"""Copy the phone app's podcast page into the web app.

The browser shows the same podcast UI as the Android app: diora-android's
web-native/static/native-podcast.js, unchanged, on top of a browser host
(static/js/podcasts-web.js). This copies that file and the podcast parts of
native.css (the bottom sheet and everything from the podcast section on) to
static/podcasts/, with the source commit in a header comment.

Usage: python tools/sync_podcast_ui.py [path/to/diora-android]
       (default: ../diora-android next to this checkout)

Afterwards bump CACHE in static/js/sw.js so browsers fetch the new files.
"""
import subprocess
import sys
from pathlib import Path

ROOT = Path(__file__).resolve().parent.parent
DEST = ROOT / 'static' / 'podcasts'

# Sections of native.css the podcast page needs: (start marker, end marker or None = to the end).
CSS_SECTIONS = [
    ('/* ---- bottom sheet', '/* ---- reader'),
    ('/* ---- podcasts (phones only', None),
]


def source_line(android, rel):
    """'diora-android <commit> <date>' of the file, plus a note if it has uncommitted changes."""
    def git(*args):
        return subprocess.run(['git', '-C', str(android), *args], capture_output=True, text=True).stdout.strip()
    line = 'diora-android ' + (git('log', '-1', '--format=%h %cs', '--', rel) or 'unknown commit')
    if git('status', '--short', '--', rel):
        line += ' + uncommitted changes'
    return line


def cut(text, start, end):
    i = text.find(start)
    if i < 0:
        sys.exit(f'sync_podcast_ui: {start!r} not found in native.css')
    j = text.find(end, i) if end else len(text)
    if j < 0:
        sys.exit(f'sync_podcast_ui: {end!r} not found after {start!r} in native.css')
    return text[i:j].rstrip() + '\n'


def main():
    android = Path(sys.argv[1]) if len(sys.argv) > 1 else ROOT.parent / 'diora-android'
    static = android / 'web-native' / 'static'
    if not (static / 'native-podcast.js').exists():
        sys.exit(f'sync_podcast_ui: no diora-android checkout at {android}')
    DEST.mkdir(parents=True, exist_ok=True)

    js_src = source_line(android, 'web-native/static/native-podcast.js')
    js = (static / 'native-podcast.js').read_text(encoding='utf-8')
    (DEST / 'native-podcast.js').write_text(
        f'// Copied from {js_src}: web-native/static/native-podcast.js\n'
        '// by tools/sync_podcast_ui.py. Do not edit here: change it in diora-android\n'
        '// and copy again. The browser host is static/js/podcasts-web.js.\n\n' + js,
        encoding='utf-8', newline='\n')

    css_src = source_line(android, 'web-native/static/native.css')
    css = (static / 'native.css').read_text(encoding='utf-8')
    parts = [cut(css, start, end) for start, end in CSS_SECTIONS]
    (DEST / 'podcast-ui.css').write_text(
        f'/* Copied from {css_src}: the podcast parts of web-native/static/native.css\n'
        '   (bottom sheet, podcasts) by tools/sync_podcast_ui.py. Do not edit here.\n'
        '   The web\'s own additions are in podcasts-web.css. */\n\n' + '\n'.join(parts),
        encoding='utf-8', newline='\n')

    print(f'native-podcast.js: {js_src}')
    print(f'podcast-ui.css:    {css_src}')
    print('Now bump CACHE in static/js/sw.js.')


if __name__ == '__main__':
    main()