"""Configuration from environment variables — no file parsing required for basic use."""

from __future__ import annotations

import os
from pathlib import Path

DATA_DIR = Path(os.environ.get("PAGEPIPER_DATA_DIR", "data"))
DATA_DIR.mkdir(parents=True, exist_ok=True)
DB_PATH = str(DATA_DIR / "pagepiper.db")
VEC_DB_PATH = str(DATA_DIR / "pagepiper_vecs.db")
WATCH_DIR = Path(os.environ.get("PAGEPIPER_WATCH_DIR", "books"))
VEC_DIMENSIONS = int(os.environ.get("PAGEPIPER_EMBED_DIMS", "1024"))


def get_llm_config() -> dict | None:
    """Build LLMRouter config from env vars. Returns None if PAGEPIPER_OLLAMA_URL is unset."""
    url = os.environ.get("PAGEPIPER_OLLAMA_URL", "").strip()
    if not url:
        return None
    _clean = url.rstrip("/")
    _base_url = _clean if _clean.endswith("/v1") else _clean + "/v1"
    chat_model = os.environ.get("PAGEPIPER_CHAT_MODEL", "mistral:7b")

    backend: dict = {
        "type": "openai_compat",
        "base_url": _base_url,
        "model": chat_model,
        "embedding_model": os.environ.get("PAGEPIPER_EMBED_MODEL", "nomic-embed-text"),
        "supports_images": False,
    }

    # Wire cf-orch allocation when coordinator is configured so the model stays warm
    # and cold-start latency doesn't cause chat timeouts.
    orch_url = os.environ.get("CF_ORCH_URL", "").strip()
    if orch_url:
        backend["cf_orch"] = {
            "service": "ollama",
            "model_candidates": [chat_model],
            "ttl_s": 3600,
        }

    return {
        "fallback_order": ["ollama"],
        "backends": {"ollama": backend},
    }