"""Writes halkyon_app's subdivision names from a release of Unicode CLDR.

The names of states, regions and provinces (ISO 3166-2) that
`AssetSubdivisionNames` reads, in English and German, from CLDR's
`common/subdivisions/` at a tagged release, with CLDR's licence beside them:

    python3 -I tool/subdivision_names.py [release-48-2]

CLDR names a subdivision by its country and code in lower case without the
hyphen (`usca`); the asset keys it as ISO 3166-2 does (`US-CA`). English is
kept whole; German only where it differs, as the app falls back to English.
Variants (`alt`) are left out. Run it again with a newer tag to update both
files, and say the release in `assets/subdivisions/ATTRIBUTION.md`.
"""

import json
import re
import sys
import urllib.request
import xml.etree.ElementTree as ElementTree
from pathlib import Path

RELEASE = sys.argv[1] if len(sys.argv) > 1 else 'release-48-2'
LANGUAGES = ('en', 'de')
SOURCE = 'https://raw.githubusercontent.com/unicode-org/cldr/' + RELEASE + '/'
ASSETS = Path(__file__).resolve().parent.parent / 'packages' / 'halkyon_app' / 'assets' / 'subdivisions'
CODE = re.compile(r'^[A-Z]{2}-[A-Z0-9]{1,3}$')


def fetch(path):
    with urllib.request.urlopen(SOURCE + path, timeout=60) as response:
        return response.read()


def names_in(language):
    root = ElementTree.fromstring(fetch('common/subdivisions/' + language + '.xml'))
    names = {}
    for element in root.iter('subdivision'):
        if 'alt' in element.attrib or not (element.text or '').strip():
            continue
        cldr = element.attrib['type']
        code = cldr[:2].upper() + '-' + cldr[2:].upper()
        if CODE.match(code):
            names[code] = element.text.strip()
    return names


def main():
    english = names_in('en')
    names = {'release': RELEASE, 'en': english}
    for language in LANGUAGES[1:]:
        names[language] = {
            code: name
            for code, name in names_in(language).items()
            if english.get(code) != name
        }
    ASSETS.mkdir(parents=True, exist_ok=True)
    (ASSETS / 'subdivisions.json').write_text(
        json.dumps(names, ensure_ascii=False, sort_keys=True, separators=(',', ':')) + '\n',
        encoding='utf-8',
    )
    (ASSETS / 'LICENSE-CLDR.txt').write_bytes(fetch('LICENSE'))
    print(RELEASE, {language: len(names[language]) for language in LANGUAGES})


main()