package floodsub

import (
	"bytes"
	"context"
	"fmt"
	"math/rand"
	"testing"
	"time"

	host "github.com/libp2p/go-libp2p-host"
)

func getGossipsubs(ctx context.Context, hs []host.Host, opts ...Option) []*PubSub {
	var psubs []*PubSub
	for _, h := range hs {
		ps, err := NewGossipSub(ctx, h, opts...)
		if err != nil {
			panic(err)
		}
		psubs = append(psubs, ps)
	}
	return psubs
}

func TestSparseGossipsub(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	hosts := getNetHosts(t, ctx, 20)

	psubs := getGossipsubs(ctx, hosts)

	var msgs []*Subscription
	for _, ps := range psubs {
		subch, err := ps.Subscribe("foobar")
		if err != nil {
			t.Fatal(err)
		}

		msgs = append(msgs, subch)
	}

	sparseConnect(t, hosts)

	// wait for heartbeats to build mesh
	time.Sleep(time.Second * 2)

	for i := 0; i < 100; i++ {
		msg := []byte(fmt.Sprintf("%d it's not a floooooood %d", i, i))

		owner := rand.Intn(len(psubs))

		psubs[owner].Publish("foobar", msg)

		for _, sub := range msgs {
			got, err := sub.Next(ctx)
			if err != nil {
				t.Fatal(sub.err)
			}
			if !bytes.Equal(msg, got.Data) {
				t.Fatal("got wrong message!")
			}
		}
	}
}

func TestDenseGossipsub(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	hosts := getNetHosts(t, ctx, 20)

	psubs := getGossipsubs(ctx, hosts)

	var msgs []*Subscription
	for _, ps := range psubs {
		subch, err := ps.Subscribe("foobar")
		if err != nil {
			t.Fatal(err)
		}

		msgs = append(msgs, subch)
	}

	denseConnect(t, hosts)

	// wait for heartbeats to build mesh
	time.Sleep(time.Second * 2)

	for i := 0; i < 100; i++ {
		msg := []byte(fmt.Sprintf("%d it's not a floooooood %d", i, i))

		owner := rand.Intn(len(psubs))

		psubs[owner].Publish("foobar", msg)

		for _, sub := range msgs {
			got, err := sub.Next(ctx)
			if err != nil {
				t.Fatal(sub.err)
			}
			if !bytes.Equal(msg, got.Data) {
				t.Fatal("got wrong message!")
			}
		}
	}
}

func TestGossipsubGossip(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	hosts := getNetHosts(t, ctx, 20)

	psubs := getGossipsubs(ctx, hosts)

	var msgs []*Subscription
	for _, ps := range psubs {
		subch, err := ps.Subscribe("foobar")
		if err != nil {
			t.Fatal(err)
		}

		msgs = append(msgs, subch)
	}

	denseConnect(t, hosts)

	// wait for heartbeats to build mesh
	time.Sleep(time.Second * 2)

	for i := 0; i < 100; i++ {
		msg := []byte(fmt.Sprintf("%d it's not a floooooood %d", i, i))

		owner := rand.Intn(len(psubs))

		psubs[owner].Publish("foobar", msg)

		for _, sub := range msgs {
			got, err := sub.Next(ctx)
			if err != nil {
				t.Fatal(sub.err)
			}
			if !bytes.Equal(msg, got.Data) {
				t.Fatal("got wrong message!")
			}
		}

		// wait a bit to have some gossip interleaved
		time.Sleep(time.Millisecond * 100)
	}

	// and wait for some gossip flushing
	time.Sleep(time.Second * 2)
}

func TestGossipsubPrune(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	hosts := getNetHosts(t, ctx, 20)

	psubs := getGossipsubs(ctx, hosts)

	var msgs []*Subscription
	for _, ps := range psubs {
		subch, err := ps.Subscribe("foobar")
		if err != nil {
			t.Fatal(err)
		}

		msgs = append(msgs, subch)
	}

	denseConnect(t, hosts)

	// wait for heartbeats to build mesh
	time.Sleep(time.Second * 2)

	// disconnect some peers from the mesh to get some PRUNEs
	for _, sub := range msgs[:5] {
		sub.Cancel()
	}

	// wait a bit to take effect
	time.Sleep(time.Millisecond * 100)

	for i := 0; i < 10; i++ {
		msg := []byte(fmt.Sprintf("%d it's not a floooooood %d", i, i))

		owner := rand.Intn(len(psubs))

		psubs[owner].Publish("foobar", msg)

		for _, sub := range msgs[5:] {
			got, err := sub.Next(ctx)
			if err != nil {
				t.Fatal(sub.err)
			}
			if !bytes.Equal(msg, got.Data) {
				t.Fatal("got wrong message!")
			}
		}
	}
}

func TestGossipsubGraft(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	hosts := getNetHosts(t, ctx, 20)

	psubs := getGossipsubs(ctx, hosts)

	sparseConnect(t, hosts)

	time.Sleep(time.Second * 1)

	var msgs []*Subscription
	for _, ps := range psubs {
		subch, err := ps.Subscribe("foobar")
		if err != nil {
			t.Fatal(err)
		}

		msgs = append(msgs, subch)

		// wait for announce to propagate
		time.Sleep(time.Millisecond * 100)
	}

	time.Sleep(time.Second * 1)

	for i := 0; i < 100; i++ {
		msg := []byte(fmt.Sprintf("%d it's not a floooooood %d", i, i))

		owner := rand.Intn(len(psubs))

		psubs[owner].Publish("foobar", msg)

		for _, sub := range msgs {
			got, err := sub.Next(ctx)
			if err != nil {
				t.Fatal(sub.err)
			}
			if !bytes.Equal(msg, got.Data) {
				t.Fatal("got wrong message!")
			}
		}
	}
}

func TestMixedGossipsub(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	hosts := getNetHosts(t, ctx, 30)

	gsubs := getGossipsubs(ctx, hosts[:20])
	fsubs := getPubsubs(ctx, hosts[20:])
	psubs := append(gsubs, fsubs...)

	var msgs []*Subscription
	for _, ps := range psubs {
		subch, err := ps.Subscribe("foobar")
		if err != nil {
			t.Fatal(err)
		}

		msgs = append(msgs, subch)
	}

	sparseConnect(t, hosts)

	// wait for heartbeats to build mesh
	time.Sleep(time.Second * 2)

	for i := 0; i < 100; i++ {
		msg := []byte(fmt.Sprintf("%d it's not a floooooood %d", i, i))

		owner := rand.Intn(len(psubs))

		psubs[owner].Publish("foobar", msg)

		for _, sub := range msgs {
			got, err := sub.Next(ctx)
			if err != nil {
				t.Fatal(sub.err)
			}
			if !bytes.Equal(msg, got.Data) {
				t.Fatal("got wrong message!")
			}
		}
	}
}

func TestGossipsubMultihops(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	hosts := getNetHosts(t, ctx, 6)

	psubs := getGossipsubs(ctx, hosts)

	connect(t, hosts[0], hosts[1])
	connect(t, hosts[1], hosts[2])
	connect(t, hosts[2], hosts[3])
	connect(t, hosts[3], hosts[4])
	connect(t, hosts[4], hosts[5])

	var subs []*Subscription
	for i := 1; i < 6; i++ {
		ch, err := psubs[i].Subscribe("foobar")
		if err != nil {
			t.Fatal(err)
		}
		subs = append(subs, ch)
	}

	// wait for heartbeats to build mesh
	time.Sleep(time.Second * 2)

	msg := []byte("i like cats")
	err := psubs[0].Publish("foobar", msg)
	if err != nil {
		t.Fatal(err)
	}

	// last node in the chain should get the message
	select {
	case out := <-subs[4].ch:
		if !bytes.Equal(out.GetData(), msg) {
			t.Fatal("got wrong data")
		}
	case <-time.After(time.Second * 5):
		t.Fatal("timed out waiting for message")
	}
}

func TestGossipsubTreeTopology(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	hosts := getNetHosts(t, ctx, 10)
	psubs := getGossipsubs(ctx, hosts)

	connect(t, hosts[0], hosts[1])
	connect(t, hosts[1], hosts[2])
	connect(t, hosts[1], hosts[4])
	connect(t, hosts[2], hosts[3])
	connect(t, hosts[0], hosts[5])
	connect(t, hosts[5], hosts[6])
	connect(t, hosts[5], hosts[8])
	connect(t, hosts[6], hosts[7])
	connect(t, hosts[8], hosts[9])

	/*
		[0] -> [1] -> [2] -> [3]
		 |      L->[4]
		 v
		[5] -> [6] -> [7]
		 |
		 v
		[8] -> [9]
	*/

	var chs []*Subscription
	for _, ps := range psubs {
		ch, err := ps.Subscribe("fizzbuzz")
		if err != nil {
			t.Fatal(err)
		}

		chs = append(chs, ch)
	}

	// wait for heartbeats to build mesh
	time.Sleep(time.Second * 2)

	assertPeerLists(t, hosts, psubs[0], 1, 5)
	assertPeerLists(t, hosts, psubs[1], 0, 2, 4)
	assertPeerLists(t, hosts, psubs[2], 1, 3)

	checkMessageRouting(t, "fizzbuzz", []*PubSub{psubs[9], psubs[3]}, chs)
}