#!/usr/bin/env python3
import hashlib
import traceback
import json
import os
import shutil
import subprocess as sp
import tempfile
import argparse
from pathlib import Path
from typing import List

OS_TEMPLATE = {
    'ubuntu-current': ["trusty", "xenial", "bionic", "eoan"],
    'ubuntu-lts': ["trusty", "xenial", "bionic"],
    'debian-current': ["jessie", "stretch", "buster"],
}

apt_download = Path(__file__).parent / "helpers" / "apt-download-binary"
if not apt_download.is_file():
    raise OSError(f"File not found: {apt_download}")

def check_args(prop: str, lst: List[str]):
    for s in lst:
        if len(s)==0 or ' ' in s:
            raise ValueError(f"Invalid item in {prop}: {repr(s)}")

def replace_os_template(os_list: List[str]) -> List[str]:
    ret = []
    for i in os_list:
        if i.startswith('@'):
            ret.extend(OS_TEMPLATE[i[1:]])
        else:
            ret.append(i)
    return ret

def main():

    parser = argparse.ArgumentParser()
    parser.add_argument("base_url", type=str, help="base URL")
    parser.add_argument("os_version", type=str, help="e.g. buster,@ubuntu-lts")
    parser.add_argument("component", type=str, help="e.g. multiverse,contrib")
    parser.add_argument("arch", type=str, help="e.g. i386,amd64")
    parser.add_argument("working_dir", type=Path, help="working directory")
    parser.add_argument("--delete", action='store_true',
                        help='delete unreferenced package files')
    args = parser.parse_args()

    os_list = args.os_version.split(',')
    check_args("os_version", os_list)
    component_list = args.component.split(',')
    check_args("component", component_list)
    arch_list = args.arch.split(',')
    check_args("arch", arch_list)

    os_list = replace_os_template(os_list)

    args.working_dir.mkdir(parents=True, exist_ok=True)
    filelist = tempfile.mkstemp()

    for os in os_list:
        for comp in component_list:
            for arch in arch_list:
                shell_args = [
                    str(apt_download.absolute()),
                    args.base_url,
                    os, comp, arch,
                    str(args.working_dir.absolute()),
                    filelist[1] ]
                print(shell_args)
                sp.run(shell_args)
    if args.delete:
        pass #TODO

if __name__ == "__main__":
    main()