"""
Centralised model storage directory management.

All downloaded HuggingFace weights are stored under a single
`models/` directory at the project root.  This module provides
`get_model_dir` to resolve and create per-model subdirectories,
keeping weight files out of source control and in a predictable
location for loaders.
"""

from pathlib import Path

# Project root is three levels up from this file: src/utils/model_store.py -> llm_hub/
_PROJECT_ROOT = Path(__file__).resolve().parent.parent.parent
MODELS_DIR = _PROJECT_ROOT / "models"


def get_model_dir(model_name: str) -> Path:
    """
    Returns the canonical directory for a model's weights and tokenizer files.
    Creates the directory if it doesn't exist.

    Args:
        model_name: e.g. "Qwen3-0.6B", "gemma-3-270m"

    Returns:
        Path to models/<model_name>/
    """
    model_dir = MODELS_DIR / model_name
    model_dir.mkdir(parents=True, exist_ok=True)
    return model_dir