p2p

type Encoder interface {
	Encode(interface{}) error
}

type P2P interface {
	// RequestHeaderByHash request a header given its hash from a peer.
	RequestHeaderByHash(ctx context.Context, peerID peer.ID, hash []byte) (*pb.Header, error)

	// RequestBlockByHash request a block given its header's hash from a peer.
	RequestBlockByHash(ctx context.Context, peerID peer.ID, hash []byte) (*pb.Block, error)

	// RequestHeadersByNumber request a batch of headers within a range in the main branch of a peer.
	RequestHeadersByNumber(ctx context.Context, peerID peer.ID, from, amount uint64) ([]*pb.Header, error)

	// RequestHeadersByNumber request a batch of blocks within a range in the main branch of a peer.
	RequestBlocksByNumber(ctx context.Context, peerID peer.ID, from, amount uint64) ([]*pb.Block, error)

	// RespondHeaderByHash responds to a HeaderRequest.
	RespondHeaderByHash(ctx context.Context, req *pb.HeaderRequest, enc Encoder, chain chain.Reader) error

	// RespondHeadersByNumber responds to a HeadersRequest.
	RespondHeadersByNumber(ctx context.Context, req *pb.HeadersRequest, enc Encoder, c chain.Reader) error

	// RespondBlockByHash responds to a BlockRequest.
	RespondBlockByHash(ctx context.Context, req *pb.BlockRequest, enc Encoder, chain chain.Reader) error

	// RespondBlocksByNumber responds to a BlocksRequest.
	RespondBlocksByNumber(ctx context.Context, req *pb.BlocksRequest, enc Encoder, c chain.Reader) error
}