# Copyright 2012 OpenStack LLC.
# All Rights Reserved.
#
#    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.
#
# vim: tabstop=4 shiftwidth=4 softtabstop=4

"""
Common client utilities
"""

import os
import uuid

import prettytable

from openstackclient.common import exceptions


# Decorator for cli-args
def arg(*args, **kwargs):
    def _decorator(func):
        # Because of the sematics of decorator composition if we just append
        # to the options list positional options will appear to be backwards.
        func.__dict__.setdefault('arguments', []).insert(0, (args, kwargs))
        return func
    return _decorator


def pretty_choice_list(l):
    return ', '.join("'%s'" % i for i in l)


def print_list(objs, fields, formatters={}):
    pt = prettytable.PrettyTable([f for f in fields], caching=False)
    pt.aligns = ['l' for f in fields]

    for o in objs:
        row = []
        for field in fields:
            if field in formatters:
                row.append(formatters[field](o))
            else:
                field_name = field.lower().replace(' ', '_')
                data = getattr(o, field_name, '')
                row.append(data)
        pt.add_row(row)

    pt.printt(sortby=fields[0])


def print_dict(d):
    pt = prettytable.PrettyTable(['Property', 'Value'], caching=False)
    pt.aligns = ['l', 'l']
    [pt.add_row(list(r)) for r in d.iteritems()]
    pt.printt(sortby='Property')


def find_resource(manager, name_or_id):
    """Helper for the _find_* methods."""
    # first try to get entity as integer id
    try:
        if isinstance(name_or_id, int) or name_or_id.isdigit():
            return manager.get(int(name_or_id))
    except exceptions.NotFound:
        pass

    # now try to get entity as uuid
    try:
        uuid.UUID(str(name_or_id))
        return manager.get(name_or_id)
    except (ValueError, exceptions.NotFound):
        pass

    # finally try to find entity by name
    try:
        return manager.find(name=name_or_id)
    except exceptions.NotFound:
        msg = "No %s with a name or ID of '%s' exists." % \
              (manager.resource_class.__name__.lower(), name_or_id)
        raise exceptions.CommandError(msg)


def skip_authentication(f):
    """Function decorator used to indicate a caller may be unauthenticated."""
    f.require_authentication = False
    return f


def is_authentication_required(f):
    """Checks to see if the function requires authentication.

    Use the skip_authentication decorator to indicate a caller may
    skip the authentication step.
    """
    return getattr(f, 'require_authentication', True)


def string_to_bool(arg):
    return arg.strip().lower() in ('t', 'true', 'yes', '1')


def env(*vars, **kwargs):
    """Search for the first defined of possibly many env vars

    Returns the first environment variable defined in vars, or
    returns the default defined in kwargs.
    """
    for v in vars:
        value = os.environ.get(v, None)
        if value:
            return value
    return kwargs.get('default', '')