"""微博商品图片下载与内嵌服务。"""

from __future__ import annotations

import base64
from concurrent.futures import ThreadPoolExecutor, as_completed
from dataclasses import dataclass
from typing import Any
from urllib.parse import urlsplit

import requests
from loguru import logger

from core.weibo import normalize_weibo_image_url

from .file_service import sniff_content_type

IMAGE_CONCURRENCY = 6
IMAGE_TIMEOUT_SECONDS = 3.0
MAX_IMAGE_BYTES = 5 << 20
_IMAGE_CONTENT_TYPES = frozenset({"image/jpeg", "image/png", "image/webp"})
_IMAGE_HEADERS = {
    "User-Agent": (
        "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) "
        "AppleWebKit/537.36 (KHTML, like Gecko) "
        "Chrome/156.0.0.0 Safari/537.36"
    ),
    "Referer": "https://vipclub.e.weibo.com/",
    "Accept": "image/avif,image/webp,image/apng,image/*,*/*;q=0.8",
}


@dataclass(frozen=True, slots=True)
class WeiboImageLoadResult:
    total: int
    loaded: int

    @property
    def failed(self) -> int:
        return max(0, self.total - self.loaded)


def fetch_weibo_image_data_url(raw_url: str) -> str:
    """下载一张微博图片，校验后转成浏览器可直接显示的 data URL。"""

    image_url = normalize_weibo_image_url(raw_url)
    parsed = urlsplit(image_url)
    if parsed.scheme not in {"http", "https"} or not parsed.hostname:
        raise ValueError("图片地址必须是 HTTP(S) URL")

    with requests.get(
        image_url,
        headers=_IMAGE_HEADERS,
        timeout=IMAGE_TIMEOUT_SECONDS,
        stream=True,
    ) as response:
        if not 200 <= response.status_code < 300:
            raise ValueError(f"图片 HTTP 状态异常: {response.status_code}")
        declared_size = response.headers.get("Content-Length", "").strip()
        if declared_size.isdigit() and int(declared_size) > MAX_IMAGE_BYTES:
            raise ValueError("图片超过 5 MiB")

        data = bytearray()
        for chunk in response.iter_content(chunk_size=64 * 1024):
            if not chunk:
                continue
            data.extend(chunk)
            if len(data) > MAX_IMAGE_BYTES:
                raise ValueError("图片超过 5 MiB")

    if not data:
        raise ValueError("图片内容为空")
    content_type = sniff_content_type(bytes(data))
    if content_type not in _IMAGE_CONTENT_TYPES:
        raise ValueError(f"响应不是支持的图片类型: {content_type or 'unknown'}")
    encoded = base64.b64encode(data).decode("ascii")
    return f"data:{content_type};base64,{encoded}"


def embed_weibo_goods_images(
    goods: list[dict[str, Any]],
    *,
    account_id: int | None = None,
) -> WeiboImageLoadResult:
    """并发把商品列表图片转成 data URL；单张失败时保留 HTTPS 兜底地址。"""

    total = len(goods)
    if total == 0:
        logger.info("微博商品图片加载完成：图片 0/0")
        return WeiboImageLoadResult(total=0, loaded=0)

    loaded = 0
    jobs: dict[Any, int] = {}
    workers = min(IMAGE_CONCURRENCY, total)
    with ThreadPoolExecutor(max_workers=workers) as executor:
        for index, item in enumerate(goods):
            image_url = normalize_weibo_image_url(item.get("goods_image"))
            item["goods_image"] = image_url
            if not image_url:
                continue
            if image_url.startswith("data:image/"):
                loaded += 1
                continue
            jobs[executor.submit(fetch_weibo_image_data_url, image_url)] = index

        for future in as_completed(jobs):
            index = jobs[future]
            try:
                goods[index]["goods_image"] = future.result()
            except Exception as exc:  # noqa: BLE001 - 单张图片失败不能影响商品列表
                logger.debug(f"微博商品图片下载失败：{type(exc).__name__}: {exc}")
            else:
                loaded += 1

    result = WeiboImageLoadResult(total=total, loaded=loaded)
    context = f"（account_id={account_id}）" if account_id is not None else ""
    logger.info(f"微博商品图片加载完成：图片 {result.loaded}/{result.total}{context}")
    return result