# -----------------------------------------------------------------------------
# Description: Runtime storage path resolution for SQLite data, saved layouts, and temporary exports.
# Inside functions: resolve_database_root
# Developer : Qin Yue @ 2026
# Organization : OptiHK Limited
# -----------------------------------------------------------------------------
import os


BACKEND_DIR = os.path.dirname(os.path.abspath(__file__))
REPO_ROOT = os.path.abspath(os.path.join(BACKEND_DIR, ".."))
DEFAULT_DATABASE_ROOT = os.path.abspath(os.path.join(REPO_ROOT, "..", "mxpic_EDA_database"))


def _is_inside_repo(path: str) -> bool:
    """Return True when a candidate runtime data folder lives inside this repo."""
    repo_root = os.path.normcase(REPO_ROOT)
    candidate = os.path.normcase(os.path.abspath(path))
    try:
        return os.path.commonpath([repo_root, candidate]) == repo_root
    except ValueError:
        return False


def resolve_database_root() -> str:
    """Resolve and validate the external runtime database root."""
    configured_root = os.environ.get("MXPIC_DATABASE_ROOT", "").strip()
    database_root = os.path.abspath(configured_root or DEFAULT_DATABASE_ROOT)

    if _is_inside_repo(database_root):
        raise RuntimeError(
            "Runtime database root must live outside the mxpic_EDA repository. "
            f"Resolved path: {database_root}. Move the database beside the repo as "
            "mxpic_EDA_database or set MXPIC_DATABASE_ROOT to an external path."
        )

    if not os.path.isdir(database_root):
        raise RuntimeError(
            "Runtime database root is missing. Move the existing database folder "
            f"beside mxpic_EDA and rename it to mxpic_EDA_database, or set "
            f"MXPIC_DATABASE_ROOT to the moved folder. Expected path: {database_root}"
        )

    return database_root


DATABASE_ROOT = resolve_database_root()
DB_FILE = os.path.join(DATABASE_ROOT, "mxpic_data.db")
EXPORT_ROOT = os.path.join(DATABASE_ROOT, "_exports")