Adds theme switcher controller and view

app/pages/theme.php

@@ -0,0 +1,57 @@
+<?php
+/**
+ * Theme Management Controller
+ *
+ * Handles theme switching and management functionality.
+ * Allows users to view available themes and change the active theme.
+ *
+ * Actions:
+ * - switch_to: Changes the active theme for the current user
+ */
+
+// Only allow access to logged-in users
+if (!Session::isValidSession()) {
+    header('Location: ' . $app_root . '?page=login');
+    exit;
+}
+
+// Handle theme switching
+if (isset($_GET['switch_to'])) {
+    $themeName = $_GET['switch_to'];
+
+    // Validate CSRF token for state-changing operations
+    require_once '../app/helpers/security.php';
+    $security = SecurityHelper::getInstance();
+
+    if (!$security->verifyCsrfToken($_GET['csrf_token'] ?? '')) {
+        Feedback::flash('SECURITY', 'CSRF_INVALID');
+        header("Location: $app_root?page=theme");
+        exit();
+    }
+
+    if (\App\Helpers\Theme::setCurrentTheme($themeName)) {
+        // Set success message
+        Feedback::flash('THEME', 'THEME_CHANGED');
+    } else {
+        // Set error message
+        Feedback::flash('THEME', 'THEME_CHANGE_FAILED');
+    }
+
+    // Redirect back to prevent form resubmission
+    $redirect = $app_root . '?page=theme';
+    header("Location: $redirect");
+    exit;
+}
+
+// Get available themes and current theme for the view
+$themes = \App\Helpers\Theme::getAvailableThemes();
+$currentTheme = \App\Helpers\Theme::getCurrentThemeName();
+
+// Generate CSRF token for the form
+$csrf_token = $security->generateCsrfToken();
+
+// Get any new feedback messages
+include '../app/helpers/feedback.php';
+
+// Load the template
+include '../app/templates/theme.php';

app/templates/theme.php

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+<?php
+/**
+ * Theme switcher template
+ *
+ * Displays available themes and allows the user to switch between them.
+ *
+ * @var array $themes List of available themes
+ * @var string $currentTheme Currently active theme ID
+ */
+?>
+                <div class="container mt-4">
+                    <h2>Theme Switcher</h2>
+                    <p class="text-muted">Select a theme to change the appearance of the application.</p>
+                    <div class="row mt-4">
+<?php foreach ($themes as $themeId => $themeName): ?>
+<?php $isActive = $themeId === $currentTheme; ?>
+                        <div class="col-md-4 mb-4">
+                            <div class="card h-100 <?= $isActive ? 'border-primary' : '' ?>">
+<?php if ($isActive) { ?>
+                                <div class="card-header bg-primary text-white">Current Theme</div>
+<?php } ?>
+                                <div class="card-body d-flex flex-column">
+                                    <h5 class="card-title"><?= htmlspecialchars($themeName) ?></h5>
+                                    <p class="card-text text-muted">Theme ID: <code><?= htmlspecialchars($themeId) ?></code></p>
+                                    <div class="mt-auto">
+<?php if (!$isActive) { ?>
+                                        <a href="?page=theme&switch_to=<?= urlencode($themeId) ?>" class="btn btn-primary">Switch to this theme</a>
+<?php } else { ?>
+                                        <button class="btn btn-outline-secondary" disabled>Currently active</button>
+<?php } ?>
+                                    </div>
+                                </div>
+                            </div>
+                        </div>
+<?php endforeach; ?>
+                    </div>
+                </div>