package docrevision

import "context"

// CoverageResolver reports whether the trace index can support a no-impact claim.
// nil or an empty result means the index has not run; that must not be shown as no impact.
func (s *Service) formalCommitReportLocked(ctx context.Context, docID string, fromID, toID int64, hunks []DiffHunk) *ChangeReport {
	impacts := s.impactLocked(ctx, docID)
	coverage := ImpactIndexPending
	if s.CoverageResolver != nil {
		if got := s.CoverageResolver(ctx, docID); got != "" {
			coverage = got
		}
	}
	rep := fallbackReport("", "", RuleRiskFloor(hunks, impacts), impacts, hunks, "formal commit")
	rep.DocID = docID
	rep.FromSnapshotID = fromID
	rep.ToSnapshotID = toID
	rep.AnalysisStatus = AnalysisFallback
	rep.Authority = ReportAuthoritative
	rep.Lifecycle = ReportCommitted
	if rep.DeterministicFacts == nil {
		rep.DeterministicFacts = map[string]any{}
	}
	rep.DeterministicFacts["coverage_status"] = coverage
	rep.DeterministicFacts["suggested_actions"] = formalSuggestions(coverage, len(impacts) > 0)
	switch coverage {
	case ImpactNoKnown:
		rep.Summary = append(rep.Summary, "索引已覆盖，未发现已知关联")
	case ImpactConfirmed, ImpactPossible:
		rep.Summary = append(rep.Summary, "这次修改可能影响其他文档，见 document_impacts")
	default:
		rep.Summary = append(rep.Summary, "分析尚未完成或失败，不能判断为无影响")
		rep.OpenQuestions = append(rep.OpenQuestions, "不能判断为无影响")
	}
	stampReportDisposition(rep)
	return rep
}

func formalSuggestions(coverage string, hasImpact bool) []string {
	switch coverage {
	case ImpactIndexPending, ImpactPartial, ImpactFailed:
		return []string{"wait_index"}
	}
	out := []string{"no_change"}
	if hasImpact || coverage == ImpactPossible || coverage == ImpactConfirmed {
		out = append(out, "l1_revise", "l2_reopen")
	}
	return out
}