"""GitHub Models provider — OpenAI-compatible, via ``GITHUB_MODEL_API_TOKEN``.

GitHub Models exposes an OpenAI-compatible endpoint backed by a GitHub Copilot
subscription. It needs a fine-grained PAT with the ``models:read`` permission.
"""

from environs import Env
from langchain_core.language_models import BaseChatModel
from langchain_openai import ChatOpenAI
from pydantic import SecretStr

from skill_eval_runner.providers import Provider, register

GITHUB_MODELS_BASE_URL = "https://models.github.ai/inference"

_env = Env()
_env.read_env()


def make_model(model_name: str) -> BaseChatModel:
    """Build a ``ChatOpenAI`` model pointed at GitHub Models' inference endpoint."""
    token = _env.str("GITHUB_MODEL_API_TOKEN", None)
    if not token:
        raise SystemExit(
            "GITHUB_MODEL_API_TOKEN is not set.\n\n"
            "Create a fine-grained PAT with Models -> Read-only permission:\n"
            "  github.com -> Settings -> Developer settings -> Fine-grained tokens\n\n"
            "Then add it to a .env file or export GITHUB_MODEL_API_TOKEN=github_pat_..."
        )
    # ChatOpenAI's pydantic field aliases aren't visible to mypy without the pydantic
    # plugin; the kwargs are valid at runtime.
    model: BaseChatModel = ChatOpenAI(  # type: ignore[call-arg]
        model=model_name,
        base_url=GITHUB_MODELS_BASE_URL,
        api_key=SecretStr(token),
        max_tokens=8192,
    )
    return model


register(
    Provider(
        name="github-models",
        default_model="openai/gpt-4.1",
        small_model="openai/gpt-4.1-mini",
        large_model="openai/gpt-4.1",
        make_model=make_model,
    )
)