syntax = "proto3";

package ethereum.beacon.rpc.v1;

import "google/protobuf/empty.proto";
import "eth/v1alpha1/beacon_block.proto";

// Slasher service API
// 
// Slasher service provides an interface for validators and beacon chain server to query
// and subscribe for slashable events on the network as well as to make sure that the 
// attestation or proposal they are going to submit to the network are not going to 
// produce a slashable event.
service Slasher {
    // Gets AttesterSlashing container if the attestation that 
    // was received produces a slashable event.
    rpc IsSlashableAttestation(ethereum.eth.v1alpha1.IndexedAttestation) returns (AttesterSlashingResponse);

    // Gets ProposerSlashing container if the block header that 
    // was received produces a slashable event.
    rpc IsSlashableBlock(ProposerSlashingRequest) returns (ProposerSlashingResponse);

    // Subscription to receive all slashable proposer slashing events found by the watchtower.
    rpc SlashableProposals(google.protobuf.Empty) returns (stream ethereum.eth.v1alpha1.ProposerSlashing);
    
    // Subscription to receive all slashable attester slashing events found by the watchtower.
    rpc SlashableAttestations(google.protobuf.Empty) returns (stream ethereum.eth.v1alpha1.AttesterSlashing);
}

message ValidatorIDToIdxAtt {
    repeated uint64 indices = 1 ;
    bytes data_root = 2;
    // 96 bytes aggregate signature.
    bytes signature = 3;
}

message ValidatorIDToIdxAttList {
    repeated ValidatorIDToIdxAtt indicesList = 1 ;
}

message ProposerSlashingRequest {
    ethereum.eth.v1alpha1.BeaconBlockHeader block_header = 1;
    uint64 validator_index = 2;
}

message ProposerSlashingResponse {
    repeated ethereum.eth.v1alpha1.ProposerSlashing proposer_slashing = 1;
}

message AttesterSlashingResponse {
    repeated ethereum.eth.v1alpha1.AttesterSlashing attester_slashing = 1;
}

// In order to detect surrounded attestation we need to compare
// each attestation source to those spans
// see https://github.com/protolambda/eth2-surround/blob/master/README.md#min-max-surround
// for further details.
message MinMaxEpochSpan {
    uint32 min_epoch_span = 1;
    uint32 max_epoch_span = 2;
}

// Every validator will have their own spans map containing min distance from each epoch
// to the closest target epoch of another attestation (surrounded) and max distance to
// a target attestation (surrounding), in order to detect slashable attestation as quickly
// as possible.
message EpochSpanMap {
    // uint64 is for storing the epoch
    map<uint64, MinMaxEpochSpan> epoch_span_map = 1;
}