package modules

import (
	"context"

	"github.com/ipfs/go-datastore"
	"github.com/ipfs/go-datastore/namespace"
	eventbus "github.com/libp2p/go-eventbus"
	event "github.com/libp2p/go-libp2p-core/event"
	"github.com/libp2p/go-libp2p-core/host"
	"github.com/libp2p/go-libp2p-core/peer"
	pubsub "github.com/libp2p/go-libp2p-pubsub"
	"go.uber.org/fx"
	"golang.org/x/xerrors"

	"github.com/filecoin-project/go-fil-markets/discovery"
	discoveryimpl "github.com/filecoin-project/go-fil-markets/discovery/impl"

	"github.com/filecoin-project/lotus/build"
	"github.com/filecoin-project/lotus/chain"
	"github.com/filecoin-project/lotus/chain/beacon"
	"github.com/filecoin-project/lotus/chain/beacon/drand"
	"github.com/filecoin-project/lotus/chain/exchange"
	"github.com/filecoin-project/lotus/chain/messagepool"
	"github.com/filecoin-project/lotus/chain/stmgr"
	"github.com/filecoin-project/lotus/chain/store"
	"github.com/filecoin-project/lotus/chain/sub"
	"github.com/filecoin-project/lotus/journal"
	"github.com/filecoin-project/lotus/lib/peermgr"
	marketevents "github.com/filecoin-project/lotus/markets/loggers"
	"github.com/filecoin-project/lotus/node/hello"
	"github.com/filecoin-project/lotus/node/modules/dtypes"
	"github.com/filecoin-project/lotus/node/modules/helpers"
	"github.com/filecoin-project/lotus/node/repo"
)

func RunHello(mctx helpers.MetricsCtx, lc fx.Lifecycle, h host.Host, svc *hello.Service) error {
	h.SetStreamHandler(hello.ProtocolID, svc.HandleStream)

	sub, err := h.EventBus().Subscribe(new(event.EvtPeerIdentificationCompleted), eventbus.BufSize(1024))
	if err != nil {
		return xerrors.Errorf("failed to subscribe to event bus: %w", err)
	}

	go func() {
		for evt := range sub.Out() {
			pic := evt.(event.EvtPeerIdentificationCompleted)
			go func() {
				if err := svc.SayHello(helpers.LifecycleCtx(mctx, lc), pic.Peer); err != nil {
					protos, _ := h.Peerstore().GetProtocols(pic.Peer)
					agent, _ := h.Peerstore().Get(pic.Peer, "AgentVersion")
					if protosContains(protos, hello.ProtocolID) {
						log.Warnw("failed to say hello", "error", err, "peer", pic.Peer, "supported", protos, "agent", agent)
					} else {
						log.Debugw("failed to say hello", "error", err, "peer", pic.Peer, "supported", protos, "agent", agent)
					}
					return
				}
			}()
		}
	}()
	return nil
}

func protosContains(protos []string, search string) bool {
	for _, p := range protos {
		if p == search {
			return true
		}
	}
	return false
}

func RunPeerMgr(mctx helpers.MetricsCtx, lc fx.Lifecycle, pmgr *peermgr.PeerMgr) {
	go pmgr.Run(helpers.LifecycleCtx(mctx, lc))
}

func RunChainExchange(h host.Host, svc exchange.Server) {
	h.SetStreamHandler(exchange.BlockSyncProtocolID, svc.HandleStream)     // old
	h.SetStreamHandler(exchange.ChainExchangeProtocolID, svc.HandleStream) // new
}

func HandleIncomingBlocks(mctx helpers.MetricsCtx, lc fx.Lifecycle, ps *pubsub.PubSub, s *chain.Syncer, bserv dtypes.ChainBlockService, chain *store.ChainStore, stmgr *stmgr.StateManager, h host.Host, nn dtypes.NetworkName) {
	ctx := helpers.LifecycleCtx(mctx, lc)

	blocksub, err := ps.Subscribe(build.BlocksTopic(nn)) //nolint
	if err != nil {
		panic(err)
	}

	v := sub.NewBlockValidator(
		h.ID(), chain, stmgr,
		func(p peer.ID) {
			ps.BlacklistPeer(p)
			h.ConnManager().TagPeer(p, "badblock", -1000)
		})

	if err := ps.RegisterTopicValidator(build.BlocksTopic(nn), v.Validate); err != nil {
		panic(err)
	}

	go sub.HandleIncomingBlocks(ctx, blocksub, s, bserv, h.ConnManager())
}

func HandleIncomingMessages(mctx helpers.MetricsCtx, lc fx.Lifecycle, ps *pubsub.PubSub, mpool *messagepool.MessagePool, h host.Host, nn dtypes.NetworkName) {
	ctx := helpers.LifecycleCtx(mctx, lc)

	msgsub, err := ps.Subscribe(build.MessagesTopic(nn)) //nolint:staticcheck
	if err != nil {
		panic(err)
	}

	v := sub.NewMessageValidator(h.ID(), mpool)

	if err := ps.RegisterTopicValidator(build.MessagesTopic(nn), v.Validate); err != nil {
		panic(err)
	}

	go sub.HandleIncomingMessages(ctx, mpool, msgsub)
}

func NewLocalDiscovery(lc fx.Lifecycle, ds dtypes.MetadataDS) (*discoveryimpl.Local, error) {
	local, err := discoveryimpl.NewLocal(namespace.Wrap(ds, datastore.NewKey("/deals/local")))
	if err != nil {
		return nil, err
	}
	local.OnReady(marketevents.ReadyLogger("discovery"))
	lc.Append(fx.Hook{
		OnStart: func(ctx context.Context) error {
			return local.Start(ctx)
		},
	})
	return local, nil
}

func RetrievalResolver(l *discoveryimpl.Local) discovery.PeerResolver {
	return discoveryimpl.Multi(l)
}

type RandomBeaconParams struct {
	fx.In

	PubSub      *pubsub.PubSub `optional:"true"`
	Cs          *store.ChainStore
	DrandConfig dtypes.DrandSchedule
}

func BuiltinDrandConfig() dtypes.DrandSchedule {
	return build.DrandConfigSchedule()
}

func RandomSchedule(p RandomBeaconParams, _ dtypes.AfterGenesisSet) (beacon.Schedule, error) {
	gen, err := p.Cs.GetGenesis()
	if err != nil {
		return nil, err
	}

	shd := beacon.Schedule{}
	for _, dc := range p.DrandConfig {
		bc, err := drand.NewDrandBeacon(gen.Timestamp, build.BlockDelaySecs, p.PubSub, dc.Config)
		if err != nil {
			return nil, xerrors.Errorf("creating drand beacon: %w", err)
		}
		shd = append(shd, beacon.BeaconPoint{Start: dc.Start, Beacon: bc})
	}

	return shd, nil
}

func OpenFilesystemJournal(lr repo.LockedRepo, lc fx.Lifecycle, disabled journal.DisabledEvents) (journal.Journal, error) {
	jrnl, err := journal.OpenFSJournal(lr, disabled)
	if err != nil {
		return nil, err
	}

	lc.Append(fx.Hook{
		OnStop: func(_ context.Context) error { return jrnl.Close() },
	})

	return jrnl, err
}