../../src/Database.php';
 
+const LANGUES_PAGE_SIZE = 25;
+
 $searchQuery = trim($_GET['q'] ?? '');
+$offset      = max(0, (int) ($_GET['offset'] ?? 0));
 
 try {
-    $db = new Database();
-    $languages = ($searchQuery !== '') ? $db->searchLanguages($searchQuery) : $db->getAllLanguagesWithCount();
+    $db        = new Database();
+    $languages = $db->getLanguagesPage($searchQuery, LANGUES_PAGE_SIZE, $offset);
+    $total     = $db->countLanguagesWithCount($searchQuery);
 } catch (Exception $e) {
     die('<div class="flash-error">Erreur : ' . htmlspecialchars($e->getMessage()) . '</div>');
 }
+
+$hasMore   = ($offset + count($languages)) < $total;
+$nextUrl   = '/admin/contenus-langues-fragment.php?offset=' . ($offset + LANGUES_PAGE_SIZE)
+           . ($searchQuery !== '' ? '&q=' . urlencode($searchQuery) : '');
+
+/**
+ * Render one <tr> for a language row.
+ */
+function render_langue_row(array $lang): void
+{
+    ?>
+        <tr>
+            <td style="width:1%"><input type="checkbox" name="selected_langs[]" value="<?= (int)$lang['id'] ?>" onchange="languesUpdateBulk()"></td>
+            <td id="lang-name-<?= (int)$lang['id'] ?>" data-name="<?= htmlspecialchars($lang['name']) ?>">
+                <span class="tag-name-cell"><?= htmlspecialchars($lang['name']) ?></span>
+                <button type="button" class="admin-icon-btn admin-icon-btn--edit" title="Renommer"
+                        onclick="languesStartRename(<?= (int)$lang['id'] ?>)">
+                    <?= icon('pencil-note') ?>
+                </button>
+            </td>
+            <td class="admin-tags-count" style="width:1%;white-space:nowrap"><?= (int)$lang['thesis_count'] ?></td>
+            <td class="admin-actions-col" style="width:1%">
+                <div class="admin-actions">
+                    <form method="post" action="actions/language.php" class="admin-inline-form">
+                        <input type="hidden" name="csrf_token" value="<?= htmlspecialchars($_SESSION['csrf_token']) ?>">
+                        <input type="hidden" name="action" value="delete">
+                        <input type="hidden" name="return" value="/admin/contenus.php">
+                        <input type="hidden" name="language_id" value="<?= (int)$lang['id'] ?>">
+                        <button type="button" class="admin-icon-btn admin-icon-btn--delete" title="Supprimer"
+                                onclick="languesConfirmDelete(this, <?= htmlspecialchars(json_encode($lang['name']), ENT_QUOTES) ?>)">
+                            <?= icon('trash') ?>
+                        </button>
+                    </form>
+                </div>
+            </td>
+        </tr>
+    <?php
+}
+
+/**
+ * Render the "load more" sentinel row (or nothing when exhausted).
+ */
+function render_langues_sentinel(bool $hasMore, string $nextUrl): void
+{
+    if (!$hasMore) {
+        return;
+    }
+    ?>
+        <tr class="admin-load-more" hx-get="<?= htmlspecialchars($nextUrl) ?>"
+            hx-trigger="intersect once root:#langues-table-wrap" hx-swap="outerHTML" hx-target="this">
+            <td colspan="4" class="admin-load-more__cell">Chargement…</td>
+        </tr>
+    <?php
+}
+
+// ── Append mode: only the rows, swapped in place of the sentinel ──────────
+if ($offset > 0) {
+    foreach ($languages as $lang) {
+        render_langue_row($lang);
+    }
+    render_langues_sentinel($hasMore, $nextUrl);
+    return;
+}
+
+// ── Initial load: full wrapper ────────────────────────────────────────────
 ?>
 <div id="langues-bulk-actions" class="admin-bulk-actions" style="display:none;position:sticky;top:0;z-index:10">
     <strong><span id="langues-selected-count">0</span> langue(s) sélectionnée(s)</strong>
@@ -68,32 +146,9 @@ try {
         <tr><td colspan="4" class="admin-empty">Aucune langue trouvée.</td></tr>
         <?php else: ?>
         <?php foreach ($languages as $lang): ?>
-        <tr>
-            <td style="width:1%"><input type="checkbox" name="selected_langs[]" value="<?= (int)$lang['id'] ?>" onchange="languesUpdateBulk()"></td>
-            <td id="lang-name-<?= (int)$lang['id'] ?>" data-name="<?= htmlspecialchars($lang['name']) ?>">
-                <span class="tag-name-cell"><?= htmlspecialchars($lang['name']) ?></span>
-                <button type="button" class="admin-icon-btn admin-icon-btn--edit" title="Renommer"
-                        onclick="languesStartRename(<?= (int)$lang['id'] ?>)">
-                    <?= icon('pencil-note') ?>
-                </button>
-            </td>
-            <td class="admin-tags-count" style="width:1%;white-space:nowrap"><?= (int)$lang['thesis_count'] ?></td>
-            <td class="admin-actions-col" style="width:1%">
-                <div class="admin-actions">
-                    <form method="post" action="actions/language.php" class="admin-inline-form">
-                        <input type="hidden" name="csrf_token" value="<?= htmlspecialchars($_SESSION['csrf_token']) ?>">
-                        <input type="hidden" name="action" value="delete">
-                        <input type="hidden" name="return" value="/admin/contenus.php">
-                        <input type="hidden" name="language_id" value="<?= (int)$lang['id'] ?>">
-                        <button type="button" class="admin-icon-btn admin-icon-btn--delete" title="Supprimer"
-                                onclick="languesConfirmDelete(this, <?= htmlspecialchars(json_encode($lang['name']), ENT_QUOTES) ?>)">
-                            <?= icon('trash') ?>
-                        </button>
-                    </form>
-                </div>
-            </td>
-        </tr>
+        <?php render_langue_row($lang); ?>
         <?php endforeach; ?>
+        <?php render_langues_sentinel($hasMore, $nextUrl); ?>
         <?php endif; ?>
     </tbody>
 </table>

app/public/admin/contenus-motscles-fragment.php

@@ -4,6 +4,15 @@
  *
  * HTMX fragment: returns the mots-clés table for the contenus page,
  * optionally filtered by a search query.
+ *
+ * Infinite scroll: rows are served in pages of PAGE_SIZE. When there are
+ * more rows, a sentinel <tr> is emitted with hx-trigger="revealed": when it
+ * scrolls into view htmx fetches the next offset and swaps itself
+ * (outerHTML) with the next chunk of rows + a new sentinel. This keeps the
+ * initial payload small instead of shipping all tags at once.
+ *
+ * When $offset > 0 the fragment returns only the <tr> rows (append mode),
+ * because the sentinel lives inside the existing <tbody>.
  */
 require_once __DIR__ . '/../../bootstrap.php';
 require_once __DIR__ . '/../../src/AdminAuth.php';
@@ -15,14 +24,83 @@ if (empty($_SESSION['csrf_token'])) {
 
 require_once __DIR__ . '/../../src/Database.php';
 
+const MOTSCLES_PAGE_SIZE = 25;
+
 $searchQuery = trim($_GET['q'] ?? '');
+$offset      = max(0, (int) ($_GET['offset'] ?? 0));
 
 try {
-    $db   = new Database();
-    $tags = ($searchQuery !== '') ? $db->searchTags($searchQuery) : $db->getAllTagsWithCount();
+    $db    = new Database();
+    $tags  = $db->getTagsPage($searchQuery, MOTSCLES_PAGE_SIZE, $offset);
+    $total = $db->countTagsWithCount($searchQuery);
 } catch (Exception $e) {
     die('<div class="flash-error">Erreur : ' . htmlspecialchars($e->getMessage()) . '</div>');
 }
+
+$hasMore = ($offset + count($tags)) < $total;
+$nextUrl = '/admin/contenus-motscles-fragment.php?offset=' . ($offset + MOTSCLES_PAGE_SIZE)
+         . ($searchQuery !== '' ? '&q=' . urlencode($searchQuery) : '');
+
+/**
+ * Render one <tr> for a tag row.
+ */
+function render_motscles_row(array $tag): void
+{
+    ?>
+        <tr>
+            <td style="width:1%"><input type="checkbox" name="selected_tags[]" value="<?= (int)$tag['id'] ?>" onchange="motsclesUpdateBulk()"></td>
+            <td id="motscles-name-<?= (int)$tag['id'] ?>" data-name="<?= htmlspecialchars($tag['name']) ?>">
+                <span class="tag-name-cell"><?= htmlspecialchars($tag['name']) ?></span>
+                <button type="button" class="admin-icon-btn admin-icon-btn--edit" title="Renommer"
+                        onclick="motsclesStartRename(<?= (int)$tag['id'] ?>)">
+                    <?= icon('pencil-note') ?>
+                </button>
+            </td>
+            <td class="admin-tags-count" style="width:1%;white-space:nowrap"><?= (int)$tag['thesis_count'] ?></td>
+            <td class="admin-actions-col" style="width:1%">
+                <div class="admin-actions">
+                    <form method="post" action="actions/tag.php" class="admin-inline-form">
+                        <input type="hidden" name="csrf_token" value="<?= htmlspecialchars($_SESSION['csrf_token']) ?>">
+                        <input type="hidden" name="action" value="delete">
+                        <input type="hidden" name="return" value="/admin/contenus.php">
+                        <input type="hidden" name="tag_id" value="<?= (int)$tag['id'] ?>">
+                        <button type="button" class="admin-icon-btn admin-icon-btn--delete" title="Supprimer"
+                                onclick="motsclesConfirmDelete(this, <?= htmlspecialchars(json_encode($tag['name']), ENT_QUOTES) ?>)">
+                            <?= icon('trash') ?>
+                        </button>
+                    </form>
+                </div>
+            </td>
+        </tr>
+    <?php
+}
+
+/**
+ * Render the "load more" sentinel row (or nothing when exhausted).
+ */
+function render_motscles_sentinel(bool $hasMore, string $nextUrl): void
+{
+    if (!$hasMore) {
+        return;
+    }
+    ?>
+        <tr class="admin-load-more" hx-get="<?= htmlspecialchars($nextUrl) ?>"
+            hx-trigger="intersect once root:#motscles-table-wrap" hx-swap="outerHTML" hx-target="this">
+            <td colspan="4" class="admin-load-more__cell">Chargement…</td>
+        </tr>
+    <?php
+}
+
+// ── Append mode: only the rows, swapped in place of the sentinel ──────────
+if ($offset > 0) {
+    foreach ($tags as $tag) {
+        render_motscles_row($tag);
+    }
+    render_motscles_sentinel($hasMore, $nextUrl);
+    return;
+}
+
+// ── Initial load: full wrapper ────────────────────────────────────────────
 ?>
 <div id="motscles-bulk-actions" class="admin-bulk-actions" style="display:none;position:sticky;top:0;z-index:10">
     <strong><span id="motscles-selected-count">0</span> mot(s)-clé(s) sélectionné(s)</strong>
@@ -68,32 +146,9 @@ try {
         <tr><td colspan="4" class="admin-empty">Aucun mot-clé trouvé.</td></tr>
         <?php else: ?>
         <?php foreach ($tags as $tag): ?>
-        <tr>
-            <td style="width:1%"><input type="checkbox" name="selected_tags[]" value="<?= (int)$tag['id'] ?>" onchange="motsclesUpdateBulk()"></td>
-            <td id="motscles-name-<?= (int)$tag['id'] ?>" data-name="<?= htmlspecialchars($tag['name']) ?>">
-                <span class="tag-name-cell"><?= htmlspecialchars($tag['name']) ?></span>
-                <button type="button" class="admin-icon-btn admin-icon-btn--edit" title="Renommer"
-                        onclick="motsclesStartRename(<?= (int)$tag['id'] ?>)">
-                    <?= icon('pencil-note') ?>
-                </button>
-            </td>
-            <td class="admin-tags-count" style="width:1%;white-space:nowrap"><?= (int)$tag['thesis_count'] ?></td>
-            <td class="admin-actions-col" style="width:1%">
-                <div class="admin-actions">
-                    <form method="post" action="actions/tag.php" class="admin-inline-form">
-                        <input type="hidden" name="csrf_token" value="<?= htmlspecialchars($_SESSION['csrf_token']) ?>">
-                        <input type="hidden" name="action" value="delete">
-                        <input type="hidden" name="return" value="/admin/contenus.php">
-                        <input type="hidden" name="tag_id" value="<?= (int)$tag['id'] ?>">
-                        <button type="button" class="admin-icon-btn admin-icon-btn--delete" title="Supprimer"
-                                onclick="motsclesConfirmDelete(this, <?= htmlspecialchars(json_encode($tag['name']), ENT_QUOTES) ?>)">
-                            <?= icon('trash') ?>
-                        </button>
-                    </form>
-                </div>
-            </td>
-        </tr>
+        <?php render_motscles_row($tag); ?>
         <?php endforeach; ?>
+        <?php render_motscles_sentinel($hasMore, $nextUrl); ?>
         <?php endif; ?>
     </tbody>
 </table>

app/public/assets/css/admin.css

@@ -255,6 +255,22 @@
   text-align: center;
 }
 
+/* "Load more" sentinel row for infinite-scroll admin tables (contenus).
+   Sits at the bottom of the <tbody>; htmx replaces it with the next page
+   of rows when it scrolls into the table's viewport. */
+.admin-load-more__cell {
+  color: var(--text-tertiary);
+  padding: var(--space-s) var(--space-2xs);
+  text-align: center;
+  font-size: var(--step--1);
+}
+
+/* Fade the sentinel out once its request is in flight so it does not
+   visually "stick" while the next page is fetched. */
+.admin-load-more.htmx-request .admin-load-more__cell {
+  opacity: 0.4;
+}
+
 /* Identifier column in the thesis table */
 .admin-table-id {
   color: var(--text-secondary);

app/src/Database.php

@@ -1390,11 +1390,41 @@ class Database
     }
 
     /**
-     * Return all tags with a count of associated (published) theses.
+     * Paged tag listing used by the admin contenus "load more" fragment.
+     * Same ordering as getAllTagsWithCount(); $query filters by name prefix.
      */
-    public function getAllTagsWithCount(): array
+    public function getTagsPage(string $query = '', int $limit = 100, int $offset = 0): array
     {
-        $stmt = $this->pdo->query('
+        $query = trim($query);
+        $sql = '
+            SELECT tg.id, tg.name,
+                   COUNT(DISTINCT t.id) as thesis_count
+            FROM tags tg
+            LEFT JOIN thesis_tags tt ON tg.id = tt.tag_id
+            LEFT JOIN theses t ON tt.thesis_id = t.id AND t.deleted_at IS NULL
+            WHERE tg.deleted_at IS NULL';
+        $params = [];
+        if ($query !== '') {
+            $sql .= ' AND tg.name LIKE ?';
+            $params[] = $query . '%';
+        }
+        $sql .= ' GROUP BY tg.id ORDER BY tg.name COLLATE NOCASE LIMIT ? OFFSET ?';
+        $params[] = $limit;
+        $params[] = $offset;
+        $stmt = $this->pdo->prepare($sql);
+        $stmt->execute($params);
+        return $stmt->fetchAll();
+    }
+
+    /**
+     * Return all tags with a count of associated (published) theses.
+     *
+     * @param int|null $limit  Optional page size (for htmx infinite scroll).
+     * @param int      $offset Row offset when $limit is set.
+     */
+    public function getAllTagsWithCount(?int $limit = null, int $offset = 0): array
+    {
+        $sql = '
             SELECT tg.id, tg.name,
                    COUNT(DISTINCT t.id) as thesis_count
             FROM tags tg
@@ -1403,8 +1433,32 @@ class Database
             WHERE tg.deleted_at IS NULL
             GROUP BY tg.id
             ORDER BY tg.name COLLATE NOCASE
-        ');
-        return $stmt->fetchAll();
+        ';
+        if ($limit !== null) {
+            $stmt = $this->pdo->prepare($sql . ' LIMIT ? OFFSET ?');
+            $stmt->execute([$limit, $offset]);
+            return $stmt->fetchAll();
+        }
+        return $this->pdo->query($sql)->fetchAll();
+    }
+
+    /**
+     * Count tags matching an optional name prefix (used to know when the
+     * infinite-scroll page has reached the end).
+     */
+    public function countTagsWithCount(string $query = ''): int
+    {
+        $query = trim($query);
+        if ($query === '') {
+            return (int) $this->pdo->query(
+                'SELECT COUNT(*) FROM tags WHERE deleted_at IS NULL'
+            )->fetchColumn();
+        }
+        $stmt = $this->pdo->prepare(
+            'SELECT COUNT(*) FROM tags WHERE name LIKE ? AND deleted_at IS NULL'
+        );
+        $stmt->execute([$query . '%']);
+        return (int) $stmt->fetchColumn();
     }
 
     /**
@@ -1514,11 +1568,14 @@ class Database
 
     /**
      * Return all languages with a count of associated theses.
+     *
+     * @param int|null $limit  Optional page size (for htmx infinite scroll).
+     * @param int      $offset Row offset when $limit is set.
      */
-    public function getAllLanguagesWithCount(): array
+    public function getAllLanguagesWithCount(?int $limit = null, int $offset = 0): array
     {
         // Group by lowercased name to deduplicate, keeping the first id
-        $stmt = $this->pdo->query('
+        $sql = '
             SELECT MIN(l.id) as id,
                    UPPER(SUBSTR(MIN(l.name),1,1)) || SUBSTR(MIN(l.name),2) as name,
                    COUNT(DISTINCT t.id) as thesis_count
@@ -1528,7 +1585,60 @@ class Database
             WHERE l.deleted_at IS NULL
             GROUP BY LOWER(l.name)
             ORDER BY LOWER(MIN(l.name)) COLLATE NOCASE
-        ');
+        ';
+        if ($limit !== null) {
+            $stmt = $this->pdo->prepare($sql . ' LIMIT ? OFFSET ?');
+            $stmt->execute([$limit, $offset]);
+            return $stmt->fetchAll();
+        }
+        return $this->pdo->query($sql)->fetchAll();
+    }
+
+    /**
+     * Count distinct languages matching an optional name prefix (used to know
+     * when the infinite-scroll page has reached the end).
+     */
+    public function countLanguagesWithCount(string $query = ''): int
+    {
+        $query = trim($query);
+        if ($query === '') {
+            return (int) $this->pdo->query(
+                'SELECT COUNT(DISTINCT LOWER(name)) FROM languages WHERE deleted_at IS NULL'
+            )->fetchColumn();
+        }
+        $stmt = $this->pdo->prepare(
+            'SELECT COUNT(DISTINCT LOWER(name)) FROM languages WHERE LOWER(name) LIKE LOWER(?) AND deleted_at IS NULL'
+        );
+        $stmt->execute([$query . '%']);
+        return (int) $stmt->fetchColumn();
+    }
+
+    /**
+     * Paged language listing used by the admin contenus "load more" fragment.
+     * Same ordering/dedup as getAllLanguagesWithCount(); $query filters by
+     * name prefix.
+     */
+    public function getLanguagesPage(string $query = '', int $limit = 100, int $offset = 0): array
+    {
+        $query = trim($query);
+        $sql = '
+            SELECT MIN(l.id) as id,
+                   UPPER(SUBSTR(MIN(l.name),1,1)) || SUBSTR(MIN(l.name),2) as name,
+                   COUNT(DISTINCT t.id) as thesis_count
+            FROM languages l
+            LEFT JOIN thesis_languages tl ON l.id = tl.language_id
+            LEFT JOIN theses t ON tl.thesis_id = t.id AND t.deleted_at IS NULL
+            WHERE l.deleted_at IS NULL';
+        $params = [];
+        if ($query !== '') {
+            $sql .= ' AND LOWER(l.name) LIKE LOWER(?)';
+            $params[] = $query . '%';
+        }
+        $sql .= ' GROUP BY LOWER(l.name) ORDER BY LOWER(MIN(l.name)) COLLATE NOCASE LIMIT ? OFFSET ?';
+        $params[] = $limit;
+        $params[] = $offset;
+        $stmt = $this->pdo->prepare($sql);
+        $stmt->execute($params);
         return $stmt->fetchAll();
     }