#!/usr/bin/python

EASY_INSTALL = None
VIRTUALENV = '/usr/local/bin/virtualenv'
ENV = None


def _find_easy_install():
    if ENV:
        return os.path.join(ENV, 'bin', 'easy_install')

    paths = ['/usr/local/bin', '/usr/bin']

    for p in paths:
        e = p + '/easy_install'
        if os.path.exists(e):
            return e


def _ensure_virtualenv():
    if os.path.exists(os.path.join(ENV, 'bin', 'activate')):
        return 0, '', ''
    else:
        return _run('%s %s' % (VIRTUALENV, ENV))


def _is_package_installed(name):
    cmd = '%s --dry-run %s' % (EASY_INSTALL, name)
    rc, status_stdout, status_stderr = _run(cmd)
    return not ('Reading' in status_stdout or 'Downloading' in status_stdout)


def _run(cmd):
    # returns (rc, stdout, stderr) from shell command
    process = subprocess.Popen(cmd, stdout=subprocess.PIPE,
                               stderr=subprocess.PIPE, shell=True)
    stdout, stderr = process.communicate()
    return (process.returncode, stdout, stderr)


def main():
    arg_spec = dict(
        name=dict(required=True),
        virtualenv=dict(default=None, required=False)
    )

    module = AnsibleModule(argument_spec=arg_spec)

    global EASY_INSTALL
    global VIRTUALENV
    global ENV

    name = module.params['name']
    ENV = module.params['virtualenv']
    EASY_INSTALL = _find_easy_install()

    rc = 0
    err = ''
    out = ''

    if ENV:
        rc_venv, out_venv, err_venv = _ensure_virtualenv()

        rc += rc_venv
        out += out_venv
        err += err_venv

    cmd = None
    changed = False
    installed = _is_package_installed(name)

    if not installed:
        cmd = '%s %s' % (EASY_INSTALL, name)
        rc_pip, out_pip, err_pip = _run(cmd)

        rc += rc_pip
        out += out_pip
        err += err_pip

        changed = True

    if rc != 0:
        module.fail_json(msg=err, cmd=cmd)

    module.exit_json(changed=changed, binary=EASY_INSTALL,
                     name=name, virtualenv=ENV)

# this is magic, see lib/ansible/module_common.py
#<<INCLUDE_ANSIBLE_MODULE_COMMON>>

main()