#    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.

"""
Command-line interface to the OpenStack Metering API.
"""

import argparse
import httplib2
import logging
import sys

import ceilometerclient
from ceilometerclient import client as ceiloclient
from ceilometerclient.common import utils
from ceilometerclient import exc


class CeilometerShell(object):

    def get_base_parser(self):
        parser = argparse.ArgumentParser(
            prog='ceilometer',
            description=__doc__.strip(),
            epilog='See "ceilometer help COMMAND" '
                   'for help on a specific command.',
            add_help=False,
            formatter_class=HelpFormatter,
        )

        # Global arguments
        parser.add_argument('-h', '--help',
                            action='store_true',
                            help=argparse.SUPPRESS,
                            )

        parser.add_argument('--version',
                            action='version',
                            version=ceilometerclient.__version__)

        parser.add_argument('-d', '--debug',
                            default=bool(utils.env('CEILOMETERCLIENT_DEBUG')),
                            action='store_true',
                            help='Defaults to env[CEILOMETERCLIENT_DEBUG]')

        parser.add_argument('-v', '--verbose',
                            default=False, action="store_true",
                            help="Print more verbose output")

        parser.add_argument('-k', '--insecure',
                            default=False,
                            action='store_true',
                            help="Explicitly allow ceilometerclient to "
                            "perform \"insecure\" SSL (https) requests. "
                            "The server's certificate will "
                            "not be verified against any certificate "
                            "authorities. This option should be used with "
                            "caution.")

        parser.add_argument('--cert-file',
                            help='Path of certificate file to use in SSL '
                            'connection. This file can optionally be prepended'
                            ' with the private key.')

        parser.add_argument('--key-file',
                            help='Path of client key to use in SSL connection.'
                            ' This option is not necessary if your key is '
                            'prepended to your cert file.')

        parser.add_argument('--ca-file',
                            help='Path of CA SSL certificate(s) used to verify'
                            ' the remote server certificate. Without this '
                            'option ceilometer looks for the default system '
                            'CA certificates.')

        parser.add_argument('--timeout',
                            default=600,
                            help='Number of seconds to wait for a response')

        parser.add_argument('--os-username',
                            default=utils.env('OS_USERNAME'),
                            help='Defaults to env[OS_USERNAME]')

        parser.add_argument('--os_username',
                            help=argparse.SUPPRESS)

        parser.add_argument('--os-password',
                            default=utils.env('OS_PASSWORD'),
                            help='Defaults to env[OS_PASSWORD]')

        parser.add_argument('--os_password',
                            help=argparse.SUPPRESS)

        parser.add_argument('--os-tenant-id',
                            default=utils.env('OS_TENANT_ID'),
                            help='Defaults to env[OS_TENANT_ID]')

        parser.add_argument('--os_tenant_id',
                            help=argparse.SUPPRESS)

        parser.add_argument('--os-tenant-name',
                            default=utils.env('OS_TENANT_NAME'),
                            help='Defaults to env[OS_TENANT_NAME]')

        parser.add_argument('--os_tenant_name',
                            help=argparse.SUPPRESS)

        parser.add_argument('--os-auth-url',
                            default=utils.env('OS_AUTH_URL'),
                            help='Defaults to env[OS_AUTH_URL]')

        parser.add_argument('--os_auth_url',
                            help=argparse.SUPPRESS)

        parser.add_argument('--os-region-name',
                            default=utils.env('OS_REGION_NAME'),
                            help='Defaults to env[OS_REGION_NAME]')

        parser.add_argument('--os_region_name',
                            help=argparse.SUPPRESS)

        parser.add_argument('--os-auth-token',
                            default=utils.env('OS_AUTH_TOKEN'),
                            help='Defaults to env[OS_AUTH_TOKEN]')

        parser.add_argument('--os_auth_token',
                            help=argparse.SUPPRESS)

        parser.add_argument('--ceilometer-url',
                            default=utils.env('CEILOMETER_URL'),
                            help='Defaults to env[CEILOMETER_URL]')

        parser.add_argument('--ceilometer_url',
                            help=argparse.SUPPRESS)

        parser.add_argument('--ceilometer-api-version',
                            default=utils.env(
                            'CEILOMETER_API_VERSION', default='2'),
                            help='Defaults to env[CEILOMETER_API_VERSION] '
                            'or 2')

        parser.add_argument('--ceilometer_api_version',
                            help=argparse.SUPPRESS)

        parser.add_argument('--os-service-type',
                            default=utils.env('OS_SERVICE_TYPE'),
                            help='Defaults to env[OS_SERVICE_TYPE]')

        parser.add_argument('--os_service_type',
                            help=argparse.SUPPRESS)

        parser.add_argument('--os-endpoint-type',
                            default=utils.env('OS_ENDPOINT_TYPE'),
                            help='Defaults to env[OS_ENDPOINT_TYPE]')

        parser.add_argument('--os_endpoint_type',
                            help=argparse.SUPPRESS)

        return parser

    def get_subcommand_parser(self, version):
        parser = self.get_base_parser()

        self.subcommands = {}
        subparsers = parser.add_subparsers(metavar='<subcommand>')
        submodule = utils.import_versioned_module(version, 'shell')
        self._find_actions(subparsers, submodule)
        self._find_actions(subparsers, self)

        return parser

    def _find_actions(self, subparsers, actions_module):
        for attr in (a for a in dir(actions_module) if a.startswith('do_')):
            # I prefer to be hypen-separated instead of underscores.
            command = attr[3:].replace('_', '-')
            callback = getattr(actions_module, attr)
            desc = callback.__doc__ or ''
            help = desc.strip().split('\n')[0]
            arguments = getattr(callback, 'arguments', [])

            subparser = subparsers.add_parser(command, help=help,
                                              description=desc,
                                              add_help=False,
                                              formatter_class=HelpFormatter)
            subparser.add_argument('-h', '--help', action='help',
                                   help=argparse.SUPPRESS)
            self.subcommands[command] = subparser
            for (args, kwargs) in arguments:
                subparser.add_argument(*args, **kwargs)
            subparser.set_defaults(func=callback)

    def _setup_debugging(self, debug):
        if debug:
            logging.basicConfig(
                format="%(levelname)s (%(module)s:%(lineno)d) %(message)s",
                level=logging.DEBUG)

            httplib2.debuglevel = 1

    def main(self, argv):
        # Parse args once to find version
        parser = self.get_base_parser()
        (options, args) = parser.parse_known_args(argv)
        self._setup_debugging(options.debug)

        # build available subcommands based on version
        api_version = options.ceilometer_api_version
        subcommand_parser = self.get_subcommand_parser(api_version)
        self.parser = subcommand_parser

        # Handle top-level --help/-h before attempting to parse
        # a command off the command line
        if options.help or not argv:
            self.do_help(options)
            return 0

        # Parse args again and call whatever callback was selected
        args = subcommand_parser.parse_args(argv)

        # Short-circuit and deal with help command right away.
        if args.func == self.do_help:
            self.do_help(args)
            return 0

        if not (args.os_auth_token and args.ceilometer_url):
            if not args.os_username:
                raise exc.CommandError("You must provide a username via "
                                       "either --os-username or via "
                                       "env[OS_USERNAME]")

            if not args.os_password:
                raise exc.CommandError("You must provide a password via "
                                       "either --os-password or via "
                                       "env[OS_PASSWORD]")

            if not (args.os_tenant_id or args.os_tenant_name):
                raise exc.CommandError("You must provide a tenant_id via "
                                       "either --os-tenant-id or via "
                                       "env[OS_TENANT_ID]")

            if not args.os_auth_url:
                raise exc.CommandError("You must provide an auth url via "
                                       "either --os-auth-url or via "
                                       "env[OS_AUTH_URL]")

        client = ceiloclient.get_client(api_version, **(args.__dict__))

        try:
            args.func(client, args)
        except exc.Unauthorized:
            raise exc.CommandError("Invalid OpenStack Identity credentials.")

    @utils.arg('command', metavar='<subcommand>', nargs='?',
               help='Display help for <subcommand>')
    def do_help(self, args):
        """Display help about this program or one of its subcommands."""
        if getattr(args, 'command', None):
            if args.command in self.subcommands:
                self.subcommands[args.command].print_help()
            else:
                raise exc.CommandError("'%s' is not a valid subcommand" %
                                       args.command)
        else:
            self.parser.print_help()


class HelpFormatter(argparse.HelpFormatter):
    def start_section(self, heading):
        # Title-case the headings
        heading = '%s%s' % (heading[0].upper(), heading[1:])
        super(HelpFormatter, self).start_section(heading)


def main():
    try:
        CeilometerShell().main(sys.argv[1:])

    except Exception as e:
        print >> sys.stderr, e
        sys.exit(1)

if __name__ == "__main__":
    main()
