# -*- coding: utf-8 -*-
# Copyright 2014 Objectif Libre
#
#    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.
#
import datetime
import decimal

from oslo_config import cfg
from oslo_log import log as logging
import pecan
from pecan import rest
from wsme import types as wtypes
import wsmeext.pecan as wsme_pecan

from cloudkitty.api.v1.datamodels import report as report_models
from cloudkitty.common import policy
from cloudkitty import tzutils
from cloudkitty import utils as ck_utils

LOG = logging.getLogger(__name__)

CONF = cfg.CONF

CONF.import_opt('scope_key', 'cloudkitty.collector', 'collect')


class InvalidFilter(Exception):
    """Exception raised when a storage filter is invalid"""


class ReportController(rest.RestController):
    """REST Controller managing the reporting.

    """

    _custom_actions = {
        'total': ['GET'],
        'tenants': ['GET'],
        'summary': ['GET']
    }

    @wsme_pecan.wsexpose([wtypes.text],
                         datetime.datetime,
                         datetime.datetime)
    def tenants(self, begin=None, end=None):
        """Return the list of rated tenants.

        """
        policy.authorize(pecan.request.context, 'report:list_tenants', {})

        if not begin:
            begin = ck_utils.get_month_start()
        if not end:
            end = ck_utils.get_next_month()

        storage = pecan.request.storage_backend
        tenants = storage.get_tenants(begin, end)
        return tenants

    @wsme_pecan.wsexpose(decimal.Decimal,
                         datetime.datetime,
                         datetime.datetime,
                         wtypes.text,
                         wtypes.text,
                         bool)
    def total(self, begin=None, end=None, tenant_id=None, service=None,
              all_tenants=False):
        """Return the amount to pay for a given period.

        """
        LOG.warning('/v1/report/total is deprecated, please use '
                    '/v1/report/summary instead.')
        if not begin:
            begin = ck_utils.get_month_start()
        if not end:
            end = ck_utils.get_next_month()

        if all_tenants:
            tenant_id = None
        else:
            tenant_context = pecan.request.context.project_id
            tenant_id = tenant_context if not tenant_id else tenant_id
        policy.authorize(pecan.request.context, 'report:get_total',
                         {"tenant_id": tenant_id})

        storage = pecan.request.storage_backend
        # FIXME(sheeprine): We should filter on user id.
        # Use keystone token information by default but make it overridable and
        # enforce it by policy engine
        scope_key = CONF.collect.scope_key
        groupby = [scope_key]
        filters = {scope_key: tenant_id} if tenant_id else None
        result = storage.total(
            groupby=groupby,
            begin=begin, end=end,
            metric_types=service,
            filters=filters)

        if result['total'] < 1:
            return decimal.Decimal('0')
        return sum(total['rate'] for total in result['results'])

    @wsme_pecan.wsexpose(report_models.SummaryCollectionModel,
                         datetime.datetime,
                         datetime.datetime,
                         wtypes.text,
                         wtypes.text,
                         wtypes.text,
                         bool)
    def summary(self, begin=None, end=None, tenant_id=None,
                service=None, groupby=None, all_tenants=False):
        """Return the summary to pay for a given period.

        """
        if not begin:
            begin = ck_utils.get_month_start()
        if not end:
            end = ck_utils.get_next_month()

        if all_tenants:
            tenant_id = None
        else:
            tenant_context = pecan.request.context.project_id
            tenant_id = tenant_context if not tenant_id else tenant_id
        policy.authorize(pecan.request.context, 'report:get_summary',
                         {"tenant_id": tenant_id})
        storage = pecan.request.storage_backend

        scope_key = CONF.collect.scope_key
        storage_groupby = []
        if groupby is not None and 'tenant_id' in groupby:
            storage_groupby.append(scope_key)
        if groupby is not None and 'res_type' in groupby:
            storage_groupby.append('type')
        filters = {scope_key: tenant_id} if tenant_id else None
        result = storage.total(
            groupby=storage_groupby,
            begin=begin, end=end,
            metric_types=service,
            filters=filters)

        summarymodels = []
        for res in result['results']:
            kwargs = {
                'res_type': res.get('type') or res.get('res_type'),
                'tenant_id': res.get(scope_key) or res.get('tenant_id'),
                'begin': tzutils.local_to_utc(res['begin'], naive=True),
                'end': tzutils.local_to_utc(res['end'], naive=True),
                'rate': res['rate'],
            }
            summarymodel = report_models.SummaryModel(**kwargs)
            summarymodels.append(summarymodel)

        return report_models.SummaryCollectionModel(summary=summarymodels)