#!/usr/bin/python3

import hashlib
import json
import os
import subprocess
import sys

from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives.asymmetric import ec
from cryptography.hazmat.primitives.serialization import load_pem_private_key

BUILD_ROOT = '/root/buildroot'
LXC_ROOT = '/var/lib/lxc'

def pack(pkg_file):
    if os.path.isdir(pkg_file):
        pkg_file = os.path.join(pkg_file, 'pkg')
    # Prepare metadata
    meta = {}
    with open(pkg_file) as fd:
        for line in fd:
            line = [l.strip() for l in line.split(':', 1)]
            meta[line[0]] = line[1]
    meta['deps'] = meta['deps'].split()
    pkg_name = meta['pkg']
    del meta['pkg']

    tar_path = os.path.join(BUILD_ROOT, '{}.tar'.format(pkg_name))
    xz_path = '{}.xz'.format(tar_path)

    # Remove old package
    try:
        os.unlink(tar_path)
        os.unlink(xz_path)
    except:
        pass

    # Create archive
    print('Archiving', meta['lxcpath'])
    subprocess.run(['tar', 'cpf', tar_path, meta['lxcpath']], cwd=LXC_ROOT)
    if '/' not in meta['lxcpath']:
        print('Archiving setup files')
        cwd = os.path.dirname(os.path.abspath(pkg_file))
        subprocess.run(['tar', 'rpf', tar_path, 'setup', 'setup.sh'], cwd=cwd)
    print('Compressing', tar_path)
    subprocess.run(['xz', '-9', tar_path])

    # Register package
    print('Registering package')
    packages = {}
    packages_file = os.path.join(BUILD_ROOT, 'packages')
    try:
        with open(packages_file, 'r') as fd:
            packages = json.load(fd)
    except:
        pass
    packages[pkg_name] = meta
    with open(packages_file, 'w') as fd:
        json.dump(packages, fd, sort_keys=True, indent=4)

    # Sign packages
    print('Signing packages')
    with open(os.path.join(BUILD_ROOT, 'packages.key'), 'rb') as fd:
        priv_key = load_pem_private_key(fd.read(), None, default_backend())
    with open(os.path.join(BUILD_ROOT, 'packages'), 'rb') as fd:
        data = fd.read()
    with open(os.path.join(BUILD_ROOT, 'packages.sha512'), 'wb') as fd:
        fd.write(priv_key.sign(data, ec.ECDSA(hashes.SHA512())))

def hash_file(file_path):
    sha512 = hashlib.sha512()
    with open(file_path, 'rb') as fd:
        while True:
            data = fd.read(65536)
            if not data:
                break
            sha512.update(data)
    return sha512.hexdigest()

if __name__ == '__main__':
    if len(sys.argv) != 2:
        print('Usage: lxc-pack <pkgfile>')
    else:
        pack(sys.argv[1])