[feature] Implement Sharp graceful degradation

tests/unit/utilsDocService.tests.js

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+ * All the Product's GUI elements, including illustrations and icon sets, as
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+
+const {describe, test, expect} = require('@jest/globals');
+const sharp = require('./../../DocService/node_modules/sharp');
+const operationContext = require('./../../Common/sources/operationContext');
+const utilsDocService = require('./../../DocService/sources/utilsDocService');
+
+describe('utilsDocService image processing', () => {
+  const ctx = operationContext.global;
+
+  describe('determineOptimalFormat', () => {
+    test('should choose PNG for images with alpha channel', () => {
+      const metadata = {
+        hasAlpha: true,
+        width: 400,
+        height: 300,
+        channels: 4
+      };
+      
+      const format = utilsDocService.determineOptimalFormat(ctx, metadata);
+      expect(format).toBe('png');
+    });
+
+    test('should choose PNG for small images (icons/logos)', () => {
+      const metadata = {
+        hasAlpha: false,
+        width: 128,
+        height: 128,
+        channels: 3
+      };
+      
+      const format = utilsDocService.determineOptimalFormat(ctx, metadata);
+      expect(format).toBe('png');
+    });
+
+
+    test('should choose JPEG for large images', () => {
+      const metadata = {
+        hasAlpha: false,
+        width: 1200,
+        height: 800,
+        channels: 3
+      };
+      
+      const format = utilsDocService.determineOptimalFormat(ctx, metadata);
+      expect(format).toBe('jpeg');
+    });
+
+    test('should choose PNG for exact small image boundary (256x256)', () => {
+      const metadata = {
+        hasAlpha: false,
+        width: 256,
+        height: 256,
+        channels: 3
+      };
+      
+      const format = utilsDocService.determineOptimalFormat(ctx, metadata);
+      expect(format).toBe('png');
+    });
+
+    test('should choose JPEG for exact large image boundary (800x600)', () => {
+      const metadata = {
+        hasAlpha: false,
+        width: 800,
+        height: 600,
+        channels: 3
+      };
+      
+      const format = utilsDocService.determineOptimalFormat(ctx, metadata);
+      expect(format).toBe('jpeg');
+    });
+
+    test('should choose JPEG as default when no specific conditions match', () => {
+      const metadata = {
+        hasAlpha: false,
+        width: 400,
+        height: 300,
+        channels: 3
+      };
+      
+      const format = utilsDocService.determineOptimalFormat(ctx, metadata);
+      expect(format).toBe('jpeg');
+    });
+  });
+
+
+  describe('processImageOptimal', () => {
+    test('should handle EXIF rotation and WebP conversion to JPEG for large images', async () => {
+      // Create a large WebP image with EXIF orientation that should be converted to JPEG
+      const webpImage = await sharp({
+        create: {width: 1000, height: 600, channels: 3, background: {r: 100, g: 150, b: 200}}
+      })
+      .composite([{
+        input: await sharp({
+          create: {width: 200, height: 120, channels: 3, background: {r: 200, g: 100, b: 50}}
+        }).png().toBuffer(),
+        top: 100,
+        left: 200
+      }])
+      .withMetadata({orientation: 6}) // rotate 90 degrees
+      .webp()
+      .toBuffer();
+      
+      const result = await utilsDocService.processImageOptimal(ctx, webpImage);
+      const metadata = await sharp(result).metadata();
+      
+      expect(metadata.format).toBe('jpeg');
+      expect(Buffer.compare(webpImage, result) !== 0).toBe(true);
+    });
+
+    test('should handle EXIF rotation and WebP conversion to PNG for small images', async () => {
+      // Create a small WebP image with EXIF orientation that should be converted to PNG
+      const webpImage = await sharp({
+        create: {width: 100, height: 100, channels: 3, background: {r: 255, g: 255, b: 255}}
+      })
+      .withMetadata({orientation: 3}) // rotate 180 degrees
+      .webp()
+      .toBuffer();
+      
+      const result = await utilsDocService.processImageOptimal(ctx, webpImage);
+      const metadata = await sharp(result).metadata();
+      
+      expect(metadata.format).toBe('png');
+      expect(Buffer.compare(webpImage, result) !== 0).toBe(true);
+    });
+
+    test('should handle EXIF rotation and TIFF conversion to optimal format', async () => {
+      // Create a medium-sized TIFF image with EXIF orientation (should use JPEG)
+      const tiffImage = await sharp({
+        create: {width: 900, height: 600, channels: 3, background: {r: 255, g: 255, b: 255}}
+      })
+      .withMetadata({orientation: 8}) // rotate 270 degrees
+      .tiff()
+      .toBuffer();
+      
+      const result = await utilsDocService.processImageOptimal(ctx, tiffImage);
+      const metadata = await sharp(result).metadata();
+      
+      expect(metadata.format).toBe('jpeg'); // large image should use JPEG
+      expect(Buffer.compare(tiffImage, result) !== 0).toBe(true);
+    });
+
+    test('should handle EXIF rotation for standard JPEG without format conversion', async () => {
+      // Create a JPEG image with EXIF orientation
+      const jpegImage = await sharp({
+        create: {width: 400, height: 300, channels: 3, background: {r: 255, g: 100, b: 50}}
+      })
+      .withMetadata({orientation: 6}) // rotate 90 degrees
+      .jpeg()
+      .toBuffer();
+      
+      const result = await utilsDocService.processImageOptimal(ctx, jpegImage);
+      const metadata = await sharp(result).metadata();
+      
+      expect(metadata.format).toBe('jpeg');
+      expect(Buffer.compare(jpegImage, result) !== 0).toBe(true);
+    });
+
+    test('should not modify images without EXIF rotation and unsupported formats', async () => {
+      // Create a standard PNG without EXIF orientation
+      const pngImage = await sharp({
+        create: {width: 400, height: 300, channels: 3, background: {r: 255, g: 255, b: 255}}
+      }).png().toBuffer();
+      
+      const result = await utilsDocService.processImageOptimal(ctx, pngImage);
+      
+      expect(Buffer.compare(pngImage, result) === 0).toBe(true);
+    });
+
+    test('should handle WebP with transparency (alpha channel)', async () => {
+      // Create WebP with alpha channel - should convert to PNG
+      const webpImage = await sharp({
+        create: {width: 400, height: 300, channels: 4, background: {r: 255, g: 255, b: 255, alpha: 0.5}}
+      }).webp().toBuffer();
+      
+      const result = await utilsDocService.processImageOptimal(ctx, webpImage);
+      const metadata = await sharp(result).metadata();
+      
+      expect(metadata.format).toBe('png'); // alpha channel should force PNG
+      expect(metadata.hasAlpha).toBe(true);
+    });
+
+    test('should handle HEIC conversion to optimal format', async () => {
+      // Note: Sharp may not support HEIC creation, so this test might need adjustment
+      // For now testing the code path exists
+      const mockHeicBuffer = Buffer.from('mock-heic-data');
+      
+      // Test doesn't crash with invalid HEIC data
+      const result = await utilsDocService.processImageOptimal(ctx, mockHeicBuffer);
+      expect(result).toEqual(mockHeicBuffer); // Should return original on error
+    });
+
+    test('should handle corrupted image data gracefully', async () => {
+      const corruptedBuffer = Buffer.from('not-an-image');
+      
+      const result = await utilsDocService.processImageOptimal(ctx, corruptedBuffer);
+      expect(result).toEqual(corruptedBuffer); // Should return original on error
+    });
+
+    test('should handle null input', async () => {
+      const result = await utilsDocService.processImageOptimal(ctx, null);
+      expect(result).toBeNull();
+    });
+
+    test('should handle empty buffer', async () => {
+      const emptyBuffer = Buffer.alloc(0);
+      const result = await utilsDocService.processImageOptimal(ctx, emptyBuffer);
+      expect(result).toEqual(emptyBuffer);
+    });
+
+    test('should produce valid JPEG output with reasonable quality', async () => {
+      // Create a large WebP that should convert to JPEG
+      const webpImage = await sharp({
+        create: {width: 1000, height: 600, channels: 3, background: {r: 100, g: 150, b: 200}}
+      }).webp().toBuffer();
+      
+      const result = await utilsDocService.processImageOptimal(ctx, webpImage);
+      const metadata = await sharp(result).metadata();
+      
+      expect(metadata.format).toBe('jpeg');
+      expect(metadata.width).toBe(1000);
+      expect(metadata.height).toBe(600);
+      // JPEG should be a reasonable size (not empty, but also not excessively large)
+      expect(result.length).toBeGreaterThan(1000); // Not too compressed
+      expect(result.length).toBeLessThan(500000); // Not excessively large for 1000x600
+    });
+
+    test('should produce smaller PNG than uncompressed for simple graphics', async () => {
+      // Create a TIFF with simple graphics that should convert to PNG
+      const tiffImage = await sharp({
+        create: {width: 200, height: 150, channels: 3, background: {r: 255, g: 255, b: 255}}
+      })
+      .composite([{
+        input: await sharp({
+          create: {width: 50, height: 50, channels: 3, background: {r: 255, g: 0, b: 0}}
+        }).png().toBuffer(),
+        top: 50,
+        left: 75
+      }])
+      .tiff().toBuffer();
+      
+      const result = await utilsDocService.processImageOptimal(ctx, tiffImage);
+      const metadata = await sharp(result).metadata();
+      
+      expect(metadata.format).toBe('png'); // small image should use PNG
+      expect(metadata.width).toBe(200);
+      expect(metadata.height).toBe(150);
+      // PNG should be compressed but reasonable size
+      expect(result.length).toBeGreaterThan(500);
+      expect(result.length).toBeLessThan(100000); // Should be well compressed
+    });
+  });
+});