/*
 * IpmiConnector.java 
 * Created on 2011-09-08
 *
 * Copyright (c) Verax Systems 2011.
 * All rights reserved.
 *
 * This software is furnished under a license. Use, duplication,
 * disclosure and all other uses are restricted to the rights
 * specified in the written license agreement.
 */
package com.veraxsystems.vxipmi.api.sync;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.InetAddress;
import java.util.List;
import java.util.Random;

import org.apache.log4j.Logger;

import com.veraxsystems.vxipmi.api.async.ConnectionHandle;
import com.veraxsystems.vxipmi.api.async.IpmiAsyncConnector;
import com.veraxsystems.vxipmi.coding.commands.IpmiCommandCoder;
import com.veraxsystems.vxipmi.coding.commands.PrivilegeLevel;
import com.veraxsystems.vxipmi.coding.commands.ResponseData;
import com.veraxsystems.vxipmi.coding.commands.session.GetChannelAuthenticationCapabilitiesResponseData;
import com.veraxsystems.vxipmi.coding.payload.CompletionCode;
import com.veraxsystems.vxipmi.coding.payload.lan.IPMIException;
import com.veraxsystems.vxipmi.coding.security.CipherSuite;
import com.veraxsystems.vxipmi.common.PropertiesManager;
import com.veraxsystems.vxipmi.connection.Connection;
import com.veraxsystems.vxipmi.connection.ConnectionException;
import com.veraxsystems.vxipmi.connection.ConnectionManager;
import com.veraxsystems.vxipmi.connection.StateConnectionException;

/**
 * <p> Synchronous API for connecting to BMC via IPMI. </p> <p> Creating connection consists of the following steps:
 * <li>Create {@link Connection} and get associated with it {@link ConnectionHandle} via
 * {@link #createConnection(InetAddress)} <li>Get {@link CipherSuite}s that are available for the connection via
 * {@link #getAvailableCipherSuites(ConnectionHandle)} <li>Pick {@link CipherSuite} and {@link PrivilegeLevel} that will
 * be used during session and get {@link GetChannelAuthenticationCapabilitiesResponseData} to find out allowed
 * authentication options via
 * {@link #getChannelAuthenticationCapabilities(ConnectionHandle, CipherSuite, PrivilegeLevel)} <li>Provide username,
 * password and (if the BMC needs it) the BMC Kg key and start session via
 * {@link #openSession(ConnectionHandle, String, String, byte[])} </p> <br> <p> Send message register via
 * {@link #sendMessage(ConnectionHandle, IpmiCommandCoder)} </p> <br> <p> To close session call
 * {@link #closeSession(ConnectionHandle)} </p> <p> When done with work, clean up via {@link #tearDown()} </p> <br>
 */
public class IpmiConnector {

	private static final Logger logger = Logger.getLogger(IpmiConnector.class);

	private final IpmiAsyncConnector asyncConnector;

	private int retries;

	private int idleTime;

	private int timeout;

	private Random random = new Random(System.currentTimeMillis());

	/**
	 * Starts {@link IpmiConnector} and initiates the {@link ConnectionManager} at the given port. Wildcard IP address
	 * will be used.
	 * @param port
	 * - the port that will be used by {@link IpmiAsyncConnector} to communicate with the remote hosts.
	 * @throws FileNotFoundException
	 * when properties file was not found
	 * @throws IOException
	 * when properties file was not found
	 */
	public IpmiConnector(int port) throws FileNotFoundException, IOException {
		asyncConnector = new IpmiAsyncConnector(port);
		loadProperties();
	}

	/**
	 * Starts {@link IpmiConnector} and initiates the {@link ConnectionManager} at the given port and IP interface.
	 * @param port
	 * - the port that will be used by {@link IpmiAsyncConnector} to communicate with the remote hosts.
	 * @param address
	 * - the IP address that will be used by {@link IpmiAsyncConnector} to communicate with the remote hosts.
	 * @throws FileNotFoundException
	 * when properties file was not found
	 * @throws IOException
	 * when properties file was not found
	 */
	public IpmiConnector(int port, InetAddress address) throws FileNotFoundException, IOException {
		asyncConnector = new IpmiAsyncConnector(port, address);
		loadProperties();
	}

	private void loadProperties() throws IOException {
		PropertiesManager manager = PropertiesManager.getInstance();
		retries = Integer.parseInt(manager.getProperty("retries"));
		idleTime = Integer.parseInt(manager.getProperty("idleTime"));
	}

	/**
	 * Creates connection to the remote host.
	 * @param address
	 * - {@link InetAddress} of the remote host
	 * @return handle to the connection to the remote host
	 * @throws IOException
	 * when properties file was not found
	 * @throws FileNotFoundException
	 * when properties file was not found
	 */
	public ConnectionHandle createConnection(InetAddress address) throws FileNotFoundException, IOException {
		return asyncConnector.createConnection(address);
	}

	/**
	 * Gets {@link CipherSuite}s available for the connection with the remote host.
	 * @param connectionHandle
	 * {@link ConnectionHandle} to the connection created before
	 * @see #createConnection(InetAddress)
	 * @return list of the {@link CipherSuite}s that are allowed during the connection
	 * @throws Exception
	 * when sending message to the managed system fails
	 */
	public List<CipherSuite> getAvailableCipherSuites(ConnectionHandle connectionHandle) throws Exception {
		return asyncConnector.getAvailableCipherSuites(connectionHandle);
	}

	/**
	 * The method getAvailableCipherSuites fails on some IPMI, because it's an anonymous request and
	 * some IPMI interfaces don't like that.
	 * 
	 * So getAllCipherSuites simulate a request (and keep the state machine happy)
	 * but returns all cipher, without requesting the IPMI.
	 * 
	 * @param connectionHandle
	 * {@link ConnectionHandle} to the connection created before
	 * @see #createConnection(InetAddress)
	 * @return list of the {@link CipherSuite}s that are allowed during the connection
	 * @throws Exception
	 * when sending message to the managed system fails
	 */
	public List<CipherSuite> getAllCipherSuites(ConnectionHandle connectionHandle) throws Exception {
		return asyncConnector.getAllCipherSuites(connectionHandle);
	}

	/**
	 * Gets the authentication capabilities for the connection with the remote host.
	 * @param connectionHandle
	 * - {@link ConnectionHandle} associated with the host
	 * @param cipherSuite
	 * - {@link CipherSuite} that will be used during the connection
	 * @param requestedPrivilegeLevel
	 * - {@link PrivilegeLevel} that is requested for the session
	 * @return - {@link GetChannelAuthenticationCapabilitiesResponseData}
	 * @throws ConnectionException
	 * when connection is in the state that does not allow to perform this operation.
	 * @throws Exception
	 * when sending message to the managed system fails
	 */
	public GetChannelAuthenticationCapabilitiesResponseData getChannelAuthenticationCapabilities(
			ConnectionHandle connectionHandle, CipherSuite cipherSuite, PrivilegeLevel requestedPrivilegeLevel)
					throws Exception {
		return asyncConnector.getChannelAuthenticationCapabilities(connectionHandle, cipherSuite,
				requestedPrivilegeLevel);
	}

	/**
	 * Establishes the session with the remote host.
	 * @param connectionHandle
	 * - {@link ConnectionHandle} associated with the remote host.
	 * @param username
	 * - the username
	 * @param password
	 * - password matching the username
	 * @param bmcKey
	 * - the key that should be provided if the two-key authentication is enabled, null otherwise.
	 * @throws ConnectionException
	 * when connection is in the state that does not allow to perform this operation.
	 * @throws Exception
	 * when sending message to the managed system or initializing one of the cipherSuite's algorithms fails
	 */
	public void openSession(ConnectionHandle connectionHandle, String username, String password, byte[] bmcKey)
			throws Exception {
		asyncConnector.openSession(connectionHandle, username, password, bmcKey);
	}

	/**
	 * Closes the session with the remote host if it is currently in open state.
	 * @param connectionHandle
	 * - {@link ConnectionHandle} associated with the remote host.
	 * @throws ConnectionException
	 * when connection is in the state that does not allow to perform this operation.
	 * @throws Exception
	 * when sending message to the managed system or initializing one of the cipherSuite's algorithms fails
	 */
	public void closeSession(ConnectionHandle connectionHandle) throws Exception {
		asyncConnector.closeSession(connectionHandle);
	}

	/**
	 * Sends the IPMI message to the remote host.
	 * @param connectionHandle
	 * - {@link ConnectionHandle} associated with the remote host.
	 * @param request
	 * - {@link IpmiCommandCoder} containing the request to be sent
	 * @return {@link ResponseData} for the <b>request</b>
	 * @throws ConnectionException
	 * when connection is in the state that does not allow to perform this operation.
	 * @throws Exception
	 * when sending message to the managed system or initializing one of the cipherSuite's algorithms fails
	 */
	public ResponseData sendMessage(ConnectionHandle connectionHandle, IpmiCommandCoder request) throws Exception {
		int tries = 0;
		MessageListener listener = new MessageListener(connectionHandle);
		asyncConnector.registerListener(listener);
		ResponseData data = null;
		int previousTag = -1;
		while (data == null) {
			try {
				++tries;
				int tag = asyncConnector.sendMessage(connectionHandle, request);
				logger.debug("Sending message with tag " + tag + ", try " + tries + ", previous tag " + previousTag);
				previousTag = tag;
				data = listener.waitForAnswer(tag, timeout);
			} catch (IllegalArgumentException e) {
				throw e;
			} catch (InterruptedException e) {
				throw e;
			} catch (StateConnectionException e) {
				throw e;
			} catch (IPMIException e) {
				if (e.getCompletionCode() == CompletionCode.InitializationInProgress
						|| e.getCompletionCode() == CompletionCode.InsufficientResources
						|| e.getCompletionCode() == CompletionCode.NodeBusy
						|| e.getCompletionCode() == CompletionCode.Timeout) {
					if (tries > retries) {
						throw e;
					} else {
						long sleepTime = (random.nextLong() % (idleTime / 2)) + (idleTime / 2);
						Thread.sleep(sleepTime);
						logger.warn("Receiving message failed, retrying", e);
					}
				} else {
					throw e;
				}
			} catch (Exception e) {
				if (tries > retries) {
					throw e;
				} else {
					if(e instanceof IOException) {
						// Network exception common case, no stack needed
						logger.warn("Receiving message failed " + e.getMessage() + ", retrying");
					} else {
						// Unexcepted exception, needs investigation
						logger.warn("Receiving message failed, retrying", e);
					}
					long sleepTime = (random.nextLong() % (idleTime / 2)) + (idleTime / 2);
					Thread.sleep(sleepTime);
				}
			}
		}
		asyncConnector.unregisterListener(listener);
		return data;
	}

	/**
	 * Closes the connection with the given handle
	 */
	public void closeConnection(ConnectionHandle handle) {
		asyncConnector.closeConnection(handle);
	}

	/**
	 * Finalizes the connector and closes all connections.
	 */
	public void tearDown() {
		asyncConnector.tearDown();
	}

	/**
	 * Changes the timeout value for connection with the given handle.
	 * @param handle
	 * - {@link ConnectionHandle} associated with the remote host.
	 * @param timeout
	 * - new timeout value in ms
	 */
	public void setTimeout(ConnectionHandle handle, int timeout) {
		asyncConnector.setTimeout(handle, timeout);
		this.timeout = timeout;
	}
}