Add product comparison feature with dynamic attribute display

compare.php

@@ -0,0 +1,159 @@
+<?php
+require_once __DIR__ . '/lib/bootstrap.php';
+$conn = db_connect();
+
+$title = "Produktvergleich | Geizkragen";
+include 'header.php';
+
+if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['remove_compare'])) {
+    $removeId = (int)$_POST['remove_compare_id'];
+    if (isset($_SESSION['compare']) && is_array($_SESSION['compare'])) {
+        foreach ($_SESSION['compare'] as $cat => &$prodList) {
+            $key = array_search($removeId, $prodList);
+            if ($key !== false) {
+                unset($prodList[$key]);
+            }
+        }
+        unset($prodList);
+    }
+}
+?>
+
+<div class="container" style="color: white; margin-top: 2rem;">
+    <h1>Produktvergleich</h1>
+    
+    <?php
+    $hasProducts = false;
+    if (isset($_SESSION['compare']) && is_array($_SESSION['compare'])) {
+        foreach ($_SESSION['compare'] as $categoryId => $productIds) {
+            if (empty($productIds)) continue;
+            $hasProducts = true;
+            
+            // Kategorie-Namen holen
+            $catName = "Kategorie $categoryId";
+            $stmtCat = $conn->prepare("SELECT name FROM categories WHERE categoryID = ?");
+            if ($stmtCat) {
+                $stmtCat->bind_param("i", $categoryId);
+                $stmtCat->execute();
+                $resCat = $stmtCat->get_result();
+                if ($row = $resCat->fetch_assoc()) {
+                    $catName = $row['name'];
+                }
+                $stmtCat->close();
+            }
+            
+            // Attribute der Kategorie holen
+            $attributes = [];
+            $stmtAttr = $conn->prepare("
+                SELECT a.attributeID, a.name, a.unit, a.dataType 
+                FROM categoryAttributes ca
+                JOIN attributes a ON ca.attributeID = a.attributeID
+                WHERE ca.categoryID = ?
+                ORDER BY a.attributeID
+            ");
+            if ($stmtAttr) {
+                $stmtAttr->bind_param("i", $categoryId);
+                $stmtAttr->execute();
+                $resAttr = $stmtAttr->get_result();
+                while ($row = $resAttr->fetch_assoc()) {
+                    $attributes[$row['attributeID']] = $row;
+                }
+                $stmtAttr->close();
+            }
+            
+            // Produktdaten holen
+            $products = [];
+            $idList = implode(',', array_map('intval', $productIds));
+            $stmtProd = $conn->query("SELECT productID, model, imagePath, description FROM products WHERE productID IN ($idList)");
+            if ($stmtProd) {
+                while ($row = $stmtProd->fetch_assoc()) {
+                    $products[$row['productID']] = $row;
+                }
+            }
+            
+            // Produktattribute holen
+            $productAttrVals = [];
+            $stmtProdAttr = $conn->query("SELECT productID, attributeID, valueString, valueNumber, valueBool FROM productAttributes WHERE productID IN ($idList)");
+            if ($stmtProdAttr) {
+                while ($row = $stmtProdAttr->fetch_assoc()) {
+                    $productAttrVals[$row['productID']][$row['attributeID']] = $row;
+                }
+            }
+            ?>
+            
+            <h2 style="margin-top: 2rem; border-bottom: 2px solid #334155; padding-bottom: 0.5rem;"><?= htmlspecialchars($catName) ?></h2>
+            
+            <div style="overflow-x: auto; margin-top: 1rem;">
+                <table style="width: 100%; border-collapse: collapse; min-width: 600px;">
+                    <thead>
+                        <tr>
+                            <th style="padding: 10px; border: 1px solid #334155; background: #1e293b; text-align: left; width: 200px;">Eigenschaft</th>
+                            <?php foreach ($productIds as $pId): ?>
+                                <?php if (!isset($products[$pId])) continue; ?>
+                                <th style="padding: 10px; border: 1px solid #334155; background: #1e293b; text-align: center; width: 250px;">
+                                    <div style="margin-bottom: 10px;">
+                                        <a href="productpage.php?id=<?= $pId ?>">
+                                            <img src="<?= htmlspecialchars($products[$pId]['imagePath'] ?? 'assets/images/placeholder.png') ?>" alt="Produktbild" style="max-height: 100px; display: block; margin: 0 auto; border-radius: 4px;">
+                                        </a>
+                                    </div>
+                                    <h3 style="font-size: 1.1rem; margin: 0;"><a href="productpage.php?id=<?= $pId ?>" style="color: #60a5fa; text-decoration: none;"><?= htmlspecialchars($products[$pId]['model']) ?></a></h3>
+                                    
+                                    <form method="POST" action="compare.php" style="margin-top: 10px;">
+                                        <input type="hidden" name="remove_compare" value="1">
+                                        <input type="hidden" name="remove_compare_id" value="<?= $pId ?>">
+                                        <button type="submit" style="background: #ef4444; border: none; color: white; padding: 5px 10px; border-radius: 4px; cursor: pointer; font-size: 0.8rem;">Entfernen</button>
+                                    </form>
+                                </th>
+                            <?php endforeach; ?>
+                        </tr>
+                    </thead>
+                    <tbody>
+                        <tr>
+                            <td style="padding: 10px; border: 1px solid #334155; font-weight: bold; background: #0f172a;">Beschreibung</td>
+                            <?php foreach ($productIds as $pId): ?>
+                                <?php if (!isset($products[$pId])) continue; ?>
+                                <td style="padding: 10px; border: 1px solid #334155; text-align: left; vertical-align: top; background: <?= $pId % 2 == 0 ? '#1e293b' : '#0f172a' ?>;">
+                                    <?= htmlspecialchars($products[$pId]['description']) ?>
+                                </td>
+                            <?php endforeach; ?>
+                        </tr>
+                        <?php foreach ($attributes as $attrId => $attr): ?>
+                            <tr>
+                                <td style="padding: 10px; border: 1px solid #334155; font-weight: bold; background: #0f172a;"><?= htmlspecialchars($attr['name']) ?></td>
+                                <?php foreach ($productIds as $pId): ?>
+                                    <?php if (!isset($products[$pId])) continue; ?>
+                                    <td style="padding: 10px; border: 1px solid #334155; text-align: center; background: <?= $pId % 2 == 0 ? '#1e293b' : '#0f172a' ?>;">
+                                        <?php
+                                        if (isset($productAttrVals[$pId][$attrId])) {
+                                            $valRow = $productAttrVals[$pId][$attrId];
+                                            if (!empty($valRow['valueString'])) {
+                                                echo htmlspecialchars($valRow['valueString']);
+                                            } elseif (!empty($valRow['valueNumber']) || $valRow['valueNumber'] === '0.00' || $valRow['valueNumber'] === 0) {
+                                                echo htmlspecialchars(floatval($valRow['valueNumber'])) . " " . htmlspecialchars($attr['unit']);
+                                            } elseif ($valRow['valueBool'] !== null) {
+                                                echo $valRow['valueBool'] ? 'Ja' : 'Nein';
+                                            } else {
+                                                echo '-';
+                                            }
+                                        } else {
+                                            echo '-';
+                                        }
+                                        ?>
+                                    </td>
+                                <?php endforeach; ?>
+                            </tr>
+                        <?php endforeach; ?>
+                    </tbody>
+                </table>
+            </div>
+            <?php
+        }
+    }
+    
+    if (!$hasProducts) {
+        echo "<p style='margin-top: 2rem;'>Du hast noch keine Produkte zum Vergleich hinzugefügt. Gehe auf eine Produktseite, um Produkte hinzuzufügen.</p>";
+    }
+    ?>
+</div>
+
+<?php include 'footer.php'; ?>

header.php

@@ -75,6 +75,9 @@
                     <li class="nav__item nav__item--mobile">
                         <a href="wunschliste.php" class="nav__link">Wunschliste</a>
                     </li>
+                    <li class="nav__item nav__item--mobile">
+                        <a href="compare.php" class="nav__link">Vergleich</a>
+                    </li>
                     <li class="nav__item nav__item--mobile">
                         <a href="account.php" class="nav__link">Account</a>
                     </li>
@@ -92,6 +95,13 @@
             <!-- ═══ /Slide-In-Menü ═══ -->
 
             <div class="nav__actions">
+                <a class="nav__login nav__wishlist" href="compare.php" aria-label="Vergleich">
+                    <svg class="icon icon-user" viewBox="0 0 24 24" aria-hidden="true" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+                        <line x1="18" y1="20" x2="18" y2="10"></line>
+                        <line x1="12" y1="20" x2="12" y2="4"></line>
+                        <line x1="6" y1="20" x2="6" y2="14"></line>
+                    </svg>
+                </a>
                 <a class="nav__login nav__wishlist" href="wunschliste.php" aria-label="Wunschliste">
                     <svg class="icon icon-user" viewBox="0 0 24 24" aria-hidden="true">
                         <path d="M16 2H8a3 3 0 0 0-3 3v16a1 1 0 0 0 .5.87a1 1 0 0 0 1 0l5.5-3.18l5.5 3.18a1 1 0 0 0 .5.13a1 1 0 0 0 .5-.13A1 1 0 0 0 19 21V5a3 3 0 0 0-3-3Zm1 17.27l-4.5-2.6a1 1 0 0 0-1 0L7 19.27V5a1 1 0 0 1 1-1h8a1 1 0 0 1 1 1Z"

productpage.php

@@ -50,7 +50,8 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['delete_review']) && i
         pa.valueBool,
         p.model,
         p.description,
-        p.imagePath
+        p.imagePath,
+        p.categoryID
     FROM products p
 
     INNER JOIN categoryAttributes ca
@@ -74,6 +75,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['delete_review']) && i
 
     $result = $stmt->get_result();
     $product = $result->fetch_assoc();
+    $categoryId = $product['categoryID'];
 
     $alreadyInWishlist = false;
 
@@ -135,6 +137,25 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_SESSION['user_id'])) {
         }
     }
 }
+
+// Vergleichslogik
+if (!isset($_SESSION['compare'])) {
+    $_SESSION['compare'] = [];
+}
+if (!isset($_SESSION['compare'][$categoryId])) {
+    $_SESSION['compare'][$categoryId] = [];
+}
+$alreadyInCompare = in_array($productId, $_SESSION['compare'][$categoryId]);
+
+if ($_SERVER['REQUEST_METHOD'] === 'POST') {
+    if (isset($_POST['add_compare']) && !$alreadyInCompare) {
+        $_SESSION['compare'][$categoryId][] = $productId;
+        $alreadyInCompare = true;
+    } elseif (isset($_POST['remove_compare']) && $alreadyInCompare) {
+        $_SESSION['compare'][$categoryId] = array_diff($_SESSION['compare'][$categoryId], [$productId]);
+        $alreadyInCompare = false;
+    }
+}
 ?>
 
 
@@ -201,6 +222,24 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_SESSION['user_id'])) {
                 </div>
             <?php endif; ?>
 
+            <?php if ($alreadyInCompare): ?>
+                <form method="POST">
+                    <input type="hidden" name="product_id" value="<?= (int)$productId ?>">
+                    <input type="hidden" name="remove_compare" value="1">
+                    <div class="auth__actions" style="margin-top: 10px;">
+                        <input class="auth__submit" type="submit" value="Aus Vergleich entfernen" style="background: #eab308; border-color: #eab308; color: white;">
+                    </div>
+                </form>
+            <?php else: ?>
+                <form method="POST">
+                    <input type="hidden" name="product_id" value="<?= (int)$productId ?>">
+                    <input type="hidden" name="add_compare" value="1">
+                    <div class="auth__actions" style="margin-top: 10px;">
+                        <input class="auth__submit" type="submit" value="Zum Vergleich hinzufügen" style="background: #3b82f6; border-color: #3b82f6; color: white;">
+                    </div>
+                </form>
+            <?php endif; ?>
+
             <div class="review-overview-box">
                 <?php if ($reviewOverview['reviewCount'] > 0): ?>
                     <div class="overview-header">