"""Workspace YAML loading — the single boundary for workspace configuration (spec D3).

Reads workspaces/<name>.yaml, expands ${VAR} from env, validates via the Config model
(ported from the reference implementation). Future migration to a DB store would replace only this module.

La struttura YAML rispecchia esattamente tht/config.py:
  database + rest (DWH), vector_rest + vector_write_rest (pgvector, doppia key top-level),
  vector_db (loading diretto, server-only), embeddings, evidence, execution.
"""
from __future__ import annotations

from pathlib import Path

from tht.config import Config, ConfigError, load_config


class WorkspaceError(Exception):
    """Errore di caricamento del workspace (file mancante, env var non definita, yaml invalido)."""


def load_workspace(path: str | Path) -> Config:
    """Carica e valida un workspace YAML.

    Espande ${VAR} dall'ambiente; se una variabile referenziata manca, raises WorkspaceError.
    Delega a load_config (portato da the reference implementation) per la validazione del modello Config.
    """
    path = Path(path)
    try:
        return load_config(path)
    except ConfigError as e:
        raise WorkspaceError(str(e)) from e