package service

import (
	"context"
	"encoding/base64"
	"encoding/json"
	"errors"
	"fmt"
	"regexp"
	"strconv"
	"strings"
	"time"

	"gorm.io/gorm"
	redisadapter "stream.api/internal/adapters/redis"
	"stream.api/internal/database/model"
	"stream.api/internal/dto"
	"stream.api/internal/repository"
	"stream.api/pkg/logger"
)

type JobQueue interface {
	Enqueue(ctx context.Context, job *model.Job) error
	Dequeue(ctx context.Context) (*model.Job, error)
}

type LogPubSub interface {
	Publish(ctx context.Context, jobID string, logLine string, progress float64) error
	PublishResource(ctx context.Context, agentID string, data []byte) error
	PublishCancel(ctx context.Context, agentID string, jobID string) error
	PublishJobUpdate(ctx context.Context, jobID string, status string, videoID string) error
	Subscribe(ctx context.Context, jobID string) (<-chan dto.LogEntry, error)
	SubscribeResources(ctx context.Context) (<-chan dto.SystemResource, error)
	SubscribeCancel(ctx context.Context, agentID string) (<-chan string, error)
	SubscribeJobUpdates(ctx context.Context) (<-chan string, error)
}

type DeadLetterQueue interface {
	Add(ctx context.Context, job *model.Job, reason string) error
	Get(ctx context.Context, jobID string) (*redisadapter.DLQEntry, error)
	List(ctx context.Context, offset, limit int64) ([]*redisadapter.DLQEntry, error)
	Count(ctx context.Context) (int64, error)
	Remove(ctx context.Context, jobID string) error
	Retry(ctx context.Context, jobID string) (*model.Job, error)
}

type JobService struct {
	queue         JobQueue
	pubsub        LogPubSub
	dlq           DeadLetterQueue
	jobRepository JobRepository
	logger        logger.Logger
}

func NewJobService(db *gorm.DB, queue JobQueue, pubsub LogPubSub, dlq DeadLetterQueue) *JobService {
	return &JobService{
		queue:         queue,
		pubsub:        pubsub,
		dlq:           dlq,
		jobRepository: repository.NewJobRepository(db),
	}
}

func (s *JobService) SetLogger(l logger.Logger) {
	s.logger = l
}

var ErrInvalidJobCursor = errors.New("invalid job cursor")

func strPtr(v string) *string        { return &v }
func int64Ptr(v int64) *int64        { return &v }
func boolPtr(v bool) *bool           { return &v }
func float64Ptr(v float64) *float64  { return &v }
func timePtr(v time.Time) *time.Time { return &v }

func parseJobConfig(raw *string) dto.JobConfigEnvelope {
	if raw == nil || strings.TrimSpace(*raw) == "" {
		return dto.JobConfigEnvelope{}
	}
	var cfg dto.JobConfigEnvelope
	_ = json.Unmarshal([]byte(*raw), &cfg)
	return cfg
}

func encodeJobConfig(raw []byte, name, userID, videoID string, timeLimit int64) string {
	cfg := parseJobConfig(strPtr(string(raw)))
	if name != "" {
		cfg.Name = name
	}
	if userID != "" {
		cfg.UserID = userID
	}
	if videoID != "" {
		cfg.VideoID = videoID
	}
	if timeLimit > 0 {
		cfg.TimeLimit = timeLimit
	}
	encoded, _ := json.Marshal(cfg)
	return string(encoded)
}

func normalizeJobPageSize(pageSize int) int {
	if pageSize <= 0 {
		return dto.DefaultJobPageSize
	}
	if pageSize > dto.MaxJobPageSize {
		return dto.MaxJobPageSize
	}
	return pageSize
}

func encodeJobListCursor(cursor dto.JobListCursor) (string, error) {
	payload, err := json.Marshal(cursor)
	if err != nil {
		return "", err
	}
	return base64.RawURLEncoding.EncodeToString(payload), nil
}

func decodeJobListCursor(raw string) (*dto.JobListCursor, error) {
	raw = strings.TrimSpace(raw)
	if raw == "" {
		return nil, nil
	}
	payload, err := base64.RawURLEncoding.DecodeString(raw)
	if err != nil {
		return nil, ErrInvalidJobCursor
	}
	var cursor dto.JobListCursor
	if err := json.Unmarshal(payload, &cursor); err != nil {
		return nil, ErrInvalidJobCursor
	}
	if cursor.Version != dto.JobCursorVersion || cursor.CreatedAtUnixNano <= 0 || strings.TrimSpace(cursor.ID) == "" {
		return nil, ErrInvalidJobCursor
	}
	cursor.ID = strings.TrimSpace(cursor.ID)
	cursor.AgentID = strings.TrimSpace(cursor.AgentID)
	return &cursor, nil
}

func buildJobListCursor(job *model.Job, agentID string) (string, error) {
	if job == nil || job.CreatedAt == nil {
		return "", nil
	}
	return encodeJobListCursor(dto.JobListCursor{
		Version:           dto.JobCursorVersion,
		CreatedAtUnixNano: job.CreatedAt.UTC().UnixNano(),
		ID:                strings.TrimSpace(job.ID),
		AgentID:           strings.TrimSpace(agentID),
	})
}

func listJobsByOffset(ctx context.Context, jobRepository JobRepository, agentID string, offset, limit int) (*dto.PaginatedJobs, error) {
	if offset < 0 {
		offset = 0
	}
	limit = normalizeJobPageSize(limit)
	jobs, total, err := jobRepository.ListByOffset(ctx, agentID, offset, limit)
	if err != nil {
		return nil, err
	}
	return &dto.PaginatedJobs{Jobs: jobs, Total: total, Offset: offset, Limit: limit, PageSize: limit, HasMore: offset+len(jobs) < int(total)}, nil
}

func (s *JobService) CreateJob(ctx context.Context, userID string, videoID string, name string, config []byte, priority int, timeLimit int64) (*model.Job, error) {
	status := string(dto.JobStatusPending)
	now := time.Now()
	job := &model.Job{
		ID:         fmt.Sprintf("job-%d", now.UnixNano()),
		Status:     strPtr(status),
		Priority:   int64Ptr(int64(priority)),
		Config:     strPtr(encodeJobConfig(config, name, userID, videoID, timeLimit)),
		Cancelled:  boolPtr(false),
		RetryCount: int64Ptr(0),
		MaxRetries: int64Ptr(3),
		CreatedAt:  timePtr(now),
		UpdatedAt:  timePtr(now),
	}
	if err := s.jobRepository.Create(ctx, job); err != nil {
		return nil, err
	}
	if err := syncVideoStatus(ctx, s.jobRepository, videoID, dto.JobStatusPending); err != nil {
		return nil, err
	}
	if s.queue == nil {
		return nil, errors.New("job queue is unavailable")
	}
	if err := s.removeFromQueue(ctx, job.ID); err != nil {
		return nil, err
	}
	if err := s.queue.Enqueue(ctx, job); err != nil {
		return nil, err
	}
	_ = s.publishJobUpdate(ctx, job.ID, status, videoID)
	return job, nil
}

func (s *JobService) ListJobs(ctx context.Context, offset, limit int) (*dto.PaginatedJobs, error) {
	return listJobsByOffset(ctx, s.jobRepository, "", offset, limit)
}

func (s *JobService) ListJobsByAgent(ctx context.Context, agentID string, offset, limit int) (*dto.PaginatedJobs, error) {
	return listJobsByOffset(ctx, s.jobRepository, strings.TrimSpace(agentID), offset, limit)
}

func (s *JobService) ListJobsByCursor(ctx context.Context, agentID string, cursor string, pageSize int) (*dto.PaginatedJobs, error) {
	agentID = strings.TrimSpace(agentID)
	pageSize = normalizeJobPageSize(pageSize)

	decodedCursor, err := decodeJobListCursor(cursor)
	if err != nil {
		return nil, err
	}
	if decodedCursor != nil && decodedCursor.AgentID != agentID {
		return nil, ErrInvalidJobCursor
	}

	var cursorTime time.Time
	if decodedCursor != nil {
		cursorTime = time.Unix(0, decodedCursor.CreatedAtUnixNano).UTC()
	}
	cursorID := ""
	if decodedCursor != nil {
		cursorID = decodedCursor.ID
	}
	jobs, hasMore, err := s.jobRepository.ListByCursor(ctx, agentID, cursorTime, cursorID, pageSize)
	if err != nil {
		return nil, err
	}

	nextCursor := ""
	if hasMore && len(jobs) > 0 {
		nextCursor, err = buildJobListCursor(jobs[len(jobs)-1], agentID)
		if err != nil {
			return nil, err
		}
	}

	return &dto.PaginatedJobs{
		Jobs:       jobs,
		Total:      0,
		Limit:      pageSize,
		PageSize:   pageSize,
		HasMore:    hasMore,
		NextCursor: nextCursor,
	}, nil
}

func (s *JobService) GetJob(ctx context.Context, id string) (*model.Job, error) {
	job, err := s.jobRepository.GetByID(ctx, id)
	if err != nil {
		return nil, err
	}
	return job, nil
}

func (s *JobService) GetNextJob(ctx context.Context) (*model.Job, error) {
	if s.queue == nil {
		return nil, errors.New("job queue is unavailable")
	}

	for {
		job, err := s.queue.Dequeue(ctx)
		if err != nil || job == nil {
			return job, err
		}

		fresh, err := s.jobRepository.GetByID(ctx, job.ID)
		if err != nil {
			if errors.Is(err, gorm.ErrRecordNotFound) {
				continue
			}
			return nil, err
		}
		if !s.canDispatchJob(fresh) {
			continue
		}
		return fresh, nil
	}
}

func (s *JobService) SubscribeSystemResources(ctx context.Context) (<-chan dto.SystemResource, error) {
	if s.pubsub == nil {
		return nil, errors.New("job pubsub is unavailable")
	}
	return s.pubsub.SubscribeResources(ctx)
}

func (s *JobService) SubscribeJobLogs(ctx context.Context, jobID string) (<-chan dto.LogEntry, error) {
	if s.pubsub == nil {
		return nil, errors.New("job pubsub is unavailable")
	}
	return s.pubsub.Subscribe(ctx, jobID)
}

func (s *JobService) SubscribeCancel(ctx context.Context, agentID string) (<-chan string, error) {
	if s.pubsub == nil {
		return nil, errors.New("job pubsub is unavailable")
	}
	return s.pubsub.SubscribeCancel(ctx, agentID)
}

func (s *JobService) SubscribeJobUpdates(ctx context.Context) (<-chan string, error) {
	if s.pubsub == nil {
		return nil, errors.New("job pubsub is unavailable")
	}
	return s.pubsub.SubscribeJobUpdates(ctx)
}

func (s *JobService) UpdateJobStatus(ctx context.Context, jobID string, status dto.JobStatus) error {
	job, err := s.jobRepository.GetByID(ctx, jobID)
	if err != nil {
		return err
	}
	currentStatus := s.jobStatus(job)
	if (currentStatus == dto.JobStatusCancelled || currentStatus == dto.JobStatusSuccess) && currentStatus != status {
		return nil
	}
	if currentStatus == status {
		return nil
	}

	now := time.Now()
	updated := false
	switch status {
	case dto.JobStatusRunning:
		updated, err = s.jobRepository.MarkJobStatusIfCurrent(ctx, jobID, []string{string(dto.JobStatusPending)}, string(status), now, false)
	case dto.JobStatusSuccess:
		updated, err = s.jobRepository.MarkJobStatusIfCurrent(ctx, jobID, []string{string(dto.JobStatusRunning)}, string(status), now, true)
		if err == nil && updated {
			err = s.removeFromQueue(ctx, jobID)
		}
	default:
		updated, err = s.jobRepository.MarkJobStatusIfCurrent(ctx, jobID, []string{string(currentStatus)}, string(status), now, status == dto.JobStatusFailure || status == dto.JobStatusCancelled)
	}
	if err != nil {
		return err
	}
	if !updated {
		return nil
	}
	cfg := parseJobConfig(job.Config)
	if err := syncVideoStatus(ctx, s.jobRepository, cfg.VideoID, status); err != nil {
		return err
	}
	return s.publishJobUpdate(ctx, jobID, string(status), cfg.VideoID)
}

func (s *JobService) AssignJob(ctx context.Context, jobID string, agentID string) error {
	job, err := s.jobRepository.GetByID(ctx, jobID)
	if err != nil {
		return err
	}
	if !s.canDispatchJob(job) {
		return fmt.Errorf("job %s is not dispatchable", jobID)
	}

	agentNumeric, err := strconv.ParseInt(agentID, 10, 64)
	if err != nil {
		return err
	}
	updated, err := s.jobRepository.AssignPendingJob(ctx, jobID, agentNumeric, time.Now())
	if err != nil {
		return err
	}
	if !updated {
		return fmt.Errorf("job %s is not dispatchable", jobID)
	}
	cfg := parseJobConfig(job.Config)
	if err := syncVideoStatus(ctx, s.jobRepository, cfg.VideoID, dto.JobStatusRunning); err != nil {
		return err
	}
	return s.publishJobUpdate(ctx, jobID, string(dto.JobStatusRunning), cfg.VideoID)
}

func (s *JobService) CancelJob(ctx context.Context, jobID string) error {
	job, err := s.jobRepository.GetByID(ctx, jobID)
	if err != nil {
		return fmt.Errorf("job not found: %w", err)
	}
	updated, err := s.jobRepository.CancelJobIfActive(ctx, jobID, time.Now())
	if err != nil {
		return err
	}
	if !updated {
		return fmt.Errorf("cannot cancel job with status %s", s.jobStatus(job))
	}
	cfg := parseJobConfig(job.Config)
	if err := syncVideoStatus(ctx, s.jobRepository, cfg.VideoID, dto.JobStatusCancelled); err != nil {
		return err
	}
	_ = s.publishJobUpdate(ctx, jobID, string(dto.JobStatusCancelled), cfg.VideoID)
	if err := s.removeFromQueue(ctx, job.ID); err != nil {
		return err
	}
	if job.AgentID != nil && s.pubsub != nil {
		_ = s.pubsub.PublishCancel(ctx, strconv.FormatInt(*job.AgentID, 10), job.ID)
	}
	return s.publishLog(ctx, jobID, "[SYSTEM] Job cancelled by admin", -1)
}

func (s *JobService) RetryJob(ctx context.Context, jobID string) (*model.Job, error) {
	job, err := s.jobRepository.GetByID(ctx, jobID)
	if err != nil {
		return nil, fmt.Errorf("job not found: %w", err)
	}
	currentStatus := s.jobStatus(job)
	if currentStatus != dto.JobStatusFailure && currentStatus != dto.JobStatusCancelled {
		return nil, fmt.Errorf("cannot retry job with status %s", currentStatus)
	}
	if err := s.requeueJob(ctx, job, false); err != nil {
		return nil, err
	}
	if s.dlq != nil {
		_ = s.dlq.Remove(ctx, jobID)
	}
	return s.jobRepository.GetByID(ctx, jobID)
}

func (s *JobService) UpdateJobProgress(ctx context.Context, jobID string, progress float64) error {
	job, err := s.jobRepository.GetByID(ctx, jobID)
	if err != nil {
		return err
	}
	now := time.Now()
	job.Progress = float64Ptr(progress)
	job.UpdatedAt = &now
	if err := s.jobRepository.Save(ctx, job); err != nil {
		return err
	}
	return s.publishLog(ctx, jobID, "", progress)
}

func (s *JobService) ProcessLog(ctx context.Context, jobID string, logData []byte) error {
	line := string(logData)
	re := regexp.MustCompile(`out_time_us=(\d+)`)
	matches := re.FindStringSubmatch(line)
	var progress float64
	if len(matches) > 1 {
		us, _ := strconv.ParseInt(matches[1], 10, 64)
		if us > 0 {
			progress = float64(us) / 1000000.0
		}
	}
	job, err := s.jobRepository.GetByID(ctx, jobID)
	if err != nil {
		return err
	}
	existingLogs := ""
	if job.Logs != nil {
		existingLogs = *job.Logs
	}
	newLog := line
	if !strings.HasSuffix(newLog, "\n") {
		newLog += "\n"
	}
	existingLogs += newLog
	if len(existingLogs) > 10*1024*1024 {
		existingLogs = existingLogs[len(existingLogs)-8*1024*1024:]
	}
	now := time.Now()
	job.Logs = &existingLogs
	if progress > 0 {
		job.Progress = float64Ptr(progress)
	}
	job.UpdatedAt = &now
	if err := s.jobRepository.Save(ctx, job); err != nil {
		return err
	}
	return s.publishLog(ctx, jobID, line, progress)
}

func syncVideoStatus(ctx context.Context, jobRepository JobRepository, videoID string, status dto.JobStatus) error {
	videoID = strings.TrimSpace(videoID)
	if videoID == "" {
		return nil
	}

	statusValue := "processing"
	processingStatus := "PROCESSING"
	switch status {
	case dto.JobStatusSuccess:
		statusValue = "ready"
		processingStatus = "READY"
	case dto.JobStatusFailure, dto.JobStatusCancelled:
		statusValue = "failed"
		processingStatus = "FAILED"
	}

	return jobRepository.UpdateVideoStatus(ctx, videoID, statusValue, processingStatus)
}

func (s *JobService) PublishSystemResources(ctx context.Context, agentID string, data []byte) error {
	if s.pubsub == nil {
		return errors.New("job pubsub is unavailable")
	}
	return s.pubsub.PublishResource(ctx, agentID, data)
}

func (s *JobService) StartInflightReclaimLoop(ctx context.Context, interval time.Duration, batchSize int64) {
	if interval <= 0 {
		interval = 30 * time.Second
	}
	if s.logger != nil {
		s.logger.Info("started inflight reclaim loop", "interval", interval.String(), "batch_size", batchSize)
	}
	ticker := time.NewTicker(interval)
	defer ticker.Stop()
	for {
		select {
		case <-ctx.Done():
			if s.logger != nil {
				s.logger.Info("stopped inflight reclaim loop")
			}
			return
		case <-ticker.C:
			_ = s.reclaimExpiredOnce(ctx, batchSize)
		}
	}
}

func (s *JobService) reclaimExpiredOnce(ctx context.Context, batchSize int64) error {
	type expirable interface {
		ListExpiredInflight(ctx context.Context, now time.Time, limit int64) ([]string, error)
	}
	queue, ok := s.queue.(expirable)
	if !ok {
		return nil
	}
	startedAt := time.Now()
	jobIDs, err := queue.ListExpiredInflight(ctx, time.Now(), batchSize)
	if err != nil {
		if s.logger != nil {
			s.logger.Error("failed to list expired inflight jobs", "error", err)
		}
		return err
	}
	for _, jobID := range jobIDs {
		_ = s.handleExpiredInflightJob(ctx, jobID)
	}
	if s.logger != nil && len(jobIDs) > 0 {
		s.logger.Info("completed inflight reclaim batch", "expired_count", len(jobIDs), "duration_ms", time.Since(startedAt).Milliseconds())
	}
	return nil
}

func (s *JobService) handleExpiredInflightJob(ctx context.Context, jobID string) error {
	job, err := s.jobRepository.GetByID(ctx, jobID)
	if err != nil {
		if s.logger != nil {
			s.logger.Warn("failed to load expired inflight job", "job_id", jobID, "error", err)
		}
		return err
	}
	status := s.jobStatus(job)
	if s.logger != nil {
		s.logger.Warn("processing expired inflight job", "job_id", jobID, "current_status", status)
	}
	switch status {
	case dto.JobStatusRunning:
		return s.HandleJobFailure(ctx, jobID, "lease_expired")
	case dto.JobStatusPending, dto.JobStatusSuccess, dto.JobStatusFailure, dto.JobStatusCancelled:
		return s.removeFromQueue(ctx, jobID)
	default:
		return s.removeFromQueue(ctx, jobID)
	}
}

func (s *JobService) RenewJobLease(ctx context.Context, jobID string) error {
	type touchable interface {
		TouchInflight(ctx context.Context, jobID string, ttl time.Duration) error
	}
	queue, ok := s.queue.(touchable)
	if !ok {
		return nil
	}
	return queue.TouchInflight(ctx, jobID, 15*time.Minute)
}

func (s *JobService) HandleDispatchFailure(ctx context.Context, jobID string, reason string, retryable bool) error {
	job, err := s.jobRepository.GetByID(ctx, jobID)
	if err != nil {
		return err
	}
	if !retryable {
		return s.moveJobToDLQ(ctx, job, reason)
	}
	return s.requeueOrDLQ(ctx, job, reason)
}

func (s *JobService) HandleJobFailure(ctx context.Context, jobID string, reason string) error {
	job, err := s.jobRepository.GetByID(ctx, jobID)
	if err != nil {
		return err
	}
	return s.requeueOrDLQ(ctx, job, reason)
}

func (s *JobService) HandleAgentDisconnect(ctx context.Context, jobID string) error {
	job, err := s.jobRepository.GetByID(ctx, jobID)
	if err != nil {
		return err
	}
	return s.requeueOrDLQ(ctx, job, "agent_unregistered")
}

func (s *JobService) requeueOrDLQ(ctx context.Context, job *model.Job, reason string) error {
	if job == nil {
		return nil
	}
	willRetry := s.canAutoRetry(job)
	if s.logger != nil {
		s.logger.Warn("evaluating retry vs dlq", "job_id", job.ID, "reason", reason, "retry_count", s.retryCount(job), "max_retries", s.maxRetries(job), "will_retry", willRetry)
	}
	if !willRetry {
		return s.moveJobToDLQ(ctx, job, reason)
	}
	return s.requeueJob(ctx, job, true)
}

func (s *JobService) requeueJob(ctx context.Context, job *model.Job, incrementRetry bool) error {
	if job == nil {
		return nil
	}
	if s.queue == nil {
		return errors.New("job queue is unavailable")
	}

	pending := string(dto.JobStatusPending)
	cancelled := false
	progress := 0.0
	now := time.Now()
	job.Status = &pending
	job.Cancelled = &cancelled
	job.Progress = &progress
	job.AgentID = nil
	job.UpdatedAt = &now
	if incrementRetry {
		job.RetryCount = int64Ptr(s.retryCount(job) + 1)
		job.Logs = appendSystemLog(job.Logs, fmt.Sprintf("[SYSTEM] Auto-retry scheduled at %s", now.UTC().Format(time.RFC3339)))
	}
	if err := s.jobRepository.Save(ctx, job); err != nil {
		return err
	}
	cfg := parseJobConfig(job.Config)
	if err := syncVideoStatus(ctx, s.jobRepository, cfg.VideoID, dto.JobStatusPending); err != nil {
		return err
	}
	if err := s.queue.Enqueue(ctx, job); err != nil {
		return err
	}
	if s.logger != nil {
		s.logger.Info("requeued job", "job_id", job.ID, "retry_count", s.retryCount(job), "max_retries", s.maxRetries(job), "action", "requeue")
	}
	return s.publishJobUpdate(ctx, job.ID, pending, cfg.VideoID)
}

func (s *JobService) moveJobToDLQ(ctx context.Context, job *model.Job, reason string) error {
	if job == nil {
		return nil
	}
	failure := string(dto.JobStatusFailure)
	now := time.Now()
	job.Status = &failure
	job.AgentID = nil
	job.UpdatedAt = &now
	job.Logs = appendSystemLog(job.Logs, fmt.Sprintf("[SYSTEM] Sent to DLQ: %s", strings.TrimSpace(reason)))
	if err := s.jobRepository.Save(ctx, job); err != nil {
		return err
	}
	cfg := parseJobConfig(job.Config)
	if err := syncVideoStatus(ctx, s.jobRepository, cfg.VideoID, dto.JobStatusFailure); err != nil {
		return err
	}
	if err := s.removeFromQueue(ctx, job.ID); err != nil {
		return err
	}
	if s.dlq != nil {
		if err := s.dlq.Add(ctx, job, strings.TrimSpace(reason)); err != nil {
			return err
		}
		if s.logger != nil {
			dlqCount, _ := s.dlq.Count(ctx)
			s.logger.Warn("moved job to dlq", "job_id", job.ID, "reason", strings.TrimSpace(reason), "retry_count", s.retryCount(job), "max_retries", s.maxRetries(job), "dlq_size", dlqCount)
		}
	}
	return s.publishJobUpdate(ctx, job.ID, failure, cfg.VideoID)
}

func (s *JobService) canDispatchJob(job *model.Job) bool {
	if job == nil {
		return false
	}
	if job.Cancelled != nil && *job.Cancelled {
		return false
	}
	return s.jobStatus(job) == dto.JobStatusPending
}

func (s *JobService) canAutoRetry(job *model.Job) bool {
	return s.retryCount(job) < s.maxRetries(job)
}

func (s *JobService) retryCount(job *model.Job) int64 {
	if job == nil || job.RetryCount == nil {
		return 0
	}
	return *job.RetryCount
}

func (s *JobService) maxRetries(job *model.Job) int64 {
	if job == nil || job.MaxRetries == nil || *job.MaxRetries <= 0 {
		return 3
	}
	return *job.MaxRetries
}

func (s *JobService) jobStatus(job *model.Job) dto.JobStatus {
	if job == nil || job.Status == nil {
		return dto.JobStatusPending
	}
	return dto.JobStatus(strings.TrimSpace(*job.Status))
}

func (s *JobService) publishJobUpdate(ctx context.Context, jobID string, status string, videoID string) error {
	if s.pubsub == nil {
		return nil
	}
	return s.pubsub.PublishJobUpdate(ctx, jobID, status, videoID)
}

func (s *JobService) publishLog(ctx context.Context, jobID string, logLine string, progress float64) error {
	if s.pubsub == nil {
		return nil
	}
	return s.pubsub.Publish(ctx, jobID, logLine, progress)
}

func (s *JobService) ListDLQ(ctx context.Context, offset, limit int) ([]*dto.DLQEntry, int64, error) {
	if s.dlq == nil {
		return []*dto.DLQEntry{}, 0, nil
	}
	if offset < 0 {
		offset = 0
	}
	if limit <= 0 {
		limit = 20
	}
	entries, err := s.dlq.List(ctx, int64(offset), int64(limit))
	if err != nil {
		return nil, 0, err
	}
	count, err := s.dlq.Count(ctx)
	if err != nil {
		return nil, 0, err
	}
	items := make([]*dto.DLQEntry, 0, len(entries))
	for _, entry := range entries {
		items = append(items, &dto.DLQEntry{Job: entry.Job, FailureTime: entry.FailureTime.Unix(), Reason: entry.Reason, RetryCount: entry.RetryCount})
	}
	return items, count, nil
}

func (s *JobService) GetDLQ(ctx context.Context, id string) (*dto.DLQEntry, error) {
	if s.dlq == nil {
		return nil, fmt.Errorf("job not found in DLQ")
	}
	entry, err := s.dlq.Get(ctx, strings.TrimSpace(id))
	if err != nil {
		return nil, err
	}
	return &dto.DLQEntry{Job: entry.Job, FailureTime: entry.FailureTime.Unix(), Reason: entry.Reason, RetryCount: entry.RetryCount}, nil
}

func (s *JobService) RetryDLQ(ctx context.Context, id string) (*model.Job, error) {
	if s.dlq == nil {
		return nil, fmt.Errorf("job not found in DLQ")
	}
	job, err := s.dlq.Retry(ctx, strings.TrimSpace(id))
	if err != nil {
		return nil, err
	}
	if job == nil {
		return nil, fmt.Errorf("job not found in DLQ")
	}
	if err := s.requeueJob(ctx, job, false); err != nil {
		return nil, err
	}
	if s.logger != nil {
		count, _ := s.dlq.Count(ctx)
		s.logger.Info("retried job from dlq", "job_id", job.ID, "dlq_size", count)
	}
	return s.jobRepository.GetByID(ctx, job.ID)
}

func (s *JobService) RemoveDLQ(ctx context.Context, id string) error {
	if s.dlq == nil {
		return fmt.Errorf("job not found in DLQ")
	}
	jobID := strings.TrimSpace(id)
	if err := s.dlq.Remove(ctx, jobID); err != nil {
		return err
	}
	if s.logger != nil {
		count, _ := s.dlq.Count(ctx)
		s.logger.Info("removed job from dlq", "job_id", jobID, "dlq_size", count)
	}
	return nil
}

func (s *JobService) removeFromQueue(ctx context.Context, jobID string) error {
	type ackable interface {
		Ack(ctx context.Context, jobID string) error
	}
	if queue, ok := s.queue.(ackable); ok {
		return queue.Ack(ctx, jobID)
	}
	return nil
}

func appendSystemLog(logs *string, line string) *string {
	line = strings.TrimSpace(line)
	if line == "" {
		return logs
	}
	existing := ""
	if logs != nil {
		existing = *logs
	}
	if existing != "" && !strings.HasSuffix(existing, "\n") {
		existing += "\n"
	}
	existing += line + "\n"
	return &existing
}