# src/paths.py
from __future__ import annotations

import os
from pathlib import Path
from typing import Dict

# Root of the Spaces persistent volume
_SPACE_PERSIST_ROOT = Path("/data")

def _is_writable(p: Path) -> bool:
    try:
        p.mkdir(parents=True, exist_ok=True)
        test = p / ".write_test"
        test.write_text("ok", encoding="utf-8")
        test.unlink(missing_ok=True)
        return True
    except Exception:
        return False

def base_dir() -> Path:
    """
    Return the base persistent directory for this app, creating it if needed.

    On Hugging Face Spaces this will be `/data/econsult`.
    For local/dev runs (where `/data` might not exist), we fall back to `./.persist/econsult`.
    """
    if _is_writable(_SPACE_PERSIST_ROOT):
        root = _SPACE_PERSIST_ROOT / "econsult"
    else:
        root = Path(".") / ".persist" / "econsult"
    root.mkdir(parents=True, exist_ok=True)
    return root

def guidelines_dir() -> Path:
    d = base_dir() / "guidelines"
    d.mkdir(parents=True, exist_ok=True)
    return d

def faiss_index_dir() -> Path:
    d = base_dir() / "faiss_index"
    d.mkdir(parents=True, exist_ok=True)
    return d

def exports_dir() -> Path:
    d = base_dir() / "exports"
    d.mkdir(parents=True, exist_ok=True)
    return d

def cases_dir() -> Path:
    d = base_dir() / "cases"
    d.mkdir(parents=True, exist_ok=True)
    return d

def audit_dir() -> Path:
    d = base_dir() / "audit"
    d.mkdir(parents=True, exist_ok=True)
    return d

def hf_cache_dir() -> Path:
    """
    Return the local Hugging Face cache directory.

    We default to `/data/econsult/hf_cache` on Spaces, or `./.persist/econsult/hf_cache` locally.
    """
    d = base_dir() / "hf_cache"
    d.mkdir(parents=True, exist_ok=True)
    return d

def initialize_environment() -> Dict[str, str]:
    """
    Ensure HF cache env vars are set to the app's cache dir and return the key environment settings.
    """
    cache = hf_cache_dir()
    os.environ.setdefault("HF_HOME", str(cache))
    os.environ.setdefault("HF_DATASETS_CACHE", str(cache))
    os.environ.setdefault("TRANSFORMERS_CACHE", str(cache))

    # Optional flags the app may honor
    env = {
        "HF_HOME": os.environ.get("HF_HOME", ""),
        "MODEL_ID": os.environ.get("MODEL_ID", "google/medgemma-27b-text-it"),
        "MODEL_FALLBACK_ID": os.environ.get("MODEL_FALLBACK_ID", "google/medgemma-4b-it"),
        "FORCE_CPU_LLM": os.environ.get("FORCE_CPU_LLM", ""),
        "E2E_STUB": os.environ.get("E2E_STUB", ""),
        "QUANT_MODE": os.environ.get("QUANT_MODE", "4bit"),
    }
    print(f"[paths] base_dir={base_dir()}  hf_cache_dir={cache}  HF_HOME={env['HF_HOME']}")
    return env

def describe_paths() -> Dict[str, str]:
    """
    Convenience helper for the health page to display all important paths.
    """
    return {
        "base_dir": str(base_dir()),
        "guidelines_dir": str(guidelines_dir()),
        "faiss_index_dir": str(faiss_index_dir()),
        "cases_dir": str(cases_dir()),
        "exports_dir": str(exports_dir()),
        "audit_dir": str(audit_dir()),
        "hf_cache_dir": str(hf_cache_dir()),
    }