from __future__ import annotations

import os
from dataclasses import dataclass


@dataclass(frozen=True)
class Settings:
    """Runtime configuration for the orchestrator Space."""

    bucket_name: str = os.getenv("SPACE_FACTORY_BUCKET_NAME", "space-factory-runs")
    bucket_mount: str = os.getenv("SPACE_FACTORY_BUCKET_MOUNT", "/output")
    job_flavor: str = os.getenv("SPACE_FACTORY_JOB_FLAVOR", "cpu-basic")
    job_timeout: str = os.getenv("SPACE_FACTORY_JOB_TIMEOUT", "30m")
    job_image: str = os.getenv("SPACE_FACTORY_JOB_IMAGE", "python:3.12")


def normalize_bucket_name(value: str | None) -> str:
    """Return a safe bucket name, defaulting to the product bucket name."""
    bucket = (value or settings.bucket_name).strip().strip("/")
    if not bucket:
        bucket = settings.bucket_name
    if "/" in bucket:
        raise ValueError("Bucket name must be a name like 'space-factory-runs', not owner/name.")
    return bucket


def user_bucket_source(*, username: str, bucket_name: str | None = None) -> str:
    """Return the per-user bucket source expected by HF Jobs volumes."""
    clean_user = (username or "").strip()
    if not clean_user:
        raise ValueError("Missing username for per-user bucket source.")
    return f"{clean_user}/{normalize_bucket_name(bucket_name)}"


def bucket_uri_from_source(bucket_source: str) -> str:
    return f"hf://buckets/{bucket_source}"


settings = Settings()