"""
Reads doc_service_config.json from the shared config volume.
Caches the result for 30 seconds to avoid hitting the filesystem on every request.
Uses asyncio.to_thread so the synchronous file read doesn't block the event loop.
"""
import asyncio
import json
import time
from pathlib import Path

from app.core.config import settings

_DEFAULT_CONFIG: dict = {
    "ai": {
        "provider": "anthropic",
        "anthropic": {"api_key": "", "model": "claude-haiku-4-5-20251001"},
        "ollama": {"base_url": "http://localhost:11434/v1", "model": "llama3.2", "api_key": "ollama"},
        "lmstudio": {"base_url": "http://localhost:1234/v1", "model": "local-model", "api_key": ""},
    },
    "documents": {"max_pdf_bytes": 20 * 1024 * 1024},
}

_cache: dict | None = None
_cache_at: float = 0.0
_CACHE_TTL = 30.0


def _read_config_sync() -> dict:
    path = Path(settings.CONFIG_PATH)
    if not path.exists():
        return _DEFAULT_CONFIG.copy()
    with open(path) as f:
        return json.load(f)


async def load_doc_config() -> dict:
    global _cache, _cache_at
    now = time.monotonic()
    if _cache is not None and (now - _cache_at) < _CACHE_TTL:
        return _cache
    data = await asyncio.to_thread(_read_config_sync)
    _cache = data
    _cache_at = now
    return data