from dataclasses import dataclass, field
from typing import Any

from openai import OpenAI


@dataclass
class LLMResponse:
    content: str | None
    tool_calls: list[dict] = field(default_factory=list)
    prompt_tokens: int = 0
    completion_tokens: int = 0


class LLMClient:
    BASE_URL = "https://openrouter.ai/api/v1"

    def __init__(self, api_key: str, model: str):
        if not api_key:
            raise ValueError("An OpenRouter API key is required.")
        self.model = model
        self._client = OpenAI(api_key=api_key, base_url=self.BASE_URL)

    def chat(self, messages: list[dict], tools: list[dict] | None = None) -> LLMResponse:
        kwargs: dict[str, Any] = {"model": self.model, "messages": messages}
        if tools:
            kwargs["tools"] = tools
        resp = self._client.chat.completions.create(**kwargs)
        msg = resp.choices[0].message
        tool_calls = []
        if getattr(msg, "tool_calls", None):
            for tc in msg.tool_calls:
                tool_calls.append(
                    {"id": tc.id, "name": tc.function.name, "arguments": tc.function.arguments}
                )
        usage = resp.usage
        return LLMResponse(
            content=msg.content,
            tool_calls=tool_calls,
            prompt_tokens=getattr(usage, "prompt_tokens", 0) if usage else 0,
            completion_tokens=getattr(usage, "completion_tokens", 0) if usage else 0,
        )