package tailnet_test

import (
	"io"
	"net"
	"sync/atomic"
	"testing"
	"time"

	"github.com/google/uuid"
	"github.com/stretchr/testify/require"
	"golang.org/x/xerrors"
	"tailscale.com/tailcfg"

	"cdr.dev/slog"
	"cdr.dev/slog/sloggers/slogtest"
	"github.com/coder/coder/v2/tailnet"
	"github.com/coder/coder/v2/tailnet/proto"
	"github.com/coder/coder/v2/tailnet/tailnettest"
	"github.com/coder/coder/v2/testutil"
)

func TestClientService_ServeClient_V2(t *testing.T) {
	t.Parallel()
	fCoord := tailnettest.NewFakeCoordinator()
	var coord tailnet.Coordinator = fCoord
	coordPtr := atomic.Pointer[tailnet.Coordinator]{}
	coordPtr.Store(&coord)
	logger := slogtest.Make(t, nil).Leveled(slog.LevelDebug)
	derpMap := &tailcfg.DERPMap{Regions: map[int]*tailcfg.DERPRegion{999: {RegionCode: "test"}}}
	uut, err := tailnet.NewClientService(
		logger, &coordPtr,
		time.Millisecond, func() *tailcfg.DERPMap { return derpMap },
	)
	require.NoError(t, err)

	ctx := testutil.Context(t, testutil.WaitShort)
	c, s := net.Pipe()
	defer c.Close()
	defer s.Close()
	clientID := uuid.MustParse("10000001-0000-0000-0000-000000000000")
	agentID := uuid.MustParse("20000001-0000-0000-0000-000000000000")
	errCh := make(chan error, 1)
	go func() {
		err := uut.ServeClient(ctx, "2.0", s, clientID, agentID)
		t.Logf("ServeClient returned; err=%v", err)
		errCh <- err
	}()

	client, err := tailnet.NewDRPCClient(c, logger)
	require.NoError(t, err)

	// Coordinate
	stream, err := client.Coordinate(ctx)
	require.NoError(t, err)
	defer stream.Close()

	err = stream.Send(&proto.CoordinateRequest{
		UpdateSelf: &proto.CoordinateRequest_UpdateSelf{Node: &proto.Node{PreferredDerp: 11}},
	})
	require.NoError(t, err)

	call := testutil.RequireRecvCtx(ctx, t, fCoord.CoordinateCalls)
	require.NotNil(t, call)
	require.Equal(t, call.ID, clientID)
	require.Equal(t, call.Name, "client")
	require.NoError(t, call.Auth.Authorize(&proto.CoordinateRequest{
		AddTunnel: &proto.CoordinateRequest_Tunnel{Id: agentID[:]},
	}))
	req := testutil.RequireRecvCtx(ctx, t, call.Reqs)
	require.Equal(t, int32(11), req.GetUpdateSelf().GetNode().GetPreferredDerp())

	call.Resps <- &proto.CoordinateResponse{PeerUpdates: []*proto.CoordinateResponse_PeerUpdate{
		{
			Kind: proto.CoordinateResponse_PeerUpdate_NODE,
			Node: &proto.Node{PreferredDerp: 22},
			Id:   agentID[:],
		},
	}}
	resp, err := stream.Recv()
	require.NoError(t, err)
	u := resp.GetPeerUpdates()
	require.Len(t, u, 1)
	require.Equal(t, int32(22), u[0].GetNode().GetPreferredDerp())

	err = stream.Close()
	require.NoError(t, err)

	// DERP Map
	dms, err := client.StreamDERPMaps(ctx, &proto.StreamDERPMapsRequest{})
	require.NoError(t, err)

	gotDermMap, err := dms.Recv()
	require.NoError(t, err)
	require.Equal(t, "test", gotDermMap.GetRegions()[999].GetRegionCode())
	err = dms.Close()
	require.NoError(t, err)

	// RPCs closed; we need to close the Conn to end the session.
	err = c.Close()
	require.NoError(t, err)
	err = testutil.RequireRecvCtx(ctx, t, errCh)
	require.True(t, xerrors.Is(err, io.EOF) || xerrors.Is(err, io.ErrClosedPipe))
}

func TestClientService_ServeClient_V1(t *testing.T) {
	t.Parallel()
	fCoord := tailnettest.NewFakeCoordinator()
	var coord tailnet.Coordinator = fCoord
	coordPtr := atomic.Pointer[tailnet.Coordinator]{}
	coordPtr.Store(&coord)
	logger := slogtest.Make(t, nil).Leveled(slog.LevelDebug)
	uut, err := tailnet.NewClientService(logger, &coordPtr, 0, nil)
	require.NoError(t, err)

	ctx := testutil.Context(t, testutil.WaitShort)
	c, s := net.Pipe()
	defer c.Close()
	defer s.Close()
	clientID := uuid.MustParse("10000001-0000-0000-0000-000000000000")
	agentID := uuid.MustParse("20000001-0000-0000-0000-000000000000")
	errCh := make(chan error, 1)
	go func() {
		err := uut.ServeClient(ctx, "1.0", s, clientID, agentID)
		t.Logf("ServeClient returned; err=%v", err)
		errCh <- err
	}()

	call := testutil.RequireRecvCtx(ctx, t, fCoord.ServeClientCalls)
	require.NotNil(t, call)
	require.Equal(t, call.ID, clientID)
	require.Equal(t, call.Agent, agentID)
	require.Equal(t, s, call.Conn)
	expectedError := xerrors.New("test error")
	select {
	case call.ErrCh <- expectedError:
	// ok!
	case <-ctx.Done():
		t.Fatalf("timeout sending error")
	}

	err = testutil.RequireRecvCtx(ctx, t, errCh)
	require.ErrorIs(t, err, expectedError)
}