# 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.

import urllib

from heatclient.common import base

DEFAULT_PAGE_SIZE = 20


class Stack(base.Resource):
    def __repr__(self):
        return "<Stack %s>" % self._info

    def update(self, **fields):
        self.manager.update(self, **fields)

    def delete(self):
        return self.manager.delete(self)

    def data(self, **kwargs):
        return self.manager.data(self, **kwargs)


class StackManager(base.Manager):
    resource_class = Stack

    def list(self, **kwargs):
        """Get a list of stacks.

        :param page_size: number of items to request in each paginated request
        :param limit: maximum number of stacks to return
        :param marker: begin returning stacks that appear later in the stack
                       list than that represented by this stack id
        :param filters: dict of direct comparison filters that mimics the
                        structure of a stack object
        :rtype: list of :class:`Stack`
        """
        absolute_limit = kwargs.get('limit')

        def paginate(qp, seen=0):
            url = '/stacks?%s' % urllib.urlencode(qp)

            stacks = self._list(url, "stacks")
            for stack in stacks:
                seen += 1
                if absolute_limit is not None and seen > absolute_limit:
                    return
                yield stack

            page_size = qp.get('limit')
            if (page_size and len(stacks) == page_size and
                    (absolute_limit is None or 0 < seen < absolute_limit)):
                qp['marker'] = stack.id
                for image in paginate(qp, seen):
                    yield image

        params = {'limit': kwargs.get('page_size', DEFAULT_PAGE_SIZE)}

        if 'marker' in kwargs:
            params['marker'] = kwargs['marker']

        filters = kwargs.get('filters', {})
        properties = filters.pop('properties', {})
        for key, value in properties.items():
            params['property-%s' % key] = value
        params.update(filters)

        return paginate(params)

    def create(self, **kwargs):
        """Create a stack"""
        resp, body = self.api.json_request(
                'POST', '/stacks', body=kwargs)

    def update(self, **kwargs):
        """Update a stack"""
        stack_id = kwargs.pop('stack_id')
        resp, body = self.api.json_request(
                'PUT', '/stacks/%s' % stack_id, body=kwargs)

    def delete(self, stack_id):
        """Delete a stack."""
        self._delete("/stacks/%s" % stack_id)

    def get(self, stack_id):
        """Get the metadata for a specific stack.

        :param stack_id: Stack ID to lookup
        """
        resp, body = self.api.json_request('GET', '/stacks/%s' % stack_id)
        return Stack(self, body['stack'])

    def template(self, stack_id):
        """Get the template content for a specific stack as a parsed JSON
        object.

        :param stack_id: Stack ID to get the template for
        """
        resp, body = self.api.json_request(
            'GET', '/stacks/%s/template' % stack_id)
        return body

    def validate(self, **kwargs):
        """Validate a stack template"""
        resp, body = self.api.json_request(
                'POST', '/validate', body=kwargs)
        return body
