package org.omicron.mysql;

import server.Constants;
import server.Server;

import java.sql.ResultSet;
import java.util.List;
import java.util.Queue;
import java.util.Vector;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.atomic.AtomicBoolean;

/**
 * @author Omicron
 */
public final class ConnectionProcessor implements Runnable {

	static {
		try {
			Class.forName("com.mysql.jdbc.Driver");
		} catch (ClassNotFoundException e) {
			throw new AssertionError(e);
		}
	}

	private final MySQLConnection connection;
	private final String username;
	private final String password;
	private final Thread thread;
	private boolean running;
	private final ConcurrentLinkedQueue<Item> items = new ConcurrentLinkedQueue<> ();
	private final Object lock = new Object();

	public ConnectionProcessor(MySQLConnection connection, String username, String password) {
		this.connection = connection;
		this.username = username;
		this.password = password;
		this.thread = new Thread(this);
	}

	public void start() {
		if (running) {
			throw new IllegalStateException("The processor is already running.");
		}
		thread.start();
	}

	public void stop() {
		if (!running) {
			throw new IllegalStateException("The processor is already stopped.");
		}
		running = false;
	}

	public boolean isConnected() {
		if (Server.getWorld() == Constants.TEST_WORLD) {
			return true;
		}
		return connection.isConnected();
	}

	@Override
	public void run() {
		if (Server.getWorld() == Constants.TEST_WORLD) {
			return;
		}
		running = true;
		MainLoop:
		while (running) {
			if (!connection.isConnected()) {
				while (!connection.safeConnect(username, password));
			}
			if (!connection.statementConnected()) {
				connection.close();
				while (!connection.safeConnect(username, password));
			}
			synchronized (lock) {
				while (!items.isEmpty()) {
					Item item = items.peek();
					if (!item.canExecute()) {
						items.remove();
						continue;
					}
					if (!item.execute(connection)) {
						continue MainLoop;
					}
					items.remove();
				}
			}
			synchronized (this) {
				try {
					this.wait();
				} catch (InterruptedException ignored) {
				}
			}
		}
		connection.close();
	}

	public boolean executeQuery(Query query) {
		if (Server.getWorld() == Constants.TEST_WORLD) {
			return true;
		}
		if (!connection.isConnected()) {
			synchronized (this) {
				notify();
			}
			return false;
		}
		boolean result = items.offer(query);
		synchronized (this) {
			notify();
		}
		return result;
	}

	public boolean forceQuery(Query query) {
		if (Server.getWorld() == Constants.TEST_WORLD) {
			return true;
		}
		boolean result = items.offer(query);
		synchronized (this) {
			notify();
		}
		return result;
	}

	public boolean executeUpdate(Update update) {
		if (Server.getWorld() == Constants.TEST_WORLD) {
			return true;
		}
		boolean result = items.offer(update);
		synchronized (this) {
			notify();
		}
		return result;
	}

	public ResultSet blockingQuery(String query) {
		synchronized (lock) {
			if (!connection.isConnected()) {
				return null;
			}
			return connection.executeQuery(query);
		}
	}
}