#!/usr/bin/env python

import os
import sys

required_packages = [
    'sudo',
    'make',
    'live-build',
    'pbuilder',
    'devscripts',
    'python-pystache'
]


def is_installed(name):
    result = os.system("dpkg-query -W --showformat='${{Status}}\n' {name} 2>&1 | grep 'install ok installed' >/dev/null".format(name=name))
    return True if result == 0 else False


missing_packages = []

print("Checking if packages required for VyOS image build are installed")

for p in required_packages:
    if not is_installed(p):
        missing_packages.append(p)

if missing_packages:
    print("Your system does not have some of the required packages installed.")
    print("Please install the following packages:")
    print(" ".join(missing_packages))
    sys.exit(1)
else:
    print("All required packages are installed")
    sys.exit(0)