package eu.siacs.conversations.xml;

import android.util.Log;

import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.TimeUnit;

import eu.siacs.conversations.Config;
import eu.siacs.conversations.xmpp.stanzas.AbstractStanza;

public class TagWriter {

	private OutputStreamWriter outputStream;
	private boolean finished = false;
	private LinkedBlockingQueue<AbstractStanza> writeQueue = new LinkedBlockingQueue<AbstractStanza>();
	private CountDownLatch stanzaWriterCountDownLatch = null;

	private Thread asyncStanzaWriter = new Thread() {

		@Override
		public void run() {
			stanzaWriterCountDownLatch = new CountDownLatch(1);
			while (!isInterrupted()) {
				if (finished && writeQueue.size() == 0) {
					break;
				}
				try {
					AbstractStanza output = writeQueue.take();
					outputStream.write(output.toString());
					if (writeQueue.size() == 0) {
						outputStream.flush();
					}
				} catch (Exception e) {
					break;
				}
			}
			stanzaWriterCountDownLatch.countDown();
		}

	};

	public TagWriter() {
	}

	public synchronized void setOutputStream(OutputStream out) throws IOException {
		if (out == null) {
			throw new IOException();
		}
		this.outputStream = new OutputStreamWriter(out);
	}

	public TagWriter beginDocument() throws IOException {
		if (outputStream == null) {
			throw new IOException("output stream was null");
		}
		outputStream.write("<?xml version='1.0'?>");
		outputStream.flush();
		return this;
	}

	public synchronized  TagWriter writeTag(Tag tag) throws IOException {
		if (outputStream == null) {
			throw new IOException("output stream was null");
		}
		outputStream.write(tag.toString());
		outputStream.flush();
		return this;
	}

	public synchronized TagWriter writeElement(Element element) throws IOException {
		if (outputStream == null) {
			throw new IOException("output stream was null");
		}
		outputStream.write(element.toString());
		outputStream.flush();
		return this;
	}

	public TagWriter writeStanzaAsync(AbstractStanza stanza) {
		if (finished) {
			Log.d(Config.LOGTAG,"attempting to write stanza to finished TagWriter");
			return this;
		} else {
			if (!asyncStanzaWriter.isAlive()) {
				try {
					asyncStanzaWriter.start();
				} catch (IllegalThreadStateException e) {
					// already started
				}
			}
			writeQueue.add(stanza);
			return this;
		}
	}

	public void finish() {
		this.finished = true;
	}

	public boolean await(long timeout, TimeUnit timeunit) throws InterruptedException {
		if (stanzaWriterCountDownLatch == null) {
			return true;
		} else {
			return stanzaWriterCountDownLatch.await(timeout, timeunit);
		}
	}

	public boolean isActive() {
		return outputStream != null;
	}

	public synchronized void forceClose() {
		asyncStanzaWriter.interrupt();
		if (outputStream != null) {
			try {
				outputStream.close();
			} catch (IOException e) {
				//ignoring
			}
		}
		outputStream = null;
	}
}
