# -*- coding: utf-8 -*-

##########################################################################
#
# pgAdmin 4 - PostgreSQL Tools
#
# Copyright (C) 2013 - 2019, The pgAdmin Development Team
# This software is released under the PostgreSQL Licence
#
##########################################################################

# Get the correct version of chromedriver for the version of Chrome on the
# machine and save it to the specified location.

import argparse
import os
import platform
import subprocess
import sys
import urllib.request
import zipfile


def read_command_line():
    """Read the command line arguments.

    Returns:
        ArgumentParser: The parsed arguments object
    """
    parser = argparse.ArgumentParser(
        description='Get the correct version of chromedriver for the '
                    'specified Chrome installation and save it.')
    if platform.system() != 'Windows':
        parser.add_argument("chrome", metavar="CHROME",
                            help="the Chrome executable")
    parser.add_argument("directory", metavar="DIRECTORY",
                        help="the directory in which to save chromedriver")

    args = parser.parse_args()

    return args


def get_chrome_version(args):
    """Get the Chrome version number.

    Args:
        args: The parsed arguments object
    Returns:
        The Chrome version number
    """
    if platform.system() == 'Windows':
        # On Windows we need to examine the resource section of the binary
        import winreg

        def _read_registry(root, key, value):
            try:
                hkey = winreg.OpenKey(root, key)
            except Exception as e:
                return None
            try:
                (val, typ) = winreg.QueryValueEx(hkey, value)
            except Exception as e:
                winreg.CloseKey(hkey)
                return None

            winreg.CloseKey(hkey)
            return val

        key = r'SOFTWARE\Google\Chrome\BLBeacon'
        version_str = _read_registry(winreg.HKEY_CURRENT_USER, key, 'Version')

        # On a 64b host, look for a 32b installation
        if not version_str:
            key = r'SOFTWARE\Wow6432Node\Google\Chrome\BLBeacon'
            version_str = _read_registry(winreg.HKEY_CURRENT_USER, key,
                                         'Version')

        if not version_str:
            print('The Chrome version could not be read from the registry.')
            sys.exit(1)

        chrome_version = '.'.join(version_str.split()[-1].split('.')[:-1])
    else:
        # On Linux/Mac we run the Chrome executable with the --version flag,
        # then parse the output.
        try:
            result = subprocess.run([args.chrome, '--version'],
                                    stdout=subprocess.PIPE)
        except FileNotFoundError as e:
            print('The specified Chrome executable could not be found.')
            sys.exit(1)

        version_str = result.stdout.decode("utf-8").strip()
        # Check for 'Chrom' not 'Chrome' in case the user is using Chromium.
        if "Chrom" not in version_str:
            print('The specified Chrome executable output an unexpected '
                  'version string: {}.'.format(version_str))
            sys.exit(1)

        chrome_version = '.'.join(version_str.split()[-1].split('.')[:-1])

    if chrome_version.count('.') != 2:
        print('The specified Chrome executable output an unexpected '
              'version string: {}.'.format(version_str))
        sys.exit(1)

    return chrome_version


def get_chromedriver_version(chrome_version):
    """Get the required chromedriver version number.

    Args:
        chrome_version: The chrome version number
    Returns:
        The chromedriver version number
    """
    url = 'https://chromedriver.storage.googleapis.com/LATEST_RELEASE_{}' \
        .format(chrome_version)

    try:
        fp = urllib.request.urlopen(url)
    except urllib.error.URLError as e:
        print('The chromedriver catalog URL could not be accessed: {}'
              .format(e))
        sys.exit(1)

    version = fp.read().decode("utf-8").strip()
    fp.close()

    return version


def get_system():
    """Get the system name as known to chromedriver

    Returns:
        The system name
    """
    if platform.system() == 'Darwin':
        return 'mac64'
    elif platform.system() == 'Linux':
        return 'linux64'
    elif platform.system() == 'Windows':
        return 'win32'
    else:
        print("Unknown or unsupported operating system: {}"
              .format(platform.system()))
        sys.exit(1)


"""The core structure of the app."""

# Read the command line options
args = read_command_line()

chrome_version = get_chrome_version(args)

# Check the directory exists
if not os.path.isdir(args.directory):
    print('The specified output directory could not be accessed.')
    sys.exit(1)

chromedriver_version = get_chromedriver_version(chrome_version)

system = get_system()

url = 'https://chromedriver.storage.googleapis.com/{}/chromedriver_{}.zip' \
    .format(chromedriver_version, system)

print('Downloading chromedriver v{} for Chrome v{} on {}...'
      .format(chromedriver_version, chrome_version, system))

try:
    file, headers = urllib.request.urlretrieve(url)
except urllib.error.URLError as e:
    print('The chromedriver download URL could not be accessed: {}'
          .format(e))
    sys.exit(1)

# Unzip chromedriver
print('Extracting chromedriver...')

found = False
fp = open(file, 'rb')
z = zipfile.ZipFile(fp)
for name in z.namelist():
    if (system == 'win32' and name == 'chromedriver.exe') or \
            (system != 'win32' and name == 'chromedriver'):
        z.extract(name, args.directory)
        found = True
fp.close()

if not found:
    print("chromedriver could not be found in the downloaded archive: {}"
          .format(file))
    sys.exit(1)

# Set the permissions
if system == 'mac64' or system == 'linux64':
    os.chmod(os.path.join(args.directory, 'chromedriver'), 0o755)

print('Chromedriver downloaded to: {}'.format(args.directory))