feat(iace): Sprint 4C — Delta Impact Analysis

Neuer Endpoint POST /projects/:id/delta-analysis:
- Input: aktuelle + vorgeschlagene Aenderung (Components, Energy, States, Roles)
- Output: Diff der Pattern-Matches (added/removed Patterns, Hazards, Measures)
- DeltaMatch() auf PatternEngine: Match(current) vs Match(proposed)
- DeltaResult mit AddedPatterns, RemovedPatterns, Counts, SummaryDE

Beispiel-Output: SPS hinzufuegen → +55 Patterns, +5 Hazard-Kategorien, +17 Massnahmen
Maintenance-State hinzufuegen → +10 Patterns, +2 Hazards, +2 Massnahmen

7 Tests: NoChange, AddComponent, RemoveComponent, AddState, AddRole, Summary, Symmetric

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ai-compliance-sdk/internal/iace/delta_analysis.go

@@ -0,0 +1,160 @@
+package iace
+
+import "strconv"
+
+// DeltaResult contains the impact of a proposed change to a project.
+// It compares Match(current) vs Match(current+proposed) and returns
+// the difference in matched patterns, hazards, measures, and evidence.
+type DeltaResult struct {
+	// Patterns that would fire with the proposed change but not currently
+	AddedPatterns []PatternMatch `json:"added_patterns"`
+	// Patterns that currently fire but would stop with the proposed change
+	RemovedPatterns []PatternMatch `json:"removed_patterns"`
+	// Net change counts
+	AddedHazardCount   int `json:"added_hazard_count"`
+	RemovedHazardCount int `json:"removed_hazard_count"`
+	AddedMeasureCount  int `json:"added_measure_count"`
+	RemovedMeasureCount int `json:"removed_measure_count"`
+	AddedEvidenceCount  int `json:"added_evidence_count"`
+	RemovedEvidenceCount int `json:"removed_evidence_count"`
+	// Added/removed hazard categories
+	AddedHazardCats   []string `json:"added_hazard_categories,omitempty"`
+	RemovedHazardCats []string `json:"removed_hazard_categories,omitempty"`
+	// Added/removed measure IDs
+	AddedMeasureIDs   []string `json:"added_measure_ids,omitempty"`
+	RemovedMeasureIDs []string `json:"removed_measure_ids,omitempty"`
+	// Summary text (German)
+	SummaryDE string `json:"summary_de"`
+}
+
+// DeltaMatch computes the impact of a proposed change by comparing
+// the current match output with the proposed match output.
+func (e *PatternEngine) DeltaMatch(current, proposed MatchInput) *DeltaResult {
+	currentOutput := e.Match(current)
+	proposedOutput := e.Match(proposed)
+
+	// Build pattern ID sets
+	currentPatterns := make(map[string]PatternMatch)
+	for _, p := range currentOutput.MatchedPatterns {
+		currentPatterns[p.PatternID] = p
+	}
+	proposedPatterns := make(map[string]PatternMatch)
+	for _, p := range proposedOutput.MatchedPatterns {
+		proposedPatterns[p.PatternID] = p
+	}
+
+	// Find added/removed patterns
+	var added, removed []PatternMatch
+	for id, p := range proposedPatterns {
+		if _, exists := currentPatterns[id]; !exists {
+			added = append(added, p)
+		}
+	}
+	for id, p := range currentPatterns {
+		if _, exists := proposedPatterns[id]; !exists {
+			removed = append(removed, p)
+		}
+	}
+
+	// Compute hazard category diff
+	currentCats := collectCats(currentOutput.SuggestedHazards)
+	proposedCats := collectCats(proposedOutput.SuggestedHazards)
+	addedCats := diffStrings(proposedCats, currentCats)
+	removedCats := diffStrings(currentCats, proposedCats)
+
+	// Compute measure ID diff
+	currentMIDs := collectMIDs(currentOutput.SuggestedMeasures)
+	proposedMIDs := collectMIDs(proposedOutput.SuggestedMeasures)
+	addedMIDs := diffStrings(proposedMIDs, currentMIDs)
+	removedMIDs := diffStrings(currentMIDs, proposedMIDs)
+
+	// Compute evidence ID diff
+	currentEIDs := collectEIDs(currentOutput.SuggestedEvidence)
+	proposedEIDs := collectEIDs(proposedOutput.SuggestedEvidence)
+
+	result := &DeltaResult{
+		AddedPatterns:        added,
+		RemovedPatterns:      removed,
+		AddedHazardCount:     len(addedCats),
+		RemovedHazardCount:   len(removedCats),
+		AddedMeasureCount:    len(addedMIDs),
+		RemovedMeasureCount:  len(removedMIDs),
+		AddedEvidenceCount:   len(diffStrings(proposedEIDs, currentEIDs)),
+		RemovedEvidenceCount: len(diffStrings(currentEIDs, proposedEIDs)),
+		AddedHazardCats:      addedCats,
+		RemovedHazardCats:    removedCats,
+		AddedMeasureIDs:      addedMIDs,
+		RemovedMeasureIDs:    removedMIDs,
+	}
+
+	result.SummaryDE = buildDeltaSummary(result)
+	return result
+}
+
+func collectCats(hazards []HazardSuggestion) []string {
+	var cats []string
+	for _, h := range hazards {
+		cats = append(cats, h.Category)
+	}
+	return cats
+}
+
+func collectMIDs(measures []MeasureSuggestion) []string {
+	var ids []string
+	for _, m := range measures {
+		ids = append(ids, m.MeasureID)
+	}
+	return ids
+}
+
+func collectEIDs(evidence []EvidenceSuggestion) []string {
+	var ids []string
+	for _, e := range evidence {
+		ids = append(ids, e.EvidenceID)
+	}
+	return ids
+}
+
+func diffStrings(a, b []string) []string {
+	bSet := make(map[string]bool)
+	for _, s := range b {
+		bSet[s] = true
+	}
+	var diff []string
+	seen := make(map[string]bool)
+	for _, s := range a {
+		if !bSet[s] && !seen[s] {
+			diff = append(diff, s)
+			seen[s] = true
+		}
+	}
+	return diff
+}
+
+func buildDeltaSummary(r *DeltaResult) string {
+	if len(r.AddedPatterns) == 0 && len(r.RemovedPatterns) == 0 {
+		return "Keine Auswirkung — die vorgeschlagene Aenderung veraendert die Risikobeurteilung nicht."
+	}
+	s := ""
+	if len(r.AddedPatterns) > 0 {
+		s += "+" + deltaItoa(len(r.AddedPatterns)) + " neue Gefaehrdungsmuster erkannt"
+	}
+	if len(r.RemovedPatterns) > 0 {
+		if s != "" {
+			s += ", "
+		}
+		s += "-" + deltaItoa(len(r.RemovedPatterns)) + " Gefaehrdungsmuster entfallen"
+	}
+	if r.AddedHazardCount > 0 {
+		s += ". +" + deltaItoa(r.AddedHazardCount) + " neue Gefaehrdungskategorien"
+	}
+	if r.AddedMeasureCount > 0 {
+		s += ". +" + deltaItoa(r.AddedMeasureCount) + " zusaetzliche Massnahmen empfohlen"
+	}
+	s += "."
+	return s
+}
+
+func deltaItoa(i int) string {
+	return strconv.Itoa(i)
+}