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.
        chunkStatus.setStartTimeMs(System.currentTimeMilliS()) ;
        double downloaded = 0.0;

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

        while (downloaded < chunkStatus.getChunkSizeMB()) {
            // TODO: Generate a random sleep delay between min and max delay.
            int minDelay = config.getMinStepDelayMs() ;
            int maxDelay = config.getMaxStepDalayMs() ;
            int delay = minDelay + random.nextInt(maxDelay-minDelay +1) ;

            // TODO: Sleep for that delay.
            Thread.sleep(delay) ;
            // TODO: Generate a random download amount for this step.
            double minStep = config.getMinStepDownloadMB() ;
            double maxStep = config.getMaxStepDownloadMB() ;
            double stepDownload = minStep +  ((maxStep-minStep)*random.nextDouble()) ;


            // TODO: Increase downloaded, but do not go beyond chunk size.
            downloaded += stepDownload ;
            if (downloaded > chunkStatus.getChunkSizeMB())
            {
                downloaded  = chunkStatus.getChunkSizeMB() ;
            }

            // TODO: Save the updated downloaded value into chunkStatus.
                chunkStatus.setDownloadedMB(downloaded) ;
            // TODO: Optionally print step-by-step progress.
        }


        // TODO: Mark the chunk as completed.
        chunkStatus.setCompleted(true );
        // TODO: Record the chunk end time in chunkStatus.
        chunkStatus.setEndTimeMs(System.currentTimeMillis()) ;
        // TODO: Print a message that this chunk has finished downloading.
        System.out.println(Thread.currentThread().getName() + " finished downloading Chunk #" + chunkStatus.getChunkId());
    }

}