feat: add login endpoint

server/auth.py

@@ -1,12 +1,24 @@
 from db.database import PostgresConnector
+from flask_bcrypt import Bcrypt
 
 class AuthManager:
-    def __init__(self, db: PostgresConnector, bcrypt):
+    def __init__(self, db: PostgresConnector, bcrypt: Bcrypt):
         self.db = db
         self.bcrypt = bcrypt
 
-    def register_user(self, username, password):
-        # Hash the password
+    def register_user(self, username, email, password):
         hashed_password = self.bcrypt.generate_password_hash(password).decode("utf-8")
-        # Save the user to the database
-        self.db.save_user(username, hashed_password)
+
+        if self.db.get_user_by_email(email):
+            raise ValueError("Email already registered")
+        
+        if self.db.get_user_by_username(username):
+            raise ValueError("Username already taken")
+
+        self.db.save_user(username, email, hashed_password)
+
+    def authenticate_user(self, username, password):
+        user = self.db.get_user_by_username(username)
+        if user and self.bcrypt.check_password_hash(user['password_hash'], password):
+            return user
+        return None