GEN2-007: add task-relative freshness assessment

modules/epistemics/domain/freshness.go

@@ -0,0 +1,30 @@
+package domain
+
+import "git.cin.su/m/Assistant/contracts/epistemics"
+
+// AssessFreshness receives the Work-owned requirement as primitive policy
+// inputs, keeping the Epistemics owner independent of Work package types.
+func AssessFreshness(applicability epistemics.TemporalApplicability, mode string, maximumAgeMillis *int64, nowMillis int64) epistemics.FreshnessAssessment {
+	age := nowMillis - applicability.ObservedAtUnixMillis
+	if age < 0 {
+		age = 0
+	}
+	state := epistemics.FreshnessAssessmentCurrent
+	reason := "observation is within applicability window"
+	if applicability.ValidUntilUnixMillis != nil && nowMillis > *applicability.ValidUntilUnixMillis {
+		state, reason = epistemics.FreshnessAssessmentStale, "valid-until elapsed"
+	}
+	if applicability.Volatility.HardStaleAfterMillis != nil && age > *applicability.Volatility.HardStaleAfterMillis {
+		state, reason = epistemics.FreshnessAssessmentStale, "hard volatility window elapsed"
+	}
+	if applicability.Volatility.RevalidateAfterMillis != nil && age > *applicability.Volatility.RevalidateAfterMillis && state == epistemics.FreshnessAssessmentCurrent {
+		state, reason = epistemics.FreshnessAssessmentAging, "revalidation window elapsed"
+	}
+	if maximumAgeMillis != nil && age > *maximumAgeMillis {
+		state, reason = epistemics.FreshnessAssessmentStale, "task maximum age exceeded"
+	}
+	if mode == "LIVE_REQUIRED" {
+		state, reason = epistemics.FreshnessAssessmentHistoricalOnly, "live source required"
+	}
+	return epistemics.FreshnessAssessment{SourceKnowledgeRef: "knowledge", TaskRef: "task", State: state, Reason: reason, AgeMillis: age, AssessedAtUnixMillis: nowMillis}
+}

modules/epistemics/domain/freshness_test.go

@@ -0,0 +1,17 @@
+package domain_test
+
+import (
+	"git.cin.su/m/Assistant/contracts/epistemics"
+	"git.cin.su/m/Assistant/modules/epistemics/domain"
+	"testing"
+)
+
+func TestFreshnessIsTaskRelative(t *testing.T) {
+	hard := int64(100)
+	app := epistemics.TemporalApplicability{ObservedAtUnixMillis: 1, Volatility: epistemics.VolatilitySpec{Mode: epistemics.VolatilityVersionBound, HardStaleAfterMillis: &hard}}
+	current := domain.AssessFreshness(app, "ANY", nil, 50)
+	historical := domain.AssessFreshness(app, "LIVE_REQUIRED", nil, 50)
+	if current.State != epistemics.FreshnessAssessmentCurrent || historical.State != epistemics.FreshnessAssessmentHistoricalOnly {
+		t.Fatalf("got %v and %v", current.State, historical.State)
+	}
+}