/*
Package core implements the Dms3Node object and related methods.

Packages underneath core/ provide a (relatively) stable, low-level API
to carry out most DMS3-related tasks.  For more details on the other
interfaces and how core/... fits into the bigger DMS3 picture, see:

  $ godoc gitlab.dms3.io/dms3/go-dms3
*/
package core

import (
	"context"
	"io"

	"gitlab.dms3.io/dms3/go-filestore"

	goprocess "github.com/jbenet/goprocess"

	bserv "gitlab.dms3.io/dms3/go-blockservice"
	bstore "gitlab.dms3.io/dms3/go-dms3-blockstore"
	exchange "gitlab.dms3.io/dms3/go-dms3-exchange-interface"
	pin "gitlab.dms3.io/dms3/go-dms3-pinner"
	provider "gitlab.dms3.io/dms3/go-dms3-provider"
	"gitlab.dms3.io/dms3/go-graphsync"
	ld "gitlab.dms3.io/dms3/go-ld-format"
	logging "gitlab.dms3.io/dms3/go-log"
	mfs "gitlab.dms3.io/dms3/go-mfs"
	resolver "gitlab.dms3.io/dms3/go-path/resolver"

	ma "gitlab.dms3.io/mf/go-multiaddr"

	connmgr "gitlab.dms3.io/p2p/go-p2p-core/connmgr"
	ic "gitlab.dms3.io/p2p/go-p2p-core/crypto"
	p2phost "gitlab.dms3.io/p2p/go-p2p-core/host"
	metrics "gitlab.dms3.io/p2p/go-p2p-core/metrics"
	peer "gitlab.dms3.io/p2p/go-p2p-core/peer"
	pstore "gitlab.dms3.io/p2p/go-p2p-core/peerstore"
	routing "gitlab.dms3.io/p2p/go-p2p-core/routing"
	ddht "gitlab.dms3.io/p2p/go-p2p-kad-dht/dual"
	pubsub "gitlab.dms3.io/p2p/go-p2p-pubsub"
	psrouter "gitlab.dms3.io/p2p/go-p2p-pubsub-router"
	record "gitlab.dms3.io/p2p/go-p2p-record"
	"gitlab.dms3.io/p2p/go-p2p/p2p/discovery"
	p2pbhost "gitlab.dms3.io/p2p/go-p2p/p2p/host/basic"

	"gitlab.dms3.io/dms3/go-dms3/core/bootstrap"
	"gitlab.dms3.io/dms3/go-dms3/core/node"
	"gitlab.dms3.io/dms3/go-dms3/core/node/dms3p2p"
	"gitlab.dms3.io/dms3/go-dms3/fuse/mount"
	"gitlab.dms3.io/dms3/go-dms3/namesys"
	dms3nsrp "gitlab.dms3.io/dms3/go-dms3/namesys/republisher"
	"gitlab.dms3.io/dms3/go-dms3/p2p"
	"gitlab.dms3.io/dms3/go-dms3/peering"
	"gitlab.dms3.io/dms3/go-dms3/repo"
)

var log = logging.Logger("core")

// Dms3Node is DMS3 Core module. It represents an DMS3 instance.
type Dms3Node 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              `optional:"true"` // the local node's private Key
	PNetFingerprint dms3p2p.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      `optional:"true"` // the filestore blockstore
	BaseBlocks      node.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             ld.DAGService             // the merkle dag service, get/add objects.
	Resolver        *resolver.Resolver        // the path resolution system
	Reporter        *metrics.BandwidthCounter `optional:"true"`
	Discovery       discovery.Service         `optional:"true"`
	FilesRoot       *mfs.Root
	RecordValidator record.Validator

	// Online
	PeerHost      p2phost.Host            `optional:"true"` // the network host (server+client)
	Peering       peering.PeeringService  `optional:"true"`
	Filters       *ma.Filters             `optional:"true"`
	Bootstrapper  io.Closer               `optional:"true"` // the periodic bootstrapper
	Routing       routing.Routing         `optional:"true"` // the routing system. recommend dms3-dht
	Exchange      exchange.Interface      // the block exchange + strategy (bitswap)
	Namesys       namesys.NameSystem      // the name system, resolves paths to hashes
	Provider      provider.System         // the value provider system
	Dms3NsRepub   *dms3nsrp.Republisher   `optional:"true"`
	GraphExchange graphsync.GraphExchange `optional:"true"`

	PubSub   *pubsub.PubSub             `optional:"true"`
	PSRouter *psrouter.PubsubValueStore `optional:"true"`
	DHT      *ddht.DHT                  `optional:"true"`
	P2P      *p2p.P2P                   `optional:"true"`

	Process goprocess.Process
	ctx     context.Context

	stop func() error

	// 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 {
	Dms3   mount.Mount
	Dms3Ns mount.Mount
}

// Close calls Close() on the App object
func (n *Dms3Node) Close() error {
	return n.stop()
}

// Context returns the Dms3Node context
func (n *Dms3Node) Context() context.Context {
	if n.ctx == nil {
		n.ctx = context.TODO()
	}
	return n.ctx
}

// Bootstrap will set and call the Dms3Nodes bootstrap function.
func (n *Dms3Node) Bootstrap(cfg bootstrap.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() []peer.AddrInfo {
			ps, err := n.loadBootstrapPeers()
			if err != nil {
				log.Warn("failed to parse bootstrap peers from config")
				return nil
			}
			return ps
		}
	}

	var err error
	n.Bootstrapper, err = bootstrap.Bootstrap(n.Identity, n.PeerHost, n.Routing, cfg)
	return err
}

func (n *Dms3Node) loadBootstrapPeers() ([]peer.AddrInfo, error) {
	cfg, err := n.Repo.Config()
	if err != nil {
		return nil, err
	}

	return cfg.BootstrapPeers()
}

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