package org.apache.kyuubi.engine.jdbc.session;

import org.apache.kyuubi.config.KyuubiConf;
import org.apache.kyuubi.engine.jdbc.connection.JdbcConnectionProvider;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.io.PrintWriter;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;
import java.util.Date;
import java.util.Properties;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.Semaphore;
import java.util.concurrent.TimeUnit;

/**
 *  自实现的基于 JdbcConnectionProvider 的数据源 连接池
 * @author zhaopx
 */

public class SimpleDataSource implements PooledDataSource {

	final Logger log = LoggerFactory.getLogger(SimpleDataSource.class);

	/**
	 * 缓存的池子
	 */
	private final ConcurrentMap<JdbcConnectionWrapper, Date> pool = new ConcurrentHashMap<JdbcConnectionWrapper, Date>();

	/**
	 * 5 个连接，最大
	 */
	private int maxSize = 10;

	/**
	 * 最小连接数
	 */
	private int minSize = 1;

	/**
	 * 连接等待时间
	 */
	private int waitTime = 30000;
	
	private Semaphore semaphore;

	private final Properties connProps = new Properties();


	private JdbcConnectionProvider jdbcConnectionProvider;
	private KyuubiConf kyuubiConf;
	
	public SimpleDataSource(JdbcConnectionProvider jdbcConnectionProvider, KyuubiConf kyuubiConf) {
		this.jdbcConnectionProvider = jdbcConnectionProvider;
		this.kyuubiConf = kyuubiConf;
		this.maxSize = Math.max(Integer.parseInt(kyuubiConf.getOption("kyuubi.engine.jdbc.pool.maxSize").getOrElse(()-> "10")), 10);
		this.minSize = Math.max(Integer.parseInt(kyuubiConf.getOption("kyuubi.engine.jdbc.pool.minSize").getOrElse(()-> "1")), 1);
		this.waitTime = Math.max(Integer.parseInt(kyuubiConf.getOption("kyuubi.engine.jdbc.pool.maxWait").getOrElse(()-> "30000")), 1000);
		initConnections();
	}

	private void initConnections() {
		log.info("Initializing simple data source{ pool.max = " + maxSize + ", pool.min = " + minSize + "}");
		semaphore = new Semaphore(maxSize, false);
		if (minSize > 0 && minSize < maxSize) {
			try {
				// 尝试获得连接
				Connection conn = getRealConnection(null, null);
				conn.close();
			} catch (SQLException e) {
				throw new RuntimeException(e);
			}
		}
	}

	public void close() throws IOException {
		Exception ex = null;
		for (JdbcConnectionWrapper conn : pool.keySet()) {
			try {
				conn.directClose();
			} catch (Exception e) { ex = e; }
		}
		pool.clear();
		if(ex != null) {
			throw new IOException(ex);
		}
		log.info("closed data source{ pool.max = " + maxSize + ", pool.min = " + minSize + "}");
	}

	/**
	 * 关闭连接，这里是软关闭
	 * @param realConnection
	 * @throws SQLException
	 */
	private void closeConnection(Connection realConnection, Connection proxyConnection) throws SQLException {
		synchronized (pool) {
			if (pool.size() <= maxSize && realConnection instanceof JdbcConnectionWrapper && ((JdbcConnectionWrapper)realConnection).isValidFlag()) {
				// 正常的连接不关闭，放到池中
				pool.put((JdbcConnectionWrapper)realConnection, new Date());
				return;
			} else if(pool.size() <= maxSize && !(realConnection instanceof JdbcConnectionWrapper)) {
				pool.put(new JdbcConnectionWrapper(proxyConnection, realConnection), new Date());
				return;
			}
		}
		try {
			realConnection.close();
		} finally {
			semaphore.release();
		}
	}

	/**
	 * 关闭连接，这里是软关闭
	 * @param realConnection
	 * @throws SQLException
	 */
	public void closeConnectionAndRemove(Connection realConnection) throws SQLException {
		if(realConnection == null) {
			return;
		}
		synchronized (pool) {
			// 从缓存移除
			if(realConnection instanceof JdbcConnectionWrapper) {
				pool.remove((JdbcConnectionWrapper) realConnection);
			} else {
				pool.remove(realConnection);
			}
		}
		try {
			if(realConnection instanceof JdbcConnectionWrapper) {
				((JdbcConnectionWrapper)realConnection).directClose();
			} else {
				realConnection.close();
			}
		} catch (Exception ignore) {
		} finally {
			semaphore.release();
		}
	}

	public Connection getConnection() throws SQLException {
		return getConnection(null, null);
	}

	public Connection getConnection(String username, String password) throws SQLException {		 
		synchronized (pool) {
			if (!pool.isEmpty()) {
				JdbcConnectionWrapper realConn = pool.keySet().iterator().next();
				pool.remove(realConn);
				if(realConn.isValidFlag()) {
					return realConn;
				}

				// hive jdbc 不支持设置  AutoCommit
				//realConn.setAutoCommit(true);
				return getProxyConnection(realConn);
			}
		}

		try {
			if (semaphore.tryAcquire(waitTime, TimeUnit.MILLISECONDS)) {
				return getProxyConnection(getRealConnection(username, password));
			} else {
				throw new RuntimeException("Connection pool is full: " + maxSize);
			}
		} catch (SQLException e) {
			semaphore.release();
			throw e;
		} catch (InterruptedException e) {
			throw new RuntimeException(e);
		}
	}
	
	private Connection getProxyConnection(final Connection realConnection) {
		InvocationHandler handler = new InvocationHandler() {
			public Object invoke(Object proxy, Method method, Object[] params) throws Exception {
				Object ret = null;
				if ("close".equals(method.getName())) {
					closeConnection(realConnection, (Connection)proxy);
				} else if ("directClose".equals(method.getName())) {
					// 实际的关闭
					try {
						realConnection.close();
					} catch (Exception ignore) {}
					ret = Void.TYPE.newInstance();
				} else if ("unwrap".equals(method.getName())) {
					ret = realConnection;
				} else {
					ret = method.invoke(realConnection, params);
				}
				return ret;
			}
		};
		return new JdbcConnectionWrapper((JdbcConnection) Proxy.newProxyInstance(JdbcConnection.class.getClassLoader(), new Class[] { JdbcConnection.class }, handler), realConnection);
	}



	public Connection getRealConnection(String username, String password) throws SQLException {
		try {
			return jdbcConnectionProvider.getConnection(kyuubiConf);
		} catch (Exception e) {
			throw new SQLException(e);
		}
	}

	public void setProperties(Properties properties){
		this.connProps.putAll(properties);
	}
	
	public PrintWriter getLogWriter() throws SQLException {
		return null;
	}

	public void setLogWriter(PrintWriter out) throws SQLException {
	}

	public void setLoginTimeout(int seconds) throws SQLException {

	}

	public int getLoginTimeout() throws SQLException {
		return 0;
	}

	public java.util.logging.Logger getParentLogger() throws SQLFeatureNotSupportedException {
		return null;
	}

	public <T> T unwrap(Class<T> iface) throws SQLException {
		return null;
	}

	public boolean isWrapperFor(Class<?> iface) throws SQLException {
		return false;
	}


	public void setIdleValidationQuery(int idleInSeconds,String validationQuery){
		//do noting
	}

	public int getMaxSize() {
		return maxSize;
	}

	public int getMinSize() {
		return minSize;
	}

	public int getWaitTime() {
		return waitTime;
	}

	public Properties getConnProps() {
		return connProps;
	}

	/**
	 * 返回内置的绑定
	 * @return
	 */
	public Set<JdbcConnectionWrapper> getPoolSet() {
		return pool.keySet();
	}
}