"""Bridge DeepTutor's runtime config into LightRAG / RAG-Anything.

LightRAG (HKUDS/LightRAG) is a text knowledge-graph RAG engine; its multimodal
story is RAG-Anything (HKUDS/RAG-Anything), built on top of LightRAG. The
``lightrag`` provider uses RAG-Anything so multimodal content (the parse layer's
``content_list``) becomes graph entities, while text-only documents fall back to
a plain text insert.

This module is the decoupling seam: it exposes availability + mode helpers and
builds the three adapters LightRAG needs from DeepTutor's already-resolved LLM /
embedding clients. It imports neither RAG-Anything nor LightRAG at module load —
the adapter builders import ``lightrag.utils`` lazily (only the embedding wrapper
needs it), and engine construction lives in ``engine.py``.

Decoupling notes:
* ``llm_model_func`` / ``vision_model_func`` wrap DeepTutor's unified model
  callables and DROP LightRAG's internal kwargs (``hashing_kv``,
  ``keyword_extraction``, …) so they never leak into ``factory.complete``.
* ``embedding_func`` reuses DeepTutor's embedding client, wrapped in LightRAG's
  ``EmbeddingFunc`` with the active model's dimension.
"""

from __future__ import annotations

import importlib.util
import logging

logger = logging.getLogger(__name__)

# LightRAG's native retrieval modes. ``hybrid`` (KG + vector) is the safest
# general default and matches the shared per-KB ``search_mode`` default.
SUPPORTED_MODES = ("naive", "local", "global", "hybrid", "mix")
DEFAULT_MODE = "hybrid"

# Conservative cap for the embedding wrapper when the model doesn't advertise one.
_DEFAULT_MAX_TOKEN_SIZE = 8192


class LightRagNotAvailableError(RuntimeError):
    """Raised when the optional ``raganything`` dependency is not installed."""


class LightRagNotConfiguredError(RuntimeError):
    """Raised when DeepTutor's LLM / embedding config can't back LightRAG."""


def is_lightrag_available() -> bool:
    """True when RAG-Anything (which bundles LightRAG) can be imported.

    Opt-in extra: ``pip install 'deeptutor[rag-lightrag]'``. Until installed the
    provider is hidden / blocked in the UI.
    """
    return importlib.util.find_spec("raganything") is not None


def normalize_mode(mode: str | None) -> str:
    """Coerce a stored ``search_mode`` to a valid LightRAG query mode.

    The per-KB ``search_mode`` field is shared across engines; anything that
    isn't a LightRAG mode falls back to :data:`DEFAULT_MODE`.
    """
    candidate = (mode or "").strip().lower()
    return candidate if candidate in SUPPORTED_MODES else DEFAULT_MODE


def query_kwargs_from_settings() -> dict:
    """Extra ``aquery`` kwargs (top_k, response_type) from runtime settings.

    Returned as a dict so the engine can pass them through to LightRAG's
    ``QueryParam`` and gracefully drop them if an older RAG-Anything rejects a
    kwarg. Empty on any read error.
    """
    try:
        from deeptutor.services.config import load_lightrag_settings

        settings = load_lightrag_settings()
        return {
            "top_k": int(settings.get("top_k", 60)),
            "response_type": str(settings.get("response_type") or "Multiple Paragraphs"),
        }
    except Exception:
        return {}


def build_llm_model_func():
    """Wrap DeepTutor's unified LLM callable for LightRAG.

    Drops LightRAG's internal kwargs while preserving explicit ``messages``.
    """
    from deeptutor.services.llm import get_llm_client

    base = get_llm_client().get_model_func()

    async def llm_model_func(
        prompt="",
        system_prompt=None,
        history_messages=None,
        messages=None,
        **_ignored,
    ):
        return await base(
            prompt or "",
            system_prompt=system_prompt,
            history_messages=history_messages or [],
            messages=messages,
        )

    return llm_model_func


def build_vision_model_func():
    """Wrap DeepTutor's vision-capable callable for RAG-Anything's image step."""
    from deeptutor.services.llm import get_llm_client

    base = get_llm_client().get_vision_model_func()

    async def vision_model_func(
        prompt="",
        system_prompt=None,
        history_messages=None,
        image_data=None,
        messages=None,
        **_ignored,
    ):
        return await base(
            prompt or "",
            system_prompt=system_prompt,
            history_messages=history_messages or [],
            image_data=image_data,
            messages=messages,
        )

    return vision_model_func


def build_embedding_func():
    """Wrap DeepTutor's embedding client in LightRAG's ``EmbeddingFunc``."""
    from lightrag.utils import EmbeddingFunc

    from deeptutor.services.embedding import get_embedding_client, get_embedding_config

    cfg = get_embedding_config()
    dim = int(getattr(cfg, "dim", 0) or 0)
    if not dim:
        raise LightRagNotConfiguredError(
            "No active embedding model with a known dimension. Configure one under "
            "Settings → Catalog before using a LightRAG knowledge base."
        )

    base_embedding_func = get_embedding_client().get_embedding_func()

    async def embedding_func(texts):
        import numpy as np

        vectors = await base_embedding_func(texts)
        return np.asarray(vectors, dtype=np.float32)

    return EmbeddingFunc(
        embedding_dim=dim,
        max_token_size=int(getattr(cfg, "max_tokens", 0) or _DEFAULT_MAX_TOKEN_SIZE),
        func=embedding_func,
    )


__all__ = [
    "SUPPORTED_MODES",
    "DEFAULT_MODE",
    "LightRagNotAvailableError",
    "LightRagNotConfiguredError",
    "is_lightrag_available",
    "normalize_mode",
    "query_kwargs_from_settings",
    "build_llm_model_func",
    "build_vision_model_func",
    "build_embedding_func",
]