initial code commit

Service/UserManager.php

@@ -0,0 +1,42 @@
+<?php
+namespace Hpz937\BillReminder\Service;
+
+use Hpz937\BillReminder\Database\DatabaseInterface;
+use Hpz937\BillReminder\Model\User;
+
+class UserManager {
+    private DatabaseInterface $db;
+
+    public function __construct(DatabaseInterface $db) {
+        $this->db = $db;
+    }
+
+    public function register(string $username, string $password): bool {
+        $passwordHash = password_hash($password, PASSWORD_DEFAULT);
+
+        $sql = "INSERT INTO users (username, passwordHash) VALUES (:username, :passwordHash)";
+        $this->db->prepare($sql);
+        return $this->db->execute([
+            ':username' => $username,
+            ':passwordHash' => $passwordHash,
+        ]);
+    }
+
+    public function login(string $username, string $password): ?User {
+        $sql = "SELECT * FROM users WHERE username = :username";
+        $this->db->prepare($sql);
+        $this->db->execute([':username' => $username]);
+        $result = $this->db->fetch();
+
+        if ($result && (new User($result['id'], $result['username'], $result['passwordHash']))->verifyPassword($password)) {
+            // Start or regenerate the session
+            session_regenerate_id();
+            $_SESSION['user_id'] = $result['id'];
+            return new User($result['id'], $result['username'], $result['passwordHash']);
+        }
+
+        return null;
+    }
+
+    // Additional methods as needed, e.g., for password change, user details update, etc.
+}