rework algorithm for password reset

- after generating token, return request id and token
- improve logic for verifying token

src/models/User.php

@@ -4,7 +4,7 @@
 
 namespace Steamy\Model;
 
-use Random\RandomException;
+use Exception;
 use Steamy\Core\Model;
 
 abstract class User
@@ -217,49 +217,97 @@ public static function getUserIdByEmail(string $email): ?int
     }
 
     /**
-     * @param int $userId
-     * @return string|null The hashed token for a password reset
-     * @throws RandomException Unable to generate token
+     * Generates a password reset token for a user. A hash of the token
+     * is stored in the database.
+     *
+     * @param int $userId ID of user to which password reset token belongs
+     * @return array|null An associative array with attributes `request_id` and `token`
+     * @throws Exception
      */
-    public static function savePasswordChangeRequest(int $userId): ?string
+    public static function generatePasswordResetToken(int $userId): ?array
     {
         if ($userId < 0) {
             return null;
         }
 
+        $info = []; // array to store token and request ID
+
         // Generate random token and its associated information
-        $token = bin2hex(random_bytes(16)); // length 32 bytes (hexadecimal format)
+        $info['token'] = "";
+        try {
+            $info['token'] = bin2hex(random_bytes(16)); // length 32 bytes (hexadecimal format)
+        } catch (Exception) {
+            throw new Exception('Token cannot be generated');
+        }
+
         $expiryDate = date('Y-m-d H:i:s', strtotime('+1 day')); // Expiry date set to 1 day from now
-        $tokenHash = password_hash($token, PASSWORD_BCRYPT); // Hashing the token for security
+        $tokenHash = password_hash($info['token'], PASSWORD_BCRYPT); // Hashing the token for security
 
-        // Save password change info to database
+        // Save token info to database
         $query = "INSERT INTO password_change_request (user_id, token_hash, expiry_date)
                   VALUES (:userId, :tokenHash, :expiryDate)";
-
         self::query($query, ['userId' => $userId, 'tokenHash' => $tokenHash, 'expiryDate' => $expiryDate]);
 
-        return $tokenHash;
+
+        // get ID of last inserted record
+        // Ref: https://stackoverflow.com/a/39141771/17627866
+        $query = <<< EOL
+            SELECT LAST_INSERT_ID(request_id)  as request_id
+            FROM password_change_request
+            ORDER BY LAST_INSERT_ID(request_id)
+            DESC LIMIT 1;
+        EOL;
+        $info['request_id'] = self::query($query)[0]->request_id;
+
+        return $info;
     }
 
 
-    public static function getUserIdByToken(string $token): ?int
+    /**
+     * Uses a password reset token to change the password of a user.
+     * @param int $requestID request ID corresponding to password reset token
+     * @param string $token Password reset token
+     * @param string $new_password New password of user in plain text (not hashed)
+     * @return bool
+     */
+    public static function resetPassword(int $requestID, string $token, string $new_password): bool
     {
-        // Implement logic to fetch user ID by token from the database
-        $query = "SELECT user_id FROM password_change_request WHERE token_hash = :token AND expiry_date > NOW() AND used = 0";
-        $result = self::query($query, ['token' => $token]);
+        // fetch matching request from database if valid (not expired and unused)
+        $query = <<< EOL
+        SELECT * FROM password_change_request
+        WHERE expiry_date > NOW() AND used = 0 AND request_id = :requestID
+        EOL;
+
+        $result = self::query($query, ['requestID' => $requestID]);
 
-        if ($result && !empty($result[0]->user_id)) {
-            return $result[0]->user_id;
+        if (empty($result)) {
+            return false;
         }
 
-        return null;
-    }
+        $request = $result[0];
 
-    public static function updatePassword(int $userId, string $hashedPassword): void
-    {
-        // Implement logic to update user's password in the database
+        // verify token
+        if (!password_verify($token, $request->token_hash)) {
+            return false;
+        }
+
+        // validate password
+        if (!empty(self::validatePlainPassword($new_password))) {
+            return false;
+        }
+
+        $hashedPassword = password_hash($new_password, PASSWORD_BCRYPT);
+
+        // Update user's password in the database
         $query = "UPDATE user SET password = :password WHERE user_id = :userId";
-        self::query($query, ['password' => $hashedPassword, 'userId' => $userId]);
+        self::query($query, ['password' => $hashedPassword, 'userId' => $request->user_id]);
+
+
+        // Invalidate password request token so that token cannot be used again
+        $query = "UPDATE password_change_request SET used = 1 WHERE request_id = :requestID";
+        self::query($query, ['requestID' => $request->request_id]);
+
+        return true;
     }
 
 }