from typing import Any

from fastapi import HTTPException, status

from app.core.config import Settings
from app.modules.ai_agent.adapters import httpx
from app.modules.ai_agent.adapters.base import AIAdapter
from app.modules.ai_agent.adapters.common import (
    _chat_completion_payload,
    _chat_messages,
)
from app.modules.ai_agent.constants import (
    AUTHORIZATION_BEARER_TEMPLATE,
    DIRECT_LLM_API_KEY_MISSING,
    UNEXPECTED_HERMES_RESPONSE,
    AIErrorKey,
    AIHttpHeader,
    AIHttpPath,
    AIHttpPayloadKey,
    AIProviderName,
    AIResponseKey,
)


class DirectLLMAdapter(AIAdapter):
    """Adapter for OpenAI-compatible chat completions APIs."""

    provider_name = AIProviderName.DIRECT_LLM

    def __init__(self, settings: Settings):
        self.settings = settings

    def ask(self, prompt: str, context: dict[str, Any] | None = None) -> dict[str, Any]:
        if not self.settings.direct_llm_api_key:
            raise HTTPException(
                status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
                detail=DIRECT_LLM_API_KEY_MISSING,
            )
        url = f"{self.settings.direct_llm_base_url.rstrip('/')}{AIHttpPath.CHAT_COMPLETIONS}"
        headers = {
            AIHttpHeader.AUTHORIZATION: AUTHORIZATION_BEARER_TEMPLATE.format(
                token=self.settings.direct_llm_api_key
            )
        }
        payload = {
            AIHttpPayloadKey.MODEL: self.settings.direct_llm_model,
            AIHttpPayloadKey.MESSAGES: _chat_messages(prompt, context),
        }
        with httpx.Client(timeout=60, trust_env=False) as client:
            response = client.post(url, json=payload, headers=headers)
        if response.status_code >= status.HTTP_400_BAD_REQUEST:
            raise HTTPException(
                status_code=status.HTTP_502_BAD_GATEWAY,
                detail={AIErrorKey.DIRECT_LLM: response.text},
            )
        data = _chat_completion_payload(response, AIErrorKey.DIRECT_LLM)
        try:
            answer = data[AIHttpPayloadKey.CHOICES][0][AIHttpPayloadKey.MESSAGE][
                AIHttpPayloadKey.CONTENT
            ]
        except (KeyError, IndexError, TypeError) as exc:
            raise HTTPException(
                status_code=status.HTTP_502_BAD_GATEWAY,
                detail={
                    AIErrorKey.DIRECT_LLM: UNEXPECTED_HERMES_RESPONSE,
                    AIResponseKey.RAW: data,
                },
            ) from exc
        return {AIResponseKey.ANSWER: answer, AIResponseKey.RAW: data}