finishing DownloadWorker, ProgressMonitor, and Main

src/main/java/DownloadWorker.java

@@ -22,22 +22,53 @@ public class DownloadWorker implements Runnable {
     @Override
     public void run() {
         // TODO: Record the chunk start time in chunkStatus.
+        chunkStatus.setStartTimeMs(System.currentTimeMillis());
         double downloaded = 0.0;
+        System.out.printf("[%s] Started — Chunk #%d (%.1f MB)%n",
+                Thread.currentThread().getName(),
+                chunkStatus.getChunkId(),
+                chunkStatus.getChunkSizeMB());
 
         // TODO: Print a message that this chunk has started downloading.
 
         while (downloaded < chunkStatus.getChunkSizeMB()) {
+            int delay = config.getMinStepDelayMs()
+                    + random.nextInt(config.getMaxStepDelayMs() - config.getMinStepDelayMs() + 1);
+
             // TODO: Generate a random sleep delay between min and max delay.
             // TODO: Sleep for that delay.
             // TODO: Generate a random download amount for this step.
             // TODO: Increase downloaded, but do not go beyond chunk size.
             // TODO: Save the updated downloaded value into chunkStatus.
             // TODO: Optionally print step-by-step progress.
-        }
+            try {
+                Thread.sleep(delay);
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+                return;
+            }
+            double step = config.getMinStepDownloadMB()
+                    + random.nextDouble() * (config.getMaxStepDownloadMB() - config.getMinStepDownloadMB());
+            downloaded = Math.min(downloaded + step, chunkStatus.getChunkSizeMB());
+            chunkStatus.setDownloadedMB(downloaded);
+            System.out.printf("[%s] Chunk #%d → %.2f / %.1f MB (%.1f%%)%n",
+                    Thread.currentThread().getName(),
+                    chunkStatus.getChunkId(),
+                    chunkStatus.getDownloadedMB(),
+                    chunkStatus.getChunkSizeMB(),
+                    chunkStatus.getProgressPercentage());
+            }
 
         // TODO: Mark the chunk as completed.
         // TODO: Record the chunk end time in chunkStatus.
         // TODO: Print a message that this chunk has finished downloading.
-    }
+    chunkStatus.setCompleted(true);
+    chunkStatus.setEndTimeMs(System.currentTimeMillis());
+
+        System.out.printf("[%s] Finished — Chunk #%d in %d ms%n",
+                Thread.currentThread().getName(),
+                chunkStatus.getChunkId(),
+                chunkStatus.getDownloadDurationMs());
+}
 
 }