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"""Objects relating to sourcing connections from environment variables."""

from __future__ import annotations

import os
import re

from airflow.secrets import BaseSecretsBackend

CONN_ENV_PREFIX = "AIRFLOW_CONN_"
VAR_ENV_PREFIX = "AIRFLOW_VAR_"


class EnvironmentVariablesBackend(BaseSecretsBackend):
    """Retrieves Connection object and Variable from environment variable."""

    def get_conn_value(self, conn_id: str, team_name: str | None = None) -> str | None:
        if self._is_team_specific_accessed_as_global(conn_id, team_name):
            return None

        if team_name and (
            team_var := os.environ.get(f"{CONN_ENV_PREFIX}_{team_name.upper()}___" + conn_id.upper())
        ):
            # Format to set a team specific connection: AIRFLOW_CONN__<TEAM_ID>___<CONN_ID>
            return team_var

        return os.environ.get(CONN_ENV_PREFIX + conn_id.upper())

    def get_variable(self, key: str, team_name: str | None = None) -> str | None:
        """
        Get Airflow Variable from Environment Variable.

        :param key: Variable Key
        :param team_name: Team name associated to the task trying to access the variable (if any)
        :return: Variable Value
        """
        if self._is_team_specific_accessed_as_global(key, team_name):
            return None

        if team_name and (
            team_var := os.environ.get(f"{VAR_ENV_PREFIX}_{team_name.upper()}___" + key.upper())
        ):
            # Format to set a team specific variable: AIRFLOW_VAR__<TEAM_ID>___<VAR_KEY>
            return team_var

        return os.environ.get(VAR_ENV_PREFIX + key.upper())

    @staticmethod
    def _is_team_specific_accessed_as_global(secret_id: str, team_name: str | None = None) -> bool:
        return team_name is None and bool(re.fullmatch(r"_[^_]+___.+", secret_id))
