package peer

import (
	"bufio"
	"context"
	"crypto/rand"
	"fmt"
	"io"
	"os"

	"github.com/libp2p/go-libp2p"
	crypto "github.com/libp2p/go-libp2p-crypto"
	inet "github.com/libp2p/go-libp2p-net"
	peerstore "github.com/libp2p/go-libp2p-peerstore"
	"github.com/multiformats/go-multiaddr"
	log "github.com/sirupsen/logrus"
)

func handleStream(stream inet.Stream) {
	log.Info("Got a new stream!")

	rw := bufio.NewReadWriter(bufio.NewReader(stream), bufio.NewWriter(stream))

	go readData(rw)
	go writeData(rw)
}

func readData(rw *bufio.ReadWriter) {
	for {
		str, err := rw.ReadString('\n')
		if err != nil {
			log.Error("Error reading from buffer")
			panic(err)
		}
		if str == "" {
			return
		}
		if str != "\n" {
			fmt.Printf("\x1b[32m%s\x1b[0m> ", str)
		}
	}
}

func writeData(rw *bufio.ReadWriter) {
	stdReader := bufio.NewReader(os.Stdin)
	for {
		fmt.Print("> ")
		sendData, err := stdReader.ReadString('\n')
		if err != nil {
			log.Error("Error reading from stdin")
			panic(err)
		}

		_, err = rw.WriteString(fmt.Sprintf("%s\n", sendData))
		if err != nil {
			log.Error("Error writing to buffer")
			panic(err)
		}
		err = rw.Flush()
		if err != nil {
			log.Error("Error flushing buffer")
			panic(err)
		}
	}
}

func Start(port int, dest string) error {
	var r io.Reader
	r = rand.Reader

	prvKey, _, err := crypto.GenerateKeyPairWithReader(crypto.RSA, 2048, r)
	if err != nil {
		return err
	}

	sourceMultiAddr, _ := multiaddr.NewMultiaddr(fmt.Sprintf("/ip4/0.0.0.0/tcp/%d", port))

	host, err := libp2p.New(
		context.Background(),
		libp2p.ListenAddrs(sourceMultiAddr),
		libp2p.Identity(prvKey),
	)
	if err != nil {
		return err
	}
	if dest == "" {
		host.SetStreamHandler("/slowlorisdb/0.0.1", handleStream)

		var port string
		for _, la := range host.Network().ListenAddresses() {
			if p, err := la.ValueForProtocol(multiaddr.P_TCP); err == nil {
				port = p
				break
			}
		}

		if port == "" {
			panic("was not able to find actual local port")
		}

		fmt.Printf("Run './slowlorisdb -d /ip4/127.0.0.1/tcp/%v/p2p/%s' on another console.\n", port, host.ID().Pretty())
		fmt.Printf("\nWaiting for incoming connection\n\n")

		// Hang forever
		<-make(chan struct{})
	} else {
		fmt.Println("This node's multiaddresses:")
		for _, la := range host.Addrs() {
			fmt.Printf(" - %v\n", la)
		}
		fmt.Println()

		maddr, err := multiaddr.NewMultiaddr(dest)
		if err != nil {
			log.Fatalln(err)
		}

		info, err := peerstore.InfoFromP2pAddr(maddr)
		if err != nil {
			log.Fatalln(err)
		}

		host.Peerstore().AddAddrs(info.ID, info.Addrs, peerstore.PermanentAddrTTL)

		s, err := host.NewStream(context.Background(), info.ID, "/slowlorisdb/0.0.1")
		if err != nil {
			panic(err)
		}

		rw := bufio.NewReadWriter(bufio.NewReader(s), bufio.NewWriter(s))

		go writeData(rw)
		go readData(rw)

		select {}
	}
	return nil
}