/*
 *
 * Copyright 2018 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 health

import (
	"context"
	"errors"
	"fmt"
	"sync"
	"testing"
	"time"

	"github.com/google/go-cmp/cmp"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
	"google.golang.org/protobuf/testing/protocmp"

	healthpb "google.golang.org/grpc/health/grpc_health_v1"
	"google.golang.org/grpc/internal/grpctest"
)

type s struct {
	grpctest.Tester
}

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

func (s) TestShutdown(t *testing.T) {
	const testService = "tteesstt"
	s := NewServer()
	s.SetServingStatus(testService, healthpb.HealthCheckResponse_SERVING)

	status := s.statusMap[testService]
	if status != healthpb.HealthCheckResponse_SERVING {
		t.Fatalf("status for %s is %v, want %v", testService, status, healthpb.HealthCheckResponse_SERVING)
	}

	var wg sync.WaitGroup
	wg.Add(2)
	// Run SetServingStatus and Shutdown in parallel.
	go func() {
		for i := 0; i < 1000; i++ {
			s.SetServingStatus(testService, healthpb.HealthCheckResponse_SERVING)
			time.Sleep(time.Microsecond)
		}
		wg.Done()
	}()
	go func() {
		time.Sleep(300 * time.Microsecond)
		s.Shutdown()
		wg.Done()
	}()
	wg.Wait()

	s.mu.Lock()
	status = s.statusMap[testService]
	s.mu.Unlock()
	if status != healthpb.HealthCheckResponse_NOT_SERVING {
		t.Fatalf("status for %s is %v, want %v", testService, status, healthpb.HealthCheckResponse_NOT_SERVING)
	}

	s.Resume()
	status = s.statusMap[testService]
	if status != healthpb.HealthCheckResponse_SERVING {
		t.Fatalf("status for %s is %v, want %v", testService, status, healthpb.HealthCheckResponse_SERVING)
	}

	s.SetServingStatus(testService, healthpb.HealthCheckResponse_NOT_SERVING)
	status = s.statusMap[testService]
	if status != healthpb.HealthCheckResponse_NOT_SERVING {
		t.Fatalf("status for %s is %v, want %v", testService, status, healthpb.HealthCheckResponse_NOT_SERVING)
	}
}

// TestList verifies that List() returns the health status of all the services if no. of services are within
// maxAllowedLimits.
func (s) TestList(t *testing.T) {
	s := NewServer()

	// Fill out status map with information
	const length = 3
	for i := 0; i < length; i++ {
		s.SetServingStatus(fmt.Sprintf("%d", i),
			healthpb.HealthCheckResponse_ServingStatus(i))
	}

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()
	var in healthpb.HealthListRequest
	got, err := s.List(ctx, &in)

	if err != nil {
		t.Fatalf("s.List(ctx, &in) returned err %v, want nil", err)
	}
	if len(got.GetStatuses()) != length+1 {
		t.Fatalf("len(out.GetStatuses()) = %d, want %d",
			len(got.GetStatuses()), length+1)
	}
	want := &healthpb.HealthListResponse{
		Statuses: map[string]*healthpb.HealthCheckResponse{
			"":  {Status: healthpb.HealthCheckResponse_SERVING},
			"0": {Status: healthpb.HealthCheckResponse_UNKNOWN},
			"1": {Status: healthpb.HealthCheckResponse_SERVING},
			"2": {Status: healthpb.HealthCheckResponse_NOT_SERVING},
		},
	}
	if diff := cmp.Diff(got, want, protocmp.Transform()); diff != "" {
		t.Fatalf("Health response did not match expectation.  Diff (-got, +want): %s", diff)
	}
}

// TestListResourceExhausted verifies that List()
// returns a ResourceExhausted error if no. of services are more than
// maxAllowedServices.
func (s) TestListResourceExhausted(t *testing.T) {
	s := NewServer()

	// Fill out status map with service information,
	// 101 (100 + 1 existing) elements will trigger an error.
	for i := 1; i <= maxAllowedServices; i++ {
		s.SetServingStatus(fmt.Sprintf("%d", i),
			healthpb.HealthCheckResponse_SERVING)
	}

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()
	var in healthpb.HealthListRequest
	_, err := s.List(ctx, &in)

	want := status.Errorf(codes.ResourceExhausted,
		"server health list exceeds maximum capacity: %d", maxAllowedServices)
	if !errors.Is(err, want) {
		t.Fatalf("s.List(ctx, &in) returned %v, want %v", err, want)
	}
}