# vim: tabstop=4 shiftwidth=4 softtabstop=4

# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# All Rights Reserved.
#
# Copyright 2010 OpenStack LLC.
#
#    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.

"""
Installation script for openstack common's development virtualenv
"""

import os
import subprocess
import sys


ROOT = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
VENV = os.path.join(ROOT, '.openstack-common-venv')
PIP_REQUIRES = os.path.join(ROOT, 'tools', 'pip-requires')


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


def run_command(cmd, redirect_output=True, check_exit_code=True):
    """
    Runs a command in an out-of-process shell, returning the
    output of that command.  Working directory is ROOT.
    """
    if redirect_output:
        stdout = subprocess.PIPE
    else:
        stdout = None

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


HAS_EASY_INSTALL = bool(run_command(['which', 'easy_install'],
                                    check_exit_code=False).strip())
HAS_VIRTUALENV = bool(run_command(['which', 'virtualenv'],
                                    check_exit_code=False).strip())


def check_dependencies():
    """Make sure virtualenv is in the path."""

    if not HAS_VIRTUALENV:
        print 'not found.'
        # Try installing it via easy_install...
        if HAS_EASY_INSTALL:
            print 'Installing virtualenv via easy_install...',
            if not run_command(['which', 'easy_install']):
                die('ERROR: virtualenv not found.\n\n'
                    'Openstack development requires virtualenv, please install'
                    ' it using your favorite package management tool')
            print 'done.'
    print 'done.'


def create_virtualenv(venv=VENV):
    """
    Creates the virtual environment and installs PIP only into the
    virtual environment
    """
    print 'Creating venv...',
    run_command(['virtualenv', '-q', '--no-site-packages', VENV])
    print 'done.'
    print 'Installing pip in virtualenv...',
    if not run_command(['tools/with_venv.sh', 'easy_install', 'pip']).strip():
        die("Failed to install pip.")
    print 'done.'


def install_package(venv=VENV):
    print 'Installing packages (this can take a while)...'
    venv_tool = 'tools/with_venv.sh'
    run_command([venv_tool, 'pip', 'install', '-E', venv, '-e', ROOT],
                redirect_output=False)

    # Tell the virtual env how to "import openstack-common"
    py_ver = _detect_python_version(venv)
    pthfile = os.path.join(venv, "lib", py_ver, "site-packages",
                           "openstack-common.pth")
    f = open(pthfile, 'w')
    f.write("%s\n" % ROOT)


def _detect_python_version(venv):
    lib_dir = os.path.join(venv, "lib")
    for pathname in os.listdir(lib_dir):
        if pathname.startswith('python'):
            return pathname
    raise Exception('Unable to detect Python version')


def print_help():
    help = """
 Openstack-Common development environment setup is complete.

 Openstack-Common development uses virtualenv to track and manage Python
 dependencies while in development and testing.

 To activate the Openstack-Common virtualenv for the extent of your
 current shell session you can run:

 $ source .openstack-common-venv/bin/activate

 Or, if you prefer, you can run commands in the virtualenv on a case by case
 basis by running:

 $ tools/with_venv.sh <your command>

 Also, make test will automatically use the virtualenv.
    """
    print help


def main(argv):
    check_dependencies()
    create_virtualenv()
    install_package()
    print_help()

if __name__ == '__main__':
    main(sys.argv)
