#!/usr/bin/env python3
"""Install one HKDJ NET component; never update other Supervisor groups."""
import configparser
import hashlib
import io
import os
from pathlib import Path
import re
import shutil
import subprocess
import sys
import time

component, revision = sys.argv[1:]
assert component in ('app', 'web') and re.fullmatch('[0-9a-f]{40}', revision)
root = Path('/server/hkdj_net')
incoming = root / '.incoming' / component
binary = incoming / ('hkdj-net-' + component)
metadata = subprocess.check_output(['strings', '-a', str(binary)], text=True)
assert 'vcs.revision=' + revision in metadata and 'vcs.modified=false' in metadata
assert 'hkdj-web-server/' + component in metadata
destination = root / component
(destination / 'conf').mkdir(parents=True, exist_ok=True)
(root / 'logs').mkdir(exist_ok=True)
previous = destination / binary.name
if previous.exists():
    old_metadata = subprocess.check_output(['strings', '-a', str(previous)], text=True)
    old_revision = re.search(r'vcs.revision=([0-9a-f]{40})', old_metadata)
    assert old_revision and 'vcs.modified=false' in old_metadata
    assert 'hkdj-web-server/' + component in old_metadata
    old_checksum = hashlib.sha256(previous.read_bytes()).hexdigest()
    rollback = destination / '.rollback'
    rollback.mkdir(exist_ok=True)
    shutil.copy2(previous, rollback / (binary.name + '.' + old_revision[1] + '.' + old_checksum))
os.chmod(binary, 0o755)
os.replace(binary, destination / binary.name)
os.replace(incoming / (component + '.yaml'), destination / 'conf' / (component + '.yaml'))
if component == 'app':
    for name in ('ip2region_v4.xdb', 'ip2region_v6.xdb'):
        os.replace(incoming / name, destination / 'conf' / name)
config = configparser.RawConfigParser()
config.read(incoming / 'supervisor.conf')
selected = configparser.RawConfigParser()
name = 'hkdj_net_' + component
selected['program:' + name] = dict(config['program:' + name])
out = io.StringIO()
selected.write(out)
target = Path('/etc/supervisor/conf.d') / (name + '.conf')
changed = not target.exists() or target.read_text() != out.getvalue()
temporary = target.with_suffix('.pending')
temporary.write_text(out.getvalue())
os.replace(temporary, target)
subprocess.run(['supervisorctl', 'reread'], check=True)
subprocess.run(['supervisorctl', 'update', name], check=True)
if not changed:
    subprocess.run(['supervisorctl', 'restart', name], check=True)
for _ in range(40):
    status = subprocess.check_output(['supervisorctl', 'status', name], text=True)
    if 'RUNNING' in status:
        break
    time.sleep(1)
else:
    raise RuntimeError('selected component did not start')
print('installed', component, revision, hashlib.sha256((destination / binary.name).read_bytes()).hexdigest())