feat: add receive message reconciliation helper

internal/isphere/message_reconciliation.go

@@ -0,0 +1,104 @@
+package isphere
+
+import "math"
+
+const reconciliationMediumTimestampWindowMillis int64 = 3000
+
+type MessageReconciliationCandidate struct {
+	Source             string
+	MessageID          string
+	ConversationID     string
+	SenderID           string
+	TimestampUnixMilli int64
+	BodyPresent        bool
+	AttachmentPresent  bool
+}
+
+type MessageReconciliationSummary struct {
+	LeftCount            int
+	RightCount           int
+	StrongMatches        int
+	MediumMatches        int
+	UnmatchedLeft        int
+	UnmatchedRight       int
+	AutoMergeRecommended bool
+}
+
+func ReconcileMessageSources(left, right []MessageReconciliationCandidate) MessageReconciliationSummary {
+	matchedLeft := make([]bool, len(left))
+	matchedRight := make([]bool, len(right))
+	summary := MessageReconciliationSummary{LeftCount: len(left), RightCount: len(right)}
+
+	for leftIndex, leftCandidate := range left {
+		if leftCandidate.MessageID == "" {
+			continue
+		}
+		for rightIndex, rightCandidate := range right {
+			if matchedRight[rightIndex] || rightCandidate.MessageID == "" {
+				continue
+			}
+			if leftCandidate.MessageID == rightCandidate.MessageID {
+				matchedLeft[leftIndex] = true
+				matchedRight[rightIndex] = true
+				summary.StrongMatches++
+				break
+			}
+		}
+	}
+
+	for leftIndex, leftCandidate := range left {
+		if matchedLeft[leftIndex] {
+			continue
+		}
+		for rightIndex, rightCandidate := range right {
+			if matchedRight[rightIndex] {
+				continue
+			}
+			if isMediumMessageMatch(leftCandidate, rightCandidate) {
+				matchedLeft[leftIndex] = true
+				matchedRight[rightIndex] = true
+				summary.MediumMatches++
+				break
+			}
+		}
+	}
+
+	summary.UnmatchedLeft = countFalse(matchedLeft)
+	summary.UnmatchedRight = countFalse(matchedRight)
+	summary.AutoMergeRecommended = shouldRecommendAutoMerge(summary)
+	return summary
+}
+
+func isMediumMessageMatch(left, right MessageReconciliationCandidate) bool {
+	if left.ConversationID == "" || right.ConversationID == "" || left.ConversationID != right.ConversationID {
+		return false
+	}
+	if left.SenderID == "" || right.SenderID == "" || left.SenderID != right.SenderID {
+		return false
+	}
+	if left.TimestampUnixMilli <= 0 || right.TimestampUnixMilli <= 0 {
+		return false
+	}
+	delta := int64(math.Abs(float64(left.TimestampUnixMilli - right.TimestampUnixMilli)))
+	return delta <= reconciliationMediumTimestampWindowMillis
+}
+
+func countFalse(values []bool) int {
+	count := 0
+	for _, value := range values {
+		if !value {
+			count++
+		}
+	}
+	return count
+}
+
+func shouldRecommendAutoMerge(summary MessageReconciliationSummary) bool {
+	if summary.LeftCount == 0 || summary.RightCount == 0 {
+		return false
+	}
+	if summary.UnmatchedLeft != 0 || summary.UnmatchedRight != 0 || summary.MediumMatches != 0 {
+		return false
+	}
+	return summary.StrongMatches == summary.LeftCount && summary.StrongMatches == summary.RightCount
+}

internal/isphere/message_reconciliation_test.go

@@ -0,0 +1,57 @@
+package isphere
+
+import "testing"
+
+func TestReconcileMessageSourcesStrongAndMediumMatches(t *testing.T) {
+	left := []MessageReconciliationCandidate{
+		{Source: "packetlog", MessageID: "same-1", ConversationID: "conv-a", SenderID: "alice", TimestampUnixMilli: 1000, BodyPresent: true},
+		{Source: "packetlog", MessageID: "left-2", ConversationID: "conv-b", SenderID: "bob", TimestampUnixMilli: 100000, BodyPresent: true},
+		{Source: "packetlog", MessageID: "left-3", ConversationID: "conv-c", SenderID: "carol", TimestampUnixMilli: 200000, AttachmentPresent: true},
+	}
+	right := []MessageReconciliationCandidate{
+		{Source: "msglib", MessageID: "same-1", ConversationID: "conv-a", SenderID: "alice", TimestampUnixMilli: 900, BodyPresent: true},
+		{Source: "msglib", MessageID: "right-2", ConversationID: "conv-b", SenderID: "bob", TimestampUnixMilli: 102500, BodyPresent: true},
+		{Source: "msglib", MessageID: "right-4", ConversationID: "conv-d", SenderID: "dave", TimestampUnixMilli: 300000, AttachmentPresent: true},
+	}
+
+	summary := ReconcileMessageSources(left, right)
+
+	if summary.LeftCount != 3 || summary.RightCount != 3 {
+		t.Fatalf("counts = %d/%d", summary.LeftCount, summary.RightCount)
+	}
+	if summary.StrongMatches != 1 {
+		t.Fatalf("strong matches = %d, want 1", summary.StrongMatches)
+	}
+	if summary.MediumMatches != 1 {
+		t.Fatalf("medium matches = %d, want 1", summary.MediumMatches)
+	}
+	if summary.UnmatchedLeft != 1 || summary.UnmatchedRight != 1 {
+		t.Fatalf("unmatched = %d/%d, want 1/1", summary.UnmatchedLeft, summary.UnmatchedRight)
+	}
+	if summary.AutoMergeRecommended {
+		t.Fatalf("auto merge should remain false with weak coverage: %+v", summary)
+	}
+}
+
+func TestReconcileMessageSourcesAutoMergeRecommendedAtHighStrongRatio(t *testing.T) {
+	left := []MessageReconciliationCandidate{
+		{Source: "packetlog", MessageID: "m1", ConversationID: "c1", SenderID: "s1", TimestampUnixMilli: 1},
+		{Source: "packetlog", MessageID: "m2", ConversationID: "c2", SenderID: "s2", TimestampUnixMilli: 2},
+		{Source: "packetlog", MessageID: "m3", ConversationID: "c3", SenderID: "s3", TimestampUnixMilli: 3},
+		{Source: "packetlog", MessageID: "m4", ConversationID: "c4", SenderID: "s4", TimestampUnixMilli: 4},
+	}
+	right := []MessageReconciliationCandidate{
+		{Source: "msglib", MessageID: "m1", ConversationID: "c1", SenderID: "s1", TimestampUnixMilli: 1},
+		{Source: "msglib", MessageID: "m2", ConversationID: "c2", SenderID: "s2", TimestampUnixMilli: 2},
+		{Source: "msglib", MessageID: "m3", ConversationID: "c3", SenderID: "s3", TimestampUnixMilli: 3},
+		{Source: "msglib", MessageID: "m4", ConversationID: "c4", SenderID: "s4", TimestampUnixMilli: 4},
+	}
+
+	summary := ReconcileMessageSources(left, right)
+	if summary.StrongMatches != 4 || summary.MediumMatches != 0 || summary.UnmatchedLeft != 0 || summary.UnmatchedRight != 0 {
+		t.Fatalf("unexpected exact summary: %+v", summary)
+	}
+	if !summary.AutoMergeRecommended {
+		t.Fatalf("auto merge should be recommended for complete strong match: %+v", summary)
+	}
+}