From d5c9b338a44c2082d2343acfaf1d1eaf809983eb7bdc9b70e426feb4bc3be291 Mon Sep 17 00:00:00 2001
From: nfel <nfilsaraee@gmail.com>
Date: Sat, 29 Aug 2026 16:32:40 +0330
Subject: [PATCH] feat(gl): compare external settlement evidence

---
 application/reconciliation/evidence.go      | 85 +++++++++++++++++++++
 application/reconciliation/evidence_test.go | 39 ++++++++++
 application/reconciliation/service.go       |  2 +-
 3 files changed, 125 insertions(+), 1 deletion(-)
 create mode 100644 application/reconciliation/evidence.go
 create mode 100644 application/reconciliation/evidence_test.go

diff --git a/application/reconciliation/evidence.go b/application/reconciliation/evidence.go
new file mode 100644
index 0000000..4192259
--- /dev/null
+++ b/application/reconciliation/evidence.go
@@ -0,0 +1,85 @@
+package reconciliation
+
+import (
+	"context"
+	"fmt"
+
+	"gl/domain/ledger"
+)
+
+// Evidence is a normalized record supplied by Wallet, Kuknos, or another
+// authoritative settlement source. Adapters remain outside the GL domain.
+type Evidence struct {
+	SourceService       string
+	SourceTransactionID string
+	EventVersion        uint32
+	BlockchainNetwork   string
+	TransactionHash     string
+}
+
+type EvidenceReport struct {
+	Compared   int
+	Missing    []Evidence
+	Duplicates []Evidence
+	Mismatched []EvidenceMismatch
+}
+
+type EvidenceMismatch struct {
+	Evidence  Evidence
+	JournalID string
+	Field     string
+	Expected  string
+	Actual    string
+}
+
+// CompareEvidence compares normalized external evidence with immutable GL
+// journals. It is read-only and safe to run repeatedly after outages.
+func CompareEvidence(ctx context.Context, repository Repository, evidence []Evidence, pageSize int) (EvidenceReport, error) {
+	if repository == nil {
+		return EvidenceReport{}, fmt.Errorf("reconciliation repository is required")
+	}
+	if pageSize <= 0 || pageSize > 200 {
+		pageSize = 100
+	}
+	journals := make(map[string]ledger.Journal)
+	for offset := 0; ; offset += pageSize {
+		page, err := repository.List(ctx, ledger.JournalFilter{Limit: pageSize, Offset: offset})
+		if err != nil {
+			return EvidenceReport{}, fmt.Errorf("list journals at offset %d: %w", offset, err)
+		}
+		for _, journal := range page {
+			journals[evidenceKey(journal.SourceService, journal.SourceTransactionID, journal.EventVersion)] = journal
+		}
+		if len(page) < pageSize {
+			break
+		}
+	}
+
+	report := EvidenceReport{Missing: make([]Evidence, 0), Duplicates: make([]Evidence, 0), Mismatched: make([]EvidenceMismatch, 0)}
+	seen := make(map[string]struct{}, len(evidence))
+	for _, item := range evidence {
+		report.Compared++
+		key := evidenceKey(item.SourceService, item.SourceTransactionID, item.EventVersion)
+		if _, exists := seen[key]; exists {
+			report.Duplicates = append(report.Duplicates, item)
+			continue
+		}
+		seen[key] = struct{}{}
+		journal, exists := journals[key]
+		if !exists {
+			report.Missing = append(report.Missing, item)
+			continue
+		}
+		if item.BlockchainNetwork != "" && item.BlockchainNetwork != journal.Blockchain.Network {
+			report.Mismatched = append(report.Mismatched, EvidenceMismatch{Evidence: item, JournalID: journal.ID, Field: "blockchain_network", Expected: item.BlockchainNetwork, Actual: journal.Blockchain.Network})
+		}
+		if item.TransactionHash != "" && item.TransactionHash != journal.Blockchain.TransactionHash {
+			report.Mismatched = append(report.Mismatched, EvidenceMismatch{Evidence: item, JournalID: journal.ID, Field: "transaction_hash", Expected: item.TransactionHash, Actual: journal.Blockchain.TransactionHash})
+		}
+	}
+	return report, nil
+}
+
+func evidenceKey(sourceService, sourceTransactionID string, eventVersion uint32) string {
+	return sourceService + "\x00" + sourceTransactionID + "\x00" + fmt.Sprint(eventVersion)
+}
diff --git a/application/reconciliation/evidence_test.go b/application/reconciliation/evidence_test.go
new file mode 100644
index 0000000..6884870
--- /dev/null
+++ b/application/reconciliation/evidence_test.go
@@ -0,0 +1,39 @@
+package reconciliation
+
+import (
+	"context"
+	"testing"
+
+	"gl/domain/ledger"
+)
+
+func TestCompareEvidenceReportsMissingDuplicateAndBlockchainMismatch(t *testing.T) {
+	journal := validJournal()
+	journal.Blockchain = ledger.BlockchainReference{Network: "kuknos", TransactionHash: "hash-1"}
+	matching := Evidence{SourceService: "wallet", SourceTransactionID: "t1", EventVersion: 1, BlockchainNetwork: "kuknos", TransactionHash: "hash-1"}
+	evidence := []Evidence{
+		matching,
+		matching,
+		{SourceService: "wallet", SourceTransactionID: "missing", EventVersion: 1},
+		{SourceService: "wallet", SourceTransactionID: "t1", EventVersion: 1, BlockchainNetwork: "kuknos", TransactionHash: "wrong"},
+	}
+	report, err := CompareEvidence(context.Background(), repositoryStub{pages: [][]ledger.Journal{{journal}}}, evidence, 10)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if report.Compared != 4 || len(report.Missing) != 1 || len(report.Duplicates) != 2 || len(report.Mismatched) != 0 {
+		t.Fatalf("unexpected report: %+v", report)
+	}
+}
+
+func TestCompareEvidenceReportsHashMismatch(t *testing.T) {
+	journal := validJournal()
+	journal.Blockchain.TransactionHash = "actual"
+	report, err := CompareEvidence(context.Background(), repositoryStub{pages: [][]ledger.Journal{{journal}}}, []Evidence{{SourceService: "wallet", SourceTransactionID: "t1", EventVersion: 1, TransactionHash: "expected"}}, 10)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(report.Mismatched) != 1 || report.Mismatched[0].Field != "transaction_hash" {
+		t.Fatalf("unexpected report: %+v", report)
+	}
+}
diff --git a/application/reconciliation/service.go b/application/reconciliation/service.go
index 875442a..7b635de 100644
--- a/application/reconciliation/service.go
+++ b/application/reconciliation/service.go
@@ -44,7 +44,7 @@ func Run(ctx context.Context, repository Repository, pageSize int) (Report, erro
 				report.Invalid = append(report.Invalid, Issue{JournalID: journal.ID, Error: err.Error()})
 				continue
 			}
-			key := journal.SourceService + "\x00" + journal.SourceTransactionID + "\x00" + fmt.Sprint(journal.EventVersion)
+			key := evidenceKey(journal.SourceService, journal.SourceTransactionID, journal.EventVersion)
 			if previous, exists := seen[key]; exists {
 				report.Invalid = append(report.Invalid, Issue{JournalID: journal.ID, Error: fmt.Sprintf("duplicate source transaction/version; first journal %s", previous)})
 				continue