"""OPML import/export for feed subscriptions."""
from __future__ import annotations

from xml.etree import ElementTree as ET

from .models import Feed


def export_opml(feeds: list[Feed]) -> str:
    """Render feeds as an OPML 2.0 document."""
    opml = ET.Element("opml", version="2.0")
    head = ET.SubElement(opml, "head")
    ET.SubElement(head, "title").text = "RSS → ntfy subscriptions"
    body = ET.SubElement(opml, "body")
    for feed in feeds:
        attrs = {
            "type": "rss",
            "text": feed.title or feed.url,
            "title": feed.title or feed.url,
            "xmlUrl": feed.url,
        }
        # Stash the ntfy topic so a re-import keeps the routing.
        if feed.ntfy_topic:
            attrs["ntfyTopic"] = feed.ntfy_topic
        if feed.ntfy_server:
            attrs["ntfyServer"] = feed.ntfy_server
        ET.SubElement(body, "outline", attrs)
    return '<?xml version="1.0" encoding="UTF-8"?>\n' + ET.tostring(
        opml, encoding="unicode"
    )


def parse_opml(content: str) -> list[dict]:
    """Extract feed definitions from an OPML document.

    Returns a list of dicts ready to build Feed rows. Raises ValueError on
    malformed XML.
    """
    try:
        root = ET.fromstring(content)
    except ET.ParseError as exc:
        raise ValueError(f"Некорректный OPML: {exc}") from exc

    feeds: list[dict] = []
    for outline in root.iter("outline"):
        url = outline.get("xmlUrl") or outline.get("xmlurl")
        if not url:
            continue
        feeds.append(
            {
                "url": url.strip(),
                "title": (outline.get("title") or outline.get("text") or "").strip(),
                "ntfy_topic": (outline.get("ntfyTopic") or "").strip(),
                "ntfy_server": (outline.get("ntfyServer") or "").strip(),
            }
        )
    return feeds