#!/usr/bin/env python3
import os
import sys
import xml.etree.ElementTree as ET
from datetime import datetime, timezone

GPX_NS = "http://www.topografix.com/GPX/1/1"
OSMAND_NS = "https://osmand.net"

ET.register_namespace("", GPX_NS)
ET.register_namespace("osmand", OSMAND_NS)

def iso_now_z():
    return datetime.now(timezone.utc).replace(microsecond=0).isoformat().replace("+00:00", "Z")

def localname(tag):
    return tag.split("}", 1)[-1] if "}" in tag else tag

def find_child_by_localname(parent, wanted):
    for ch in list(parent):
        if localname(ch.tag) == wanted:
            return ch
    return None

def get_metadata_name_anyns(root):
    md = find_child_by_localname(root, "metadata")
    if md is None:
        return None
    nm = find_child_by_localname(md, "name")
    if nm is None:
        return None
    txt = (nm.text or "").strip()
    return txt or None

def guess_group(in_path, root, prefix):
    base = get_metadata_name_anyns(root)
    if not base:
        base = os.path.splitext(os.path.basename(in_path))[0]
    if prefix:
        return f"{prefix.rstrip('/')}/{base}"
    return base

def main():
    if len(sys.argv) not in (3, 4):
        print(
            "Usage: gpx_to_osmand_favorites_autogroup_fixed.py input.gpx output.gpx [prefix]\n"
            "Example: gpx_to_osmand_favorites_autogroup_fixed.py 4x4.gpx 4x4_osmand.gpx Norwegen",
            file=sys.stderr
        )
        sys.exit(2)

    in_path = sys.argv[1]
    out_path = sys.argv[2]
    prefix = sys.argv[3] if len(sys.argv) == 4 else ""

    tree = ET.parse(in_path)
    root = tree.getroot()

    group = guess_group(in_path, root, prefix)

    in_wpts = [el for el in root.iter() if localname(el.tag) == "wpt"]
    if not in_wpts:
        raise SystemExit(f"No <wpt> elements found in {in_path}")

    out_root = ET.Element(f"{{{GPX_NS}}}gpx", {
        "version": "1.1",
        "creator": "gpx_to_osmand_favorites_autogroup_fixed.py",
    })

    md = ET.SubElement(out_root, f"{{{GPX_NS}}}metadata")
    ET.SubElement(md, f"{{{GPX_NS}}}name").text = f"OsmAnd favorites: {group}"
    ET.SubElement(md, f"{{{GPX_NS}}}time").text = iso_now_z()

    written = 0
    for w in in_wpts:
        lat = w.attrib.get("lat")
        lon = w.attrib.get("lon")
        if lat is None or lon is None:
            continue

        out_wpt = ET.SubElement(out_root, f"{{{GPX_NS}}}wpt", {"lat": str(lat), "lon": str(lon)})

        # Copy common fields if present
        for ch in list(w):
            ln = localname(ch.tag)
            if ln in ("name", "cmt", "desc", "ele", "time") and ch.text not in (None, ""):
                ET.SubElement(out_wpt, f"{{{GPX_NS}}}{ln}").text = ch.text

        # Ensure we have a name
        if find_child_by_localname(out_wpt, "name") is None:
            ET.SubElement(out_wpt, f"{{{GPX_NS}}}name").text = f"Favorite {written+1}"

        # OsmAnd favorites group (key field)
        ET.SubElement(out_wpt, f"{{{GPX_NS}}}type").text = group

        # Optional OsmAnd hint (safe if ignored)
        ext = ET.SubElement(out_wpt, f"{{{GPX_NS}}}extensions")
        ET.SubElement(ext, f"{{{OSMAND_NS}}}category").text = group

        written += 1

    ET.ElementTree(out_root).write(out_path, encoding="UTF-8", xml_declaration=True)
    print(f"Wrote {written} waypoint(s) to {out_path} with OsmAnd favorites group '{group}'")

if __name__ == "__main__":
    main()