syntax = "proto3";

package komp_ac.ecb;

// Read-only access to ECB conversion audit evidence.
//
// This service exists for manual visual verification. It exposes conversions
// already recorded by backend posting workflows and never recalculates money.
service EcbService {
  // List immutable ECB conversion evidence for one money value.
  rpc ListEcbConversionEvidence(ListEcbConversionEvidenceRequest)
      returns (ListEcbConversionEvidenceResponse);
}

// Identify one logical money cell whose conversion history should be inspected.
message ListEcbConversionEvidenceRequest {
  // Required. Profile containing the table.
  string profile_name = 1;

  // Required. Logical table name within the profile.
  string table_name = 2;

  // Required. Dynamic table row id.
  int64 record_id = 3;

  // Required. Current display name of the money column. The server resolves it
  // to the stable physical column name used by immutable evidence.
  string column_name = 4;

  // Optional. Maximum rows to return. Zero uses 100; maximum is 500.
  int32 limit = 5;

  // Optional cursor. Return evidence ids lower than this value.
  optional int64 before_evidence_id = 6;
}

// One immutable explanation of how a posted EUR value was determined.
message EcbConversionEvidence {
  int64 evidence_id = 1;
  string original_amount = 2;
  string original_currency = 3;
  string eur_amount = 4;
  string conversion_context = 5;
  string anchor_date = 6;
  string determination_method = 7;
  string rounding_method = 8;
  optional string rate_date = 9;
  optional string units_per_eur = 10;
  optional int64 rate_observation_id = 11;
  optional string observation_hash = 12;
  optional string source_payload_hash = 13;
  optional string rate_fetched_at = 14;
  optional int64 import_batch_id = 15;
  optional string source_endpoint = 16;
  string evidence_created_at = 17;
}

message ListEcbConversionEvidenceResponse {
  // True when at least one evidence row for this cell used an ECB rate.
  bool has_exchange = 1;

  // Newest-first immutable history for this page.
  repeated EcbConversionEvidence evidence = 2;

  // True when another page exists using the last evidence_id as the cursor.
  bool has_more = 3;
}