package transport_test

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

	"go.uber.org/zap"
	"google.golang.org/protobuf/proto"

	toki "git.toki-labs.com/toki/proto-socket/go"

	"iop/apps/node/internal/transport"
	eventpkg "iop/packages/go/events"
	iop "iop/proto/gen/iop"
)

// startMiniEdge starts a minimal mock edge server that accepts one connection
// and responds to RegisterRequest. Returns the server, the accepted edge-side
// client channel, and the listen address.
func startMiniEdge(t *testing.T, ctx context.Context) (server *toki.TcpServer, acceptedCh chan *toki.TcpClient, addr string) {
	t.Helper()
	listenAddr := getFreePort(t)
	host, portStr, _ := net.SplitHostPort(listenAddr)
	port := 0
	fmt.Sscanf(portStr, "%d", &port)

	ch := make(chan *toki.TcpClient, 4)
	srv := toki.NewTcpServer(host, port, func(conn net.Conn) *toki.TcpClient {
		client := toki.NewTcpClient(conn, 30, 10, edgeParserMap())
		toki.AddRequestListenerTyped[*iop.RegisterRequest, *iop.RegisterResponse](
			&client.Communicator,
			func(_ *iop.RegisterRequest) (*iop.RegisterResponse, error) {
				return &iop.RegisterResponse{
					Accepted: true,
					NodeId:   "sess-test-node",
					Config:   &iop.NodeConfigPayload{},
				}, nil
			},
		)
		ch <- client
		return client
	})
	if err := srv.Start(ctx); err != nil {
		t.Fatalf("start mini edge: %v", err)
	}
	t.Cleanup(func() { srv.Stop() })
	return srv, ch, listenAddr
}

// TestSessionDoneSignalOnRemoteDisconnect verifies that Done() is closed when
// edge closes the connection, and IsLocalShutdown() returns false.
func TestSessionDoneSignalOnRemoteDisconnect(t *testing.T) {
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	_, acceptedCh, addr := startMiniEdge(t, ctx)
	result, err := transport.DialEdge(ctx, addr, "tok", zap.NewNop())
	if err != nil {
		t.Fatalf("dial: %v", err)
	}

	edgeClient := waitForAcceptedClient(t, acceptedCh)

	// Done() must not be closed yet.
	select {
	case <-result.Session.Done():
		t.Fatal("Done() closed before disconnect")
	default:
	}

	// Remote close → Done() must close.
	_ = edgeClient.Close()
	select {
	case <-result.Session.Done():
	case <-time.After(2 * time.Second):
		t.Fatal("timeout: Done() did not close after remote disconnect")
	}

	if result.Session.IsLocalShutdown() {
		t.Fatal("IsLocalShutdown() must be false for remote disconnect")
	}
}

// TestSessionDoneSignalOnLocalClose verifies Done() is closed on local Close()
// and IsLocalShutdown() returns true.
func TestSessionDoneSignalOnLocalClose(t *testing.T) {
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	_, _, addr := startMiniEdge(t, ctx)
	result, err := transport.DialEdge(ctx, addr, "tok", zap.NewNop())
	if err != nil {
		t.Fatalf("dial: %v", err)
	}

	_ = result.Session.Close()

	select {
	case <-result.Session.Done():
	case <-time.After(2 * time.Second):
		t.Fatal("timeout: Done() did not close after local Close()")
	}

	if !result.Session.IsLocalShutdown() {
		t.Fatal("IsLocalShutdown() must be true after local Close()")
	}
}

type mockHandler struct {
	runReqCh chan *iop.RunRequest
}

func (m *mockHandler) OnRunRequest(ctx context.Context, sess *transport.Session, req *iop.RunRequest) error {
	m.runReqCh <- req
	return sess.Send(&iop.RunEvent{RunId: req.GetRunId(), Type: "test_event", NodeId: "test-node"})
}

func (m *mockHandler) OnCancel(ctx context.Context, sess *transport.Session, req *iop.CancelRequest) error {
	return nil
}

func (m *mockHandler) OnCommandRequest(ctx context.Context, sess *transport.Session, req *iop.NodeCommandRequest) (*iop.NodeCommandResponse, error) {
	return &iop.NodeCommandResponse{Error: "not implemented in mock"}, nil
}

func (m *mockHandler) OnConfigRefresh(_ context.Context, _ *transport.Session, req *iop.NodeConfigRefreshRequest) (*iop.NodeConfigRefreshResponse, error) {
	return &iop.NodeConfigRefreshResponse{
		RequestId: req.GetRequestId(),
		Status:    iop.NodeConfigRefreshStatus_NODE_CONFIG_REFRESH_STATUS_RESTART_REQUIRED,
	}, nil
}

func (m *mockHandler) OnProviderTunnelRequest(ctx context.Context, sess *transport.Session, req *iop.ProviderTunnelRequest) error {
	return nil
}

func getFreePort(t *testing.T) string {
	l, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		t.Fatalf("listen: %v", err)
	}
	addr := l.Addr().String()
	l.Close()
	return addr
}

func edgeParserMap() toki.ParserMap {
	return toki.ParserMap{
		toki.TypeNameOf(&iop.RunEvent{}): func(b []byte) (proto.Message, error) {
			m := &iop.RunEvent{}
			return m, proto.Unmarshal(b, m)
		},
		toki.TypeNameOf(&iop.RegisterRequest{}): func(b []byte) (proto.Message, error) {
			m := &iop.RegisterRequest{}
			return m, proto.Unmarshal(b, m)
		},
	}
}

func waitForAcceptedClient(t *testing.T, acceptedCh <-chan *toki.TcpClient) *toki.TcpClient {
	t.Helper()

	select {
	case client := <-acceptedCh:
		return client
	case <-time.After(2 * time.Second):
		t.Fatal("edge server did not accept connection")
		return nil
	}
}

func TestNodeClientIntegration(t *testing.T) {
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	logger := zap.NewNop()
	listenAddr := getFreePort(t)
	host, portStr, _ := net.SplitHostPort(listenAddr)
	port := 0
	fmt.Sscanf(portStr, "%d", &port)

	// 1. Mock Edge 서버 구동
	acceptedCh := make(chan *toki.TcpClient, 1)
	registerReqCh := make(chan *iop.RegisterRequest, 1)
	server := toki.NewTcpServer(host, port, func(conn net.Conn) *toki.TcpClient {
		client := toki.NewTcpClient(conn, 30, 10, edgeParserMap())
		toki.AddRequestListenerTyped[*iop.RegisterRequest, *iop.RegisterResponse](
			&client.Communicator,
			func(req *iop.RegisterRequest) (*iop.RegisterResponse, error) {
				registerReqCh <- req
				return &iop.RegisterResponse{
					Accepted: true,
					NodeId:   "test-node",
					Alias:    "test-alias",
					Config: &iop.NodeConfigPayload{
						Runtime: &iop.NodeRuntimeConfig{Concurrency: 1},
					},
				}, nil
			},
		)
		acceptedCh <- client
		return client
	})
	if err := server.Start(ctx); err != nil {
		t.Fatalf("failed to start mock edge server: %v", err)
	}
	defer server.Stop()

	// 2. Node 클라이언트 접속
	handler := &mockHandler{
		runReqCh: make(chan *iop.RunRequest, 1),
	}

	result, err := transport.DialEdge(ctx, listenAddr, "test-token", logger)
	if err != nil {
		t.Fatalf("failed to dial edge: %v", err)
	}
	defer result.Session.Close()
	edgeEventCh := make(chan *iop.EdgeNodeEvent, 1)
	result.Session.SetEventHandler(func(event *iop.EdgeNodeEvent) {
		edgeEventCh <- event
	})
	result.Session.SetHandler(handler)

	if result.NodeID != "test-node" {
		t.Fatalf("expected node id %q, got %q", "test-node", result.NodeID)
	}
	if result.Alias != "test-alias" {
		t.Fatalf("expected alias %q, got %q", "test-alias", result.Alias)
	}

	select {
	case req := <-registerReqCh:
		if req.GetToken() != "test-token" {
			t.Fatalf("expected token %q, got %q", "test-token", req.GetToken())
		}
	case <-time.After(2 * time.Second):
		t.Fatal("timeout waiting for register request")
	}

	edgeClient := waitForAcceptedClient(t, acceptedCh)
	runEventCh := make(chan *iop.RunEvent, 1)
	toki.AddListenerTyped[*iop.RunEvent](&edgeClient.Communicator, func(event *iop.RunEvent) {
		runEventCh <- event
	})

	// 3. Edge -> Node 로 RunRequest 전송
	runReq := &iop.RunRequest{
		RunId:   "test-run",
		Adapter: "test-adapter",
	}
	if err := edgeClient.Send(runReq); err != nil {
		t.Fatalf("failed to send run request: %v", err)
	}

	// 4. Node에서 RunRequest 수신 확인
	select {
	case receivedReq := <-handler.runReqCh:
		if receivedReq.GetRunId() != runReq.GetRunId() {
			t.Fatalf("expected run id %q, got %q", runReq.GetRunId(), receivedReq.GetRunId())
		}
	case <-time.After(2 * time.Second):
		t.Fatal("timeout waiting for run request on node handler")
	}

	select {
	case event := <-runEventCh:
		if event.GetRunId() != runReq.GetRunId() {
			t.Fatalf("expected run event id %q, got %q", runReq.GetRunId(), event.GetRunId())
		}
		if event.GetType() != "test_event" {
			t.Fatalf("expected run event type %q, got %q", "test_event", event.GetType())
		}
	case <-time.After(2 * time.Second):
		t.Fatal("timeout waiting for run event from node session")
	}

	if err := edgeClient.Close(); err != nil {
		t.Fatalf("close edge client: %v", err)
	}
	select {
	case event := <-edgeEventCh:
		if event.GetType() != eventpkg.TypeEdgeDisconnected {
			t.Fatalf("event type: got %q want %q", event.GetType(), eventpkg.TypeEdgeDisconnected)
		}
		if event.GetNodeId() != "test-node" || event.GetAlias() != "test-alias" || event.GetReason() != eventpkg.ReasonTransportClosed {
			t.Fatalf("unexpected edge disconnected event: %+v", event)
		}
		if event.GetMetadata()[eventpkg.MetadataTransportCloseReason] != toki.DisconnectReasonRemoteClosed {
			t.Fatalf("transport close reason: got %q want %q", event.GetMetadata()[eventpkg.MetadataTransportCloseReason], toki.DisconnectReasonRemoteClosed)
		}
		if event.GetMetadata()[eventpkg.MetadataTransportCloseError] == "" {
			t.Fatalf("expected transport close error metadata, got %+v", event.GetMetadata())
		}
	case <-time.After(2 * time.Second):
		t.Fatal("timeout waiting for edge disconnected event")
	}
}