"""OPML import/export.

Feeds are exported as an OPML 2.0 outline grouped by ntfy topic. ntfy-specific
options are stored as custom ``ntfy*`` attributes so an export/import round-trip
preserves everything. Import also accepts plain OPML files from other readers:
feeds without an ``ntfyTopic`` attribute inherit the parent outline's text as the
topic (falling back to ``rss``).
"""

import xml.etree.ElementTree as ET


def _int(value, default):
    try:
        return int(value)
    except (TypeError, ValueError):
        return default


def feeds_to_opml(feeds):
    opml = ET.Element("opml", version="2.0")
    head = ET.SubElement(opml, "head")
    ET.SubElement(head, "title").text = "rss-bridge-ntfy feeds"
    body = ET.SubElement(opml, "body")

    # Group feeds by topic, preserving insertion order.
    groups = {}
    for feed in feeds:
        groups.setdefault(feed.get("topic", "") or "feeds", []).append(feed)

    for topic, items in groups.items():
        group = ET.SubElement(body, "outline", text=topic, title=topic)
        for feed in items:
            label = feed.get("name") or feed.get("url", "")
            ET.SubElement(group, "outline", **{
                "type": "rss",
                "text": label,
                "title": label,
                "xmlUrl": feed.get("url", ""),
                "htmlUrl": feed.get("url", ""),
                "ntfyTopic": feed.get("topic", "") or "",
                "ntfyPriority": str(feed.get("priority", 3)),
                "ntfyIcon": feed.get("icon", "") or "",
                "ntfyQuietHours": feed.get("quiet_hours", "") or "",
                "ntfyQuietPriority": str(feed.get("quiet_priority", 1)),
                "ntfyInclude": feed.get("include_regex", "") or "",
                "ntfyExclude": feed.get("exclude_regex", "") or "",
                "ntfyEnabled": "true" if feed.get("enabled", True) else "false",
            })

    xml = ET.tostring(opml, encoding="unicode")
    return '<?xml version="1.0" encoding="UTF-8"?>\n' + xml


def opml_to_feeds(xml_str):
    root = ET.fromstring(xml_str)
    body = root.find("body")
    if body is None:
        return []

    feeds = []

    def walk(node, parent_topic):
        for outline in node.findall("outline"):
            xml_url = outline.get("xmlUrl") or outline.get("xmlurl")
            text = outline.get("text") or outline.get("title") or ""
            if xml_url:
                topic = outline.get("ntfyTopic") or parent_topic or text or "rss"
                feeds.append({
                    "name": text or xml_url,
                    "url": xml_url,
                    "topic": topic,
                    "priority": _int(outline.get("ntfyPriority"), 3),
                    "icon": outline.get("ntfyIcon", "") or "",
                    "quiet_hours": outline.get("ntfyQuietHours", "") or "",
                    "quiet_priority": _int(outline.get("ntfyQuietPriority"), 1),
                    "include_regex": outline.get("ntfyInclude", "") or "",
                    "exclude_regex": outline.get("ntfyExclude", "") or "",
                    "enabled": (outline.get("ntfyEnabled", "true").lower() != "false"),
                })
            # A container outline (no xmlUrl) defines the topic for its children.
            child_topic = text if (not xml_url and text) else parent_topic
            walk(outline, child_topic)

    walk(body, "")
    return feeds