Implement scheduler input claiming

docs/input-folder-scheduler-plan.md

@@ -22,7 +22,7 @@ Note: the local machine's filesystem root is read-only in this workspace, so abs
 2. [x] Add folder scheduler configuration properties.
 3. [x] Create startup directory initialization for input, output, working, processed, and rejected folders.
 4. [x] Add deterministic scanner that picks one candidate video at a time.
-5. [ ] Add repeat-prevention by moving selected inputs to a working folder before processing.
+5. [x] Add repeat-prevention by moving selected inputs to a working folder before processing.
 6. [ ] Add valid-video detection using extension filtering and `ffprobe`.
 7. [ ] Add invalid-file handling that logs the reason and moves files to rejected storage.
 8. [ ] Add FFmpeg clipping into `/output/clips/<video-name>/` using 8-second MP4/H.264/AAC segments.

src/main/java/org/example/videoclips/folder/FolderVideoScanScheduler.java

@@ -11,6 +11,7 @@ import java.io.IOException;
 import java.math.BigInteger;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.nio.file.StandardCopyOption;
 import java.util.Comparator;
 import java.util.Optional;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -38,7 +39,10 @@ public class FolderVideoScanScheduler {
 
         try {
             findNextCandidate().ifPresentOrElse(
-                    candidate -> log.info("Selected folder video candidate for processing: {}", candidate.getFileName()),
+                    candidate -> {
+                        Path workingFile = moveToWorking(candidate);
+                        log.info("Claimed folder video candidate for processing: {}", workingFile.getFileName());
+                    },
                     () -> log.debug("No folder video candidate found in {}", properties.getInputDirectory())
             );
         } finally {
@@ -46,6 +50,16 @@ public class FolderVideoScanScheduler {
         }
     }
 
+    Path moveToWorking(Path candidate) {
+        Path workingFile = Path.of(properties.getWorkingDirectory()).resolve(candidate.getFileName());
+        try {
+            return Files.move(candidate, workingFile, StandardCopyOption.ATOMIC_MOVE);
+        } catch (IOException ex) {
+            throw new IllegalStateException("Unable to move folder video candidate to working directory: "
+                    + candidate.getFileName(), ex);
+        }
+    }
+
     Optional<Path> findNextCandidate() {
         Path inputDirectory = Path.of(properties.getInputDirectory());
         if (!Files.isDirectory(inputDirectory)) {

src/test/java/org/example/videoclips/folder/FolderVideoScanSchedulerTest.java

@@ -92,6 +92,8 @@ class FolderVideoScanSchedulerTest {
         scheduler.scan();
 
         assertFalse(((AtomicBoolean) scanningField.get(scheduler)).get());
+        assertFalse(Files.exists(tempDir.resolve("1.mp4")));
+        assertTrue(Files.exists(tempDir.resolve("working/1.mp4")));
     }
 
     @Test
@@ -105,9 +107,38 @@ class FolderVideoScanSchedulerTest {
         assertFalse(((AtomicBoolean) scanningField.get(scheduler)).get());
     }
 
+    @Test
+    void claimedCandidateIsNotSelectedAgain() throws Exception {
+        Files.writeString(tempDir.resolve("1.mp4"), "video");
+        FolderVideoScanScheduler scheduler = scheduler(tempDir);
+
+        scheduler.scan();
+
+        assertTrue(scheduler.findNextCandidate().isEmpty());
+        assertEquals("video", Files.readString(tempDir.resolve("working/1.mp4")));
+    }
+
+    @Test
+    void failsWhenCandidateCannotBeMovedToWorkingDirectory() throws Exception {
+        Path candidate = Files.writeString(tempDir.resolve("1.mp4"), "video");
+        Files.writeString(tempDir.resolve("working"), "not a directory");
+
+        assertThrows(IllegalStateException.class, () -> scheduler(tempDir).moveToWorking(candidate));
+        assertTrue(Files.exists(candidate));
+    }
+
     private FolderVideoScanScheduler scheduler(Path inputDirectory) {
         VideoClippingProperties properties = new VideoClippingProperties();
         properties.getFolderScheduler().setInputDirectory(inputDirectory.toString());
+        Path workingDirectory = tempDir.resolve("working");
+        if (!Files.exists(workingDirectory)) {
+            try {
+                Files.createDirectory(workingDirectory);
+            } catch (Exception ex) {
+                throw new IllegalStateException(ex);
+            }
+        }
+        properties.getFolderScheduler().setWorkingDirectory(workingDirectory.toString());
         return new FolderVideoScanScheduler(properties);
     }
 }