package org.openslx.bwlp.sat.fileserv;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

import org.apache.log4j.Logger;
import org.openslx.bwlp.sat.util.Constants;
import org.openslx.bwlp.sat.util.Formatter;
import org.openslx.bwlp.thrift.iface.ImageDetailsRead;
import org.openslx.bwlp.thrift.iface.TTransferRejectedException;
import org.openslx.bwlp.thrift.iface.UserInfo;
import org.openslx.filetransfer.Downloader;
import org.openslx.filetransfer.IncomingEvent;
import org.openslx.filetransfer.Listener;
import org.openslx.filetransfer.Uploader;

public class FileServer implements IncomingEvent {

	private static final Logger LOGGER = Logger.getLogger(FileServer.class);

	/**
	 * Listener for incoming unencrypted connections
	 */
	private final Listener plainListener = new Listener(this, null, 9092, Constants.TRANSFER_TIMEOUT); // TODO: Config
	
	private final ThreadPoolExecutor transferPool = new ThreadPoolExecutor(2, Constants.MAX_UPLOADS + Constants.MAX_DOWNLOADS, 1, TimeUnit.MINUTES, new ArrayBlockingQueue<Runnable>(1));

	/**
	 * All currently running uploads, indexed by token
	 */
	private final Map<String, ActiveUpload> uploads = new ConcurrentHashMap<>();

	private static final FileServer globalInstance = new FileServer();

	private FileServer() {
	}

	public static FileServer instance() {
		return globalInstance;
	}

	public boolean start() {
		boolean ret = plainListener.start();
		// TODO: Start SSL listener too
		return ret;
	}

	@Override
	public void incomingDownloadRequest(Uploader uploader) throws IOException {
		// TODO Auto-generated method stub

	}

	@Override
	public void incomingUploadRequest(Downloader downloader) throws IOException {
		String token = downloader.getToken();
		LOGGER.info("Incoming filetransfer with token " + token);
		ActiveUpload upload = uploads.get(token);
		if (upload == null) {
			LOGGER.warn("Unknown token " + token);
			downloader.cancel();
			return;
		}
		upload.addConnection(downloader, transferPool);
	}

	/**
	 * Get an upload instance by given token.
	 * 
	 * @param uploadToken
	 * @return
	 */
	public ActiveUpload getUploadByToken(String uploadToken) {
		return uploads.get(uploadToken);
	}

	public String createNewUserUpload(UserInfo owner, ImageDetailsRead image, long fileSize, List<ByteBuffer> sha1Sums)
			throws TTransferRejectedException {
		Iterator<ActiveUpload> it = uploads.values().iterator();
		int activeUploads = 0;
		while (it.hasNext()) {
			ActiveUpload upload = it.next();
			if (upload.isComplete()) {
				// TODO: Check age (short timeout) and remove
				continue;
			} else {
				// Check age (long timeout) and remove
			}
			activeUploads++;
		}
		if (activeUploads > Constants.MAX_UPLOADS)
			throw new TTransferRejectedException("Server busy. Too many running uploads.");
		File destinationFile = null;
		do {
			destinationFile = Formatter.getTempImageName();
		} while (destinationFile.exists());
		destinationFile.getParentFile().mkdirs();

		String key = UUID.randomUUID().toString();
		ActiveUpload upload;
		try {
			upload = new ActiveUpload(key, owner, image, destinationFile, fileSize, sha1Sums);
		} catch (FileNotFoundException e) {
			LOGGER.error("Could not open destination file for writing", e);
			throw new TTransferRejectedException("Destination file not writable!");
		}

		uploads.put(key, upload);
		return key;
	}

	public int getPlainPort() {
		return plainListener.getPort();
	}

	public int getSslPort() {
		return 0; // TODO
	}

}