from flask import current_app
from app.models.user_model import User
from app.services.db_service import db
from app.services.ldap_service import LDAPService

class UserService:

    @staticmethod
    def register_user(name, email, password):
        if User.query.filter_by(email=email).first():
            return None

        user = User(name=name, email=email, auth_source="local")
        user.set_password(password)

        db.session.add(user)
        db.session.commit()
        return user

    @staticmethod
    def validate_login(identifier, password):
        """
        identifier = whatever was typed in the login form. Can be an email
        (local users) or an LDAP username, depending on USE_LDAP_AUTH.
        """
        if current_app.config.get("USE_LDAP_AUTH"):
            ldap_user = UserService._validate_ldap_login(identifier, password)
            if ldap_user:
                return ldap_user
            return None
        user = User.query.filter_by(email=identifier).first()
        if user and user.check_password(password):
            return user
        return None

    @staticmethod
    def _validate_ldap_login(username, password):
        ldap_info = LDAPService.authenticate(username, password)
        if not ldap_info:
            return None
        return UserService._get_or_create_ldap_user(ldap_info)

    @staticmethod
    def _get_or_create_ldap_user(ldap_info):
        """
        LDAP is the source of truth for the password. We still keep a row in
        our local `users` table (no password) so the rest of the app - which
        expects a User with an id - keeps working unchanged.
        """
        user = User.query.filter_by(email=ldap_info["email"]).first()
        if user is None:
            user = User(
                name=ldap_info["name"],
                email=ldap_info["email"],
                auth_source="ldap",
            )
            db.session.add(user)
            db.session.commit()
        elif user.name != ldap_info["name"]:
            user.name = ldap_info["name"]
            db.session.commit()
        return user

    @staticmethod
    def get_all_users():
        return User.query.all()