import os
import requests
import logging
import json
import uuid
import time
from typing import List, Optional
from parser import ParsedItem

logger = logging.getLogger(__name__)

YANDEX_GPT_URL = "https://llm.api.cloud.yandex.net/foundationModels/v1/completion"
GIGACHAT_OAUTH_URL = "https://ngw.devices.sberbank.ru:9443/api/v2/oauth"
GIGACHAT_COMPLETION_URL = "https://gigachat.devices.sberbank.ru/api/v1/chat/completions"

class YandexGPTParser:
    def __init__(self):
        self.folder_id = os.getenv("YANDEX_FOLDER_ID")
        self.api_key = os.getenv("YANDEX_OAUTH_TOKEN")

    def parse(self, raw_text: str, iam_token: str) -> List[ParsedItem]:
        if not iam_token:
            return []
        
        prompt = {
            "modelUri": f"gpt://{self.folder_id}/yandexgpt/latest",
            "completionOptions": {"stream": False, "temperature": 0.1, "maxTokens": "2000"},
            "messages": [
                {
                    "role": "system",
                    "text": (
                        "Ты — помощник по бухгалтерии. Извлеки список товаров из текста документа. "
                        "Верни ответ строго в формате JSON: "
                        '[{"raw_name": string, "amount": float, "price": float, "sum": float}]. '
                        "Если количество не указано, считай 1.0. Не пиши ничего, кроме JSON."
                    )
                },
                {"role": "user", "text": raw_text}
            ]
        }

        headers = {
            "Content-Type": "application/json",
            "Authorization": f"Bearer {iam_token}",
            "x-folder-id": self.folder_id
        }

        try:
            response = requests.post(YANDEX_GPT_URL, headers=headers, json=prompt, timeout=30)
            response.raise_for_status()
            content = response.json()['result']['alternatives'][0]['message']['text']
            clean_json = content.replace("```json", "").replace("```", "").strip()
            return [ParsedItem(**item) for item in json.loads(clean_json)]
        except Exception as e:
            logger.error(f"YandexGPT Parsing error: {e}")
            return []

class GigaChatParser:
    def __init__(self):
        self.auth_key = os.getenv("GIGACHAT_AUTH_KEY")
        self._access_token = None
        self._expires_at = 0

    def _get_token(self) -> Optional[str]:
        if self._access_token and time.time() < self._expires_at:
            return self._access_token

        logger.info("Obtaining GigaChat access token...")
        headers = {
            'Content-Type': 'application/x-www-form-urlencoded',
            'Accept': 'application/json',
            'RqUID': str(uuid.uuid4()),
            'Authorization': f'Basic {self.auth_key}'
        }
        payload = {'scope': 'GIGACHAT_API_PERS'}

        try:
            # verify=False может понадобиться, если сертификаты Минцифры не в системном хранилище, 
            # но вы указали, что установите их в контейнер.
            response = requests.post(GIGACHAT_OAUTH_URL, headers=headers, data=payload, timeout=10)
            response.raise_for_status()
            data = response.json()
            self._access_token = data['access_token']
            self._expires_at = data['expires_at'] / 1000 # Переводим мс в сек
            return self._access_token
        except Exception as e:
            logger.error(f"GigaChat Auth error: {e}")
            return None

    def parse(self, raw_text: str) -> List[ParsedItem]:
        token = self._get_token()
        if not token:
            return []

        headers = {
            'Content-Type': 'application/json',
            'Accept': 'application/json',
            'Authorization': f'Bearer {token}'
        }

        payload = {
            "model": "GigaChat",
            "messages": [
                {
                    "role": "system",
                    "content": (
                        "Ты — эксперт по распознаванию чеков. Извлеки товары из текста. "
                        "Верни ТОЛЬКО JSON массив объектов с полями: raw_name (строка), "
                        "amount (число), price (число), sum (число). "
                        "Если данных нет, верни []. Никаких пояснений."
                    )
                },
                {"role": "user", "content": raw_text}
            ],
            "temperature": 0.1
        }

        try:
            response = requests.post(GIGACHAT_COMPLETION_URL, headers=headers, json=payload, timeout=30)
            response.raise_for_status()
            content = response.json()['choices'][0]['message']['content']
            clean_json = content.replace("```json", "").replace("```", "").strip()
            return [ParsedItem(**item) for item in json.loads(clean_json)]
        except Exception as e:
            logger.error(f"GigaChat Parsing error: {e}")
            return []

class LLMManager:
    def __init__(self):
        self.yandex = YandexGPTParser()
        self.giga = GigaChatParser()
        self.engine = os.getenv("LLM_ENGINE", "yandex").lower()

    def parse_with_priority(self, raw_text: str, yandex_iam_token: Optional[str] = None) -> List[ParsedItem]:
        if self.engine == "gigachat":
            logger.info("Using GigaChat as primary LLM")
            items = self.giga.parse(raw_text)
            if not items and yandex_iam_token:
                logger.info("GigaChat failed, falling back to YandexGPT")
                items = self.yandex.parse(raw_text, yandex_iam_token)
            return items
        else:
            logger.info("Using YandexGPT as primary LLM")
            items = self.yandex.parse(raw_text, yandex_iam_token) if yandex_iam_token else []
            if not items:
                logger.info("YandexGPT failed, falling back to GigaChat")
                items = self.giga.parse(raw_text)
            return items

llm_parser = LLMManager()