/*
Copyright 2016 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 spdy

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

	"github.com/moby/spdystream"
	"k8s.io/apimachinery/pkg/util/httpstream"
)

func runProxy(t *testing.T, backendUrl string, proxyUrl chan<- string, proxyDone chan<- struct{}, errCh chan<- error) {
	listener, err := net.Listen("tcp4", "localhost:0")
	if err != nil {
		errCh <- err
		return
	}
	defer listener.Close()

	proxyUrl <- listener.Addr().String()

	clientConn, err := listener.Accept()
	if err != nil {
		t.Errorf("proxy: error accepting client connection: %v", err)
		return
	}

	backendConn, err := net.Dial("tcp4", backendUrl)
	if err != nil {
		t.Errorf("proxy: error dialing backend: %v", err)
		return
	}
	defer backendConn.Close()

	var wg sync.WaitGroup
	wg.Add(2)

	go func() {
		defer wg.Done()
		io.Copy(backendConn, clientConn)
	}()

	go func() {
		defer wg.Done()
		io.Copy(clientConn, backendConn)
	}()

	wg.Wait()

	proxyDone <- struct{}{}
}

func runServer(t *testing.T, backendUrl chan<- string, serverDone chan<- struct{}, errCh chan<- error) {
	listener, err := net.Listen("tcp4", "localhost:0")
	if err != nil {
		errCh <- err
		return
	}
	defer listener.Close()

	backendUrl <- listener.Addr().String()

	conn, err := listener.Accept()
	if err != nil {
		t.Errorf("server: error accepting connection: %v", err)
		return
	}

	streamChan := make(chan httpstream.Stream)
	replySentChan := make(chan (<-chan struct{}))
	spdyConn, err := NewServerConnection(conn, func(stream httpstream.Stream, replySent <-chan struct{}) error {
		streamChan <- stream
		replySentChan <- replySent
		return nil
	})
	if err != nil {
		t.Errorf("server: error creating spdy connection: %v", err)
		return
	}

	stream := <-streamChan
	replySent := <-replySentChan
	<-replySent

	buf := make([]byte, 1)
	_, err = stream.Read(buf)
	if err != io.EOF {
		t.Errorf("server: unexpected read error: %v", err)
		return
	}

	<-spdyConn.CloseChan()
	raw := spdyConn.(*connection).conn
	if err := raw.Wait(15 * time.Second); err != nil {
		t.Errorf("server: timed out waiting for connection closure: %v", err)
	}

	serverDone <- struct{}{}
}

func TestConnectionCloseIsImmediateThroughAProxy(t *testing.T) {
	errCh := make(chan error)

	serverDone := make(chan struct{}, 1)
	backendUrlChan := make(chan string)
	go runServer(t, backendUrlChan, serverDone, errCh)

	var backendUrl string
	select {
	case err := <-errCh:
		t.Fatalf("server: error listening: %v", err)
	case backendUrl = <-backendUrlChan:
	}

	proxyDone := make(chan struct{}, 1)
	proxyUrlChan := make(chan string)
	go runProxy(t, backendUrl, proxyUrlChan, proxyDone, errCh)

	var proxyUrl string
	select {
	case err := <-errCh:
		t.Fatalf("error listening: %v", err)
	case proxyUrl = <-proxyUrlChan:
	}

	conn, err := net.Dial("tcp4", proxyUrl)
	if err != nil {
		t.Fatalf("client: error connecting to proxy: %v", err)
	}

	spdyConn, err := NewClientConnection(conn)
	if err != nil {
		t.Fatalf("client: error creating spdy connection: %v", err)
	}

	if _, err := spdyConn.CreateStream(http.Header{}); err != nil {
		t.Fatalf("client: error creating stream: %v", err)
	}

	spdyConn.Close()
	raw := spdyConn.(*connection).conn
	if err := raw.Wait(15 * time.Second); err != nil {
		t.Fatalf("client: timed out waiting for connection closure: %v", err)
	}

	expired := time.NewTimer(15 * time.Second)
	defer expired.Stop()
	i := 0
	for {
		select {
		case <-expired.C:
			t.Fatalf("timed out waiting for proxy and/or server closure")
		case <-serverDone:
			i++
		case <-proxyDone:
			i++
		}
		if i == 2 {
			break
		}
	}
}

func TestConnectionPings(t *testing.T) {
	const pingPeriod = 10 * time.Millisecond
	timeout := time.After(10 * time.Second)

	// Set up server connection.
	listener, err := net.Listen("tcp4", "localhost:0")
	if err != nil {
		t.Fatal(err)
	}
	defer listener.Close()

	srvErr := make(chan error, 1)
	go func() {
		defer close(srvErr)

		srvConn, err := listener.Accept()
		if err != nil {
			srvErr <- fmt.Errorf("server: error accepting connection: %v", err)
			return
		}
		defer srvConn.Close()

		spdyConn, err := spdystream.NewConnection(srvConn, true)
		if err != nil {
			srvErr <- fmt.Errorf("server: error creating spdy connection: %v", err)
			return
		}

		var pingsSent int64
		srvSPDYConn := newConnection(
			spdyConn,
			func(stream httpstream.Stream, replySent <-chan struct{}) error {
				// Echo all the incoming data.
				go io.Copy(stream, stream)
				return nil
			},
			pingPeriod,
			func() (time.Duration, error) {
				atomic.AddInt64(&pingsSent, 1)
				return 0, nil
			})
		defer srvSPDYConn.Close()

		// Wait for the connection to close, to prevent defers from running
		// early.
		select {
		case <-timeout:
			srvErr <- fmt.Errorf("server: timeout waiting for connection to close")
			return
		case <-srvSPDYConn.CloseChan():
		}

		// Count pings sent by the server.
		gotPings := atomic.LoadInt64(&pingsSent)
		if gotPings < 1 {
			t.Errorf("server: failed to send any pings (check logs)")
		}
	}()

	// Set up client connection.
	clConn, err := net.Dial("tcp4", listener.Addr().String())
	if err != nil {
		t.Fatalf("client: error connecting to proxy: %v", err)
	}
	defer clConn.Close()
	clSPDYConn, err := NewClientConnection(clConn)
	if err != nil {
		t.Fatalf("client: error creating spdy connection: %v", err)
	}
	defer clSPDYConn.Close()
	start := time.Now()
	clSPDYStream, err := clSPDYConn.CreateStream(http.Header{})
	if err != nil {
		t.Fatalf("client: error creating stream: %v", err)
	}
	defer clSPDYStream.Close()

	// Send some data both ways, to make sure pings don't interfere with
	// regular messages.
	in := "foo"
	if _, err := fmt.Fprintln(clSPDYStream, in); err != nil {
		t.Fatalf("client: error writing data to stream: %v", err)
	}
	var out string
	if _, err := fmt.Fscanln(clSPDYStream, &out); err != nil {
		t.Fatalf("client: error reading data from stream: %v", err)
	}
	if in != out {
		t.Errorf("client: received data doesn't match sent data: got %q, want %q", out, in)
	}

	// Wait for at least 2 pings to get sent each way before closing the
	// connection.
	elapsed := time.Since(start)
	if elapsed < 3*pingPeriod {
		time.Sleep(3*pingPeriod - elapsed)
	}
	clSPDYConn.Close()

	select {
	case err, ok := <-srvErr:
		if ok && err != nil {
			t.Error(err)
		}
	case <-timeout:
		t.Errorf("timed out waiting for server to exit")
	}
}

type fakeStream struct{ id uint32 }

func (*fakeStream) Read(p []byte) (int, error)  { return 0, nil }
func (*fakeStream) Write(p []byte) (int, error) { return 0, nil }
func (*fakeStream) Close() error                { return nil }
func (*fakeStream) Reset() error                { return nil }
func (*fakeStream) Headers() http.Header        { return nil }
func (f *fakeStream) Identifier() uint32        { return f.id }

func TestConnectionRemoveStreams(t *testing.T) {
	c := &connection{streams: make(map[uint32]httpstream.Stream)}
	stream0 := &fakeStream{id: 0}
	stream1 := &fakeStream{id: 1}
	stream2 := &fakeStream{id: 2}

	c.registerStream(stream0)
	c.registerStream(stream1)

	if len(c.streams) != 2 {
		t.Fatalf("should have two streams, has %d", len(c.streams))
	}

	// not exists
	c.RemoveStreams(stream2)

	if len(c.streams) != 2 {
		t.Fatalf("should have two streams, has %d", len(c.streams))
	}

	// remove all existing
	c.RemoveStreams(stream0, stream1)

	// remove nil stream should not crash
	c.RemoveStreams(nil)

	if len(c.streams) != 0 {
		t.Fatalf("should not have any streams, has %d", len(c.streams))
	}

}