package corerouting

import (
	"errors"

	ds "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-datastore"
	context "github.com/ipfs/go-ipfs/Godeps/_workspace/src/golang.org/x/net/context"
	core "github.com/ipfs/go-ipfs/core"
	"github.com/ipfs/go-ipfs/p2p/host"
	"github.com/ipfs/go-ipfs/p2p/peer"
	routing "github.com/ipfs/go-ipfs/routing"
	supernode "github.com/ipfs/go-ipfs/routing/supernode"
	gcproxy "github.com/ipfs/go-ipfs/routing/supernode/proxy"
)

// NB: DHT option is included in the core to avoid 1) because it's a sane
// default and 2) to avoid a circular dependency (it needs to be referenced in
// the core if it's going to be the default)

var (
	errHostMissing      = errors.New("supernode routing client requires a Host component")
	errIdentityMissing  = errors.New("supernode routing server requires a peer ID identity")
	errPeerstoreMissing = errors.New("supernode routing server requires a peerstore")
	errServersMissing   = errors.New("supernode routing client requires at least 1 server peer")
)

// SupernodeServer returns a configuration for a routing server that stores
// routing records to the provided datastore. Only routing records are store in
// the datastore.
func SupernodeServer(recordSource ds.ThreadSafeDatastore) core.RoutingOption {
	return func(ctx context.Context, ph host.Host, dstore ds.ThreadSafeDatastore) (routing.IpfsRouting, error) {
		server, err := supernode.NewServer(recordSource, ph.Peerstore(), ph.ID())
		if err != nil {
			return nil, err
		}
		proxy := &gcproxy.Loopback{
			Handler: server,
			Local:   ph.ID(),
		}
		ph.SetStreamHandler(gcproxy.ProtocolSNR, proxy.HandleStream)
		return supernode.NewClient(proxy, ph, ph.Peerstore(), ph.ID())
	}
}

// TODO doc
func SupernodeClient(remotes ...peer.PeerInfo) core.RoutingOption {
	return func(ctx context.Context, ph host.Host, dstore ds.ThreadSafeDatastore) (routing.IpfsRouting, error) {
		if len(remotes) < 1 {
			return nil, errServersMissing
		}

		proxy := gcproxy.Standard(ph, remotes)
		ph.SetStreamHandler(gcproxy.ProtocolSNR, proxy.HandleStream)
		return supernode.NewClient(proxy, ph, ph.Peerstore(), ph.ID())
	}
}
