"""Startup-cached, non-secret application metadata."""

from dataclasses import dataclass
from pathlib import Path

from alembic.config import Config
from alembic.script import ScriptDirectory

from app.config import settings


def _clean_build_value(value: str | None) -> str | None:
    if value is None:
        return None
    cleaned = value.strip()
    return cleaned[:128] if cleaned else None


def _expected_migration_head() -> str | None:
    try:
        backend_root = Path(__file__).resolve().parents[2]
        config = Config(str(backend_root / "alembic.ini"))
        config.set_main_option("script_location", str(backend_root / "alembic"))
        return ScriptDirectory.from_config(config).get_current_head()
    except Exception:
        return None


@dataclass(frozen=True)
class ApplicationMetadata:
    environment: str
    build_commit: str | None
    build_version: str | None
    expected_migration_head: str | None


APPLICATION_METADATA = ApplicationMetadata(
    environment=settings.app_env,
    build_commit=_clean_build_value(settings.minerops_build_commit),
    build_version=_clean_build_value(settings.minerops_build_version),
    expected_migration_head=_expected_migration_head(),
)