# inference.py
# -------------------------------------------------------------
# Unified wrapper around hf_client.get_inference_client
# with automatic provider‑routing based on model registry
# (see models.py) and graceful fall‑back to Groq.
# -------------------------------------------------------------
from __future__ import annotations

from typing import Dict, Generator, List, Optional

from hf_client import get_inference_client
from models import find_model


# ------------------------------------------------------------------
# Helpers
# ------------------------------------------------------------------
def _resolve_provider(model_id: str, override: str | None) -> str:
    """
    Decide which provider to use.

    Priority:
    1. Explicit *override* arg supplied by caller.
    2. Model registry default_provider (see models.py).
    3. "auto" – lets HF route to the first available provider.
    """
    if override:
        return override

    meta = find_model(model_id)
    return getattr(meta, "default_provider", "auto") if meta else "auto"


# ------------------------------------------------------------------
# Public API
# ------------------------------------------------------------------
def chat_completion(
    model_id: str,
    messages: List[Dict[str, str]],
    provider: Optional[str] = None,
    max_tokens: int = 4096,
    **kwargs,
) -> str:
    """
    Blocking convenience wrapper – returns the full assistant reply.

    Parameters
    ----------
    model_id      : HF or provider‑qualified model path (e.g. "openai/gpt-4").
    messages      : OpenAI‑style [{'role': ..., 'content': ...}, …].
    provider      : Optional provider override; otherwise auto‑resolved.
    max_tokens    : Token budget for generation.
    kwargs        : Forward‑compatible extra arguments (temperature, etc.).

    Returns
    -------
    str – assistant message content.
    """
    client = get_inference_client(model_id, _resolve_provider(model_id, provider))
    resp = client.chat.completions.create(
        model=model_id,
        messages=messages,
        max_tokens=max_tokens,
        **kwargs,
    )
    return resp.choices[0].message.content


def stream_chat_completion(
    model_id: str,
    messages: List[Dict[str, str]],
    provider: Optional[str] = None,
    max_tokens: int = 4096,
    **kwargs,
) -> Generator[str, None, None]:
    """
    Yield the assistant response *incrementally*.

    Example
    -------
    >>> for chunk in stream_chat_completion(model, msgs):
    ...     print(chunk, end='', flush=True)
    """
    client = get_inference_client(model_id, _resolve_provider(model_id, provider))
    stream = client.chat.completions.create(
        model=model_id,
        messages=messages,
        max_tokens=max_tokens,
        stream=True,
        **kwargs,
    )

    # HF Inference returns chunks with .choices[0].delta.content
    for chunk in stream:
        delta: str | None = getattr(chunk.choices[0].delta, "content", None)
        if delta:
            yield delta