package redis.clients.util;

import java.io.Closeable;
import java.util.NoSuchElementException;
import org.apache.commons.pool2.PooledObjectFactory;
import org.apache.commons.pool2.impl.GenericObjectPool;
import org.apache.commons.pool2.impl.GenericObjectPoolConfig;
import org.slf4j.Logger;
import redis.clients.common.utils.Loggers;
import redis.clients.jedis.exceptions.JedisConnectionException;
import redis.clients.jedis.exceptions.JedisException;
import redis.clients.jedis.exceptions.JedisExhaustedPoolException;

public abstract class Pool<T> implements Closeable {

	protected static Logger logger = Loggers.jedisLogger;
	protected GenericObjectPool<T> internalPool;

	/**
	 * Using this constructor means you have to set and initialize the internalPool
	 * yourself.
	 */
	public Pool() {
	}

	public Pool(final GenericObjectPoolConfig poolConfig, PooledObjectFactory<T> factory) {
		initPool(poolConfig, factory);
	}

	@Override
	public void close() {
		destroy();
	}

	public boolean isClosed() {
		return this.internalPool.isClosed();
	}

	public void initPool(final GenericObjectPoolConfig poolConfig, PooledObjectFactory<T> factory) {

		if (this.internalPool != null) {
			try {
				closeInternalPool();
			} catch (Exception e) {
			}
		}

		this.internalPool = new GenericObjectPool<T>(factory, poolConfig);
	}

	public T getResource() {
		try {
			return internalPool.borrowObject();
		} catch (NoSuchElementException nse) {
			if (null == nse.getCause()) { // The exception was caused by an exhausted pool
				throw new JedisExhaustedPoolException("Could not get a resource since the pool is exhausted", nse);
			}
			// Otherwise, the exception was caused by the implemented activateObject() or
			// ValidateObject()
			throw new JedisException("Could not get a resource from the pool", nse);
		} catch (Exception e) {
			throw new JedisConnectionException("Could not get a resource from the pool", e);
		}
	}

	/**
	 * @deprecated starting from Jedis 3.0 this method will not be exposed. Resource
	 *             cleanup should be done using @see
	 *             {@link io.jedis#close()}
	 */
	@Deprecated
	public void returnResourceObject(final T resource) {
		if (resource == null) {
			return;
		}
		try {
			internalPool.returnObject(resource);
		} catch (Exception e) {
			throw new JedisException("Could not return the resource to the pool", e);
		}
	}

	/**
	 * @deprecated starting from Jedis 3.0 this method will not be exposed. Resource
	 *             cleanup should be done using @see
	 *             {@link io.jedis#close()}
	 */
	@Deprecated
	public void returnBrokenResource(final T resource) {
		if (resource != null) {
			returnBrokenResourceObject(resource);
		}
	}

	/**
	 * @deprecated starting from Jedis 3.0 this method will not be exposed. Resource
	 *             cleanup should be done using @see
	 *             {@link io.jedis#close()}
	 */
	@Deprecated
	public void returnResource(final T resource) {
		if (resource != null) {
			returnResourceObject(resource);
		}
	}

	public void destroy() {
		closeInternalPool();
	}

	protected void returnBrokenResourceObject(final T resource) {
		try {
			internalPool.invalidateObject(resource);
		} catch (Exception e) {
			throw new JedisException("Could not return the resource to the pool", e);
		}
	}

	protected void closeInternalPool() {
		try {
			internalPool.close();
		} catch (Exception e) {
			throw new JedisException("Could not destroy the pool", e);
		}
	}

	/**
	 * Returns the number of instances currently borrowed from this pool.
	 *
	 * @return The number of instances currently borrowed from this pool, -1 if the
	 *         pool is inactive.
	 */
	public int getNumActive() {
		if (poolInactive()) {
			return -1;
		}

		return this.internalPool.getNumActive();
	}

	/**
	 * Returns the number of instances currently idle in this pool.
	 *
	 * @return The number of instances currently idle in this pool, -1 if the pool
	 *         is inactive.
	 */
	public int getNumIdle() {
		if (poolInactive()) {
			return -1;
		}

		return this.internalPool.getNumIdle();
	}

	/**
	 * Returns an estimate of the number of threads currently blocked waiting for a
	 * resource from this pool.
	 *
	 * @return The number of threads waiting, -1 if the pool is inactive.
	 */
	public int getNumWaiters() {
		if (poolInactive()) {
			return -1;
		}

		return this.internalPool.getNumWaiters();
	}

	/**
	 * Returns the mean waiting time spent by threads to obtain a resource from this
	 * pool.
	 *
	 * @return The mean waiting time, in milliseconds, -1 if the pool is inactive.
	 */
	public long getMeanBorrowWaitTimeMillis() {
		if (poolInactive()) {
			return -1;
		}

		return this.internalPool.getMeanBorrowWaitTimeMillis();
	}

	/**
	 * Returns the maximum waiting time spent by threads to obtain a resource from
	 * this pool.
	 *
	 * @return The maximum waiting time, in milliseconds, -1 if the pool is
	 *         inactive.
	 */
	public long getMaxBorrowWaitTimeMillis() {
		if (poolInactive()) {
			return -1;
		}

		return this.internalPool.getMaxBorrowWaitTimeMillis();
	}

	private boolean poolInactive() {
		return this.internalPool == null || this.internalPool.isClosed();
	}

	public void addObjects(int count) {
		try {
			for (int i = 0; i < count; i++) {
				this.internalPool.addObject();
			}
		} catch (Exception e) {
			throw new JedisException("Error trying to add idle objects", e);
		}
	}
}