package self_test

import (
	"context"
	"fmt"
	"io"
	"net"
	"time"

	"github.com/lucas-clemente/quic-go"
	quicproxy "github.com/lucas-clemente/quic-go/integrationtests/tools/proxy"
	"github.com/lucas-clemente/quic-go/internal/protocol"

	. "github.com/onsi/ginkgo/v2"
	. "github.com/onsi/gomega"
)

var _ = Describe("non-zero RTT", func() {
	for _, v := range protocol.SupportedVersions {
		version := v

		runServer := func() quic.Listener {
			ln, err := quic.ListenAddr(
				"localhost:0",
				getTLSConfig(),
				getQuicConfig(&quic.Config{Versions: []protocol.VersionNumber{version}}),
			)
			Expect(err).ToNot(HaveOccurred())
			go func() {
				defer GinkgoRecover()
				conn, err := ln.Accept(context.Background())
				Expect(err).ToNot(HaveOccurred())
				str, err := conn.OpenStream()
				Expect(err).ToNot(HaveOccurred())
				_, err = str.Write(PRData)
				Expect(err).ToNot(HaveOccurred())
				str.Close()
			}()
			return ln
		}

		downloadFile := func(port int) {
			conn, err := quic.DialAddr(
				fmt.Sprintf("localhost:%d", port),
				getTLSClientConfig(),
				getQuicConfig(&quic.Config{Versions: []protocol.VersionNumber{version}}),
			)
			Expect(err).ToNot(HaveOccurred())
			str, err := conn.AcceptStream(context.Background())
			Expect(err).ToNot(HaveOccurred())
			data, err := io.ReadAll(str)
			Expect(err).ToNot(HaveOccurred())
			Expect(data).To(Equal(PRData))
			conn.CloseWithError(0, "")
		}

		Context(fmt.Sprintf("with QUIC version %s", version), func() {
			for _, r := range [...]time.Duration{
				10 * time.Millisecond,
				50 * time.Millisecond,
				100 * time.Millisecond,
				200 * time.Millisecond,
			} {
				rtt := r

				It(fmt.Sprintf("downloads a message with %s RTT", rtt), func() {
					ln := runServer()
					defer ln.Close()
					serverPort := ln.Addr().(*net.UDPAddr).Port
					proxy, err := quicproxy.NewQuicProxy("localhost:0", &quicproxy.Opts{
						RemoteAddr: fmt.Sprintf("localhost:%d", serverPort),
						DelayPacket: func(quicproxy.Direction, []byte) time.Duration {
							return rtt / 2
						},
					})
					Expect(err).ToNot(HaveOccurred())
					defer proxy.Close()

					conn, err := quic.DialAddr(
						fmt.Sprintf("localhost:%d", proxy.LocalPort()),
						getTLSClientConfig(),
						getQuicConfig(&quic.Config{Versions: []protocol.VersionNumber{version}}),
					)
					Expect(err).ToNot(HaveOccurred())
					str, err := conn.AcceptStream(context.Background())
					Expect(err).ToNot(HaveOccurred())
					data, err := io.ReadAll(str)
					Expect(err).ToNot(HaveOccurred())
					Expect(data).To(Equal(PRData))
					conn.CloseWithError(0, "")
				})
			}

			for _, r := range [...]time.Duration{
				10 * time.Millisecond,
				40 * time.Millisecond,
			} {
				rtt := r

				It(fmt.Sprintf("downloads a message with %s RTT, with reordering", rtt), func() {
					ln := runServer()
					defer ln.Close()
					serverPort := ln.Addr().(*net.UDPAddr).Port
					proxy, err := quicproxy.NewQuicProxy("localhost:0", &quicproxy.Opts{
						RemoteAddr: fmt.Sprintf("localhost:%d", serverPort),
						DelayPacket: func(quicproxy.Direction, []byte) time.Duration {
							return randomDuration(rtt/2, rtt*3/2) / 2
						},
					})
					Expect(err).ToNot(HaveOccurred())
					defer proxy.Close()

					downloadFile(proxy.LocalPort())
				})
			}
		})
	}
})