Add likes, comments, email notifications, and pagination to gallery

2 files changed, 98 insertions, 0 deletions

diff --git a/src/app/Models/Comment.php b/src/app/Models/Comment.php
new file mode 100644
index 0000000..464cfe2
--- /dev/null
+++ b/src/app/Models/Comment.php
@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+// Comment model: database operations for the comments table.
+
+namespace App\Models;
+
+use App\Database;
+
+class Comment
+{
+    private \PDO $pdo;
+
+    public function __construct()
+    {
+        $this->pdo = Database::getInstance()->getPdo();
+    }
+
+    public function create(int $userId, int $postId, string $content): int
+    {
+        $stmt = $this->pdo->prepare(
+            'INSERT INTO comments (user_id, post_id, content) VALUES (:user_id, :post_id, :content)'
+        );
+        $stmt->execute(['user_id' => $userId, 'post_id' => $postId, 'content' => $content]);
+        return (int) $this->pdo->lastInsertId();
+    }
+
+    public function findByPostId(int $postId): array
+    {
+        $stmt = $this->pdo->prepare(
+            'SELECT comments.*, users.username FROM comments
+             JOIN users ON comments.user_id = users.id
+             WHERE comments.post_id = :post_id
+             ORDER BY comments.created_at ASC'
+        );
+        $stmt->execute(['post_id' => $postId]);
+        return $stmt->fetchAll();
+    }
+}
diff --git a/src/app/Models/Like.php b/src/app/Models/Like.php
new file mode 100644
index 0000000..dc019a0
--- /dev/null
+++ b/src/app/Models/Like.php
@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types=1);
+// Like model: database operations for the likes table.
+
+namespace App\Models;
+
+use App\Database;
+
+class Like
+{
+    private \PDO $pdo;
+
+    public function __construct()
+    {
+        $this->pdo = Database::getInstance()->getPdo();
+    }
+
+    /**
+     * Toggle a like: insert if not yet liked, delete if already liked.
+     * Returns true if the post is now liked, false if unliked.
+     */
+    public function toggle(int $userId, int $postId): bool
+    {
+        // INSERT IGNORE silently fails when the UNIQUE(user_id, post_id) constraint
+        // is violated, meaning the user already liked this post
+        $stmt = $this->pdo->prepare(
+            'INSERT IGNORE INTO likes (user_id, post_id) VALUES (:user_id, :post_id)'
+        );
+        $stmt->execute(['user_id' => $userId, 'post_id' => $postId]);
+
+        if ($stmt->rowCount() > 0) {
+            return true;
+        }
+
+        // Row wasn't inserted → already liked → remove the like
+        $stmt = $this->pdo->prepare(
+            'DELETE FROM likes WHERE user_id = :user_id AND post_id = :post_id'
+        );
+        $stmt->execute(['user_id' => $userId, 'post_id' => $postId]);
+        return false;
+    }
+
+    public function countByPost(int $postId): int
+    {
+        $stmt = $this->pdo->prepare('SELECT COUNT(*) FROM likes WHERE post_id = :post_id');
+        $stmt->execute(['post_id' => $postId]);
+        return (int) $stmt->fetchColumn();
+    }
+
+    public function hasUserLiked(int $userId, int $postId): bool
+    {
+        $stmt = $this->pdo->prepare(
+            'SELECT 1 FROM likes WHERE user_id = :user_id AND post_id = :post_id LIMIT 1'
+        );
+        $stmt->execute(['user_id' => $userId, 'post_id' => $postId]);
+        return $stmt->fetch() !== false;
+    }
+}