fraud

type Broadcaster[H header.Header[H]] interface {
	// Broadcast takes a fraud `Proof` data structure interface and broadcasts it to local
	// subscriptions and peers. It may additionally cache/persist Proofs for future
	// access via Getter and to serve Proof requests to peers in the network.
	Broadcast(context.Context, Proof[H]) error
}

type ErrFraudExists[H header.Header[H]] struct {
	Proof []Proof[H]
}

type ErrNoUnmarshaler struct {
	ProofType ProofType
}

type Getter[H header.Header[H]] interface {
	// Get fetches fraud proofs from the disk by its type.
	Get(context.Context, ProofType) ([]Proof[H], error)
}

type HeadGetter[H header.Header[H]] func(ctx context.Context) (H, error)

type HeaderFetcher[H header.Header[H]] func(context.Context, uint64) (H, error)

type MultiUnmarshaler[H header.Header[H]] struct {
	Unmarshalers map[ProofType]func([]byte) (Proof[H], error)
}

type Proof[H header.Header[H]] interface {
	// Type returns the exact type of fraud proof.
	Type() ProofType
	// HeaderHash returns the block hash.
	HeaderHash() []byte
	// Height returns the block height corresponding to the Proof.
	Height() uint64
	// Validate check the validity of fraud proof.
	// Validate throws an error if some conditions don't pass and thus fraud proof is not valid.
	// NOTE: header.ExtendedHeader should pass basic validation otherwise it will panic if it's
	// malformed.
	Validate(H) error

	encoding.BinaryMarshaler
	encoding.BinaryUnmarshaler
}

type ProofType string

type ProofUnmarshaler[H header.Header[H]] interface {
	// List supported ProofTypes.
	List() []ProofType
	// Unmarshal decodes bytes into a Proof of a given ProofType.
	Unmarshal(ProofType, []byte) (Proof[H], error)
}

type Service[H header.Header[H]] interface {
	Subscriber[H]
	Broadcaster[H]
	Getter[H]
}

type Subscriber[H header.Header[H]] interface {
	// Subscribe allows to subscribe on a Proof pub sub topic by its type.
	Subscribe(ProofType) (Subscription[H], error)
	// AddVerifier allows for supplying additional verification logic which
	// will be run as part of processing the incoming fraud proof.
	// This only supplements the main validation done by Proof.Validate
	AddVerifier(ProofType, Verifier[H]) error
}

type Subscription[H header.Header[H]] interface {
	// Proof returns already verified valid proof.
	Proof(context.Context) (Proof[H], error)
	Cancel()
}

type Verifier[H header.Header[H]] func(fraud Proof[H]) (bool, error)