package botlink

import (
	"fmt"
	"net"
	"testing"
	"time"

	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"

	botlinkv1 "scrabble/pkg/proto/botlink/v1"
	telegramv1 "scrabble/pkg/proto/telegram/v1"
)

// testLinkServer registers one bot, pushes a single Notify command, and records the
// Ack the client returns.
type testLinkServer struct {
	botlinkv1.UnimplementedBotLinkServer
	acks chan *botlinkv1.Ack
}

func (s *testLinkServer) Link(stream grpc.BidiStreamingServer[botlinkv1.FromBot, botlinkv1.ToBot]) error {
	hello, err := stream.Recv()
	if err != nil {
		return err
	}
	if hello.GetHello() == nil {
		return fmt.Errorf("first message was not Hello")
	}
	if err := stream.Send(&botlinkv1.ToBot{Command: &botlinkv1.Command{
		CommandId: "c1",
		Payload: &botlinkv1.Command_Notify{Notify: &telegramv1.NotifyRequest{
			ExternalId: "12345", Kind: "your_turn",
			Payload: yourTurnPayload("7c9e6679-7425-40de-944b-e07fc1f90ae7"), Language: "en",
		}},
	}}); err != nil {
		return err
	}
	for {
		msg, err := stream.Recv()
		if err != nil {
			return err
		}
		if ack := msg.GetAck(); ack != nil {
			s.acks <- ack
			return nil
		}
	}
}

// TestClientServesCommands verifies the bot client dials, registers, executes a
// pushed command through the executor, and acks it.
func TestClientServesCommands(t *testing.T) {
	lis, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		t.Fatalf("listen: %v", err)
	}
	ts := &testLinkServer{acks: make(chan *botlinkv1.Ack, 1)}
	srv := grpc.NewServer()
	botlinkv1.RegisterBotLinkServer(srv, ts)
	go func() { _ = srv.Serve(lis) }()
	t.Cleanup(srv.Stop)

	sender := &fakeSender{}
	client := NewClient(ClientConfig{
		GatewayAddr:    lis.Addr().String(),
		InstanceID:     "test",
		Creds:          insecure.NewCredentials(),
		ReconnectDelay: 50 * time.Millisecond,
	}, NewExecutor(sender, 0, nil), nil)

	go func() { _ = client.Run(t.Context()) }()

	select {
	case ack := <-ts.acks:
		if ack.GetCommandId() != "c1" || !ack.GetDelivered() {
			t.Errorf("ack = %+v, want command_id c1 delivered=true", ack)
		}
	case <-time.After(2 * time.Second):
		t.Fatal("server received no ack")
	}
	// The channel receive above happens-after the client wrote the sender call.
	if len(sender.notify) != 1 || sender.notify[0].chatID != 12345 {
		t.Errorf("sender notify calls = %+v, want one call to chat 12345", sender.notify)
	}
}