"""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"))

LOCAL_USER_ID = "__local__"


def user_data_dir(user_id: str) -> Path:
    """Return (and create) the per-user data directory under DATA_DIR/users/."""
    d = DATA_DIR / "users" / user_id
    d.mkdir(parents=True, exist_ok=True)
    return d


def get_llm_config() -> dict | None:
    """Build LLMRouter config from env vars.

    Returns None only when neither PAGEPIPER_OLLAMA_URL nor CF_ORCH_URL is set.
    CF_ORCH_URL alone is sufficient — the coordinator resolves the service URL at
    allocation time so PAGEPIPER_OLLAMA_URL becomes optional.
    """
    url = os.environ.get("PAGEPIPER_OLLAMA_URL", "").strip()
    orch_url = os.environ.get("CF_ORCH_URL", "").strip()

    if not url and not orch_url:
        return None

    chat_model = os.environ.get("PAGEPIPER_CHAT_MODEL", "mistral:7b")

    _base_url = ""
    if url:
        _clean = url.rstrip("/")
        _base_url = _clean if _clean.endswith("/v1") else _clean + "/v1"

    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,
    }

    if orch_url:
        backend["cf_orch"] = {
            "service": os.environ.get("PAGEPIPER_ORCH_SERVICE", "ollama"),
            "model_candidates": [chat_model],
            "ttl_s": 3600,
        }

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