import hashlib
import random
import time
from typing import Dict, List

import requests

from app.infra.internal.aigc_decode_server import AigcDecodeServer

from ._const import DecodeCardConst

# 封面下载重试配置
COVER_DOWNLOAD_MAX_RETRIES = 3
COVER_DOWNLOAD_BACKOFF_BASE = 1.0  # 基础退避秒数
COVER_DOWNLOAD_BACKOFF_MAX = 10.0  # 最大退避秒数


class CardDecodeUtils(DecodeCardConst):
    decode_server = AigcDecodeServer()

    async def submit_decode_batch(
        self, posts: List[Dict], *, config_id: int, skip_completed: bool = False
    ) -> Dict[str, Dict]:
        """分批提交卡片解构任务，返回 {content_id: {status, errorMessage}}"""
        result = {}
        for i in range(0, len(posts), self.SUBMIT_BATCH):
            batch = posts[i : i + self.SUBMIT_BATCH]
            response = await self.decode_server.submit_decode(
                config_id=config_id, posts=batch, skip_completed=skip_completed
            )
            if response.get("code") == 0:
                for item in response.get("data", []):
                    result[item["channelContentId"]] = item
            else:
                for post in batch:
                    cid = post["channelContentId"]
                    result[cid] = {
                        "channelContentId": cid,
                        "status": "FAILED",
                        "errorMessage": f"batch submit failed: {response}",
                    }
        return result

    async def query_decode_results_batch(
        self, content_ids: List[str], *, config_id: int
    ) -> Dict[str, Dict]:
        """分批查询卡片解构结果"""
        result = {}
        for i in range(0, len(content_ids), self.SUBMIT_BATCH):
            batch = content_ids[i : i + self.SUBMIT_BATCH]
            response = await self.decode_server.query_decode_results(
                config_id=config_id, channel_content_ids=batch
            )
            if response.get("code") == 0:
                for item in response.get("data", []):
                    result[item["channelContentId"]] = item
            else:
                for cid in batch:
                    result[cid] = {
                        "channelContentId": cid,
                        "status": "API_ERROR",
                        "errorMessage": f"query API failed: {response}",
                    }
        return result

    COVER_CDN_PREFIX = "https://rescdn.yishihui.com/"

    @staticmethod
    def _normalize_cover_url(url: str) -> str:
        """不以 https: 开头的封面 URL 拼接 CDN 前缀"""
        if not url.startswith("https:"):
            return f"{CardDecodeUtils.COVER_CDN_PREFIX}{url}"
        return url

    @staticmethod
    def compute_cover_md5(image_url: str) -> str:
        """下载封面图片并计算 MD5，带重试 + 指数退避 + 抖动，应对高并发 CDN 限流"""
        url = CardDecodeUtils._normalize_cover_url(image_url)
        last_exc = None
        for attempt in range(COVER_DOWNLOAD_MAX_RETRIES):
            try:
                resp = requests.get(url, timeout=30)
                resp.raise_for_status()
                return hashlib.md5(resp.content).hexdigest()
            except requests.RequestException as e:
                last_exc = e
                if attempt < COVER_DOWNLOAD_MAX_RETRIES - 1:
                    delay = min(
                        COVER_DOWNLOAD_BACKOFF_BASE * (2 ** attempt),
                        COVER_DOWNLOAD_BACKOFF_MAX,
                    )
                    jitter = random.uniform(0, delay * 0.5)
                    time.sleep(delay + jitter)
        raise last_exc

    @staticmethod
    def prepare_posts(cards: List[Dict]) -> List[Dict]:
        """将卡片数据转换为 AIGC 解构 API 所需的 post 格式"""
        posts = []
        for card in cards:
            images = []
            cover = card.get("share_cover")
            if cover:
                images.append(CardDecodeUtils._normalize_cover_url(cover))
            posts.append(
                {
                    "channelContentId": str(card["card_cover_id"]),
                    "title": card.get("share_title", ""),
                    "bodyText": "",
                    "images": images,
                    "video": None,
                    "contentModal": DecodeCardConst.ContentModal.PICTURE_TEXT,
                    "channel": DecodeCardConst.Channel.GROWTH_AUTO_REPLY_CARD,
                }
            )
        return posts


__all__ = ["CardDecodeUtils"]