#!/usr/bin/python3
import argparse
import copy
from distutils.version import LooseVersion
import sys

import apt

# Virtual package mapping
virtual_mapping = {'awk': 'gawk'}

def main():
    
    parser = argparse.ArgumentParser(description='Process some integers.')
    parser.add_argument('-v', '--verbose', action='store_true')
    parser.add_argument('input_package_files', action='store')
    args = parser.parse_args()
    
    # Input packages
    in_packages = []
    
    # Parse input package files
    for filename in args.input_package_files.split(','):
        with open(filename) as in_file:
            for line in in_file:
                line = line.strip()
                if line:
                    in_packages.append(line)
    
    # Open APT cache
    cache = apt.Cache(memonly=True)
    cache.open()
    
    packages = set()

    while True:
        try:
            # Grab next package 
            pkg_name = in_packages.pop()        
            #~ print('Package: {:s}'.format(pkg_name))
      
            if pkg_name not in cache:
                if pkg_name in virtual_mapping:
                    pkg_name = virtual_mapping[pkg_name]
                else:
                    continue
      
            # Add this package (with version) to the list of packages
            if pkg_name not in packages:
                packages.add(pkg_name)

            # Get package dependencies
            for pdep in cache[pkg_name].versions[0].dependencies:
                dep_name = pdep[0].name
                #~ print('\tDependency: {:s}'.format(dep_name))
                if dep_name not in packages:
                    if dep_name in virtual_mapping:
                        dep_name = virtual_mapping[dep_name]
                    packages.add(dep_name)
                    in_packages.insert(0, dep_name)
        except IndexError:
            break

    # Print out the gathered package names
    for package in sorted(packages):
        print(package)
    
if __name__ == '__main__':
    sys.exit(main())