/*
 *
 * Copyright 2020 gRPC authors.
 *
 * 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.
 *
 */

package client_test

import (
	"context"
	"testing"
	"time"

	v2corepb "github.com/envoyproxy/go-control-plane/envoy/api/v2/core"
	endpointpb "github.com/envoyproxy/go-control-plane/envoy/api/v2/endpoint"
	lrspb "github.com/envoyproxy/go-control-plane/envoy/service/load_stats/v2"
	durationpb "github.com/golang/protobuf/ptypes/duration"
	"github.com/google/go-cmp/cmp"
	"google.golang.org/grpc"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/credentials/insecure"
	"google.golang.org/grpc/internal/grpctest"
	"google.golang.org/grpc/status"
	"google.golang.org/grpc/xds/internal/client"
	"google.golang.org/grpc/xds/internal/client/bootstrap"
	"google.golang.org/grpc/xds/internal/testutils/fakeserver"
	"google.golang.org/grpc/xds/internal/version"
	"google.golang.org/protobuf/testing/protocmp"

	_ "google.golang.org/grpc/xds/internal/client/v2" // Register the v2 xDS API client.
)

const (
	defaultTestTimeout      = 5 * time.Second
	defaultTestShortTimeout = 10 * time.Millisecond // For events expected to *not* happen.

	defaultClientWatchExpiryTimeout = 15 * time.Second
)

type s struct {
	grpctest.Tester
}

func Test(t *testing.T) {
	grpctest.RunSubTests(t, s{})
}

func (s) TestLRSClient(t *testing.T) {
	fs, sCleanup, err := fakeserver.StartServer()
	if err != nil {
		t.Fatalf("failed to start fake xDS server: %v", err)
	}
	defer sCleanup()

	xdsC, err := client.NewWithConfigForTesting(&bootstrap.Config{
		BalancerName: fs.Address,
		Creds:        grpc.WithTransportCredentials(insecure.NewCredentials()),
		NodeProto:    &v2corepb.Node{},
		TransportAPI: version.TransportV2,
	}, defaultClientWatchExpiryTimeout)
	if err != nil {
		t.Fatalf("failed to create xds client: %v", err)
	}
	defer xdsC.Close()
	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
	defer cancel()
	if u, err := fs.NewConnChan.Receive(ctx); err != nil {
		t.Errorf("unexpected timeout: %v, %v, want NewConn", u, err)
	}

	// Report to the same address should not create new ClientConn.
	store1, lrsCancel1 := xdsC.ReportLoad(fs.Address)
	defer lrsCancel1()
	sCtx, sCancel := context.WithTimeout(context.Background(), defaultTestShortTimeout)
	defer sCancel()
	if u, err := fs.NewConnChan.Receive(sCtx); err != context.DeadlineExceeded {
		t.Errorf("unexpected NewConn: %v, %v, want channel recv timeout", u, err)
	}

	fs2, sCleanup2, err := fakeserver.StartServer()
	if err != nil {
		t.Fatalf("failed to start fake xDS server: %v", err)
	}
	defer sCleanup2()

	// Report to a different address should create new ClientConn.
	store2, lrsCancel2 := xdsC.ReportLoad(fs2.Address)
	defer lrsCancel2()
	if u, err := fs2.NewConnChan.Receive(ctx); err != nil {
		t.Errorf("unexpected timeout: %v, %v, want NewConn", u, err)
	}

	if store1 == store2 {
		t.Fatalf("got same store for different servers, want different")
	}

	if u, err := fs2.LRSRequestChan.Receive(ctx); err != nil {
		t.Errorf("unexpected timeout: %v, %v, want NewConn", u, err)
	}
	store2.PerCluster("cluster", "eds").CallDropped("test")

	// Send one resp to the client.
	fs2.LRSResponseChan <- &fakeserver.Response{
		Resp: &lrspb.LoadStatsResponse{
			SendAllClusters:       true,
			LoadReportingInterval: &durationpb.Duration{Nanos: 50000000},
		},
	}

	// Server should receive a req with the loads.
	u, err := fs2.LRSRequestChan.Receive(ctx)
	if err != nil {
		t.Fatalf("unexpected LRS request: %v, %v, want error canceled", u, err)
	}
	receivedLoad := u.(*fakeserver.Request).Req.(*lrspb.LoadStatsRequest).ClusterStats
	if len(receivedLoad) <= 0 {
		t.Fatalf("unexpected load received, want load for cluster, eds, dropped for test")
	}
	receivedLoad[0].LoadReportInterval = nil
	want := &endpointpb.ClusterStats{
		ClusterName:          "cluster",
		ClusterServiceName:   "eds",
		TotalDroppedRequests: 1,
		DroppedRequests:      []*endpointpb.ClusterStats_DroppedRequests{{Category: "test", DroppedCount: 1}},
	}
	if d := cmp.Diff(want, receivedLoad[0], protocmp.Transform()); d != "" {
		t.Fatalf("unexpected load received, want load for cluster, eds, dropped for test, diff (-want +got):\n%s", d)
	}

	// Cancel this load reporting stream, server should see error canceled.
	lrsCancel2()

	// Server should receive a stream canceled error.
	if u, err := fs2.LRSRequestChan.Receive(ctx); err != nil || status.Code(u.(*fakeserver.Request).Err) != codes.Canceled {
		t.Errorf("unexpected LRS request: %v, %v, want error canceled", u, err)
	}
}