import json
import logging

from django.conf import settings
from openai import OpenAI, APITimeoutError, APIConnectionError, APIStatusError

from config.exceptions import AppError

logger = logging.getLogger(__name__)


def get_client():
    return OpenAI(
        api_key=settings.DEEPSEEK_API_KEY,
        base_url=settings.DEEPSEEK_BASE_URL,
        timeout=settings.DEEPSEEK_TIMEOUT_SECONDS,
    )


def call_deepseek(system_prompt: str, user_content: str) -> dict:
    """调用 DeepSeek，返回解析后的 JSON dict + usage 信息。

    自带 1 次重试：首次失败时将错误信息附给第二次调用。
    """
    client = get_client()
    messages = [
        {"role": "system", "content": system_prompt},
        {"role": "user", "content": user_content},
    ]

    last_error = None
    for attempt in range(1 + settings.DEEPSEEK_MAX_RETRIES):
        if attempt > 0 and last_error:
            messages.append({
                "role": "user",
                "content": f"上一次输出不是合法 JSON，错误：{last_error}。请严格输出合法 JSON。",
            })

        try:
            response = client.chat.completions.create(
                model=settings.DEEPSEEK_MODEL,
                messages=messages,
                response_format={"type": "json_object"},
                temperature=0.3,
            )
        except APITimeoutError:
            raise AppError('AI_TIMEOUT', 'DeepSeek 请求超时', status_code=504)
        except (APIConnectionError, APIStatusError) as e:
            logger.error('DeepSeek API error: %s', e)
            raise AppError('AI_PROVIDER_ERROR', f'DeepSeek 服务异常: {e}', status_code=502)

        raw = response.choices[0].message.content
        usage = {
            'prompt_tokens': response.usage.prompt_tokens,
            'completion_tokens': response.usage.completion_tokens,
        } if response.usage else {}

        try:
            parsed = json.loads(raw)
            return {'data': parsed, 'usage': usage}
        except (json.JSONDecodeError, TypeError) as e:
            last_error = str(e)
            logger.warning('DeepSeek JSON parse failed (attempt %d): %s', attempt + 1, e)

    raise AppError('AI_BAD_JSON', f'AI 返回非合法 JSON（重试后仍失败）: {last_error}', status_code=500)