import java.util.List;

public class ProgressMonitor implements Runnable {

    private final String fileName;
    private final int totalSizeMB;
    private final List<ChunkStatus> chunks;
    private final long monitorDelayMs;

    public ProgressMonitor(DownloadConfig config, List<ChunkStatus> chunks) {
        this.fileName = config.getFileName();
        this.totalSizeMB = config.getTotalSizeMB();
        this.chunks = chunks;
        this.monitorDelayMs = 500;
    }

    @Override
    public void run() {
        // TODO:
        // Repeatedly check chunk progress until all chunks are completed.
        // In each loop:
        // 1. Read the downloaded size from every chunk
        // 2. Add all downloaded amounts to totalDownloadedMB
        // 3. Count completed chunks
        // 4. Print a progress message
        // 5. If completedChunks == chunks.size(), print a final monitor message and stop
        // 6. Otherwise sleep for monitorDelayMs and continue
        while (true){
            double totalDownloadedMB = 0.0;
            int completedChunks = 0;

            for (ChunkStatus chunk : chunks){
                totalDownloadedMB += chunk.getDownloadedMB();

                if (chunk.isCompleted()){
                    completedChunks++;
                }
            }
            double percent = 0.0;
            if (totalSizeMB > 0){
                percent = (totalDownloadedMB * 100.0) / totalSizeMB;
            }
            System.out.printf("Progress for %s: %.1f/%.1f MB (%.2f%%), completed chunks: %d/%d%n", fileName, totalDownloadedMB, (double) totalSizeMB, percent, completedChunks, chunks.size());

            // TODO:
            // If all chunks are completed, print a final message and exit the loop
            if (completedChunks == chunks.size()){
                System.out.println("Monitor: All chunks have been successfully downloaded.");
                break;
            }
            try {
                Thread.sleep(monitorDelayMs);
            } catch (InterruptedException e) {
                System.out.println("Progress monitor interrupted.");
                return;
            }
        }
    }
}