"""
Centralized path management for persistent model storage.

HF Spaces mounts persistent storage at /data. Local development falls back to
~/.cache/ocr-demo so model downloads survive app restarts.
"""

from __future__ import annotations

import os
from pathlib import Path

_IS_HF_SPACE = os.path.isdir("/data") or os.environ.get("SPACE_ID") is not None

if _IS_HF_SPACE:
    _BASE = Path("/data")
else:
    _BASE = Path(os.getenv("OCR_DEMO_CACHE_DIR", Path.home() / ".cache" / "ocr-demo"))

PATHS = {
    "hf_home": _BASE / "huggingface",
    "tmp": Path("/tmp") / "ocr-demo",
}


def ensure_dirs() -> None:
    for path in PATHS.values():
        path.mkdir(parents=True, exist_ok=True)


def get_env_overrides() -> dict[str, str]:
    hf_home = PATHS["hf_home"]
    return {
        "HF_HOME": str(hf_home),
        "HUGGINGFACE_HUB_CACHE": str(hf_home / "hub"),
        "TRANSFORMERS_CACHE": str(hf_home / "hub"),
        "HF_XET_HIGH_PERFORMANCE": os.getenv("HF_XET_HIGH_PERFORMANCE", "1"),
        "CUDA_VISIBLE_DEVICES": os.getenv("CUDA_VISIBLE_DEVICES", ""),
        "PYTHONUNBUFFERED": "1",
    }


def is_model_cached(model_id: str) -> bool:
    repo_dir = f"models--{model_id.replace('/', '--')}"
    snapshots = PATHS["hf_home"] / "hub" / repo_dir / "snapshots"
    if not snapshots.exists():
        return False

    weight_patterns = (
        "model*.safetensors",
        "*.safetensors",
        "pytorch_model*.bin",
        "model*.bin",
        "*.gguf",
    )
    for snapshot in snapshots.iterdir():
        if not snapshot.is_dir():
            continue
        for pattern in weight_patterns:
            if any(snapshot.glob(pattern)):
                return True
    return False


def storage_info() -> dict:
    import shutil

    info = {
        "environment": "HuggingFace Spaces" if _IS_HF_SPACE else "Local Dev",
        "base_path": str(_BASE),
        "paths": {k: str(v) for k, v in PATHS.items()},
    }
    if _BASE.exists():
        total, used, free = shutil.disk_usage(str(_BASE))
        info["disk"] = {
            "total_gb": round(total / 1e9, 2),
            "used_gb": round(used / 1e9, 2),
            "free_gb": round(free / 1e9, 2),
        }
    return info