package server

import (
	"bufio"
	"context"
	"crypto/tls"
	"crypto/x509"
	"net/http"
	"testing"
	"time"

	"github.com/quic-go/quic-go"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"github.com/traefik/traefik/v3/pkg/config/static"
	tcprouter "github.com/traefik/traefik/v3/pkg/server/router/tcp"
	"github.com/traefik/traefik/v3/pkg/types"
)

// LocalhostCert is a PEM-encoded TLS cert with SAN IPs
// "127.0.0.1" and "[::1]", expiring at Jan 29 16:00:00 2084 GMT.
// generated from src/crypto/tls:
// go run generate_cert.go  --rsa-bits 2048 --host 127.0.0.1,::1,example.com --ca --start-date "Jan 1 00:00:00 1970" --duration=1000000h
var (
	localhostCert = types.FileOrContent(`-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----`)

	// LocalhostKey is the private key for localhostCert.
	localhostKey = types.FileOrContent(`-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----`)
)

func TestHTTP3AdvertisedPort(t *testing.T) {
	certContent, err := localhostCert.Read()
	require.NoError(t, err)

	keyContent, err := localhostKey.Read()
	require.NoError(t, err)

	tlsCert, err := tls.X509KeyPair(certContent, keyContent)
	require.NoError(t, err)

	epConfig := &static.EntryPointsTransport{}
	epConfig.SetDefaults()

	entryPoint, err := NewTCPEntryPoint(context.Background(), &static.EntryPoint{
		Address:          "127.0.0.1:0",
		Transport:        epConfig,
		ForwardedHeaders: &static.ForwardedHeaders{},
		HTTP2:            &static.HTTP2Config{},
		HTTP3: &static.HTTP3Config{
			AdvertisedPort: 8080,
		},
	}, nil, nil)
	require.NoError(t, err)

	router, err := tcprouter.NewRouter()
	require.NoError(t, err)

	router.AddHTTPTLSConfig("*", &tls.Config{
		Certificates: []tls.Certificate{tlsCert},
	})
	router.SetHTTPSHandler(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
		rw.WriteHeader(http.StatusOK)
	}), nil)

	ctx := context.Background()
	go entryPoint.Start(ctx)
	entryPoint.SwitchRouter(router)

	conn, err := tls.Dial("tcp", entryPoint.listener.Addr().String(), &tls.Config{
		InsecureSkipVerify: true,
	})
	require.NoError(t, err)

	t.Cleanup(func() {
		_ = conn.Close()
		entryPoint.Shutdown(ctx)
	})

	// We are racing with the http3Server readiness happening in the goroutine starting the entrypoint
	time.Sleep(time.Second)

	request, err := http.NewRequest(http.MethodGet, "https://127.0.0.1:8090", nil)
	require.NoError(t, err)

	err = request.Write(conn)
	require.NoError(t, err)

	r, err := http.ReadResponse(bufio.NewReader(conn), nil)
	require.NoError(t, err)

	assert.NotContains(t, r.Header.Get("Alt-Svc"), ":8090")
	assert.Contains(t, r.Header.Get("Alt-Svc"), ":8080")
}

func TestHTTP30RTT(t *testing.T) {
	certContent, err := localhostCert.Read()
	require.NoError(t, err)

	keyContent, err := localhostKey.Read()
	require.NoError(t, err)

	tlsCert, err := tls.X509KeyPair(certContent, keyContent)
	require.NoError(t, err)

	epConfig := &static.EntryPointsTransport{}
	epConfig.SetDefaults()

	entryPoint, err := NewTCPEntryPoint(context.Background(), &static.EntryPoint{
		Address:          "127.0.0.1:8090",
		Transport:        epConfig,
		ForwardedHeaders: &static.ForwardedHeaders{},
		HTTP2:            &static.HTTP2Config{},
		HTTP3:            &static.HTTP3Config{},
	}, nil, nil)
	require.NoError(t, err)

	router, err := tcprouter.NewRouter()
	require.NoError(t, err)

	router.AddHTTPTLSConfig("example.com", &tls.Config{
		Certificates: []tls.Certificate{tlsCert},
	})
	router.SetHTTPSHandler(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
		rw.WriteHeader(http.StatusOK)
	}), nil)

	ctx := context.Background()
	go entryPoint.Start(ctx)
	entryPoint.SwitchRouter(router)

	// We are racing with the http3Server readiness happening in the goroutine starting the entrypoint.
	time.Sleep(time.Second)

	certPool := x509.NewCertPool()
	certPool.AppendCertsFromPEM(certContent)

	tlsConf := &tls.Config{
		RootCAs:    certPool,
		ServerName: "example.com",
		NextProtos: []string{"h3"},
	}

	// Define custom cache.
	gets := make(chan string, 100)
	puts := make(chan string, 100)
	cache := newClientSessionCache(tls.NewLRUClientSessionCache(10), gets, puts)
	tlsConf.ClientSessionCache = cache

	// This first DialAddrEarly connection is here to populate the cache.
	earlyConnection, err := quic.DialAddrEarly(context.Background(), "127.0.0.1:8090", tlsConf, &quic.Config{})
	require.NoError(t, err)

	t.Cleanup(func() {
		_ = earlyConnection.CloseWithError(0, "")
		entryPoint.Shutdown(ctx)
	})

	// wait for the handshake complete.
	<-earlyConnection.HandshakeComplete()

	// 0RTT is always false on the first connection.
	require.False(t, earlyConnection.ConnectionState().Used0RTT)

	earlyConnection, err = quic.DialAddrEarly(context.Background(), "127.0.0.1:8090", tlsConf, &quic.Config{})
	require.NoError(t, err)

	<-earlyConnection.HandshakeComplete()

	// 0RTT need to be false.
	assert.False(t, earlyConnection.ConnectionState().Used0RTT)
}

type clientSessionCache struct {
	cache tls.ClientSessionCache

	gets chan<- string
	puts chan<- string
}

func newClientSessionCache(cache tls.ClientSessionCache, gets, puts chan<- string) *clientSessionCache {
	return &clientSessionCache{
		cache: cache,
		gets:  gets,
		puts:  puts,
	}
}

var _ tls.ClientSessionCache = &clientSessionCache{}

func (c *clientSessionCache) Get(sessionKey string) (*tls.ClientSessionState, bool) {
	session, ok := c.cache.Get(sessionKey)
	c.gets <- sessionKey
	return session, ok
}

func (c *clientSessionCache) Put(sessionKey string, cs *tls.ClientSessionState) {
	c.cache.Put(sessionKey, cs)
	c.puts <- sessionKey
}