"""子站解析器注册表与商品页分派

乐天部分官方旗舰店的商品页会 302 跳出 item.rakuten.co.jp，落到各自独立的站点。
这里按落地域名把页面分派给对应解析器；落到未登记的站点时抛 OffIchibaRedirectError，
让上游能明确区分「站点不支持」与「被反爬拦截」，而不是白白重试。
"""
from __future__ import annotations

from urllib.parse import urlsplit

from app.scraping.core import site
from app.shared.errors import OffIchibaRedirectError, ScrapeParseError
from app.scraping.models.scrape import ItemDetailData
from app.scraping.parsers.state import PageValidator, require_state_marker
from app.scraping.parsers.subsites import biccamera, books, brandavenue
from app.scraping.parsers.subsites.base import SubsitePage, SubsiteParser

SUBSITE_PARSERS: dict[str, SubsiteParser] = {
    module.HOST: SubsiteParser(
        host=module.HOST,
        source=module.SOURCE,
        shop_name=module.SHOP_NAME,
        validate=module.validate,
        parse=module.parse,
    )
    for module in (books, brandavenue, biccamera)
}


def host_of(url: str) -> str:
    return urlsplit(url).hostname or ""


def build_item_page_validator(requested_url: str) -> PageValidator:
    """构造商品页校验器：按落地域名选用对应的页面校验规则

    落到未登记的站点时直接抛错——换 cookie 或上浏览器都改变不了页面归属。
    """

    def validate(html: str, final_url: str) -> str | None:
        host = host_of(final_url)
        if host == site.ITEM_HOST:
            return require_state_marker(html, final_url)
        parser = SUBSITE_PARSERS.get(host)
        if parser is None:
            raise OffIchibaRedirectError(requested_url, final_url)
        return parser.validate(html)

    return validate


def parse_subsite_item(page: SubsitePage) -> ItemDetailData:
    """把子站页面交给对应解析器"""
    parser = SUBSITE_PARSERS.get(host_of(page.final_url))
    if parser is None:
        raise ScrapeParseError(f"没有匹配的子站解析器：{page.final_url}")
    return parser.parse(page)