import html
import urllib.parse
import os
import requests
import redis
import xml.etree.ElementTree as ET
import re
import unicodedata
from flask import request, Response

PROXY_URL = os.getenv("PROXY_URL")
REDIS_URL = os.getenv("REDIS_URL", "redis://localhost:6379/0")
CACHE_TTL = int(os.getenv("CACHE_TTL", 3600))

rdb = redis.from_url(REDIS_URL)

_head_html = f"""<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0">
<channel><title>Tapochek.net RSS</title>
<link>http://tapochek.net/</link>
<ttl>15</ttl>"""


def normalize_text(text):
    """Приводит текст к нормальному виду, устраняя странные символы."""
    if text:
        return unicodedata.normalize("NFKC", text)
    return text


def extract_viewtopic_link(description):
    decoded_description = html.unescape(description)
    match = re.search(r'href="(https?://[^"]+)"', decoded_description)
    return match.group(1) if match else None


def normalize_xml_texts(elem):
    """Применяет normalize_text ко всем текстовым узлам XML."""
    if elem.text:
        elem.text = normalize_text(elem.text)
    if elem.tail:
        elem.tail = normalize_text(elem.tail)
    for child in elem:
        normalize_xml_texts(child)


def init_proxy(app):
    @app.route("/proxy")
    def proxy():
        """Proxy RSS feed with per-item caching and GUID replacement."""
        raw_query = request.query_string.decode()
        if raw_query.startswith("url="):
            url = urllib.parse.unquote(raw_query[4:])
            url = html.unescape(url)
        else:
            return "Missing URL", 400

        try:
            proxies = {"http": PROXY_URL, "https": PROXY_URL} if PROXY_URL else None
            r = requests.get(url, timeout=10, proxies=proxies)

            xml_data = r.text
            xml_data = xml_data.replace("&", "&amp;")
            _encoding = xml_data.split('encoding="')[1].split('"')[0]
            if '<?xml version="1.0" encoding="' in xml_data:
                xml_data = xml_data.replace(
                    f'<?xml version="1.0" encoding="{_encoding}"?>',
                    '<?xml version="1.0" encoding="UTF-8"?>'
                )

            if '<?xml version="1.0" encoding="UTF-8"?>' not in xml_data:
                xml_data = f'<?xml version="1.0" encoding="UTF-8"?>{xml_data}'

            root = ET.fromstring(xml_data)
            items = root.findall(".//item")

            cached_items = []
            new_items = []

            for item in items:
                guid = item.find("guid")
                if guid is None or not guid.text:
                    continue

                cache_key = f"rss:item:{guid.text}"
                cached_item = rdb.get(cache_key)

                title = item.find("title")
                new_title = re.sub(r'&#\d+', '', title.text)
                title.text = new_title

                if cached_item:
                    cached_items.append(cached_item.decode())
                else:

                    normalize_xml_texts(item)

                    item_str = ET.tostring(item, encoding="unicode")
                    item_str = html.unescape(item_str)
                    rdb.setex(cache_key, CACHE_TTL, item_str)
                    new_items.append(item_str)

            final_items = cached_items + new_items
            response_xml = f"""{_head_html}{"".join(final_items)}</channel></rss>"""

            return Response(response_xml, content_type="application/xml; charset=utf-8")

        except Exception as e:
            return f"Error: {e}", 500