Verify that the given package is installed and is at the correct version
    (if specified).

    .. code-block:: yaml

        ShellCheck-0.3.5:
          cabal:
            - installed:

    name
        The package to install
    user
        The user to run cabal install with
    install_global
        Install package globally instead of locally
    env
        A list of environment variables to be set prior to execution. The
        format is the same as the :py:func:`cmd.run <salt.states.cmd.run>`.
        state function.

def installed(name,
              pkgs=None,
              user=None,
              install_global=False,
              env=None):
    '''
    Verify that the given package is installed and is at the correct version
    (if specified).

    .. code-block:: yaml

        ShellCheck-0.3.5:
          cabal:
            - installed:

    name
        The package to install
    user
        The user to run cabal install with
    install_global
        Install package globally instead of locally
    env
        A list of environment variables to be set prior to execution. The
        format is the same as the :py:func:`cmd.run <salt.states.cmd.run>`.
        state function.
    '''
    ret = {'name': name, 'result': None, 'comment': '', 'changes': {}}

    try:
        call = __salt__['cabal.update'](user=user, env=env)
    except (CommandNotFoundError, CommandExecutionError) as err:
        ret['result'] = False
        ret['comment'] = 'Could not run cabal update {0}'.format(err)
        return ret

    if pkgs is not None:
        pkg_list = pkgs
    else:
        pkg_list = [name]

    try:
        installed_pkgs = __salt__['cabal.list'](
            user=user, installed=True, env=env)
    except (CommandNotFoundError, CommandExecutionError) as err:
        ret['result'] = False
        ret['comment'] = 'Error looking up \'{0}\': {1}'.format(name, err)
        return ret

    pkgs_satisfied = []
    pkgs_to_install = []

    for pkg in pkg_list:
        pkg_name, _, pkg_ver = _parse_pkg_string(pkg)

        if pkg_name not in installed_pkgs:
            pkgs_to_install.append(pkg)
        else:
            if pkg_ver:  # version is specified
                if installed_pkgs[pkg_name] != pkg_ver:
                    pkgs_to_install.append(pkg)
                else:
                    pkgs_satisfied.append(pkg)
            else:
                pkgs_satisfied.append(pkg)

    if __opts__['test']:
        ret['result'] = None

        comment_msg = []

        if pkgs_to_install:
            comment_msg.append(
                'Packages(s) \'{0}\' are set to be installed'.format(
                    ', '.join(pkgs_to_install)))

        if pkgs_satisfied:
            comment_msg.append(
                'Packages(s) \'{0}\' satisfied by {1}'.format(
                    ', '.join(pkg_list), ', '.join(pkgs_satisfied)))

        ret['comment'] = '. '.join(comment_msg)
        return ret

    if not pkgs_to_install:
        ret['result'] = True
        ret['comment'] = ('Packages(s) \'{0}\' satisfied by {1}'.format(
            ', '.join(pkg_list), ', '.join(pkgs_satisfied)))

        return ret

    try:
        call = __salt__['cabal.install'](pkgs=pkg_list,
                                         user=user,
                                         install_global=install_global,
                                         env=env)
    except (CommandNotFoundError, CommandExecutionError) as err:
        ret['result'] = False
        ret['comment'] = 'Error installing \'{0}\': {1}'.format(
            ', '.join(pkg_list), err)
        return ret

    if call and isinstance(call, dict):
        ret['result'] = True
        ret['changes'] = {'old': [], 'new': pkgs_to_install}
        ret['comment'] = 'Packages(s) \'{0}\' successfully installed'.format(
            ', '.join(pkgs_to_install))
    else:
        ret['result'] = False
        ret['comment'] = 'Could not install packages(s) \'{0}\''.format(
            ', '.join(pkg_list))

    return ret