#!c:\conda\python.exe
# This is a small script for backing up directories on windows. Just drop a directory in the explorer
# on this script and you get a file with the directory name which includes a time stamp.
#
# Requirements:
#
# 1) 7z must be installed with the installer
# 2) A registration of python. This is default for CPython
#
# Usage: Drag and Drop a file or directory on this script
#

import sys
import winreg
import time
import subprocess as sp
from pathlib import Path

regkey_zip = r"HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\7-Zip"

msg_missing7z = """Error:\n7z must be installed with the installer or\nI can't find the path to the executable"""
msg_missingarg = """Error:\nYou must provide exact one argument!"""
msg_argfile = """Error:\nThe argument must be an readable directory or a file!"""
msg_startup = """Make a backup"""

def regkey_value(path, name="", start_key = None):
    if isinstance(path, str):
        path = path.split("\\")
    if start_key is None:
        start_key = getattr(winreg, path[0])
        return regkey_value(path[1:], name, start_key)
    else:
        subkey = path.pop(0)
    with winreg.OpenKey(start_key, subkey) as handle:
        assert handle
        if path:
            return regkey_value(path, name, handle)
        else:
            desc, i = None, 0
            while not desc or desc[0] != name:
                desc = winreg.EnumValue(handle, i)
                i += 1
            return desc[1]

def msg(text):
    lines = text.split('\n')
    linelen = max(len(s) for s in lines)

    print('+'+'-'*linelen+'+')
    for line in lines:
        print('|{:{length}}|'.format(line,length=linelen))
    print('+' + '-' * linelen + '+')


if len(sys.argv)!=2:
    msg(msg_missingarg)
    _ = input('Press a key')
    quit(-1)

try:
    value = regkey_value(regkey_zip,'InstallLocation')
except:
    msg(msg_missing7z)
    _ = input('Press a key')
    quit(-1)

zipper = Path(value) / '7z.exe'

try:
    archive_src = Path(sys.argv[1])
    if not archive_src.exists():
        raise FileNotFoundError
except:
    msg(msg_argfile)
    _ = input('Press a key')
    quit(-1)

archive_dst = archive_src.parent / Path(str(archive_src.name) + ' ' + time.strftime('%Y%m%d-%H%M%S'))

args = ['{}'.format(str(zipper)), 'a', str(archive_dst), str(archive_src)]

msg(msg_startup)
process = sp.Popen(args)
process.wait()

msg('Ready! ')
_ = input('Press a key')