feat: Add payer reports (#256)

* feat: Add payer reports

* Add missing import

* Sort imports

* Rename fields

* Simplify report structure

Author: neekolas

proto/xmtpv4/envelopes/envelopes.proto

@@ -6,6 +6,7 @@ package xmtp.xmtpv4.envelopes;
 import "identity/associations/association.proto";
 import "identity/associations/signature.proto";
 import "mls/api/v1/mls.proto";
+import "xmtpv4/envelopes/payer_report.proto";
 
 option go_package = "github.com/xmtp/proto/v3/go/xmtpv4/envelopes";
 
@@ -30,6 +31,8 @@ message ClientEnvelope {
     xmtp.mls.api.v1.WelcomeMessageInput welcome_message = 3;
     xmtp.mls.api.v1.UploadKeyPackageRequest upload_key_package = 4;
     xmtp.identity.associations.IdentityUpdate identity_update = 5;
+    PayerReport payer_report = 6;
+    PayerReportAttestation payer_report_attestation = 7;
   }
 }
 

proto/xmtpv4/envelopes/payer_report.proto

@@ -0,0 +1,30 @@
+// Message API for XMTP V4
+syntax = "proto3";
+
+package xmtp.xmtpv4.envelopes;
+
+import "identity/associations/signature.proto";
+
+option go_package = "github.com/xmtp/proto/v3/go/xmtpv4/envelopes";
+
+// A report of the payers and nodes that sent messages in a given range of messages
+message PayerReport {
+  // The originator this report is referring to
+  uint32 originator_node_id = 1;
+  // The sequence_id that the report starts at [exclusive]
+  uint64 start_sequence_id = 2;
+  // The sequence_id that the report ends at [inclusive]
+  uint64 end_sequence_id = 3;
+  // The merkle root of the payer balance diff tree
+  bytes payers_merkle_root = 4;
+  // The node IDs that are active in the network at the time of the report
+  repeated uint32 active_node_ids = 5;
+}
+
+// An attestation of a payer report
+message PayerReportAttestation {
+  // The ID of the report, determined by hashing the report contents
+  bytes report_id = 1;
+  // The signature of the attester
+  xmtp.identity.associations.RecoverableEcdsaSignature signature = 2;
+}