// Copyright 2018 Google LLC
//
// 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 pubsub

import (
	"context"
	"testing"
	"time"

	"cloud.google.com/go/internal/testutil"
	"cloud.google.com/go/pubsub/pstest"
	gax "github.com/googleapis/gax-go/v2"
	"google.golang.org/api/option"
	pb "google.golang.org/genproto/googleapis/pubsub/v1"
	"google.golang.org/grpc"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

func TestPullStreamGet(t *testing.T) {
	// Test that we retry on the initial Send call from pullstream.get. We don't do this
	// test with the server in fake_test.go because there's no clear way to get Send
	// to fail from the server.
	t.Parallel()
	for _, test := range []struct {
		desc     string
		errors   []error
		wantCode codes.Code
	}{
		{
			desc:     "nil error",
			errors:   []error{nil},
			wantCode: codes.OK,
		},
		{
			desc:     "non-retryable error",
			errors:   []error{status.Errorf(codes.InvalidArgument, "")},
			wantCode: codes.InvalidArgument,
		},
		{
			desc: "retryable errors",
			errors: []error{
				status.Errorf(codes.Unavailable, "first"),
				status.Errorf(codes.Unavailable, "second"),
				nil,
			},
			wantCode: codes.OK,
		},
	} {
		streamingPull := func(context.Context, ...gax.CallOption) (pb.Subscriber_StreamingPullClient, error) {
			if len(test.errors) == 0 {
				panic("out of errors")
			}
			err := test.errors[0]
			test.errors = test.errors[1:]
			return &testStreamingPullClient{sendError: err}, nil
		}
		ps := newPullStream(context.Background(), streamingPull, "")
		_, err := ps.get(nil)
		if got := status.Code(err); got != test.wantCode {
			t.Errorf("%s: got %s, want %s", test.desc, got, test.wantCode)
		}
	}
}

func TestPullStreamGet_ResourceUnavailable(t *testing.T) {
	ctx := context.Background()

	srv, err := testutil.NewServer()
	if err != nil {
		t.Fatal(err)
	}
	defer srv.Close()

	ps := pstest.NewServer()
	defer ps.Close()

	s := ExhaustedServer{ps.GServer}
	pb.RegisterPublisherServer(srv.Gsrv, &s)
	pb.RegisterSubscriberServer(srv.Gsrv, &s)
	srv.Start()

	client, err := NewClient(ctx, "P",
		option.WithEndpoint(srv.Addr),
		option.WithoutAuthentication(),
		option.WithGRPCDialOption(grpc.WithInsecure()))
	if err != nil {
		t.Fatal(err)
	}
	defer client.Close()

	errc := make(chan error)
	go func() {
		errc <- client.Subscription("foo").Receive(ctx, func(context.Context, *Message) {
			t.Error("should not have received any data")
		})
	}()

	select {
	case <-time.After(5 * time.Second):
		t.Fatal("Receive should have failed immediately")
	case err := <-errc:
		if gerr, ok := status.FromError(err); ok {
			if gerr.Code() != codes.ResourceExhausted {
				t.Fatal("expected to receive a grpc ResourceExhausted error")
			}
		} else {
			t.Fatal("expected to receive a grpc ResourceExhausted error")
		}
	}
}

type ExhaustedServer struct {
	pstest.GServer
}

func (*ExhaustedServer) StreamingPull(_ pb.Subscriber_StreamingPullServer) error {
	return status.Errorf(codes.ResourceExhausted, "This server is exhausted!")
}

type testStreamingPullClient struct {
	pb.Subscriber_StreamingPullClient
	sendError error
}

func (c *testStreamingPullClient) Send(*pb.StreamingPullRequest) error { return c.sendError }