/*
Copyright 2024 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package portforward

import (
	"io"
	"net"
	"net/http"
	"net/http/httptest"
	"net/url"
	"strings"
	"testing"
	"time"

	gwebsocket "github.com/gorilla/websocket"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"k8s.io/apimachinery/pkg/util/httpstream"
	"k8s.io/apimachinery/pkg/util/httpstream/spdy"
	constants "k8s.io/apimachinery/pkg/util/portforward"
	"k8s.io/apimachinery/pkg/util/wait"
	"k8s.io/client-go/rest"
	"k8s.io/client-go/transport/websocket"
)

func TestTunnelingConnection_ReadWriteClose(t *testing.T) {
	// Stream channel that will receive streams created on upstream SPDY server.
	streamChan := make(chan httpstream.Stream)
	defer close(streamChan)
	stopServerChan := make(chan struct{})
	defer close(stopServerChan)
	// Create tunneling connection server endpoint with fake upstream SPDY server.
	tunnelingServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		var upgrader = gwebsocket.Upgrader{
			CheckOrigin:  func(r *http.Request) bool { return true },
			Subprotocols: []string{constants.WebsocketsSPDYTunnelingPortForwardV1},
		}
		conn, err := upgrader.Upgrade(w, req, nil)
		require.NoError(t, err)
		defer conn.Close() //nolint:errcheck
		require.Equal(t, constants.WebsocketsSPDYTunnelingPortForwardV1, conn.Subprotocol())
		tunnelingConn := NewTunnelingConnection("server", conn)
		spdyConn, err := spdy.NewServerConnection(tunnelingConn, justQueueStream(streamChan))
		require.NoError(t, err)
		defer spdyConn.Close() //nolint:errcheck
		<-stopServerChan
	}))
	defer tunnelingServer.Close()
	// Dial the client tunneling connection to the tunneling server.
	url, err := url.Parse(tunnelingServer.URL)
	require.NoError(t, err)
	dialer, err := NewSPDYOverWebsocketDialer(url, &rest.Config{Host: url.Host})
	require.NoError(t, err)
	spdyClient, protocol, err := dialer.Dial(constants.PortForwardV1Name)
	require.NoError(t, err)
	assert.Equal(t, constants.PortForwardV1Name, protocol)
	defer spdyClient.Close() //nolint:errcheck
	// Create a SPDY client stream, which will queue a SPDY server stream
	// on the stream creation channel. Send data on the client stream
	// reading off the SPDY server stream, and validating it was tunneled.
	expected := "This is a test tunneling SPDY data through websockets."
	var actual []byte
	go func() {
		clientStream, err := spdyClient.CreateStream(http.Header{})
		require.NoError(t, err)
		_, err = io.Copy(clientStream, strings.NewReader(expected))
		require.NoError(t, err)
		clientStream.Close() //nolint:errcheck
	}()
	select {
	case serverStream := <-streamChan:
		actual, err = io.ReadAll(serverStream)
		require.NoError(t, err)
		defer serverStream.Close() //nolint:errcheck
	case <-time.After(wait.ForeverTestTimeout):
		t.Fatalf("timeout waiting for spdy stream to arrive on channel.")
	}
	assert.Equal(t, expected, string(actual), "error validating tunneled string")
}

func TestTunnelingConnection_LocalRemoteAddress(t *testing.T) {
	stopServerChan := make(chan struct{})
	defer close(stopServerChan)
	tunnelingServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		var upgrader = gwebsocket.Upgrader{
			CheckOrigin:  func(r *http.Request) bool { return true },
			Subprotocols: []string{constants.WebsocketsSPDYTunnelingPortForwardV1},
		}
		conn, err := upgrader.Upgrade(w, req, nil)
		require.NoError(t, err)
		defer conn.Close() //nolint:errcheck
		require.Equal(t, constants.WebsocketsSPDYTunnelingPortForwardV1, conn.Subprotocol())
		<-stopServerChan
	}))
	defer tunnelingServer.Close()
	// Create the client side tunneling connection.
	url, err := url.Parse(tunnelingServer.URL)
	require.NoError(t, err)
	tConn, err := dialForTunnelingConnection(url)
	require.NoError(t, err, "error creating client tunneling connection")
	defer tConn.Close() //nolint:errcheck
	// Validate "LocalAddr()" and "RemoteAddr()"
	localAddr := tConn.LocalAddr()
	remoteAddr := tConn.RemoteAddr()
	assert.Equal(t, "tcp", localAddr.Network(), "tunneling connection must be TCP")
	assert.Equal(t, "tcp", remoteAddr.Network(), "tunneling connection must be TCP")
	_, err = net.ResolveTCPAddr("tcp", localAddr.String())
	assert.NoError(t, err, "tunneling connection local addr should parse")
	_, err = net.ResolveTCPAddr("tcp", remoteAddr.String())
	assert.NoError(t, err, "tunneling connection remote addr should parse")
}

func TestTunnelingConnection_ReadWriteDeadlines(t *testing.T) {
	stopServerChan := make(chan struct{})
	defer close(stopServerChan)
	tunnelingServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		var upgrader = gwebsocket.Upgrader{
			CheckOrigin:  func(r *http.Request) bool { return true },
			Subprotocols: []string{constants.WebsocketsSPDYTunnelingPortForwardV1},
		}
		conn, err := upgrader.Upgrade(w, req, nil)
		require.NoError(t, err)
		defer conn.Close() //nolint:errcheck
		require.Equal(t, constants.WebsocketsSPDYTunnelingPortForwardV1, conn.Subprotocol())
		<-stopServerChan
	}))
	defer tunnelingServer.Close()
	// Create the client side tunneling connection.
	url, err := url.Parse(tunnelingServer.URL)
	require.NoError(t, err)
	tConn, err := dialForTunnelingConnection(url)
	require.NoError(t, err, "error creating client tunneling connection")
	defer tConn.Close() //nolint:errcheck
	// Validate the read and write deadlines.
	err = tConn.SetReadDeadline(time.Time{})
	assert.NoError(t, err, "setting zero deadline should always succeed; turns off deadline")
	err = tConn.SetWriteDeadline(time.Time{})
	assert.NoError(t, err, "setting zero deadline should always succeed; turns off deadline")
	err = tConn.SetDeadline(time.Time{})
	assert.NoError(t, err, "setting zero deadline should always succeed; turns off deadline")
	err = tConn.SetReadDeadline(time.Now().AddDate(10, 0, 0))
	assert.NoError(t, err, "setting deadline 10 year from now succeeds")
	err = tConn.SetWriteDeadline(time.Now().AddDate(10, 0, 0))
	assert.NoError(t, err, "setting deadline 10 year from now succeeds")
	err = tConn.SetDeadline(time.Now().AddDate(10, 0, 0))
	assert.NoError(t, err, "setting deadline 10 year from now succeeds")
}

// dialForTunnelingConnection upgrades a request at the passed "url", creating
// a websocket connection. Returns the TunnelingConnection injected with the
// websocket connection or an error if one occurs.
func dialForTunnelingConnection(url *url.URL) (*TunnelingConnection, error) {
	req, err := http.NewRequest("GET", url.String(), nil)
	if err != nil {
		return nil, err
	}
	// Tunneling must initiate a websocket upgrade connection, using tunneling portforward protocol.
	tunnelingProtocols := []string{constants.WebsocketsSPDYTunnelingPortForwardV1}
	transport, holder, err := websocket.RoundTripperFor(&rest.Config{Host: url.Host})
	if err != nil {
		return nil, err
	}
	conn, err := websocket.Negotiate(transport, holder, req, tunnelingProtocols...)
	if err != nil {
		return nil, err
	}
	return NewTunnelingConnection("client", conn), nil
}

func justQueueStream(streams chan httpstream.Stream) func(httpstream.Stream, <-chan struct{}) error {
	return func(stream httpstream.Stream, replySent <-chan struct{}) error {
		streams <- stream
		return nil
	}
}