xchain

type Attestation struct {
	BlockHeader                 // BlockHeader identifies the cross-chain Block
	ValidatorSetID  uint64      // Validator set that approved this attestation.
	AttestationRoot common.Hash // Attestation merkle root of the cross-chain Block
	Signatures      []SigTuple  // Validator signatures and public keys
}

type Block struct {
	BlockHeader
	Msgs      []Msg     // All cross-chain messages sent/emittted in the block
	Receipts  []Receipt // Receipts of all submitted cross-chain messages applied in the block
	Timestamp time.Time // Timestamp of the source chain block
}

type BlockHeader struct {
	SourceChainID uint64      // Source chain ID as per https://chainlist.org
	BlockHeight   uint64      // Height of the source chain block
	BlockHash     common.Hash // Hash of the source chain block
}

type BlockTree [][32]byte

type Msg struct {
	MsgID                          // Unique ID of the message
	SourceMsgSender common.Address // Sender on source chain, set to msg.Sender
	DestAddress     common.Address // Target/To address to "call" on destination chain
	Data            []byte         // Data to provide to "call" on destination chain
	DestGasLimit    uint64         // Gas limit to use for "call" on destination chain
	TxHash          common.Hash    // Hash of the source chain transaction that emitted the message
}

type MsgID struct {
	StreamID            // Unique ID of the Stream this message belongs to
	StreamOffset uint64 // Monotonically incremented offset of Msg in the Steam
}

type Provider interface {
	// StreamAsync starts a goroutine that streams xblocks forever from the provided source chain and height (inclusive).
	// It returns immediately. It only returns an error if the chainID in invalid.
	// This is the async version of StreamBlocks.
	// It retries forever (with backoff) on all fetch and callback errors.
	StreamAsync(ctx context.Context, chainID uint64, fromHeight uint64, callback ProviderCallback) error

	// StreamBlocks is the synchronous fail-fast version of Subscribe. It streams
	// xblocks as they become available but returns on the first callback error.
	// This is useful for workers that need to reset on application errors.
	StreamBlocks(ctx context.Context, chainID uint64, fromHeight uint64, callback ProviderCallback) error

	// GetBlock returns the block for the given chain and height, or false if not available (not finalized yet),
	// or an error.
	GetBlock(ctx context.Context, chainID uint64, height uint64) (Block, bool, error)

	// GetSubmittedCursor returns the submitted cursor for the source chain on the destination chain,
	// or false if not available, or an error. Calls the destination chain portal InXStreamOffset method.
	// Note this is only supported for EVM chains, no the consensus chain.
	GetSubmittedCursor(ctx context.Context, destChainID uint64, sourceChainID uint64) (StreamCursor, bool, error)

	// GetEmittedCursor returns the emitted cursor for the destination chain on the source chain,
	// or false if not available, or an error. Calls the source chain portal OutXStreamOffset method.
	// Note this is only supported for EVM chains, no the consensus chain.
	GetEmittedCursor(ctx context.Context, srcChainID uint64, destChainID uint64) (StreamCursor, bool, error)
}

type ProviderCallback func(context.Context, Block) error

type Receipt struct {
	MsgID                         // Unique ID of the cross chain message that was applied.
	GasUsed        uint64         // Gas used during message "call"
	Success        bool           // Result, true for success, false for revert
	RelayerAddress common.Address // Address of relayer that submitted the message
	TxHash         common.Hash    // Hash of the relayer submission transaction
}

type SigTuple struct {
	ValidatorAddress common.Address // Validator Ethereum address
	Signature        Signature65    // Validator signature over XBlockRoot; Ethereum 65 bytes [R || S || V] format.
}

type Signature65 [65]byte

type StreamCursor struct {
	StreamID                 // Stream ID of the Stream this cursor belongs to
	Offset            uint64 // Latest applied Msg offset of the Stream
	SourceBlockHeight uint64 // Height of the source chain block
}

type StreamID struct {
	SourceChainID uint64 // Source chain ID as per https://chainlist.org/
	DestChainID   uint64 // Destination chain ID as per https://chainlist.org/
}

type Submission struct {
	AttestationRoot common.Hash // Attestation merkle root of the cross-chain Block
	ValidatorSetID  uint64      // Validator set that approved the attestation.
	BlockHeader     BlockHeader // BlockHeader identifies the cross-chain Block
	Msgs            []Msg       // Messages to be submitted
	Proof           [][32]byte  // Merkle multi proofs of the messages
	ProofFlags      []bool      // Flags indicating whether the proof is a left or right proof
	Signatures      []SigTuple  // Validator signatures and public keys
	DestChainID     uint64      // Destination chain ID, for internal use only
}

type Vote struct {
	BlockHeader                 // BlockHeader identifies the cross-chain Block
	AttestationRoot common.Hash // Attestation merkle root of the cross-chain Block
	Signature       SigTuple    // Validator signature and public key
}