exchange

type BSTipSet struct {
	// List of blocks belonging to a single tipset to which the
	// `CompactedMessages` are linked.
	Blocks   []*types.BlockHeader
	Messages *CompactedMessages
}

type Client interface {
	// GetBlocks fetches block headers from the network, from the provided
	// tipset *backwards*, returning as many tipsets as the count parameter,
	// or less.
	GetBlocks(ctx context.Context, tsk types.TipSetKey, count int) ([]*types.TipSet, error)

	// GetChainMessages fetches messages from the network, starting from the first provided tipset
	// and returning messages from as many tipsets as requested or less.
	GetChainMessages(ctx context.Context, tipsets []*types.TipSet) ([]*CompactedMessages, error)

	// GetFullTipSet fetches a full tipset from a given peer. If successful,
	// the fetched object contains block headers and all messages in full form.
	GetFullTipSet(ctx context.Context, peer peer.ID, tsk types.TipSetKey) (*types.FullTipSet, error)

	// AddPeer adds a peer to the pool of peers that the Client requests
	// data from.
	AddPeer(ctx context.Context, peer peer.ID)

	// RemovePeer removes a peer from the pool of peers that the Client
	// requests data from.
	RemovePeer(ctx context.Context, peer peer.ID)
}

type CompactedMessages struct {
	Bls         []*types.Message
	BlsIncludes [][]uint64

	Secpk         []*types.SignedMessage
	SecpkIncludes [][]uint64
}

type CompactedMessagesCBOR struct {
	Bls         []*types.Message `cborgen:"maxlen=150000"`
	BlsIncludes []messageIndices

	Secpk         []*types.SignedMessage `cborgen:"maxlen=150000"`
	SecpkIncludes []messageIndices
}

type Options struct {
	IncludeHeaders  bool
	IncludeMessages bool
}

type Request struct {
	// List of ordered CIDs comprising a `TipSetKey` from where to start
	// fetching backwards.
	// FIXME: Consider using `TipSetKey` now (introduced after the creation
	//  of this protocol) instead of converting back and forth.
	Head []cid.Cid
	// Number of block sets to fetch from `Head` (inclusive, should always
	// be in the range `[1, MaxRequestLength]`).
	Length uint64
	// Request options, see `Options` type for more details. Compressed
	// in a single `uint64` to save space.
	Options uint64
}

type Response struct {
	Status status
	// String that complements the error status when converting to an
	// internal error (see `statusToError()`).
	ErrorMessage string

	Chain []*BSTipSet
}