Updated the interfaces and dropped oauth version

Seems the oauth lib's stable version is 3.2, dropped down from the 4 version
to that.

src/OAuth2/AccessTokenStorage.php

@@ -3,6 +3,7 @@
 namespace Pickles\OAuth2;
 
 use \League\OAuth2\Server\Entity\AbstractTokenEntity;
+use \League\OAuth2\Server\Entity\AccessTokenEntity;
 use \League\OAuth2\Server\Entity\ScopeEntity;
 use \League\OAuth2\Server\Storage\AccessTokenInterface;
 
@@ -10,27 +11,74 @@ class AccessTokenStorage extends StorageAdapter implements AccessTokenInterface
 {
     public function get($token)
     {
+        $sql = 'SELECT oauth_session_access_tokens.*'
+             . ' FROM oauth_session_access_tokens'
+             . ' WHERE access_token = ?'
+             . ' AND access_token_expires >= ?;';
 
+        $results = $this->db->fetch($sql, [$token, time()]);
+
+        if (count($results) === 1)
+        {
+            return (new AccessTokenEntity($this->server))
+                ->setId($results[0]['access_token'])
+                ->setExpireTime($results[0]['access_token_expires']);
+        }
+
+        return null;
     }
 
     public function getScopes(AbstractTokenEntity $token)
     {
+        $sql = 'SELECT oauth_scopes.id, oauth_scopes.description'
+             . ' FROM oauth_session_token_scopes'
+             . ' INNER JOIN oauth_scopes'
+             . ' ON oauth_session_token_scopes.scope_id = oauth_scopes.id'
+             . ' WHERE oauth_session_token_scopes.session_access_token_id = ?;';
 
+        $results  = $this->db->fetch($sql, [$token->getId()]);
+        $response = [];
+
+        if (count($results) > 0)
+        {
+            foreach ($results as $row)
+            {
+                $response[] = (new ScopeEntity($this->server))->hydrate([
+                    'id'          => $row['id'],
+                    'description' => $row['description']
+                ]);
+            }
+        }
+
+        return $response;
     }
 
     public function create($token, $expiration, $session_id)
     {
+        $sql = 'INSERT INTO oauth_session_access_tokens'
+             . ' (access_token, session_id, access_token_expires)'
+             . ' VALUES'
+             . ' (?, ?, ?);';
 
+        $this->db->execute($sql, [$token, $session_id, $expiration]);
     }
 
     public function associateScope(AbstractTokenEntity $token, ScopeEntity $scope)
     {
+        $sql = 'INSERT INTO oauth_session_token_scopes'
+             . ' (access_token, scope)'
+             . ' VALUES'
+             . ' (?, ?);';
 
+        $this->db->execute($sql, [$token->getId(), $scope->getId()]);
     }
 
     public function delete(AbstractTokenEntity $token)
     {
+        $sql = 'DELETE FROM oauth_session_token_scopes'
+             . ' WHERE access_token = ?;';
 
+        $this->db->execute($sql, [$token->getId()]);
     }
 }