from __future__ import annotations

import asyncio
from pathlib import Path

import requests

from app.models import Offer


class OfferReplyGenerator:
    def __init__(
        self,
        api_base_url: str,
        api_key: str,
        model: str,
        system_prompt_file: Path,
        timeout_seconds: int,
    ) -> None:
        self._api_base_url = api_base_url.rstrip("/")
        self._api_key = api_key
        self._model = model
        self._system_prompt = system_prompt_file.read_text(encoding="utf-8").strip()
        self._timeout_seconds = timeout_seconds

    async def generate_reply(self, offer: Offer) -> str:
        return await asyncio.to_thread(self._generate_reply_sync, offer)

    def _generate_reply_sync(self, offer: Offer) -> str:
        response = requests.post(
            f"{self._api_base_url}/chat/completions",
            headers={
                "Authorization": f"Bearer {self._api_key}",
                "Content-Type": "application/json",
            },
            json={
                "model": self._model,
                "messages": [
                    {"role": "system", "content": self._system_prompt},
                    {"role": "user", "content": _build_offer_prompt(offer)},
                ],
            },
            timeout=self._timeout_seconds,
        )
        response.raise_for_status()
        payload = response.json()
        choices = payload.get("choices") or []
        if not choices:
            raise ValueError("OpenAI-compatible API returned no choices")

        message = choices[0].get("message") or {}
        content = message.get("content")
        if isinstance(content, str) and content.strip():
            return content.strip()

        if isinstance(content, list):
            text_parts = [item.get("text", "") for item in content if isinstance(item, dict)]
            text = "\n".join(part.strip() for part in text_parts if part and part.strip()).strip()
            if text:
                return text

        raise ValueError("OpenAI-compatible API returned empty content")


def _build_offer_prompt(offer: Offer) -> str:
    seller_line = f"Исполнитель: @{offer.seller_username}\n" if offer.seller_username else ""
    price_amount_line = f"Числовой бюджет: {offer.price_amount}\n" if offer.price_amount is not None else ""
    return (
        f"Подготовь сообщение для отклика на этот оффер.\n"
        f"Источник: {offer.source}\n"
        f"ID: {offer.external_id}\n"
        f"Заголовок: {offer.title}\n"
        f"Категория: {offer.category_id}\n"
        f"Бюджет: {offer.price}\n"
        f"{price_amount_line}"
        f"Опубликовано: {offer.published_at}\n"
        f"{seller_line}"
        f"Описание:\n{offer.description}\n\n"
        f"Ссылка: {offer.url}"
    )