package serveur.modele.persistance.pool;

import java.util.*;
import java.sql.*;

import serveur.modele.transfertobject.ConnectionDBTO;



public class ConnectionPoolManager {


	private final int MAX_POOL_SIZE = 10;
	private final int NB_MS_DELAIS_CONNECTION = 1000;

	String server = "";
	String port = "";

	String databaseUrl = "";
	String userName = "";
	String password = "";

	Vector<Connection> connectionPool = new Vector<Connection>();

	static ConnectionPoolManager instance;

	ConnectionDBTO connectionBDTO;


	public static ConnectionPoolManager getInstance() {
		if(instance == null) {
			instance = new ConnectionPoolManager();
		}
		return instance;
	}

	public ConnectionDBTO getConnectionDBTO(){

		if(connectionBDTO != null)
			return connectionBDTO;
		else
			return  new ConnectionDBTO(server, port, userName, password);
	}

	public void setConnectionBDTO(ConnectionDBTO myConnectionBDTO){

		server = myConnectionBDTO.server;
		port = myConnectionBDTO.port;

		databaseUrl = "";
		userName = myConnectionBDTO.userName;
		password = myConnectionBDTO.password;

		connectionBDTO = new ConnectionDBTO(server, port, userName, password);
	}

	private ConnectionPoolManager() {
		initialize();
	}

	public ConnectionPoolManager(
		//String databaseName,
		String databaseUrl,
		String userName,
		String password
		) {
		this.databaseUrl = databaseUrl;
		this.userName = userName;
		this.password = password;
		initialize();
	}

	private void initialize() {
		//Here we can initialize all the information that we need
		initializeConnectionPool();
	}

	private void initializeConnectionPool() {
		while(!checkIfConnectionPoolIsFull()) {
			//System.out.println("Connection Pool is NOT full. Proceeding with adding new connections");
			//Adding new connection instance until the pool is full
			connectionPool.addElement(createNewConnectionForPool());
		}
		//System.out.println("Connection Pool is full.\n\n");
	}

	private boolean checkIfConnectionPoolIsFull() {


		//Check if the pool size
		if(connectionPool.size() < MAX_POOL_SIZE) {
			return false;
		}

		return true;
	}

	//Creating a connection
	private Connection createNewConnectionForPool() {
		Connection connection = null;

		try{
			Class.forName("oracle.jdbc.driver.OracleDriver");
			connection = DriverManager.getConnection(databaseUrl, userName, password);
		}
		catch(SQLException sqle) {
			System.err.println("SQLException: "+sqle);
			return null;
		}
		catch(ClassNotFoundException cnfe) {
			System.err.println("ClassNotFoundException: "+cnfe);
			return null;
		}

		return connection;
	}

	public Connection getConnectionFromPool() {
		Connection connection = null;

		//Check if there is a connection available. There are times when all the connections in the pool may be used up
		if(connectionPool.size() > 0) {
			connection = (Connection) connectionPool.firstElement();
			connectionPool.removeElementAt(0);
		} else {
			String erreur = "Il manque de connection : " + MAX_POOL_SIZE + " connections atteind";
			System.out.println(erreur);

			// tant que la connection est null
			while(connection == null) {

				// attend 1000 ms seconde
				try {
					Thread.currentThread().sleep(NB_MS_DELAIS_CONNECTION);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}

				// Notification dans le log file
				String erreurNbEssaie = "Delais de " + NB_MS_DELAIS_CONNECTION + " ms d'une connection : " + MAX_POOL_SIZE + " connections atteind";
				System.out.println(erreurNbEssaie);

				// reessaie d'obtenir une connection
				if(connectionPool.size() > 0) {
					connection = (Connection) connectionPool.firstElement();
					connectionPool.removeElementAt(0);
				}
			}
		}
		//Giving away the connection from the connection pool
		return connection;
	}

	public void returnConnectionToPool(Connection connection) {
		//Adding the connection from the client back to the connection pool
		//System.out.println("returned :" + connection);
		connectionPool.addElement(connection);
	}

	public void closeAllConnectionPool(){

		for(int i=0; i< connectionPool.size(); i++ ){
			try {
				connectionPool.get(i).close();
				//System.out.println("connection no : " + i + " closed");

			} catch (SQLException sqle) {
				System.err.println("SQLException closeAllConnection: " + sqle);
			}
		}
		// Clear all the connection in the pool
		connectionPool.clear();
	}

	public static void main(String args[]) {
		ConnectionPoolManager ConnectionPoolManager = new ConnectionPoolManager();

		Connection connection1 = ConnectionPoolManager.getConnectionFromPool();
		Connection connection2 = ConnectionPoolManager.getConnectionFromPool();
		ConnectionPoolManager.returnConnectionToPool(connection1);

		ConnectionPoolManager.getConnectionFromPool();

		/*

	    	InterfaceDAO monDAOMySQL = DAOMySQL.getInstance();
	    	monDAOMySQL.connection();
	    	System.out.println(monDAOMySQL.getRepresentation(1));
	    	System.out.println(monDAOMySQL.decrementerBillet(1,10));
	    	System.out.println(monDAOMySQL.getRepresentation(1));
	    	monDAOMySQL.incrementerBillet(1,10);
	    	System.out.println(monDAOMySQL.getRepresentation(1));
	    	monDAOMySQL.fermerConnection();
		*/
	}

}