"""PostgreSQL connection configuration."""

from __future__ import annotations

from dataclasses import dataclass
import os

from python_utils import check_env

from python_repositories.config.dotenv_loader import load_dotenv


@dataclass(frozen=True)
class PostgresConfig:
    """Configuration for connecting to PostgreSQL."""

    uri: str
    table: str
    primary_key: str = "id"

    @classmethod
    def from_env(
        cls,
        uri_env_var_name: str = "POSTGRES_URI",
        table_env_var_name: str = "POSTGRES_TABLE",
        primary_key_env_var_name: str = "POSTGRES_PRIMARY_KEY",
        *,
        use_dotenv: bool = True,
    ) -> PostgresConfig:
        """Load configuration from environment variables."""
        if use_dotenv:
            load_dotenv()
        env_var_names = {uri_env_var_name, table_env_var_name}
        check_env(env_var_names)
        primary_key = os.getenv(primary_key_env_var_name)
        if primary_key is None or primary_key == "":
            primary_key = "id"
        return cls(
            uri=str(os.getenv(uri_env_var_name)),
            table=str(os.getenv(table_env_var_name)),
            primary_key=primary_key,
        )