feat: add login endpoint

db/database.py

@@ -1,5 +1,6 @@
 import os
 import psycopg2
+from psycopg2.extras import RealDictCursor
 
 
 class PostgresConnector:
@@ -18,19 +19,34 @@ class PostgresConnector:
         self.connection.autocommit = False
 
     def execute(self, query, params=None, fetch=False):
-        with self.connection.cursor() as cursor:
+        with self.connection.cursor(cursor_factory=RealDictCursor) as cursor:
             cursor.execute(query, params)
-
             if fetch:
                 return cursor.fetchall()
-
             self.connection.commit()
 
     def executemany(self, query, param_list):
-        with self.connection.cursor() as cursor:
+        with self.connection.cursor(cursor_factory=RealDictCursor) as cursor:
             cursor.executemany(query, param_list)
             self.connection.commit()
 
+    def save_user(self, username, email, password_hash):
+        query = """
+            INSERT INTO users (username, email, password_hash)
+            VALUES (%s, %s, %s)
+        """
+        self.execute(query, (username, email, password_hash))
+
+    def get_user_by_username(self, username) -> dict:
+        query = "SELECT id, username, email, password_hash FROM users WHERE username = %s"
+        result = self.execute(query, (username,), fetch=True)
+        return result[0] if result else None
+    
+    def get_user_by_email(self, email) -> dict:
+        query = "SELECT id, username, email, password_hash FROM users WHERE email = %s"
+        result = self.execute(query, (email,), fetch=True)
+        return result[0] if result else None
+
     def close(self):
         if self.connection:
             self.connection.close()