#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

"""Provides methods needed by installation script for OpenStack development
virtual environments.

Since this script is used to bootstrap a virtualenv from the system's Python
environment, it should be kept strictly compatible with Python 2.6.

Synced in from openstack-common
"""

from __future__ import print_function

import optparse
import os
import subprocess
import sys


class InstallVenv(object):

    def __init__(self, root, venv, requirements,
                 test_requirements, py_version,
                 project):
        self.root = root
        self.venv = venv
        self.requirements = requirements
        self.test_requirements = test_requirements
        self.py_version = py_version
        self.project = project

    def die(self, message, *args):
        print(message % args, file=sys.stderr)
        sys.exit(1)

    def check_python_version(self):
        if sys.version_info < (2, 6):
            self.die("Need Python Version >= 2.6")

    def run_command_with_code(self, cmd, redirect_output=True,
                              check_exit_code=True):
        """Runs a command in an out-of-process shell.

        Returns the output of that command. Working directory is self.root.
        """
        if redirect_output:
            stdout = subprocess.PIPE
        else:
            stdout = None

        proc = subprocess.Popen(cmd, cwd=self.root, stdout=stdout)
        output = proc.communicate()[0]
        if check_exit_code and proc.returncode != 0:
            self.die('Command "%s" failed.\n%s', ' '.join(cmd), output)
        return (output, proc.returncode)

    def run_command(self, cmd, redirect_output=True, check_exit_code=True):
        return self.run_command_with_code(cmd, redirect_output,
                                          check_exit_code)[0]

    def get_distro(self):
        if (os.path.exists('/etc/fedora-release') or
                os.path.exists('/etc/redhat-release')):
            return Fedora(
                self.root, self.venv, self.requirements,
                self.test_requirements, self.py_version, self.project)
        else:
            return Distro(
                self.root, self.venv, self.requirements,
                self.test_requirements, self.py_version, self.project)

    def check_dependencies(self):
        self.get_distro().install_virtualenv()

    def create_virtualenv(self, no_site_packages=True):
        """Creates the virtual environment and installs PIP.

        Creates the virtual environment and installs PIP only into the
        virtual environment.
        """
        if not os.path.isdir(self.venv):
            print('Creating venv...', end=' ')
            if no_site_packages:
                self.run_command(['virtualenv', '-q', '--no-site-packages',
                                 self.venv])
            else:
                self.run_command(['virtualenv', '-q', self.venv])
            print('done.')
        else:
            print("venv already exists...")
            pass

    def pip_install(self, *args):
        self.run_command(['tools/with_venv.sh',
                         'pip', 'install', '--upgrade'] + list(args),
                         redirect_output=False)

    def install_dependencies(self):
        print('Installing dependencies with pip (this can take a while)...')

        # First things first, make sure our venv has the latest pip and
        # setuptools and pbr
        self.pip_install('pip>=1.4')
        self.pip_install('setuptools')
        self.pip_install('pbr')

        self.pip_install('-r', self.requirements, '-r', self.test_requirements)

    def parse_args(self, argv):
        """Parses command-line arguments."""
        parser = optparse.OptionParser()
        parser.add_option('-n', '--no-site-packages',
                          action='store_true',
                          help="Do not inherit packages from global Python "
                               "install.")
        return parser.parse_args(argv[1:])[0]


class Distro(InstallVenv):

    def check_cmd(self, cmd):
        return bool(self.run_command(['which', cmd],
                    check_exit_code=False).strip())

    def install_virtualenv(self):
        if self.check_cmd('virtualenv'):
            return

        if self.check_cmd('easy_install'):
            print('Installing virtualenv via easy_install...', end=' ')
            if self.run_command(['easy_install', 'virtualenv']):
                print('Succeeded')
                return
            else:
                print('Failed')

        self.die('ERROR: virtualenv not found.\n\n%s development'
                 ' requires virtualenv, please install it using your'
                 ' favorite package management tool' % self.project)


class Fedora(Distro):
    """This covers all Fedora-based distributions.

    Includes: Fedora, RHEL, CentOS, Scientific Linux
    """

    def check_pkg(self, pkg):
        return self.run_command_with_code(['rpm', '-q', pkg],
                                          check_exit_code=False)[1] == 0

    def install_virtualenv(self):
        if self.check_cmd('virtualenv'):
            return

        if not self.check_pkg('python-virtualenv'):
            self.die("Please install 'python-virtualenv'.")

        super(Fedora, self).install_virtualenv()