"""
Thin wrapper around litellm.completion.
Keeps litellm import isolated so the rest of the codebase doesn't depend on it directly,
and makes the call easy to mock in tests.
"""

from loguru import logger

# Output token cap for all LLM calls — our JSON response is always <50 tokens,
# so 200 is a generous hard cap that prevents runaway per-call cost.
_MAX_COMPLETION_TOKENS = 200


def completion(model: str, messages: list, api_key: str = None,
               api_base: str = None, timeout: int = 30,
               max_tokens: int = None) -> tuple[str, int]:
    """
    Call the LLM and return (response_text, total_tokens_used).
    total_tokens_used is 0 if the provider doesn't return usage data.
    Raises on network/auth errors — callers handle gracefully.
    """
    try:
        import litellm
    except ImportError:
        raise RuntimeError("litellm is not installed. Add it to requirements.txt.")

    kwargs = {
        'model': model,
        'messages': messages,
        'timeout': timeout,
        'temperature': 0,
        'max_tokens': max_tokens if max_tokens is not None else _MAX_COMPLETION_TOKENS,
    }
    if api_key:
        kwargs['api_key'] = api_key
    if api_base:
        kwargs['api_base'] = api_base

    try:
        response = litellm.completion(**kwargs)
        text = response.choices[0].message.content
        usage = getattr(response, 'usage', None)
        total_tokens = int(getattr(usage, 'total_tokens', 0) or 0) if usage else 0
        return text, total_tokens
    except Exception as e:
        logger.warning(f"LLM call failed: {e}")
        raise