package p2p

import (
	"fmt"
	"net"
	"reflect"
	"sync"
	"testing"

	"github.com/ethereum/go-ethereum/crypto"
)

type peerId struct {
	privKey, pubkey []byte
}

func (self *peerId) String() string {
	return fmt.Sprintf("test peer %x", self.Pubkey()[:4])
}

func (self *peerId) Pubkey() (pubkey []byte) {
	pubkey = self.pubkey
	if len(pubkey) == 0 {
		pubkey = crypto.GenerateNewKeyPair().PublicKey
		self.pubkey = pubkey
	}
	return
}

func (self *peerId) PrivKey() (privKey []byte) {
	privKey = self.privKey
	if len(privKey) == 0 {
		privKey = crypto.GenerateNewKeyPair().PublicKey
		self.privKey = privKey
	}
	return
}

func newTestPeer() (peer *Peer) {
	peer = NewPeer(&peerId{}, []Cap{})
	peer.pubkeyHook = func(*peerAddr) error { return nil }
	peer.ourID = &peerId{}
	peer.listenAddr = &peerAddr{}
	peer.otherPeers = func() []*Peer { return nil }
	return
}

func TestBaseProtocolPeers(t *testing.T) {
	peerList := []*peerAddr{
		{IP: net.ParseIP("1.2.3.4"), Port: 2222, Pubkey: []byte{}},
		{IP: net.ParseIP("5.6.7.8"), Port: 3333, Pubkey: []byte{}},
	}
	listenAddr := &peerAddr{IP: net.ParseIP("1.3.5.7"), Port: 1111, Pubkey: []byte{}}
	rw1, rw2 := MsgPipe()
	defer rw1.Close()
	wg := new(sync.WaitGroup)

	// run matcher, close pipe when addresses have arrived
	numPeers := len(peerList) + 1
	addrChan := make(chan *peerAddr)
	wg.Add(1)
	go func() {
		i := 0
		for got := range addrChan {
			var want *peerAddr
			switch {
			case i < len(peerList):
				want = peerList[i]
			case i == len(peerList):
				want = listenAddr // listenAddr should be the last thing sent
			}
			t.Logf("got peer %d/%d: %v", i+1, numPeers, got)
			if !reflect.DeepEqual(want, got) {
				t.Errorf("mismatch: got %+v, want %+v", got, want)
			}
			i++
			if i == numPeers {
				break
			}
		}
		if i != numPeers {
			t.Errorf("wrong number of peers received: got %d, want %d", i, numPeers)
		}
		rw1.Close()
		wg.Done()
	}()

	// run first peer (in background)
	peer1 := newTestPeer()
	peer1.ourListenAddr = listenAddr
	peer1.otherPeers = func() []*Peer {
		pl := make([]*Peer, len(peerList))
		for i, addr := range peerList {
			pl[i] = &Peer{listenAddr: addr}
		}
		return pl
	}
	wg.Add(1)
	go func() {
		runBaseProtocol(peer1, rw1)
		wg.Done()
	}()

	// run second peer
	peer2 := newTestPeer()
	peer2.newPeerAddr = addrChan // feed peer suggestions into matcher
	if err := runBaseProtocol(peer2, rw2); err != ErrPipeClosed {
		t.Errorf("peer2 terminated with unexpected error: %v", err)
	}

	// terminate matcher
	close(addrChan)
	wg.Wait()
}

func TestBaseProtocolDisconnect(t *testing.T) {
	peer := NewPeer(&peerId{}, nil)
	peer.ourID = &peerId{}
	peer.pubkeyHook = func(*peerAddr) error { return nil }

	rw1, rw2 := MsgPipe()
	done := make(chan struct{})
	go func() {
		if err := expectMsg(rw2, handshakeMsg); err != nil {
			t.Error(err)
		}
		err := EncodeMsg(rw2, handshakeMsg,
			baseProtocolVersion,
			"",
			[]interface{}{},
			0,
			make([]byte, 64),
		)
		if err != nil {
			t.Error(err)
		}
		if err := expectMsg(rw2, getPeersMsg); err != nil {
			t.Error(err)
		}
		if err := EncodeMsg(rw2, discMsg, DiscQuitting); err != nil {
			t.Error(err)
		}

		close(done)
	}()

	if err := runBaseProtocol(peer, rw1); err == nil {
		t.Errorf("base protocol returned without error")
	} else if reason, ok := err.(discRequestedError); !ok || reason != DiscQuitting {
		t.Errorf("base protocol returned wrong error: %v", err)
	}
	<-done
}

func expectMsg(r MsgReader, code uint64) error {
	msg, err := r.ReadMsg()
	if err != nil {
		return err
	}
	if err := msg.Discard(); err != nil {
		return err
	}
	if msg.Code != code {
		return fmt.Errorf("wrong message code: got %d, expected %d", msg.Code, code)
	}
	return nil
}