'''
    Auto-updater
'''
from distutils.version import StrictVersion
import os
from subprocess import Popen
import sys
import tempfile

import requests

VERSIONFILE_URL = "http://codebox/lab/ModelePython/raw/master/VERSION"
SETUPFILE_URL = "http://codebox/lab/ModelePython/raw/master/setup-hello_world.exe"

CURDIR = os.path.dirname(__file__)

TMPDIR = os.path.join(tempfile.gettempdir(), os.path.basename(CURDIR), "update")
TMP_SETUPFILE = os.path.join(TMPDIR, "setup.exe")

class UpdateNeeded(Exception):
    pass

class Unavailable(requests.exceptions.RequestException):
    pass

def autoupdate():
    clean_old()
    try:
        if update_needed():
            update()
    except Unavailable:
        pass

def clean_old():
    try:
        os.rmdir(TMPDIR)
    except:
        pass

def update_needed():
    # Available version
    try:
        raw = requests.get(VERSIONFILE_URL).text
        available_version = StrictVersion(raw)
    except (ValueError, requests.exceptions.RequestException):
        raise Unavailable()

    # Installed version
    with open(os.path.join(CURDIR, "VERSION")) as f:
        installed_version = f.read()

    return available_version > installed_version

def update():

    # Download the setup.exe
    response = requests.get(SETUPFILE_URL, stream=True)

    os.mkdir(TMPDIR)
    with open(TMP_SETUPFILE, "wb") as handle:
        for chunk in response.iter_content(chunk_size=1024):
            if chunk:
                handle.write(chunk)

    # Run the installer and restart the start command
    args = "/c {} /SILENT & {} {}".format(TMP_SETUPFILE, sys.executable, " ".join(sys.argv[:]))

    Popen(["cmd.exe", args], shell=True)

    # An UpdateNeeded exception is raised so the script exit before being restarted by subprocess
    raise UpdateNeeded()