ocr is working

backend/repository/ocr_jobs.go

@@ -3,6 +3,7 @@ package repository
 import (
 	"database/sql"
 	"errors"
+	"time"
 )
 
 // OcrJobRow maps ocr_jobs.
@@ -18,6 +19,9 @@ type OcrJobRow struct {
 // ErrJobNotFound marks an OCR job absent or owned by another device.
 var ErrJobNotFound = errors.New("ocr job not found")
 
+// ErrNoQueuedJobs marks an OCR queue drained (no job to claim).
+var ErrNoQueuedJobs = errors.New("no queued ocr jobs")
+
 type OcrJobs struct{ DB *sql.DB }
 
 func (o *OcrJobs) Create(jobID, deviceID, fileID string) error {
@@ -62,6 +66,49 @@ func (o *OcrJobs) TouchProcessing(deviceID, jobID string) error {
 	return err
 }
 
+// ClaimNext atomically picks the oldest queued job (FIFO) and moves it to
+// `processing`. Safe for concurrent workers: `FOR UPDATE SKIP LOCKED` blocks
+// the row as part of the same statement. Empty queue → ErrNoQueuedJobs.
+func (o *OcrJobs) ClaimNext() (OcrJobRow, error) {
+	var row OcrJobRow
+	err := o.DB.QueryRow(
+		`WITH next AS (
+		    SELECT job_id FROM ocr_jobs
+		    WHERE status = 'queued'
+		    ORDER BY created_at, job_id
+		    LIMIT 1
+		    FOR UPDATE SKIP LOCKED
+		)
+		UPDATE ocr_jobs
+		SET status = 'processing', started_at = NOW()
+		FROM next
+		WHERE ocr_jobs.job_id = next.job_id
+		RETURNING ocr_jobs.job_id, ocr_jobs.file_id, ocr_jobs.device_id, ocr_jobs.status`,
+	).Scan(&row.ID, &row.FileID, &row.DeviceID, &row.Status)
+	if err == sql.ErrNoRows {
+		return OcrJobRow{}, ErrNoQueuedJobs
+	}
+	if err != nil {
+		return OcrJobRow{}, err
+	}
+	return row, nil
+}
+
+// ResetStaleProcessing requeues jobs stuck in `processing` (worker crash /
+// processus redémarré) et plus vieux que `olderThan`. Retourne le nb de jobs
+// requeued.
+func (o *OcrJobs) ResetStaleProcessing(olderThan time.Duration) (int64, error) {
+	res, err := o.DB.Exec(
+		`UPDATE ocr_jobs SET status = 'queued', started_at = NULL
+		 WHERE status = 'processing' AND started_at < $1`,
+		time.Now().Add(-olderThan),
+	)
+	if err != nil {
+		return 0, err
+	}
+	return res.RowsAffected()
+}
+
 func (o *OcrJobs) Complete(deviceID, jobID, text string) error {
 	_, err := o.DB.Exec(
 		`UPDATE ocr_jobs SET status = 'done', text = NULLIF($3, ''), started_at = COALESCE(started_at, NOW()), completed_at = NOW()