package main

import (
	"context"
	"net"
	"testing"

	pb "git.strikerlulu.me/strikerlulu/grpc-mocker/pb"

	"github.com/stretchr/testify/assert"
	"google.golang.org/grpc"
	"google.golang.org/grpc/reflection"
	"google.golang.org/grpc/test/bufconn"
)

type mockServer struct {
	pb.UnimplementedCalcServiceServer
	response *pb.AdditionResponse
	err      error
}

func (s *mockServer) Add(ctx context.Context, req *pb.AdditionRequest) (*pb.AdditionResponse, error) {
	return s.response, s.err
}

func TestCalcService(t *testing.T) {
	bufSize := 1024 * 1024
	listener := bufconn.Listen(bufSize)

	// Create a gRPC server and register the mock service
	server := grpc.NewServer()
	mock := &mockServer{
		response: &pb.AdditionResponse{Result: 3},
		err:      nil,
	}
	pb.RegisterCalcServiceServer(server, mock)
	reflection.Register(server)

	go func() {
		if err := server.Serve(listener); err != nil {
			t.Fatalf("server failed to start: %v", err)
		}
	}()

	// Create a gRPC client to use in tests
	conn, err := grpc.DialContext(context.Background(), "bufnet",
		grpc.WithContextDialer(func(context.Context, string) (net.Conn, error) {
			return listener.Dial()
		}),
		grpc.WithInsecure())
	if err != nil {
		t.Fatalf("failed to dial bufnet: %v", err)
	}
	client := pb.NewCalcServiceClient(conn)

	resp, err := client.Add(context.Background(), &pb.AdditionRequest{X: 5,Y: 5})
	assert.NoError(t, err)
    // we get mocker 3 instead of 5
	assert.Equal(t, uint64(3), resp.Result)

	server.Stop()
}