/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */

/*
 *
 * Copyright 2021 gRPC authors.
 *
 */

package client

import (
	_struct "github.com/golang/protobuf/ptypes/struct"

	"google.golang.org/grpc/resolver"
)

import (
	"dubbo.apache.org/dubbo-go/v3/xds/client/bootstrap"
	"dubbo.apache.org/dubbo-go/v3/xds/client/load"
	"dubbo.apache.org/dubbo-go/v3/xds/client/resource"
)

type clientKeyType string

const clientKey = clientKeyType("grpc.xds.internal.client.Client")

// XDSClient is a full fledged gRPC client which queries a set of discovery APIs
// (collectively termed as xDS) on a remote management server, to discover
// various dynamic resources.
type XDSClient interface {
	WatchListener(string, func(resource.ListenerUpdate, error)) func()
	WatchRouteConfig(string, func(resource.RouteConfigUpdate, error)) func()
	WatchCluster(string, func(resource.ClusterUpdate, error)) func()
	WatchEndpoints(clusterName string, edsCb func(resource.EndpointsUpdate, error)) (cancel func())
	ReportLoad(server string) (*load.Store, func())

	DumpLDS() map[string]resource.UpdateWithMD
	DumpRDS() map[string]resource.UpdateWithMD
	DumpCDS() map[string]resource.UpdateWithMD
	DumpEDS() map[string]resource.UpdateWithMD

	BootstrapConfig() *bootstrap.Config
	Close()

	/*
		SetMetadata would reconnect tcp link with new metadata
	*/
	SetMetadata(*_struct.Struct) error
}

// FromResolverState returns the Client from state, or nil if not present.
func FromResolverState(state resolver.State) XDSClient {
	cs, _ := state.Attributes.Value(clientKey).(XDSClient)
	return cs
}

// SetClient sets c in state and returns the new state.
func SetClient(state resolver.State, c XDSClient) resolver.State {
	state.Attributes = state.Attributes.WithValue(clientKey, c)
	return state
}