/*
Package core implements the IpfsNode object and related methods.

Packages underneath core/ provide a (relatively) stable, low-level API
to carry out most IPFS-related tasks.  For more details on the other
interfaces and how core/... fits into the bigger IPFS picture, see:

  $ godoc github.com/ipfs/go-ipfs
*/
package core

import (
	"context"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"strings"
	"time"

	"go.uber.org/fx"

	version "github.com/ipfs/go-ipfs"
	rp "github.com/ipfs/go-ipfs/exchange/reprovide"
	"github.com/ipfs/go-ipfs/filestore"
	"github.com/ipfs/go-ipfs/fuse/mount"
	"github.com/ipfs/go-ipfs/namesys"
	ipnsrp "github.com/ipfs/go-ipfs/namesys/republisher"
	"github.com/ipfs/go-ipfs/p2p"
	"github.com/ipfs/go-ipfs/pin"
	"github.com/ipfs/go-ipfs/provider"
	"github.com/ipfs/go-ipfs/repo"

	bserv "github.com/ipfs/go-blockservice"
	"github.com/ipfs/go-cid"
	ds "github.com/ipfs/go-datastore"
	bstore "github.com/ipfs/go-ipfs-blockstore"
	config "github.com/ipfs/go-ipfs-config"
	exchange "github.com/ipfs/go-ipfs-exchange-interface"
	nilrouting "github.com/ipfs/go-ipfs-routing/none"
	ipld "github.com/ipfs/go-ipld-format"
	logging "github.com/ipfs/go-log"
	"github.com/ipfs/go-merkledag"
	"github.com/ipfs/go-mfs"
	"github.com/ipfs/go-path/resolver"
	ft "github.com/ipfs/go-unixfs"
	"github.com/jbenet/goprocess"
	"github.com/libp2p/go-libp2p"
	autonat "github.com/libp2p/go-libp2p-autonat-svc"
	circuit "github.com/libp2p/go-libp2p-circuit"
	ic "github.com/libp2p/go-libp2p-crypto"
	p2phost "github.com/libp2p/go-libp2p-host"
	ifconnmgr "github.com/libp2p/go-libp2p-interface-connmgr"
	dht "github.com/libp2p/go-libp2p-kad-dht"
	dhtopts "github.com/libp2p/go-libp2p-kad-dht/opts"
	metrics "github.com/libp2p/go-libp2p-metrics"
	peer "github.com/libp2p/go-libp2p-peer"
	pstore "github.com/libp2p/go-libp2p-peerstore"
	pubsub "github.com/libp2p/go-libp2p-pubsub"
	psrouter "github.com/libp2p/go-libp2p-pubsub-router"
	record "github.com/libp2p/go-libp2p-record"
	routing "github.com/libp2p/go-libp2p-routing"
	"github.com/libp2p/go-libp2p/p2p/discovery"
	p2pbhost "github.com/libp2p/go-libp2p/p2p/host/basic"
	"github.com/libp2p/go-libp2p/p2p/protocol/identify"
	mafilter "github.com/libp2p/go-maddr-filter"
	smux "github.com/libp2p/go-stream-muxer"
	ma "github.com/multiformats/go-multiaddr"
	mplex "github.com/whyrusleeping/go-smux-multiplex"
	yamux "github.com/whyrusleeping/go-smux-yamux"
	mamask "github.com/whyrusleeping/multiaddr-filter"
)

const kReprovideFrequency = time.Hour * 12
const discoveryConnTimeout = time.Second * 30
const DefaultIpnsCacheSize = 128

var log = logging.Logger("core")

func init() {
	identify.ClientVersion = "go-ipfs/" + version.CurrentVersionNumber + "/" + version.CurrentCommit
}

// IpfsNode is IPFS Core module. It represents an IPFS instance.
type IpfsNode struct {

	// Self
	Identity peer.ID // the local node's identity

	Repo repo.Repo

	// Local node
	Pinning         pin.Pinner      // the pinning manager
	Mounts          Mounts          `optional:"true"` // current mount state, if any.
	PrivateKey      ic.PrivKey      // the local node's private Key
	PNetFingerprint PNetFingerprint `optional:"true"` // fingerprint of private network

	// Services
	Peerstore       pstore.Peerstore     `optional:"true"` // storage for other Peer instances
	Blockstore      bstore.GCBlockstore  // the block store (lower level)
	Filestore       *filestore.Filestore // the filestore blockstore
	BaseBlocks      BaseBlocks           // the raw blockstore, no filestore wrapping
	GCLocker        bstore.GCLocker      // the locker used to protect the blockstore during gc
	Blocks          bserv.BlockService   // the block service, get/add blocks.
	DAG             ipld.DAGService      // the merkle dag service, get/add objects.
	Resolver        *resolver.Resolver   // the path resolution system
	Reporter        metrics.Reporter     `optional:"true"`
	Discovery       discovery.Service    `optional:"true"`
	FilesRoot       *mfs.Root
	RecordValidator record.Validator

	// Online
	PeerHost     p2phost.Host        `optional:"true"` // the network host (server+client)
	Bootstrapper io.Closer           `optional:"true"` // the periodic bootstrapper
	Routing      routing.IpfsRouting `optional:"true"` // the routing system. recommend ipfs-dht
	Exchange     exchange.Interface  // the block exchange + strategy (bitswap)
	Namesys      namesys.NameSystem  // the name system, resolves paths to hashes
	Provider     provider.Provider   // the value provider system
	Reprovider   *rp.Reprovider      `optional:"true"` // the value reprovider system
	IpnsRepub    *ipnsrp.Republisher `optional:"true"`

	AutoNAT  *autonat.AutoNATService    `optional:"true"`
	PubSub   *pubsub.PubSub             `optional:"true"`
	PSRouter *psrouter.PubsubValueStore `optional:"true"`
	DHT      *dht.IpfsDHT               `optional:"true"`
	P2P      *p2p.P2P                   `optional:"true"`

	Process goprocess.Process
	ctx     context.Context

	app *fx.App

	// Flags
	IsOnline bool `optional:"true"` // Online is set when networking is enabled.
	IsDaemon bool `optional:"true"` // Daemon is set when running on a long-running daemon.
}

// Mounts defines what the node's mount state is. This should
// perhaps be moved to the daemon or mount. It's here because
// it needs to be accessible across daemon requests.
type Mounts struct {
	Ipfs mount.Mount
	Ipns mount.Mount
}

func makeAddrsFactory(cfg config.Addresses) (p2pbhost.AddrsFactory, error) {
	var annAddrs []ma.Multiaddr
	for _, addr := range cfg.Announce {
		maddr, err := ma.NewMultiaddr(addr)
		if err != nil {
			return nil, err
		}
		annAddrs = append(annAddrs, maddr)
	}

	filters := mafilter.NewFilters()
	noAnnAddrs := map[string]bool{}
	for _, addr := range cfg.NoAnnounce {
		f, err := mamask.NewMask(addr)
		if err == nil {
			filters.AddDialFilter(f)
			continue
		}
		maddr, err := ma.NewMultiaddr(addr)
		if err != nil {
			return nil, err
		}
		noAnnAddrs[maddr.String()] = true
	}

	return func(allAddrs []ma.Multiaddr) []ma.Multiaddr {
		var addrs []ma.Multiaddr
		if len(annAddrs) > 0 {
			addrs = annAddrs
		} else {
			addrs = allAddrs
		}

		var out []ma.Multiaddr
		for _, maddr := range addrs {
			// check for exact matches
			ok := noAnnAddrs[maddr.String()]
			// check for /ipcidr matches
			if !ok && !filters.AddrBlocked(maddr) {
				out = append(out, maddr)
			}
		}
		return out
	}, nil
}

func makeSmuxTransportOption(mplexExp bool) libp2p.Option {
	const yamuxID = "/yamux/1.0.0"
	const mplexID = "/mplex/6.7.0"

	ymxtpt := &yamux.Transport{
		AcceptBacklog:          512,
		ConnectionWriteTimeout: time.Second * 10,
		KeepAliveInterval:      time.Second * 30,
		EnableKeepAlive:        true,
		MaxStreamWindowSize:    uint32(16 * 1024 * 1024), // 16MiB
		LogOutput:              ioutil.Discard,
	}

	if os.Getenv("YAMUX_DEBUG") != "" {
		ymxtpt.LogOutput = os.Stderr
	}

	muxers := map[string]smux.Transport{yamuxID: ymxtpt}
	if mplexExp {
		muxers[mplexID] = mplex.DefaultTransport
	}

	// Allow muxer preference order overriding
	order := []string{yamuxID, mplexID}
	if prefs := os.Getenv("LIBP2P_MUX_PREFS"); prefs != "" {
		order = strings.Fields(prefs)
	}

	opts := make([]libp2p.Option, 0, len(order))
	for _, id := range order {
		tpt, ok := muxers[id]
		if !ok {
			log.Warning("unknown or duplicate muxer in LIBP2P_MUX_PREFS: %s", id)
			continue
		}
		delete(muxers, id)
		opts = append(opts, libp2p.Muxer(id, tpt))
	}

	return libp2p.ChainOptions(opts...)
}

// Close calls Close() on the App object
func (n *IpfsNode) Close() error {
	return n.app.Stop(n.ctx)
}

// Context returns the IpfsNode context
func (n *IpfsNode) Context() context.Context {
	if n.ctx == nil {
		n.ctx = context.TODO()
	}
	return n.ctx
}

// Bootstrap will set and call the IpfsNodes bootstrap function.
func (n *IpfsNode) Bootstrap(cfg BootstrapConfig) error {
	// TODO what should return value be when in offlineMode?
	if n.Routing == nil {
		return nil
	}

	if n.Bootstrapper != nil {
		n.Bootstrapper.Close() // stop previous bootstrap process.
	}

	// if the caller did not specify a bootstrap peer function, get the
	// freshest bootstrap peers from config. this responds to live changes.
	if cfg.BootstrapPeers == nil {
		cfg.BootstrapPeers = func() []pstore.PeerInfo {
			ps, err := n.loadBootstrapPeers()
			if err != nil {
				log.Warning("failed to parse bootstrap peers from config")
				return nil
			}
			return ps
		}
	}

	var err error
	n.Bootstrapper, err = Bootstrap(n, cfg)
	return err
}

func (n *IpfsNode) loadBootstrapPeers() ([]pstore.PeerInfo, error) {
	cfg, err := n.Repo.Config()
	if err != nil {
		return nil, err
	}

	parsed, err := cfg.BootstrapPeers()
	if err != nil {
		return nil, err
	}
	return toPeerInfos(parsed), nil
}

func listenAddresses(cfg *config.Config) ([]ma.Multiaddr, error) {
	var listen []ma.Multiaddr
	for _, addr := range cfg.Addresses.Swarm {
		maddr, err := ma.NewMultiaddr(addr)
		if err != nil {
			return nil, fmt.Errorf("failure to parse config.Addresses.Swarm: %s", cfg.Addresses.Swarm)
		}
		listen = append(listen, maddr)
	}

	return listen, nil
}

type ConstructPeerHostOpts struct {
	AddrsFactory      p2pbhost.AddrsFactory
	DisableNatPortMap bool
	DisableRelay      bool
	EnableRelayHop    bool
	ConnectionManager ifconnmgr.ConnManager
}

type HostOption func(ctx context.Context, id peer.ID, ps pstore.Peerstore, options ...libp2p.Option) (p2phost.Host, error)

var DefaultHostOption HostOption = constructPeerHost

// isolates the complex initialization steps
func constructPeerHost(ctx context.Context, id peer.ID, ps pstore.Peerstore, options ...libp2p.Option) (p2phost.Host, error) {
	pkey := ps.PrivKey(id)
	if pkey == nil {
		return nil, fmt.Errorf("missing private key for node ID: %s", id.Pretty())
	}
	options = append([]libp2p.Option{libp2p.Identity(pkey), libp2p.Peerstore(ps)}, options...)
	return libp2p.New(ctx, options...)
}

func filterRelayAddrs(addrs []ma.Multiaddr) []ma.Multiaddr {
	var raddrs []ma.Multiaddr
	for _, addr := range addrs {
		_, err := addr.ValueForProtocol(circuit.P_CIRCUIT)
		if err == nil {
			continue
		}
		raddrs = append(raddrs, addr)
	}
	return raddrs
}

func composeAddrsFactory(f, g p2pbhost.AddrsFactory) p2pbhost.AddrsFactory {
	return func(addrs []ma.Multiaddr) []ma.Multiaddr {
		return f(g(addrs))
	}
}

// startListening on the network addresses
func startListening(host p2phost.Host, cfg *config.Config) error {
	listenAddrs, err := listenAddresses(cfg)
	if err != nil {
		return err
	}

	// Actually start listening:
	if err := host.Network().Listen(listenAddrs...); err != nil {
		return err
	}

	// list out our addresses
	addrs, err := host.Network().InterfaceListenAddresses()
	if err != nil {
		return err
	}
	log.Infof("Swarm listening at: %s", addrs)
	return nil
}

func constructDHTRouting(ctx context.Context, host p2phost.Host, dstore ds.Batching, validator record.Validator) (routing.IpfsRouting, error) {
	return dht.New(
		ctx, host,
		dhtopts.Datastore(dstore),
		dhtopts.Validator(validator),
	)
}

func constructClientDHTRouting(ctx context.Context, host p2phost.Host, dstore ds.Batching, validator record.Validator) (routing.IpfsRouting, error) {
	return dht.New(
		ctx, host,
		dhtopts.Client(true),
		dhtopts.Datastore(dstore),
		dhtopts.Validator(validator),
	)
}

type RoutingOption func(context.Context, p2phost.Host, ds.Batching, record.Validator) (routing.IpfsRouting, error)

type DiscoveryOption func(context.Context, p2phost.Host) (discovery.Service, error)

var DHTOption RoutingOption = constructDHTRouting
var DHTClientOption RoutingOption = constructClientDHTRouting
var NilRouterOption RoutingOption = nilrouting.ConstructNilRouting