from __future__ import annotations

from dataclasses import dataclass

from ingestion.common.env import require_env
from ingestion.common.load_config import LoadConfigBase, TableTargets, load_config_file

# Re-exported so importers (and tests) can use ``from ...config import TableTargets``.
__all__ = ["LoadConfig", "TableTargets", "load_load_config"]


@dataclass(frozen=True)
class LoadConfig(LoadConfigBase):
    """GCS bulk-load source: the storage-agnostic base plus the GCS read credential.

    The base supplies the Cloud Lake DSN, target databases, source-contract resolution, and
    (for external sources) the storage-agnostic `external` accessors. This subclass adds only
    how Cloud Lake reads GCS: a base64 service-account key Databend uses for the gcs:// stage.
    """

    @property
    def gcs_credential_env(self) -> str:
        return self.data.get("gcs", {}).get("credential_env", "GCS_CREDENTIAL")

    @property
    def gcs_credential(self) -> str:
        return require_env(self.gcs_credential_env)

    @property
    def gcs_credential_env_names(self) -> list[str]:
        return [self.gcs_credential_env]


def load_load_config(path) -> LoadConfig:
    return load_config_file(path, LoadConfig)