package notify

import (
	"context"
	"errors"
	"testing"
	"time"
)

func TestBindTransferControlValidation(t *testing.T) {
	if err := BindTransferControlClient(nil, TransferControlHandler{}); !errors.Is(err, errTransferControlClientNil) {
		t.Fatalf("BindTransferControlClient nil error mismatch: %v", err)
	}
	if err := BindTransferControlServer(nil, TransferControlHandler{}); !errors.Is(err, errTransferControlServerNil) {
		t.Fatalf("BindTransferControlServer nil error mismatch: %v", err)
	}

	client := NewClient()
	if err := BindTransferControlClient(client, TransferControlHandler{}); !errors.Is(err, errTransferControlHandlerEmpty) {
		t.Fatalf("BindTransferControlClient empty handler error mismatch: %v", err)
	}

	server := NewServer()
	if err := BindTransferControlServer(server, TransferControlHandler{}); !errors.Is(err, errTransferControlHandlerEmpty) {
		t.Fatalf("BindTransferControlServer empty handler error mismatch: %v", err)
	}

	if _, err := SendTransferBeginClient(context.Background(), nil, TransferBeginRequest{}); !errors.Is(err, errTransferControlClientNil) {
		t.Fatalf("SendTransferBeginClient nil client error mismatch: %v", err)
	}
	if _, err := SendTransferBeginServer(context.Background(), nil, nil, TransferBeginRequest{}); !errors.Is(err, errTransferControlServerNil) {
		t.Fatalf("SendTransferBeginServer nil server error mismatch: %v", err)
	}
	if _, err := SendTransferBeginServer(context.Background(), server, nil, TransferBeginRequest{}); !errors.Is(err, errTransferControlLogicalConnNil) {
		t.Fatalf("SendTransferBeginServer nil conn error mismatch: %v", err)
	}
}

func TestTransferControlRoundTripTCP(t *testing.T) {
	server := NewServer().(*ServerCommon)
	if err := UseModernPSKServer(server, integrationSharedSecret, integrationModernPSKOptions()); err != nil {
		t.Fatalf("UseModernPSKServer failed: %v", err)
	}
	disableBuiltinTransferControlForServer(server)

	beginReqCh := make(chan TransferBeginRequest, 1)
	commitReqCh := make(chan TransferCommitRequest, 2)
	if err := BindTransferControlServer(server, TransferControlHandler{
		Begin: func(_ *Message, req TransferBeginRequest) (TransferBeginResponse, error) {
			beginReqCh <- req
			return TransferBeginResponse{
				TransferID: req.TransferID,
				Accepted:   true,
				NextOffset: 512,
				Missing: []TransferRange{
					{Offset: 768, Length: 128},
				},
			}, nil
		},
		Commit: func(_ *Message, req TransferCommitRequest) (TransferCommitResponse, error) {
			commitReqCh <- req
			return TransferCommitResponse{
				TransferID: req.TransferID,
				Accepted:   true,
			}, nil
		},
	}); err != nil {
		t.Fatalf("BindTransferControlServer failed: %v", err)
	}

	if err := server.Listen("tcp", "127.0.0.1:0"); err != nil {
		t.Fatalf("server Listen failed: %v", err)
	}
	defer func() {
		_ = server.Stop()
	}()

	addr := server.listener.Addr().String()
	client := NewClient().(*ClientCommon)
	if err := UseModernPSKClient(client, integrationSharedSecret, integrationModernPSKOptions()); err != nil {
		t.Fatalf("UseModernPSKClient failed: %v", err)
	}
	disableBuiltinTransferControlForClient(client)

	if err := BindTransferControlClient(client, TransferControlHandler{
		Begin: func(_ *Message, req TransferBeginRequest) (TransferBeginResponse, error) {
			beginReqCh <- req
			return TransferBeginResponse{
				TransferID: req.TransferID,
				Accepted:   true,
				NextOffset: 256,
			}, nil
		},
		Commit: func(_ *Message, req TransferCommitRequest) (TransferCommitResponse, error) {
			commitReqCh <- req
			return TransferCommitResponse{
				TransferID: req.TransferID,
				Accepted:   true,
			}, nil
		},
	}); err != nil {
		t.Fatalf("BindTransferControlClient failed: %v", err)
	}

	if err := client.Connect("tcp", addr); err != nil {
		t.Fatalf("client Connect failed: %v", err)
	}
	defer func() {
		_ = client.Stop()
	}()

	beginResp, err := SendTransferBeginClient(context.Background(), client, TransferBeginRequest{
		TransferID: "tx-client",
		Channel:    TransferChannelData,
		Size:       1024,
		Checksum:   "sha256:demo",
		Metadata: map[string]string{
			"name": "demo.bin",
		},
	})
	if err != nil {
		t.Fatalf("SendTransferBeginClient failed: %v", err)
	}
	if !beginResp.Accepted || beginResp.TransferID != "tx-client" || beginResp.NextOffset != 512 {
		t.Fatalf("begin response mismatch: %+v", beginResp)
	}
	if len(beginResp.Missing) != 1 || beginResp.Missing[0].Offset != 768 || beginResp.Missing[0].Length != 128 {
		t.Fatalf("begin response missing mismatch: %+v", beginResp.Missing)
	}

	select {
	case got := <-beginReqCh:
		if got.TransferID != "tx-client" || got.Channel != TransferChannelData || got.Size != 1024 || got.Checksum != "sha256:demo" {
			t.Fatalf("begin request mismatch: %+v", got)
		}
		if got.Metadata["name"] != "demo.bin" {
			t.Fatalf("begin request metadata mismatch: %+v", got.Metadata)
		}
	case <-time.After(2 * time.Second):
		t.Fatal("timed out waiting for begin request")
	}

	commitClientResp, err := SendTransferCommitClient(context.Background(), client, TransferCommitRequest{
		TransferID: "tx-client",
		Size:       1024,
		Checksum:   "sha256:demo",
	})
	if err != nil {
		t.Fatalf("SendTransferCommitClient failed: %v", err)
	}
	if !commitClientResp.Accepted || commitClientResp.TransferID != "tx-client" {
		t.Fatalf("client commit response mismatch: %+v", commitClientResp)
	}

	select {
	case got := <-commitReqCh:
		if got.TransferID != "tx-client" || got.Size != 1024 || got.Checksum != "sha256:demo" {
			t.Fatalf("client commit request mismatch: %+v", got)
		}
	case <-time.After(2 * time.Second):
		t.Fatal("timed out waiting for client commit request")
	}

	logical := waitForTransferControlLogicalConn(t, server, 2*time.Second)
	conn := clientConnFromLogical(logical)
	serverScope := serverFileScope(conn)

	clientSnapshot, ok, err := GetClientTransferSnapshotByID(client, "tx-client")
	if err != nil {
		t.Fatalf("GetClientTransferSnapshotByID failed: %v", err)
	}
	if !ok {
		t.Fatal("client snapshot should exist")
	}
	if got, want := clientSnapshot.Direction, TransferDirectionSend; got != want {
		t.Fatalf("client snapshot direction = %v, want %v", got, want)
	}
	if got, want := clientSnapshot.Scope, clientFileScope(); got != want {
		t.Fatalf("client snapshot scope = %q, want %q", got, want)
	}
	if got, want := clientSnapshot.State, TransferStateDone; got != want {
		t.Fatalf("client snapshot state = %v, want %v", got, want)
	}
	if got, want := clientSnapshot.AckedBytes, int64(512); got != want {
		t.Fatalf("client snapshot acked bytes = %d, want %d", got, want)
	}
	if got, want := clientSnapshot.Stage, "commit"; got != want {
		t.Fatalf("client snapshot stage = %q, want %q", got, want)
	}

	serverSnapshot, ok, err := GetServerTransferSnapshotByID(server, "tx-client")
	if err != nil {
		t.Fatalf("GetServerTransferSnapshotByID failed: %v", err)
	}
	if !ok {
		t.Fatal("server snapshot should exist")
	}
	if got, want := serverSnapshot.Direction, TransferDirectionReceive; got != want {
		t.Fatalf("server snapshot direction = %v, want %v", got, want)
	}
	if got, want := serverSnapshot.Scope, serverScope; got != want {
		t.Fatalf("server snapshot scope = %q, want %q", got, want)
	}
	if got, want := serverSnapshot.RuntimeScope, serverTransportScope(conn); got != want {
		t.Fatalf("server snapshot runtime scope = %q, want %q", got, want)
	}
	if got, want := serverSnapshot.TransportGeneration, uint64(1); got != want {
		t.Fatalf("server snapshot transport generation = %d, want %d", got, want)
	}
	if got, want := serverSnapshot.State, TransferStateDone; got != want {
		t.Fatalf("server snapshot state = %v, want %v", got, want)
	}
	if got, want := serverSnapshot.ReceivedBytes, int64(512); got != want {
		t.Fatalf("server snapshot received bytes = %d, want %d", got, want)
	}
	if got, want := serverSnapshot.Stage, "commit"; got != want {
		t.Fatalf("server snapshot stage = %q, want %q", got, want)
	}

	beginServerResp, err := SendTransferBeginServer(context.Background(), server, conn, TransferBeginRequest{
		TransferID: "tx-server",
		Channel:    TransferChannelControl,
		Size:       512,
		Checksum:   "sha256:server",
	})
	if err != nil {
		t.Fatalf("SendTransferBeginServer failed: %v", err)
	}
	if !beginServerResp.Accepted || beginServerResp.TransferID != "tx-server" || beginServerResp.NextOffset != 256 {
		t.Fatalf("server begin response mismatch: %+v", beginServerResp)
	}

	select {
	case got := <-beginReqCh:
		if got.TransferID != "tx-server" || got.Channel != TransferChannelControl || got.Size != 512 || got.Checksum != "sha256:server" {
			t.Fatalf("server begin request mismatch: %+v", got)
		}
	case <-time.After(2 * time.Second):
		t.Fatal("timed out waiting for server begin request")
	}

	commitResp, err := SendTransferCommitServer(context.Background(), server, conn, TransferCommitRequest{
		TransferID: "tx-server",
		Size:       512,
		Checksum:   "sha256:server",
	})
	if err != nil {
		t.Fatalf("SendTransferCommitServer failed: %v", err)
	}
	if !commitResp.Accepted || commitResp.TransferID != "tx-server" {
		t.Fatalf("commit response mismatch: %+v", commitResp)
	}

	select {
	case got := <-commitReqCh:
		if got.TransferID != "tx-server" || got.Size != 512 || got.Checksum != "sha256:server" {
			t.Fatalf("server commit request mismatch: %+v", got)
		}
	case <-time.After(2 * time.Second):
		t.Fatal("timed out waiting for server commit request")
	}

	serverSendSnapshot, ok, err := GetServerTransferSnapshotByID(server, "tx-server")
	if err != nil {
		t.Fatalf("GetServerTransferSnapshotByID server-send failed: %v", err)
	}
	if !ok {
		t.Fatal("server send snapshot should exist")
	}
	if got, want := serverSendSnapshot.Direction, TransferDirectionSend; got != want {
		t.Fatalf("server send snapshot direction = %v, want %v", got, want)
	}
	if got, want := serverSendSnapshot.Scope, serverScope; got != want {
		t.Fatalf("server send snapshot scope = %q, want %q", got, want)
	}
	if got, want := serverSendSnapshot.RuntimeScope, serverTransportScope(conn); got != want {
		t.Fatalf("server send snapshot runtime scope = %q, want %q", got, want)
	}
	if got, want := serverSendSnapshot.TransportGeneration, uint64(1); got != want {
		t.Fatalf("server send snapshot transport generation = %d, want %d", got, want)
	}
	if got, want := serverSendSnapshot.Channel, TransferChannelControl; got != want {
		t.Fatalf("server send snapshot channel = %q, want %q", got, want)
	}
	if got, want := serverSendSnapshot.State, TransferStateDone; got != want {
		t.Fatalf("server send snapshot state = %v, want %v", got, want)
	}
	if got, want := serverSendSnapshot.AckedBytes, int64(256); got != want {
		t.Fatalf("server send snapshot acked bytes = %d, want %d", got, want)
	}

	clientRecvSnapshot, ok, err := GetClientTransferSnapshotByID(client, "tx-server")
	if err != nil {
		t.Fatalf("GetClientTransferSnapshotByID client-recv failed: %v", err)
	}
	if !ok {
		t.Fatal("client receive snapshot should exist")
	}
	if got, want := clientRecvSnapshot.Direction, TransferDirectionReceive; got != want {
		t.Fatalf("client receive snapshot direction = %v, want %v", got, want)
	}
	if got, want := clientRecvSnapshot.Scope, clientFileScope(); got != want {
		t.Fatalf("client receive snapshot scope = %q, want %q", got, want)
	}
	if got, want := clientRecvSnapshot.Channel, TransferChannelControl; got != want {
		t.Fatalf("client receive snapshot channel = %q, want %q", got, want)
	}
	if got, want := clientRecvSnapshot.State, TransferStateDone; got != want {
		t.Fatalf("client receive snapshot state = %v, want %v", got, want)
	}
	if got, want := clientRecvSnapshot.ReceivedBytes, int64(256); got != want {
		t.Fatalf("client receive snapshot received bytes = %d, want %d", got, want)
	}
}

func waitForTransferControlLogicalConn(t *testing.T, server *ServerCommon, timeout time.Duration) *LogicalConn {
	t.Helper()

	deadline := time.Now().Add(timeout)
	for time.Now().Before(deadline) {
		logicals := server.GetLogicalConnList()
		if len(logicals) > 0 && logicals[0] != nil {
			return logicals[0]
		}
		time.Sleep(10 * time.Millisecond)
	}
	t.Fatal("timed out waiting for logical connection")
	return nil
}

func waitForTransferControlClientConn(t *testing.T, server *ServerCommon, timeout time.Duration) *ClientConn {
	return clientConnFromLogical(waitForTransferControlLogicalConn(t, server, timeout))
}

func disableBuiltinTransferControlForClient(client *ClientCommon) {
	if client == nil {
		return
	}
	state := client.getTransferState()
	state.mu.Lock()
	state.controlEnabled = false
	state.handler = nil
	state.builtinHandler = nil
	state.mu.Unlock()
}

func disableBuiltinTransferControlForServer(server *ServerCommon) {
	if server == nil {
		return
	}
	state := server.getTransferState()
	state.mu.Lock()
	state.controlEnabled = false
	state.handler = nil
	state.builtinHandler = nil
	state.mu.Unlock()
}