certctl/internal/service/renewal.go

package service

import (
	"context"
	"crypto/rand"
	"crypto/rsa"
	"crypto/sha256"
	"crypto/x509"
	"crypto/x509/pkix"
	"encoding/hex"
	"encoding/pem"
	"fmt"
	"log/slog"
	"math/big"
	"strings"
	"sync/atomic"
	"time"

	"github.com/shankar0123/certctl/internal/domain"
	"github.com/shankar0123/certctl/internal/repository"
)

// RenewalService manages certificate renewal workflows.
type RenewalService struct {
	certRepo          repository.CertificateRepository
	jobRepo           repository.JobRepository
	renewalPolicyRepo repository.RenewalPolicyRepository
	profileRepo       repository.CertificateProfileRepository
	targetRepo        repository.TargetRepository
	auditService      *AuditService
	notificationSvc   *NotificationService
	issuerRegistry    *IssuerRegistry
	keygenMode        string // "agent" (default) or "server" (demo only)
	// tx — when set, wraps the cert version insert + cert update + audit
	// row in a single transaction. Closes the #3 audit-readiness blocker
	// for the renewal path. Optional via SetTransactor.
	tx repository.Transactor
}

// SetTargetRepo sets the target repository for resolving agent_id on deployment jobs.
func (s *RenewalService) SetTargetRepo(repo repository.TargetRepository) {
	s.targetRepo = repo
}

// SetTransactor wires a Transactor for atomic renewal completion (cert
// version insert + cert update + audit row in a single transaction).
// Closes the #3 audit-readiness blocker for the renewal path. Optional
// — nil reverts to legacy non-transactional behavior.
func (s *RenewalService) SetTransactor(tx repository.Transactor) {
	s.tx = tx
}

// IssuerConnector defines the service-layer interface for interacting with certificate issuers.
// This is distinct from the connector-layer issuer.Connector interface to maintain dependency
// inversion. Use IssuerConnectorAdapter to bridge between the two.
type IssuerConnector interface {
	// IssueCertificate issues a new certificate using the provided CSR PEM.
	// maxTTLSeconds caps the certificate validity period (0 = no cap, use
	// issuer default). mustStaple, when true, instructs the issuer to add
	// the RFC 7633 id-pe-tlsfeature extension to the issued cert (only the
	// local issuer honors this; upstream connectors silently ignore it).
	// SCEP RFC 8894 + Intune master bundle Phase 5.6 follow-up.
	IssueCertificate(ctx context.Context, commonName string, sans []string, csrPEM string, ekus []string, maxTTLSeconds int, mustStaple bool) (*IssuanceResult, error)
	// RenewCertificate renews a certificate using the provided CSR PEM.
	// maxTTLSeconds caps the certificate validity period (0 = no cap, use
	// issuer default). mustStaple has the same semantics as on
	// IssueCertificate so renewed certs match their initial-issuance
	// extension set when the bound profile changed mid-lifetime.
	RenewCertificate(ctx context.Context, commonName string, sans []string, csrPEM string, ekus []string, maxTTLSeconds int, mustStaple bool) (*IssuanceResult, error)
	// RevokeCertificate revokes a certificate by serial number with an optional reason.
	RevokeCertificate(ctx context.Context, serial string, reason string) error
	// GenerateCRL generates a DER-encoded X.509 CRL from the given revocation entries.
	GenerateCRL(ctx context.Context, revokedCerts []CRLEntry) ([]byte, error)
	// SignOCSPResponse signs an OCSP response for the given certificate serial.
	SignOCSPResponse(ctx context.Context, req OCSPSignRequest) ([]byte, error)
	// GetCACertPEM returns the PEM-encoded CA certificate chain for this issuer.
	GetCACertPEM(ctx context.Context) (string, error)
	// GetRenewalInfo retrieves ACME Renewal Information (ARI) per RFC 9773 for a certificate.
	// certPEM is the PEM-encoded certificate. Returns nil, nil if the issuer does not support ARI.
	GetRenewalInfo(ctx context.Context, certPEM string) (*RenewalInfoResult, error)
}

// RenewalInfoResult holds the ARI response from a CA.
type RenewalInfoResult struct {
	SuggestedWindowStart time.Time
	SuggestedWindowEnd   time.Time
	RetryAfter           time.Time
	ExplanationURL       string
}

// IssuanceResult holds the result of a certificate issuance or renewal operation.
type IssuanceResult struct {
	CertPEM   string
	ChainPEM  string
	Serial    string
	NotBefore time.Time
	NotAfter  time.Time
}

// CRLEntry represents a revoked certificate for CRL generation.
type CRLEntry struct {
	SerialNumber *big.Int
	RevokedAt    time.Time
	ReasonCode   int
}

// OCSPSignRequest contains the parameters for OCSP response signing.
type OCSPSignRequest struct {
	CertSerial       *big.Int
	CertStatus       int // 0=good, 1=revoked, 2=unknown
	RevokedAt        time.Time
	RevocationReason int
	ThisUpdate       time.Time
	NextUpdate       time.Time
	// Nonce — RFC 6960 §4.4.1 nonce-extension echo. When non-nil, the
	// responder includes this value in the response's singleExtensions
	// field. Production hardening II Phase 1 — mirrors the same-named
	// field on internal/connector/issuer/interface.go::OCSPSignRequest.
	Nonce []byte
}

// NewRenewalService creates a new renewal service.
func NewRenewalService(
	certRepo repository.CertificateRepository,
	jobRepo repository.JobRepository,
	renewalPolicyRepo repository.RenewalPolicyRepository,
	profileRepo repository.CertificateProfileRepository,
	auditService *AuditService,
	notificationSvc *NotificationService,
	issuerRegistry *IssuerRegistry,
	keygenMode string,
) *RenewalService {
	if keygenMode == "" {
		keygenMode = "agent"
	}
	return &RenewalService{
		certRepo:          certRepo,
		jobRepo:           jobRepo,
		renewalPolicyRepo: renewalPolicyRepo,
		profileRepo:       profileRepo,
		auditService:      auditService,
		notificationSvc:   notificationSvc,
		issuerRegistry:    issuerRegistry,
		keygenMode:        keygenMode,
	}
}

// CheckExpiringCertificates identifies certificates needing renewal and sends threshold-based
// expiration alerts. For each certificate, it looks up the renewal policy's configured alert
// thresholds (default: 30, 14, 7, 0 days) and sends deduplicated notifications at each threshold.
// Certificates are also transitioned to Expiring/Expired status as appropriate.
func (s *RenewalService) CheckExpiringCertificates(ctx context.Context) error {
	// Use the maximum possible threshold window (30 days) plus buffer for query
	renewalWindow := time.Now().AddDate(0, 0, 31)

	expiring, err := s.certRepo.GetExpiringCertificates(ctx, renewalWindow)
	if err != nil {
		return fmt.Errorf("failed to fetch expiring certificates: %w", err)
	}

	// Cache renewal policies to avoid repeated lookups
	policyCache := make(map[string]*domain.RenewalPolicy)

	for _, cert := range expiring {
		// Skip certs in terminal or non-renewable states:
		// - RenewalInProgress: already being renewed
		// - Archived: no longer managed
		// - Revoked: intentionally revoked, should not be auto-renewed
		// - Failed: requires manual intervention (the failure cause hasn't been resolved)
		// - Expired: requires manual review (why did it expire without renewal?)
		if cert.Status == domain.CertificateStatusRenewalInProgress ||
			cert.Status == domain.CertificateStatusArchived ||
			cert.Status == domain.CertificateStatusRevoked ||
			cert.Status == domain.CertificateStatusFailed ||
			cert.Status == domain.CertificateStatusExpired {
			continue
		}

		// Calculate days until expiry
		daysUntil := time.Until(cert.ExpiresAt).Hours() / 24

		// Look up renewal policy for alert thresholds
		thresholds := domain.DefaultAlertThresholds()
		if cert.RenewalPolicyID != "" {
			policy, ok := policyCache[cert.RenewalPolicyID]
			if !ok {
				policy, err = s.renewalPolicyRepo.Get(ctx, cert.RenewalPolicyID)
				if err != nil {
					// Log but continue with defaults
					slog.Error("failed to fetch renewal policy, using defaults", "policy_id", cert.RenewalPolicyID, "cert_id", cert.ID, "error", err)
				} else {
					policyCache[cert.RenewalPolicyID] = policy
				}
			}
			if policy != nil {
				thresholds = policy.EffectiveAlertThresholds()
			}
		}

		// Update certificate status based on expiry
		s.updateCertExpiryStatus(ctx, cert, daysUntil)

		// Send threshold-based alerts with deduplication
		s.sendThresholdAlerts(ctx, cert, int(daysUntil), thresholds)

		// Only create renewal job if an issuer connector is registered for this cert's issuer
		connector, hasIssuer := s.issuerRegistry.Get(cert.IssuerID)
		if !hasIssuer {
			continue
		}

		// ARI check (RFC 9773): if the issuer supports ARI, let the CA direct renewal timing.
		// Fetch the latest cert version to get the PEM chain for the ARI query.
		ariChecked := false
		if version, vErr := s.certRepo.GetLatestVersion(ctx, cert.ID); vErr == nil && version != nil && version.PEMChain != "" {
			if ariResult, ariErr := connector.GetRenewalInfo(ctx, version.PEMChain); ariErr != nil {
				// ARI error is non-fatal — log and fall through to threshold-based renewal
				slog.Warn("ARI check failed, falling back to threshold-based renewal",
					"cert_id", cert.ID, "issuer_id", cert.IssuerID, "error", ariErr)
			} else if ariResult != nil {
				ariChecked = true
				now := time.Now()
				if now.Before(ariResult.SuggestedWindowStart) {
					// CA says it's too early to renew — skip this cert
					slog.Debug("ARI: renewal not yet suggested by CA",
						"cert_id", cert.ID,
						"suggested_start", ariResult.SuggestedWindowStart,
						"suggested_end", ariResult.SuggestedWindowEnd)
					continue
				}
				slog.Info("ARI: CA suggests renewal now",
					"cert_id", cert.ID,
					"suggested_start", ariResult.SuggestedWindowStart,
					"suggested_end", ariResult.SuggestedWindowEnd)
			}
			// ariResult == nil means issuer doesn't support ARI — fall through to threshold logic
		}
		_ = ariChecked // used for audit metadata below

		// Check for existing pending/running renewal jobs to avoid duplicates
		existingJobs, err := s.jobRepo.ListByCertificate(ctx, cert.ID)
		if err == nil {
			hasActiveRenewal := false
			for _, j := range existingJobs {
				if j.Type == domain.JobTypeRenewal &&
					(j.Status == domain.JobStatusPending || j.Status == domain.JobStatusRunning) {
					hasActiveRenewal = true
					break
				}
			}
			if hasActiveRenewal {
				continue
			}
		}

		// Create renewal job
		job := &domain.Job{
			ID:            generateID("job"),
			CertificateID: cert.ID,
			Type:          domain.JobTypeRenewal,
			Status:        domain.JobStatusPending,
			MaxAttempts:   3,
			ScheduledAt:   time.Now(),
			CreatedAt:     time.Now(),
		}

		if err := s.jobRepo.Create(ctx, job); err != nil {
			slog.Error("failed to create renewal job for cert", "cert_id", cert.ID, "error", err)
			continue
		}

		// Update certificate status to RenewalInProgress
		cert.Status = domain.CertificateStatusRenewalInProgress
		if err := s.certRepo.Update(ctx, cert); err != nil {
			slog.Error("failed to update cert status", "cert_id", cert.ID, "error", err)
		}

		// Record audit event
		auditMeta := map[string]interface{}{"days_until_expiry": daysUntil, "job_id": job.ID}
		if ariChecked {
			auditMeta["renewal_trigger"] = "ari"
		}
		if auditErr := s.auditService.RecordEvent(ctx, "system", domain.ActorTypeSystem,
			"renewal_job_created", "certificate", cert.ID, auditMeta); auditErr != nil {
			slog.Error("failed to record audit event", "error", auditErr)
		}
	}

	return nil
}

// sendThresholdAlerts sends deduplicated expiration notifications based on configured thresholds.
// For each threshold that the certificate has crossed (e.g., ≤30 days, ≤14 days), it checks
// whether a notification for that threshold was already sent. Only new threshold crossings
// trigger notifications.
func (s *RenewalService) sendThresholdAlerts(ctx context.Context, cert *domain.ManagedCertificate, daysUntil int, thresholds []int) {
	for _, threshold := range thresholds {
		// Only alert if the cert has crossed this threshold (days remaining ≤ threshold)
		if daysUntil > threshold {
			continue
		}

		// Check if we already sent a notification for this threshold (deduplication)
		alreadySent, err := s.notificationSvc.HasThresholdNotification(ctx, cert.ID, threshold)
		if err != nil {
			slog.Error("failed to check notification dedup", "cert_id", cert.ID, "threshold", threshold, "error", err)
			continue
		}
		if alreadySent {
			continue
		}

		// Send the threshold alert
		if err := s.notificationSvc.SendThresholdAlert(ctx, cert, daysUntil, threshold); err != nil {
			slog.Error("failed to send threshold alert for cert", "cert_id", cert.ID, "threshold", threshold, "error", err)
		}

		// Record audit event for the alert
		if auditErr := s.auditService.RecordEvent(ctx, "system", domain.ActorTypeSystem,
			"expiration_alert_sent", "certificate", cert.ID,
			map[string]interface{}{
				"threshold_days":    threshold,
				"days_until_expiry": daysUntil,
			}); auditErr != nil {
			slog.Error("failed to record audit event", "error", auditErr)
		}
	}
}

// updateCertExpiryStatus transitions a certificate to Expiring or Expired status based on
// how many days remain before expiry. Expired = 0 or fewer days, Expiring = within 30 days.
func (s *RenewalService) updateCertExpiryStatus(ctx context.Context, cert *domain.ManagedCertificate, daysUntil float64) {
	var newStatus domain.CertificateStatus

	if daysUntil <= 0 {
		newStatus = domain.CertificateStatusExpired
	} else {
		newStatus = domain.CertificateStatusExpiring
	}

	// Only update if status is changing and cert isn't already in a terminal/active renewal state
	if cert.Status == newStatus {
		return
	}
	if cert.Status == domain.CertificateStatusRenewalInProgress ||
		cert.Status == domain.CertificateStatusArchived ||
		cert.Status == domain.CertificateStatusRevoked {
		return
	}

	cert.Status = newStatus
	cert.UpdatedAt = time.Now()
	if err := s.certRepo.Update(ctx, cert); err != nil {
		slog.Error("failed to update cert status", "cert_id", cert.ID, "new_status", newStatus, "error", err)
	}
}

// ProcessRenewalJob executes a renewal job. Behavior depends on keygen mode:
//
// Agent mode (default, production): Sets job to AwaitingCSR. The agent generates keys
// locally, submits a CSR, and the server signs it. Private keys never leave the agent.
//
// Server mode (demo only, Local CA): Server generates RSA key + CSR, signs via issuer,
// stores cert version with private key so agent can retrieve it for deployment.
func (s *RenewalService) ProcessRenewalJob(ctx context.Context, job *domain.Job) error {
	// Update job status to in-progress
	if err := s.jobRepo.UpdateStatus(ctx, job.ID, domain.JobStatusRunning, ""); err != nil {
		return fmt.Errorf("failed to update job status: %w", err)
	}

	// Fetch certificate
	cert, err := s.certRepo.Get(ctx, job.CertificateID)
	if err != nil {
		s.failJob(ctx, job, fmt.Sprintf("certificate fetch failed: %v", err))
		return fmt.Errorf("failed to fetch certificate: %w", err)
	}

	// Get issuer connector
	issuerID := cert.IssuerID
	if issuerID == "" {
		s.failJob(ctx, job, "certificate has no issuer assigned")
		return fmt.Errorf("certificate has no issuer assigned")
	}

	_, ok := s.issuerRegistry.Get(issuerID)
	if !ok {
		s.failJob(ctx, job, fmt.Sprintf("issuer connector not found for %s", issuerID))
		return fmt.Errorf("issuer connector not found for %s", issuerID)
	}

	// Branch on keygen mode
	if s.keygenMode == "agent" {
		return s.processRenewalAgentKeygen(ctx, job, cert)
	}
	return s.processRenewalServerKeygen(ctx, job, cert)
}

// processRenewalAgentKeygen sets the job to AwaitingCSR so an agent can generate keys
// locally and submit a CSR. The server never touches the private key.
func (s *RenewalService) processRenewalAgentKeygen(ctx context.Context, job *domain.Job, cert *domain.ManagedCertificate) error {
	// Transition job to AwaitingCSR — agent will pick this up during work polling
	if err := s.jobRepo.UpdateStatus(ctx, job.ID, domain.JobStatusAwaitingCSR, ""); err != nil {
		return fmt.Errorf("failed to set job to AwaitingCSR: %w", err)
	}

	// Update certificate status
	cert.Status = domain.CertificateStatusRenewalInProgress
	cert.UpdatedAt = time.Now()
	if err := s.certRepo.Update(ctx, cert); err != nil {
		slog.Error("failed to update cert status", "cert_id", cert.ID, "error", err)
	}

	// Record audit event
	if auditErr := s.auditService.RecordEvent(ctx, "system", domain.ActorTypeSystem,
		"renewal_awaiting_csr", "certificate", job.CertificateID,
		map[string]interface{}{"job_id": job.ID, "keygen_mode": "agent"}); auditErr != nil {
		slog.Error("failed to record audit event", "error", auditErr)
	}

	return nil
}

// processRenewalServerKeygen is the legacy server-side keygen flow for Local CA demo.
// The server generates an ephemeral RSA key + CSR, signs via issuer, and stores the
// private key in the cert version so agents can retrieve it for deployment.
// WARNING: Private keys touch the control plane. Use only for development/demo.
func (s *RenewalService) processRenewalServerKeygen(ctx context.Context, job *domain.Job, cert *domain.ManagedCertificate) error {
	connector, _ := s.issuerRegistry.Get(cert.IssuerID)

	// Generate server-side RSA key + CSR
	privKey, err := rsa.GenerateKey(rand.Reader, 2048)
	if err != nil {
		s.failJob(ctx, job, fmt.Sprintf("key generation failed: %v", err))
		return fmt.Errorf("failed to generate private key: %w", err)
	}

	// Split SANs into DNS names and email addresses for proper CSR encoding
	var csrDNSNames []string
	var csrEmailAddresses []string
	for _, san := range cert.SANs {
		if strings.Contains(san, "@") {
			csrEmailAddresses = append(csrEmailAddresses, san)
		} else {
			csrDNSNames = append(csrDNSNames, san)
		}
	}

	csrTemplate := &x509.CertificateRequest{
		Subject: pkix.Name{
			CommonName: cert.CommonName,
		},
		DNSNames:       csrDNSNames,
		EmailAddresses: csrEmailAddresses,
	}

	csrDER, err := x509.CreateCertificateRequest(rand.Reader, csrTemplate, privKey)
	if err != nil {
		s.failJob(ctx, job, fmt.Sprintf("CSR generation failed: %v", err))
		return fmt.Errorf("failed to generate CSR: %w", err)
	}

	csrPEM := string(pem.EncodeToMemory(&pem.Block{
		Type:  "CERTIFICATE REQUEST",
		Bytes: csrDER,
	}))

	// Encode private key to PEM for storage (server mode: stored so agent can retrieve)
	privKeyPEM := string(pem.EncodeToMemory(&pem.Block{
		Type:  "RSA PRIVATE KEY",
		Bytes: x509.MarshalPKCS1PrivateKey(privKey),
	}))

	// Resolve EKUs + MaxTTL + must-staple from the certificate profile.
	// SCEP RFC 8894 + Intune master bundle Phase 5.6 follow-up: thread
	// must-staple through the renewal path too so renewed certs match
	// their initial-issuance extension set.
	var (
		ekus          []string
		maxTTLSeconds int
		mustStaple    bool
	)
	if cert.CertificateProfileID != "" && s.profileRepo != nil {
		if profile, profileErr := s.profileRepo.Get(ctx, cert.CertificateProfileID); profileErr == nil && profile != nil {
			ekus = profile.AllowedEKUs
			maxTTLSeconds = profile.MaxTTLSeconds
			mustStaple = profile.MustStaple
		}
	}

	// Call issuer connector to renew
	result, err := connector.RenewCertificate(ctx, cert.CommonName, cert.SANs, csrPEM, ekus, maxTTLSeconds, mustStaple)
	if err != nil {
		s.failJob(ctx, job, fmt.Sprintf("issuer renewal failed: %v", err))
		if notifErr := s.notificationSvc.SendRenewalNotification(ctx, cert, false, err); notifErr != nil {
			slog.Error("failed to send renewal failure notification", "error", notifErr)
		}
		if auditErr := s.auditService.RecordEvent(ctx, "system", domain.ActorTypeSystem,
			"renewal_job_failed", "certificate", job.CertificateID,
			map[string]interface{}{"job_id": job.ID, "error": err.Error()}); auditErr != nil {
			slog.Error("failed to record audit event", "error", auditErr)
		}
		return fmt.Errorf("issuer renewal failed: %w", err)
	}

	// Compute SHA-256 fingerprint of the issued certificate
	fingerprint := computeCertFingerprint(result.CertPEM)

	// Create new certificate version
	version := &domain.CertificateVersion{
		ID:                generateID("certver"),
		CertificateID:     job.CertificateID,
		SerialNumber:      result.Serial,
		NotBefore:         result.NotBefore,
		NotAfter:          result.NotAfter,
		FingerprintSHA256: fingerprint,
		PEMChain:          result.CertPEM + "\n" + result.ChainPEM,
		CSRPEM:            privKeyPEM, // Server mode: stores private key for agent deployment
		KeyAlgorithm:      domain.KeyAlgorithmRSA,
		KeySize:           2048,
		CreatedAt:         time.Now(),
	}

	// Update certificate status and expiry
	cert.Status = domain.CertificateStatusActive
	cert.ExpiresAt = result.NotAfter
	now := time.Now()
	cert.LastRenewalAt = &now
	cert.UpdatedAt = now

	auditDetails := map[string]interface{}{
		"job_id":      job.ID,
		"serial":      result.Serial,
		"not_after":   result.NotAfter,
		"keygen_mode": "server",
	}

	// Atomic three-write path (when SetTransactor was wired): version
	// insert + cert update + audit row in a single transaction. Closes
	// the #3 audit-readiness blocker for the renewal path.
	if s.tx != nil {
		if err := s.tx.WithinTx(ctx, func(q repository.Querier) error {
			if err := s.certRepo.CreateVersionWithTx(ctx, q, version); err != nil {
				return fmt.Errorf("failed to create certificate version: %w", err)
			}
			if err := s.certRepo.UpdateWithTx(ctx, q, cert); err != nil {
				return fmt.Errorf("failed to update certificate: %w", err)
			}
			if err := s.auditService.RecordEventWithTx(ctx, q, "system", domain.ActorTypeSystem,
				"renewal_job_completed", "certificate", job.CertificateID, auditDetails); err != nil {
				return fmt.Errorf("failed to record audit event: %w", err)
			}
			return nil
		}); err != nil {
			s.failJob(ctx, job, err.Error())
			return err
		}
	} else {
		// Legacy non-transactional path — pre-fix behavior.
		if err := s.certRepo.CreateVersion(ctx, version); err != nil {
			s.failJob(ctx, job, fmt.Sprintf("version creation failed: %v", err))
			return fmt.Errorf("failed to create certificate version: %w", err)
		}
		if err := s.certRepo.Update(ctx, cert); err != nil {
			s.failJob(ctx, job, fmt.Sprintf("cert update failed: %v", err))
			return fmt.Errorf("failed to update certificate: %w", err)
		}
		if auditErr := s.auditService.RecordEvent(ctx, "system", domain.ActorTypeSystem,
			"renewal_job_completed", "certificate", job.CertificateID, auditDetails); auditErr != nil {
			slog.Error("failed to record audit event", "error", auditErr)
		}
	}

	// Mark renewal job as completed (independent of the cert/audit
	// transaction — job state lives outside the audit-atomicity scope).
	if err := s.jobRepo.UpdateStatus(ctx, job.ID, domain.JobStatusCompleted, ""); err != nil {
		return fmt.Errorf("failed to update job status: %w", err)
	}

	// Create deployment jobs for each target
	s.createDeploymentJobs(ctx, cert)

	// Send success notification
	if err := s.notificationSvc.SendRenewalNotification(ctx, cert, true, nil); err != nil {
		slog.Error("failed to send renewal notification", "error", err)
	}

	return nil
}

// CompleteAgentCSRRenewal is called when an agent submits a CSR for an AwaitingCSR job.
// It signs the CSR via the issuer connector, stores the cert version (without private key),
// completes the renewal job, and creates deployment jobs.
func (s *RenewalService) CompleteAgentCSRRenewal(ctx context.Context, job *domain.Job, cert *domain.ManagedCertificate, csrPEM string) error {
	connector, ok := s.issuerRegistry.Get(cert.IssuerID)
	if !ok {
		s.failJob(ctx, job, fmt.Sprintf("issuer connector not found for %s", cert.IssuerID))
		return fmt.Errorf("issuer connector not found for %s", cert.IssuerID)
	}

	// Validate CSR against certificate profile (crypto policy enforcement)
	var profile *domain.CertificateProfile
	if cert.CertificateProfileID != "" && s.profileRepo != nil {
		var profileErr error
		profile, profileErr = s.profileRepo.Get(ctx, cert.CertificateProfileID)
		if profileErr != nil {
			slog.Warn("failed to fetch certificate profile, skipping crypto validation",
				"profile_id", cert.CertificateProfileID, "cert_id", cert.ID, "error", profileErr)
		}
	}
	csrInfo, csrErr := ValidateCSRAgainstProfile(csrPEM, profile)
	if csrErr != nil {
		s.failJob(ctx, job, fmt.Sprintf("CSR validation failed: %v", csrErr))
		return fmt.Errorf("CSR validation failed: %w", csrErr)
	}

	// Update job to running
	if err := s.jobRepo.UpdateStatus(ctx, job.ID, domain.JobStatusRunning, ""); err != nil {
		return fmt.Errorf("failed to update job status: %w", err)
	}

	// Resolve EKUs + MaxTTL + must-staple from the certificate profile.
	// SCEP RFC 8894 + Intune master bundle Phase 5.6 follow-up.
	var (
		ekus          []string
		maxTTLSeconds int
		mustStaple    bool
	)
	if profile != nil {
		if len(profile.AllowedEKUs) > 0 {
			ekus = profile.AllowedEKUs
		}
		maxTTLSeconds = profile.MaxTTLSeconds
		mustStaple = profile.MustStaple
	}

	// Sign the agent-submitted CSR via issuer
	result, err := connector.RenewCertificate(ctx, cert.CommonName, cert.SANs, csrPEM, ekus, maxTTLSeconds, mustStaple)
	if err != nil {
		s.failJob(ctx, job, fmt.Sprintf("issuer signing failed: %v", err))
		if notifErr := s.notificationSvc.SendRenewalNotification(ctx, cert, false, err); notifErr != nil {
			slog.Error("failed to send renewal failure notification", "error", notifErr)
		}
		if auditErr := s.auditService.RecordEvent(ctx, "system", domain.ActorTypeSystem,
			"renewal_job_failed", "certificate", job.CertificateID,
			map[string]interface{}{"job_id": job.ID, "error": err.Error()}); auditErr != nil {
			slog.Error("failed to record audit event", "error", auditErr)
		}
		return fmt.Errorf("issuer signing failed: %w", err)
	}

	fingerprint := computeCertFingerprint(result.CertPEM)

	// Store cert version — CSRPEM holds the actual CSR (not the private key!)
	version := &domain.CertificateVersion{
		ID:                generateID("certver"),
		CertificateID:     cert.ID,
		SerialNumber:      result.Serial,
		NotBefore:         result.NotBefore,
		NotAfter:          result.NotAfter,
		FingerprintSHA256: fingerprint,
		PEMChain:          result.CertPEM + "\n" + result.ChainPEM,
		CSRPEM:            csrPEM, // Agent mode: stores actual CSR, not private key
		CreatedAt:         time.Now(),
	}
	if csrInfo != nil {
		version.KeyAlgorithm = csrInfo.KeyAlgorithm
		version.KeySize = csrInfo.KeySize
	}

	if err := s.certRepo.CreateVersion(ctx, version); err != nil {
		s.failJob(ctx, job, fmt.Sprintf("version creation failed: %v", err))
		return fmt.Errorf("failed to create certificate version: %w", err)
	}

	// Update certificate status and expiry
	cert.Status = domain.CertificateStatusActive
	cert.ExpiresAt = result.NotAfter
	now := time.Now()
	cert.LastRenewalAt = &now
	cert.UpdatedAt = now
	if err := s.certRepo.Update(ctx, cert); err != nil {
		s.failJob(ctx, job, fmt.Sprintf("cert update failed: %v", err))
		return fmt.Errorf("failed to update certificate: %w", err)
	}

	// Mark job completed
	if err := s.jobRepo.UpdateStatus(ctx, job.ID, domain.JobStatusCompleted, ""); err != nil {
		return fmt.Errorf("failed to update job status: %w", err)
	}

	// Create deployment jobs for each target
	s.createDeploymentJobs(ctx, cert)

	// Send success notification
	if err := s.notificationSvc.SendRenewalNotification(ctx, cert, true, nil); err != nil {
		slog.Error("failed to send renewal notification", "error", err)
	}

	// Record audit event
	if auditErr := s.auditService.RecordEvent(ctx, "system", domain.ActorTypeSystem,
		"renewal_job_completed", "certificate", cert.ID,
		map[string]interface{}{
			"job_id":      job.ID,
			"serial":      result.Serial,
			"not_after":   result.NotAfter,
			"keygen_mode": "agent",
		}); auditErr != nil {
		slog.Error("failed to record audit event", "error", auditErr)
	}

	return nil
}

// createDeploymentJobs creates pending deployment jobs for each target associated with a cert.
// If cert.TargetIDs is empty (common — the repository doesn't populate this field),
// falls back to querying certificate_target_mappings via targetRepo.ListByCertificate.
func (s *RenewalService) createDeploymentJobs(ctx context.Context, cert *domain.ManagedCertificate) {
	// Resolve targets: prefer in-memory TargetIDs, fall back to DB query
	type targetInfo struct {
		id      string
		agentID string
	}
	var targets []targetInfo

	if len(cert.TargetIDs) > 0 {
		// TargetIDs populated (e.g. from test or manual wiring)
		for _, tid := range cert.TargetIDs {
			ti := targetInfo{id: tid}
			if s.targetRepo != nil {
				if target, err := s.targetRepo.Get(ctx, tid); err == nil && target.AgentID != "" {
					ti.agentID = target.AgentID
				}
			}
			targets = append(targets, ti)
		}
	} else if s.targetRepo != nil {
		// TargetIDs empty — query certificate_target_mappings via repository
		dbTargets, err := s.targetRepo.ListByCertificate(ctx, cert.ID)
		if err != nil {
			slog.Error("failed to query targets for certificate", "cert_id", cert.ID, "error", err)
			return
		}
		for _, t := range dbTargets {
			targets = append(targets, targetInfo{id: t.ID, agentID: t.AgentID})
		}
	}

	if len(targets) == 0 {
		slog.Debug("no targets found for certificate, skipping deployment", "cert_id", cert.ID)
		return
	}

	for _, t := range targets {
		tid := t.id
		var agentIDPtr *string
		if t.agentID != "" {
			aid := t.agentID
			agentIDPtr = &aid
		}

		deployJob := &domain.Job{
			ID:            generateID("job"),
			CertificateID: cert.ID,
			Type:          domain.JobTypeDeployment,
			Status:        domain.JobStatusPending,
			TargetID:      &tid,
			AgentID:       agentIDPtr,
			MaxAttempts:   3,
			ScheduledAt:   time.Now(),
			CreatedAt:     time.Now(),
		}
		if err := s.jobRepo.Create(ctx, deployJob); err != nil {
			slog.Error("failed to create deployment job for target", "target_id", tid, "cert_id", cert.ID, "error", err)
		} else {
			slog.Info("created deployment job", "job_id", deployJob.ID, "cert_id", cert.ID, "target_id", tid, "agent_id", t.agentID)
		}
	}
}

// GetAwaitingCSRJobs returns all jobs in AwaitingCSR state for a given certificate.
func (s *RenewalService) GetAwaitingCSRJobs(ctx context.Context, certID string) ([]*domain.Job, error) {
	jobs, err := s.jobRepo.ListByCertificate(ctx, certID)
	if err != nil {
		return nil, err
	}
	var awaiting []*domain.Job
	for _, j := range jobs {
		if j.Status == domain.JobStatusAwaitingCSR {
			awaiting = append(awaiting, j)
		}
	}
	return awaiting, nil
}

// failJob is a helper to mark a job as failed with an error message.
func (s *RenewalService) failJob(ctx context.Context, job *domain.Job, errMsg string) {
	if updateErr := s.jobRepo.UpdateStatus(ctx, job.ID, domain.JobStatusFailed, errMsg); updateErr != nil {
		slog.Error("failed to update job status", "job_id", job.ID, "error", updateErr)
	}
}

// computeCertFingerprint computes the SHA-256 fingerprint of a PEM-encoded certificate.
func computeCertFingerprint(certPEM string) string {
	block, _ := pem.Decode([]byte(certPEM))
	if block == nil {
		return ""
	}
	hash := sha256.Sum256(block.Bytes)
	return hex.EncodeToString(hash[:])
}

// RetryFailedJobs resets failed renewal jobs for retry if they haven't exceeded max attempts.
func (s *RenewalService) RetryFailedJobs(ctx context.Context, maxRetries int) error {
	failedJobs, err := s.jobRepo.ListByStatus(ctx, domain.JobStatusFailed)
	if err != nil {
		return fmt.Errorf("failed to fetch failed jobs: %w", err)
	}

	for _, job := range failedJobs {
		if job.Type != domain.JobTypeRenewal {
			continue
		}

		// Check if we've exceeded max attempts
		if job.Attempts >= job.MaxAttempts {
			continue
		}

		// Reset status to pending for retry
		if err := s.jobRepo.UpdateStatus(ctx, job.ID, domain.JobStatusPending, ""); err != nil {
			slog.Error("failed to reset job status for retry", "job_id", job.ID, "error", err)
			continue
		}
	}

	return nil
}

// ExpireShortLivedCertificates finds active certificates with short-lived profiles
// whose TTL has elapsed and marks them as Expired. For certs with TTL < 1 hour,
// expiry is the revocation mechanism — no CRL/OCSP needed.
func (s *RenewalService) ExpireShortLivedCertificates(ctx context.Context) error {
	if s.profileRepo == nil {
		return nil
	}

	// Get all Active certificates and check if any have expired based on their actual expiry time
	// This catches short-lived certs that expire between normal renewal check cycles
	now := time.Now()
	expiring, err := s.certRepo.GetExpiringCertificates(ctx, now)
	if err != nil {
		return fmt.Errorf("failed to fetch expired certificates: %w", err)
	}

	for _, cert := range expiring {
		if cert.Status != domain.CertificateStatusActive && cert.Status != domain.CertificateStatusExpiring {
			continue
		}

		// Only auto-expire certs that have actually passed their expiry time
		if cert.ExpiresAt.After(now) {
			continue
		}

		// Check if this cert has a short-lived profile
		if cert.CertificateProfileID == "" {
			continue
		}

		profile, err := s.profileRepo.Get(ctx, cert.CertificateProfileID)
		if err != nil {
			slog.Warn("failed to fetch profile for short-lived expiry check",
				"profile_id", cert.CertificateProfileID, "cert_id", cert.ID, "error", err)
			continue
		}

		if !profile.IsShortLived() {
			continue
		}

		// Mark as expired
		cert.Status = domain.CertificateStatusExpired
		cert.UpdatedAt = now
		if err := s.certRepo.Update(ctx, cert); err != nil {
			slog.Error("failed to expire short-lived cert", "cert_id", cert.ID, "error", err)
			continue
		}

		slog.Info("short-lived certificate expired (expiry = revocation)",
			"cert_id", cert.ID, "profile_id", cert.CertificateProfileID,
			"expired_at", cert.ExpiresAt)

		if auditErr := s.auditService.RecordEvent(ctx, "system", domain.ActorTypeSystem,
			"short_lived_cert_expired", "certificate", cert.ID,
			map[string]interface{}{
				"profile_id": cert.CertificateProfileID,
				"expired_at": cert.ExpiresAt,
			}); auditErr != nil {
			slog.Error("failed to record audit event", "error", auditErr)
		}
	}

	return nil
}

// generateID is a helper to generate unique IDs. In production, use a proper ID generator.
var idCounter atomic.Int64

func generateID(prefix string) string {
	counter := idCounter.Add(1)
	return fmt.Sprintf("%s-%d-%d", prefix, time.Now().UnixNano(), counter)
}