from __future__ import annotations

import html
from typing import Final
from urllib.parse import urlparse
from xml.etree import ElementTree

import requests

from app.models import Offer
from app.sources.base import OfferSource


class FlSource(OfferSource):
    source_name = "fl"
    _default_category_id: Final[int] = 5

    def __init__(self, rss_url: str, timeout_seconds: int) -> None:
        self._rss_url = rss_url
        self._timeout_seconds = timeout_seconds
        self._session = requests.Session()
        self._session.headers.update(
            {
                "User-Agent": (
                    "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 "
                    "(KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36"
                )
            }
        )

    def fetch_offers(self) -> list[Offer]:
        response = self._session.get(self._rss_url, timeout=self._timeout_seconds)
        response.raise_for_status()

        root = ElementTree.fromstring(response.content)
        offers: list[Offer] = []

        for item in root.findall("./channel/item"):
            url = _get_item_text(item, "link")
            external_id = _extract_external_id(url)
            if external_id is None:
                continue

            offers.append(
                Offer(
                    source=self.source_name,
                    external_id=external_id,
                    title=_get_item_text(item, "title", "Без названия"),
                    description=_get_item_text(item, "description"),
                    price="Не указан",
                    price_amount=None,
                    url=url,
                    category_id=self._default_category_id,
                    published_at=_get_item_text(item, "pubDate"),
                )
            )

        return offers


def _get_item_text(item: ElementTree.Element, tag_name: str, default: str = "") -> str:
    element = item.find(tag_name)
    if element is None or element.text is None:
        return default
    return html.unescape(element.text.strip())


def _extract_external_id(url: str) -> str | None:
    path_parts = [part for part in urlparse(url).path.split("/") if part]
    if len(path_parts) < 2 or path_parts[0] != "projects":
        return None
    return path_parts[1]