#!/usr/bin/env python3

import argparse
import subprocess
import sys
import os
import tempfile

def register_all():
    register_stretchsecurity()

def register_stretchsecurity():
    name = "stretch-security"
    repo = """
deb http://security.debian.org stretch/updates main contrib non-free
deb http://deb.debian.org/debian/ stretch main contrib non-free
"""
    pref = """
Package: *
Pin: release l=Debian-Security
Pin-Priority: 990

Package: *
Pin: release l=Debian
Pin-Priority: 99
"""
    register_info(name, repo, pref)

InfoRegister = {}
class Info:
    def __init__(self, repo, pref):
       self.repo = repo
       self.pref = pref

def register_info(name, repo, pref):
    new = Info(repo, pref)
    InfoRegister[name] = new

def exec_cmd(cmd, verbose):
    if verbose:
        print(cmd)
    ret = subprocess.call(cmd, shell=True)
    if ret != 0:
        print("something failed")
        sys.exit(ret)

def generate_args(repo_file, pref_file):
    args = " -o Dir::Etc::SourceList=" + repo_file
    args = args + " -o Dir::Etc::Preferences=" + pref_file
    args = args + " -o Dir::Etc::SourceParts=/dev/null"
    args = args + " -q -y"
    args = args + " -o Dpkg::Options::='--force-confdef'"
    args = args + " -o Dpkg::Options::='--force-confold'"
    return args

def exec_apt_update(args, verbose):
    cmd = "DEBIAN_FRONTEND=noninteractive apt-get update" + args
    exec_cmd(cmd, verbose)

def exec_apt_upgrade(args, verbose):
    cmd = "DEBIAN_FRONTEND=noninteractive apt-get upgrade" + args
    exec_cmd(cmd, verbose)

def run(name, verbose, simulate):
    repo_file = tempfile.NamedTemporaryFile(mode='r+', encoding='utf-8')
    repo_file.write(InfoRegister[name].repo)
    pref_file = tempfile.NamedTemporaryFile(mode='r+', encoding='utf-8')
    pref_file.write(InfoRegister[name].pref)
    args = generate_args(repo_file.name, pref_file.name)
    exec_apt_update(args, verbose)
    if simulate:
         args = args + " -s"
    exec_apt_upgrade(args, verbose)
    repo_file.close()
    pref_file.close()

def list_registers():
    for name in InfoRegister:
        print("\t\t\t" + name)
        print("-" * 80)
        print(InfoRegister[name].repo.strip())
        print("-" * 80)
        print(InfoRegister[name].pref.strip())
        print("-" * 80)

def main():
    parser = argparse.ArgumentParser(description="Run a targetted upgrade of packages")
    parser.add_argument('--list', action='store_true', help="list the repos this script can run with")
    parser.add_argument('--verbose', action='store_true', help="be verbose")
    parser.add_argument('-s', action='store_true', help="simulate operations, pass '-s' to apt-get")
    parser.add_argument('target', help="target source repository/channel to upgrade from")
    args = parser.parse_args()

    register_all()

    if args.list:
        list_registers()
        sys.exit(0)

    for name in InfoRegister:
        if name == args.target:
             run(name, args.verbose, args.s)
             sys.exit(0)

    print("I don't know how to handle repo: " +args.target)
    print("Use --list to know the repos this script can run with")
    sys.exit(1)

if __name__ == "__main__":
  main()