package de.podfetcher.asynctask;

import de.podfetcher.storage.DownloadRequester;
import de.podfetcher.feed.*;
import de.podfetcher.R;
import android.content.Context;
import android.app.DownloadManager;
import android.util.Log;
import android.database.Cursor;
import java.util.concurrent.Callable;
import android.os.AsyncTask;

/** Observes the status of a specific Download */
public class DownloadObserver extends
		AsyncTask<FeedFile, DownloadStatus, Boolean> {
	private static final String TAG = "DownloadObserver";

	/** Types of downloads to observe. */
	public static final int TYPE_FEED = 0;
	public static final int TYPE_IMAGE = 1;
	public static final int TYPE_MEDIA = 2;

	/** Error codes */
	public static final int ALREADY_DOWNLOADED = 1;
	public static final int NO_DOWNLOAD_FOUND = 2;

	private final long DEFAULT_WAITING_INTERVALL = 1000L;

	private DownloadRequester requester;
	private Context context;
	private DownloadStatus[] statusList;

	public DownloadObserver(Context context) {
		super();
		this.context = context;
		requester = DownloadRequester.getInstance();
	}

	@Override
	protected void onCancelled(Boolean result) {
		Log.d(TAG, "Task was cancelled.");
	}

	protected Boolean doInBackground(FeedFile... files) {
		Log.d(TAG, "Background Task started.");
		statusList = new DownloadStatus[files.length];
		for (int i = 0; i < files.length; i++) {
			FeedFile feedfile = files[i];
			statusList[i] = new DownloadStatus(feedfile);

			if (feedfile.getFile_url() == null) {
				statusList[i].reason = NO_DOWNLOAD_FOUND;
				statusList[i].successful = false;
				statusList[i].done = true;
			}

			if (feedfile.isDownloaded()) {
				statusList[i].reason = ALREADY_DOWNLOADED;
				statusList[i].successful = false;
				statusList[i].done = true;
			}
		}

		while (downloadsLeft() && !isCancelled()) {
			for (DownloadStatus status : statusList) {
				if (status.done == false) {
					Cursor cursor = getDownloadCursor(status.feedfile);
					int statusId = getDownloadStatus(cursor,
							DownloadManager.COLUMN_STATUS);
					getDownloadProgress(cursor, status);
					switch (statusId) {
					case DownloadManager.STATUS_SUCCESSFUL:
						status.statusMsg = R.string.download_successful;
						status.successful = true;
						status.done = true;
					case DownloadManager.STATUS_RUNNING:
						status.statusMsg = R.string.download_running;
						break;
					case DownloadManager.STATUS_FAILED:
						status.statusMsg = R.string.download_failed;
						requester.notifyDownloadService(context);
						status.successful = false;
						status.done = true;
						status.reason = getDownloadStatus(cursor,
								DownloadManager.COLUMN_REASON);
					case DownloadManager.STATUS_PENDING:
						status.statusMsg = R.string.download_pending;
						break;
					default:
						status.done = true;
						status.successful = false;
						status.statusMsg = R.string.download_cancelled_msg;
					}
				}
			}

			publishProgress(statusList);

			try {
				Thread.sleep(DEFAULT_WAITING_INTERVALL);
			} catch (InterruptedException e) {
				Log.w(TAG, "Thread was interrupted while waiting.");
			}
		}
		Log.d(TAG, "Background Task finished.");
		return Boolean.valueOf(true);
	}

	public Cursor getDownloadCursor(FeedFile feedfile) {
		DownloadManager.Query query = buildQuery(feedfile.getDownloadId());
		DownloadManager manager = (DownloadManager) context
				.getSystemService(Context.DOWNLOAD_SERVICE);

		Cursor result = manager.query(query);
		return result;
	}

	public int getDownloadStatus(Cursor c, String column) {
		if (c.moveToFirst()) {
			int status = c.getInt(c.getColumnIndex(column));
			return status;
		} else {
			return -1;
		}
	}

	private void getDownloadProgress(Cursor c, DownloadStatus status) {
		if (c.moveToFirst()) {
			status.size = c.getLong(c
					.getColumnIndex(DownloadManager.COLUMN_TOTAL_SIZE_BYTES));
			status.soFar = c
					.getLong(c
							.getColumnIndex(DownloadManager.COLUMN_BYTES_DOWNLOADED_SO_FAR));
			status.progressPercent = (int) (((double) status.soFar / (double) status.size) * 100);
			Log.d(TAG, "Setting progress to " + status.progressPercent);
		}
	}

	private DownloadManager.Query buildQuery(long id) {
		DownloadManager.Query query = new DownloadManager.Query();
		query.setFilterById(id);
		return query;
	}

	public Context getContext() {
		return context;
	}

	public DownloadStatus[] getStatusList() {
		return statusList;
	}

	private boolean downloadsLeft() {
		boolean result = false;
		for (int i = 0; i < statusList.length; i++) {
			if (statusList[i].done == false) {
				return true;
			}
		}
		return result;
	}

}