from ldap3 import (
    Server,
    Connection,
    ALL,
    NTLM,
    SIMPLE,
    SUBTREE
)

from flask import current_app
from app.config import Config


class LDAPService:
    """
    LDAP / Active Directory Authentication Service
    """

    @staticmethod
    def authenticate(username, password):
        """
        Authenticate LDAP User

        Returns:
            {
                "success": True,
                "user": {
                    "username": "...",
                    "name": "...",
                    "email": "..."
                }
            }

        OR

            {
                "success": False,
                "message": "Invalid username or password"
            }
        """

        if not username or not password:
            return {
                "success": False,
                "message": "Username and Password are required."
            }

        try:

            # -----------------------------------
            # LDAP SERVER
            # -----------------------------------
            server = Server(
                Config.LDAP_SERVER,
                port=Config.LDAP_PORT,
                use_ssl=Config.LDAP_USE_SSL,
                get_info=ALL
            )

            # -----------------------------------
            # Login Format
            #
            # username@domain.com
            # -----------------------------------
            user_dn = f"{username}@{Config.LDAP_DOMAIN}"

            conn = Connection(
                server,
                user=user_dn,
                password=password,
                authentication=SIMPLE,
                auto_bind=True
            )

            # -----------------------------------
            # Search User
            # -----------------------------------
            search_filter = f"(sAMAccountName={username})"

            conn.search(
                search_base=Config.LDAP_SEARCH_BASE,
                search_filter=search_filter,
                search_scope=SUBTREE,
                attributes=[
                    "displayName",
                    "mail",
                    "givenName",
                    "sn",
                    "cn"
                ]
            )

            display_name = username
            email = ""

            if conn.entries:

                entry = conn.entries[0]

                if "displayName" in entry:
                    display_name = str(entry.displayName)

                if "mail" in entry:
                    email = str(entry.mail)

            conn.unbind()

            current_app.logger.info(
                f"LDAP Login Success : {username}"
            )

            return {
                "success": True,
                "user": {
                    "username": username,
                    "name": display_name,
                    "email": email
                }
            }

        except Exception as ex:

            current_app.logger.warning(
                f"LDAP Login Failed : {username} : {str(ex)}"
            )

            return {
                "success": False,
                "message": "Invalid Username or Password."
            }