import java.util.Random;

/**
 * Simulates downloading a single chunk of a file.
 *
 * <p>This class is intentionally provided as a skeleton for students.
 * The main multithreading and simulation logic should be completed
 * in the run() method.</p>
 */
public class DownloadWorker implements Runnable {

    private final ChunkStatus chunkStatus;
    private final DownloadConfig config;
    private final Random random;

    public DownloadWorker(ChunkStatus chunkStatus, DownloadConfig config) {
        this.chunkStatus = chunkStatus;
        this.config = config;
        this.random = new Random();
    }

    @Override
    public void run() {
        // TODO: Record the chunk start time in chunkStatus.
        double downloaded = 0.0;
        chunkStatus.setStartTimeMs(System.currentTimeMillis());
        chunkStatus.setDownloadedMB(downloaded);

        // TODO: Print a message that this chunk has started downloading.
        System.out.println("Chunk #" + chunkStatus.getChunkId() + " started downloading.");

        while (downloaded < chunkStatus.getChunkSizeMB()) {
            // 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.
            int delay = config.getMinStepDelayMs() + random.nextInt(config.getMaxStepDelayMs() - config.getMinStepDelayMs());
            try {
                Thread.sleep(delay);
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }

            downloaded+=0.5;

            if (downloaded > chunkStatus.getChunkSizeMB())
                downloaded = chunkStatus.getChunkSizeMB();
            chunkStatus.setDownloadedMB(downloaded);

        }


        // 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.setEndTimeMs(System.currentTimeMillis());
        chunkStatus.setCompleted(true);
        System.out.println("Chunk #" + chunkStatus.getChunkId() + " finished downloading.");
    }

}