Refactor

src/test/java/com/imgfloat/app/ChannelDirectoryServiceTest.java

@@ -8,6 +8,10 @@ import com.imgfloat.app.model.Channel;
 import com.imgfloat.app.repository.AssetRepository;
 import com.imgfloat.app.repository.ChannelRepository;
 import com.imgfloat.app.service.ChannelDirectoryService;
+import com.imgfloat.app.service.AssetStorageService;
+import com.imgfloat.app.service.media.MediaDetectionService;
+import com.imgfloat.app.service.media.MediaOptimizationService;
+import com.imgfloat.app.service.media.MediaPreviewService;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.mockito.ArgumentCaptor;
@@ -52,8 +56,12 @@ class ChannelDirectoryServiceTest {
         setupInMemoryPersistence();
         Path assetRoot = Files.createTempDirectory("imgfloat-assets-test");
         Path previewRoot = Files.createTempDirectory("imgfloat-previews-test");
+        AssetStorageService assetStorageService = new AssetStorageService(assetRoot.toString(), previewRoot.toString());
+        MediaPreviewService mediaPreviewService = new MediaPreviewService();
+        MediaOptimizationService mediaOptimizationService = new MediaOptimizationService(mediaPreviewService);
+        MediaDetectionService mediaDetectionService = new MediaDetectionService();
         service = new ChannelDirectoryService(channelRepository, assetRepository, messagingTemplate,
-                assetRoot.toString(), previewRoot.toString());
+                assetStorageService, mediaDetectionService, mediaOptimizationService);
     }
 
     @Test

src/test/java/com/imgfloat/app/service/AssetStorageServiceTest.java

@@ -0,0 +1,57 @@
+package com.imgfloat.app.service;
+
+import com.imgfloat.app.service.media.AssetContent;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+class AssetStorageServiceTest {
+    private AssetStorageService service;
+    private Path assets;
+    private Path previews;
+
+    @BeforeEach
+    void setUp() throws IOException {
+        assets = Files.createTempDirectory("asset-storage-service");
+        previews = Files.createTempDirectory("preview-storage-service");
+        service = new AssetStorageService(assets.toString(), previews.toString());
+    }
+
+    @Test
+    void refusesToStoreEmptyAsset() {
+        assertThatThrownBy(() -> service.storeAsset("caster", "id", new byte[0], "image/png"))
+                .isInstanceOf(IOException.class)
+                .hasMessageContaining("empty");
+    }
+
+    @Test
+    void storesAndLoadsAssets() throws IOException {
+        byte[] bytes = new byte[]{1, 2, 3};
+
+        String path = service.storeAsset("caster", "id", bytes, "image/png");
+        assertThat(Files.exists(Path.of(path))).isTrue();
+
+        AssetContent loaded = service.loadAssetFile(path, "image/png").orElseThrow();
+        assertThat(loaded.bytes()).containsExactly(bytes);
+        assertThat(loaded.mediaType()).isEqualTo("image/png");
+    }
+
+    @Test
+    void ignoresEmptyPreview() throws IOException {
+        assertThat(service.storePreview("caster", "id", new byte[0])).isNull();
+    }
+
+    @Test
+    void storesAndLoadsPreviews() throws IOException {
+        byte[] preview = new byte[]{9, 8, 7};
+
+        String path = service.storePreview("caster", "id", preview);
+        assertThat(service.loadPreview(path)).isPresent();
+    }
+}

src/test/java/com/imgfloat/app/service/media/MediaDetectionServiceTest.java

@@ -0,0 +1,34 @@
+package com.imgfloat.app.service.media;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.mock.web.MockMultipartFile;
+
+import java.io.IOException;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class MediaDetectionServiceTest {
+    private final MediaDetectionService service = new MediaDetectionService();
+
+    @Test
+    void prefersProvidedContentType() throws IOException {
+        MockMultipartFile file = new MockMultipartFile("file", "image.png", "image/png", new byte[]{1, 2, 3});
+
+        assertThat(service.detectMediaType(file, file.getBytes())).isEqualTo("image/png");
+    }
+
+    @Test
+    void fallsBackToFilenameAndStream() throws IOException {
+        byte[] png = new byte[]{(byte) 0x89, 0x50, 0x4E, 0x47};
+        MockMultipartFile file = new MockMultipartFile("file", "picture.png", null, png);
+
+        assertThat(service.detectMediaType(file, file.getBytes())).isEqualTo("image/png");
+    }
+
+    @Test
+    void returnsOctetStreamForUnknownType() throws IOException {
+        MockMultipartFile file = new MockMultipartFile("file", "unknown.bin", null, new byte[]{1, 2, 3});
+
+        assertThat(service.detectMediaType(file, file.getBytes())).isEqualTo("application/octet-stream");
+    }
+}

src/test/java/com/imgfloat/app/service/media/MediaOptimizationServiceTest.java

@@ -0,0 +1,53 @@
+package com.imgfloat.app.service.media;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import javax.imageio.ImageIO;
+import java.awt.image.BufferedImage;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class MediaOptimizationServiceTest {
+    private MediaOptimizationService service;
+
+    @BeforeEach
+    void setUp() {
+        service = new MediaOptimizationService(new MediaPreviewService());
+    }
+
+    @Test
+    void returnsNullForEmptyInput() throws IOException {
+        assertThat(service.optimizeAsset(new byte[0], "image/png")).isNull();
+    }
+
+    @Test
+    void optimizesPngImages() throws IOException {
+        byte[] png = samplePng();
+
+        OptimizedAsset optimized = service.optimizeAsset(png, "image/png");
+
+        assertThat(optimized).isNotNull();
+        assertThat(optimized.mediaType()).isEqualTo("image/png");
+        assertThat(optimized.width()).isEqualTo(2);
+        assertThat(optimized.height()).isEqualTo(2);
+        assertThat(optimized.previewBytes()).isNull();
+    }
+
+    @Test
+    void returnsNullForUnsupportedBytes() throws IOException {
+        OptimizedAsset optimized = service.optimizeAsset(new byte[]{1, 2, 3}, "application/octet-stream");
+
+        assertThat(optimized).isNull();
+    }
+
+    private byte[] samplePng() throws IOException {
+        BufferedImage image = new BufferedImage(2, 2, BufferedImage.TYPE_INT_ARGB);
+        try (ByteArrayOutputStream out = new ByteArrayOutputStream()) {
+            ImageIO.write(image, "png", out);
+            return out.toByteArray();
+        }
+    }
+}