# vim: tabstop=4 shiftwidth=4 softtabstop=4

#
#    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 logging
import json

from webob.exc import Response

from heat.common import wsgi
from heat.metadata import db as db_api
from heat.metadata.db import (ConflictError, StackNotFoundError,
                              ResourceNotFoundError)


def json_response(http_status, data):
    """Create a JSON response with a specific HTTP code."""
    response = Response(json.dumps(data))
    response.status = http_status
    response.content_type = 'application/json'
    return response

def json_error(http_status, message):
    """Create a JSON error response."""
    body = {'error': message}
    return json_response(http_status, body)

class MetadataController:
    def __init__(self, options):
        self.options = options

    def entry_point(self, req):
        return {
            'name': 'Heat Metadata Server API',
            'version': '1',
        }

    def list_stacks(self, req):
        return db_api.list_stacks()

    def list_resources(self, req, stack_name):
        try:
            resources = db_api.list_resources(stack_name)
        except StackNotFoundError:
            return json_error(404, 'The stack "%s" does not exist.' % stack_name)
        return resources

    def get_resource(self, req, stack_name, resource_id):
        try:
            resource = db_api.get_resource(stack_name, resource_id)
        except StackNotFoundError:
            return json_error(404, 'The stack "%s" does not exist.' % stack_name)
        except ResourceNotFoundError:
            return json_error(404, 'The resource "%s" does not exist.' % resource_id)
        return resource

    def create_stack(self, req, body, stack_name):
        try:
            stack = db_api.create_stack(stack_name, body)
        except ConflictError:
            return json_error(409, 'The stack "%s" already exists.' % stack_name)
        return json_response(201, stack)

    def update_metadata(self, req, body, stack_name, resource_id):
        try:
            db_api.update_resource_metadata(stack_name, resource_id, body)
        except StackNotFoundError:
            return json_error(409, 'The stack "%s" does not exist.' % stack_name)
        except ResourceNotFoundError:
            # The resource doesn't exit yet, create it.
            db_api.create_resource_metadata(stack_name, resource_id, body)
        return json_response(201, {
            'resource': resource_id,
            'metadata': body,
        })

def create_resource(options):
    """
    Stacks resource factory method.
    """
    deserializer = wsgi.JSONRequestDeserializer()
    serializer = wsgi.JSONResponseSerializer()
    return wsgi.Resource(MetadataController(options), deserializer, serializer)