package de.memtext.db;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.math.BigDecimal;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import de.memtext.baseobjects.NamedIdObject;
import de.memtext.baseobjects.NamedIdObjectWithParent;
import de.memtext.baseobjects.coll.NamedIdObjectList;
import de.memtext.baseobjects.coll.NamedIdObjectWithParentList;
import de.memtext.tree.KeyParentEqualException;
import de.memtext.util.StringUtils;


/**
 * This class faciliates access to databases. It offers easy standardized
 * access. To start with one has to call the create method with an existing
 * Connection to the database and a name for this connection. In other parts of
 * your programme database access is possible using
 * DBAccess.get("connectionname").function
 * 
 * WICHTIG: Einige Methoden werden nicht für SuperX aber für Joolap benötigt,
 * daher nicht einfach entfernen.
 * 
 * @author: MB
 */
public class DBAccess {
	private String name;
	private Connection con = null;
	private Statement stmt = null;
	private boolean isInJar = false;
	private int updateCount;
	private static IllegalStateException illegalStateEx = new IllegalStateException(
			"DBAccess not inited - connection is null");
	private static Map<String, DBAccess> entries = new HashMap<String, DBAccess>();

	public static DBAccess get(String name) {
		DBAccess one = entries.get(name);
		if (one != null) {
			Connection con = one.getConnection();
			try {
				if (con.isClosed()) {
					throw new RuntimeException("DBAccess: Connection already closed!");
				}
			} catch (SQLException e) {
				throw new RuntimeException("DBAccess: Cannot check for closed connection.", e);
			}
		}
		return one;
	}

	public Connection getConn() {
		return con;
	}

	public static boolean hasConnection(String name) {
		return entries.containsKey(name);
	}

	/**
	 * 
	 * when adding an hsqldb connection also notices from the url if the db is
	 * inside a jar, can be questioned by isInJar()
	 * 
	 * @param name
	 * @param con
	 * @throws SQLException
	 * 
	 */
	public static void addConnection(String name, Connection con) throws SQLException {
		DBAccess dba = DBAccess.get(name);
		if (dba != null && !dba.getConnection().isClosed()) {
			// System.out.println("There is already an entry with the name " + name);
		} else {
			entries.put(name, new DBAccess(name, con));
		}
	}

	public static void removeConnection(String name) throws SQLException {
		DBAccess dba = DBAccess.get(name);
		if (dba != null && !dba.getConnection().isClosed()) {
			dba.closeConnection();
			entries.remove(name);
		}
	}

	public void closeConnection() throws SQLException {
		if (stmt != null)
			stmt.close();
		con.close();
		con = null;
		entries.remove(this);
	}

	static public void closeConnection(String name) throws SQLException {
		DBAccess.get(name).closeConnection();
	}

	private DBAccess(String name, Connection con) throws SQLException {
		this.name = name;
		this.con = con;
		if (con.getMetaData().getDriverName().equals("HSQL Database Engine Driver")
				&& con.getMetaData().getURL().indexOf("res:") > 0)
			isInJar = true;
		stmt = con.createStatement();
	}

	/**
	 * Returns the java.sql.Connection with the given name. Normally get(name)
	 * returns a DBAccess object this method is only used when the very Connection
	 * is needed.
	 * 
	 * @param name
	 * @return
	 */

	public Connection getConnection() {
		return con;
	}

	/**
	 * WICHTIG: Einige Methoden werden nicht für SuperX aber für Joolap benötigt, daher nicht einfach entfernen.
	 * @return
	 */
	public boolean isInJar() {
		return isInJar;
	}

	public String getName() {
		return name;
	}

	/**
	 * WICHTIG: Einige Methoden werden nicht für SuperX aber für Joolap benötigt, daher nicht einfach entfernen.
	 * @return
	 * @throws SQLException
	 */
	public String getTableNames() throws SQLException {
		StringBuffer result = new StringBuffer("Tabellen in der Datenbank:");
		DatabaseMetaData meta = con.getMetaData();
		ResultSet rs = null;
		rs = meta.getTables(null, null, null, null);
		while (rs.next()) {
			result.append(rs.getObject(3) + "  ");
		}
		rs.close();
		return result.toString();
	}

	public boolean hasTable(String tablename) throws SQLException {
		boolean result = false;
		ResultSet rs = con.getMetaData().getTables(null, null, null, null);
		while (rs.next()) {
			if (tablename.equalsIgnoreCase(rs.getObject(3).toString())) {
				result = true;
				break;
			}
		}
		rs.close();
		return result;
	}

	public static boolean hasTable(Connection c, String tablename) throws SQLException {
		boolean result = false;
		ResultSet rs = c.getMetaData().getTables(null, null, null, null);
		while (rs.next()) {
			if (tablename.equalsIgnoreCase(rs.getObject(3).toString())) {
				result = true;
				break;
			}
		}
		rs.close();
		return result;
	}

	/**
	 * select key from blueprint; _> "1,2,3,4,5,6,7"
	 * 
	 * WICHTIG: Einige Methoden werden nicht für SuperX aber für Joolap benötigt,
	 * daher nicht einfach entfernen.
	 * 
	 * @param sql separator is comma null is ignored
	 * @throws SQLException
	 */
	public StringBuffer getSeperatedString(String sql) throws SQLException {
		return getSeperatedString(sql, ",");
	}

	/**
	 * select key from blueprint; _> "'1','2','3','4','5','6','7'" WICHTIG: Einige
	 * Methoden werden nicht für SuperX aber für Joolap benötigt, daher nicht
	 * einfach entfernen.
	 * 
	 * @param sql
	 * @param separator null is ignored
	 * @throws SQLException
	 */
	public StringBuffer getSeperatedString(String sql, String separator) throws SQLException {
		StringBuffer erg = new StringBuffer();
		ResultSet result = stmt.executeQuery(sql);
		Object value;
		while (result.next()) {
			value = result.getObject(1);
			if (value == null)
				erg.append("null" + separator);
			else
				erg.append("'" + value + "'" + separator);
		}
		result.close();

		if (erg.length() > 0)
			StringUtils.deleteLastChar(erg);
		return erg;
	}

	/**
	 * WICHTIG: Einige Methoden werden nicht für SuperX aber für Joolap benötigt,
	 * daher nicht einfach entfernen.
	 * 
	 * @param pstSql
	 * @param args
	 * @return
	 * @throws SQLException
	 */
	public String getString(String pstSql, Object... args) throws SQLException {
		String erg = null;
		PreparedStatement pst = null;
		ResultSet rs = null;
		pst = this.con.prepareStatement(pstSql);
		int paramPos = 1;
		for (Object arg : args) {
			pst.setObject(paramPos, arg);
			paramPos++;
		}
		rs = pst.executeQuery();
		while (rs.next()) {
			erg = rs.getString(1);
			break;
		}
		rs.close();
		return erg;
	}

	public int execute(String sql) throws SQLException {
		if (con == null)
			throw illegalStateEx;
		updateCount = stmt.executeUpdate(sql);
		return updateCount;

	}

	public ResultSet executeQuery(String sql) throws SQLException {
		if (con == null)
			throw illegalStateEx;
		if (stmt != null)
			stmt.close();
		stmt = con.createStatement();
		ResultSet rs = stmt.executeQuery(sql);
		return rs;

	}

	/**
	 * WICHTIG: Einige Methoden werden nicht für SuperX aber für Joolap benötigt, daher nicht einfach entfernen.
	 * @param prefix
	 * @return
	 * @throws SQLException
	 */
	public Object[] getTablesStartingWith(String prefix) throws SQLException {
		if (con == null)
			throw illegalStateEx;
		ArrayList list = new ArrayList();
		ResultSet rs = con.getMetaData().getTables(null, null, prefix + "%", null);
		while (rs.next()) {
			list.add(rs.getString(3));
		}
		rs.close();
		Object[] result = list.toArray();
		Arrays.sort(result);
		return result;
	}

	/**
	 * Es wird einfach das erste Objekt der ersten Spalte genommen
	 * WICHTIG: Einige Methoden werden nicht für SuperX aber für Joolap benötigt, daher nicht einfach entfernen.
	 * @param sql
	 * @return
	 * @throws SQLException
	 */
	public Double getDoubleValue(String sql) throws SQLException {
		Double val = null;
		ResultSet rs = executeQuery(sql);
		rs.next();
		Object o = rs.getObject(1);
		rs.close();
		if (o instanceof Double)
			val = (Double) o;
		else if (o instanceof java.math.BigDecimal) {
			BigDecimal merk = (BigDecimal) o;
			val = Double.valueOf(merk.doubleValue());
		} else if (o != null)
			val = Double.valueOf(o.toString());
		return val;
	}

	/**
	 * Method hasColumn. can be problem for other databases.
	 * WICHTIG: Einige Methoden werden nicht für SuperX aber für Joolap benötigt, daher nicht einfach entfernen.
	 * @param aTablename
	 * @param string
	 * @return boolean
	 * @throws SQLException
	 */
	public boolean hasColumn(String aTablename, String colname) throws SQLException {
		if (con == null)
			throw illegalStateEx;
		boolean result = false;

		if (!hasTable(aTablename))
			throw new IllegalArgumentException("Database doesn't contain table " + aTablename);
		// Hsql had problems with metadata stuff
		ResultSet rs = con.getMetaData().getColumns(null, null, aTablename.toUpperCase(), colname.toUpperCase());
		// ResultSetMetaData rsmd = rs.getMetaData();
		// int numberOfColumns = rsmd.getColumnCount();
		while (rs.next()) {
			// wenn etwas gefunden wurde, gibt's die Spalte
			result = true;
		}
		rs.close();
		return result;

	}

	public int getInt(String query, Object... args) throws SQLException {
		Integer result = getInteger(query, args);
		if (result == null)
			throw new RuntimeException("nothing or null found");
		return result.intValue();
	}

	/*
	 * If more than one value is found, only considers the first
	 */
	public Integer getInteger(String pstSQL, Object... args) throws SQLException {
		Integer erg = null;
		PreparedStatement pst = null;
		ResultSet rs = null;
		pst = this.con.prepareStatement(pstSQL);
		int paramPos = 1;
		for (Object arg : args) {
			pst.setObject(paramPos, arg);
			paramPos++;
		}
		rs = pst.executeQuery();
		Object o = null;
		boolean isFirst = true;
		while (rs.next()) {
			if (isFirst) {
				o = rs.getObject(1);
				isFirst = false;
			}
		}
		if (o != null) {
			if (o instanceof Integer)
				erg = (Integer) o;
			else if (o instanceof Long)
				erg = Integer.valueOf(((Long) o).intValue());
			else if (o instanceof Short)
				erg = Integer.valueOf(((Short) o).intValue());
			else {
				throw new IllegalArgumentException(
						"Unbekannter Datentyp in DBAccess getInteger:" + o.getClass() + " - " + pstSQL);

			}
		}
		rs.close();
		return erg;
	}

	/**
	 * WICHTIG: Einige Methoden werden nicht für SuperX aber für Joolap benötigt, daher nicht einfach entfernen.
	 * @return
	 * @throws SQLException
	 */
	public List getTableList() throws SQLException {
		if (con == null)
			throw illegalStateEx;
		List result = new LinkedList();
		ResultSet rs = con.getMetaData().getTables(null, null, null, null);
		while (rs.next()) {
			result.add(rs.getObject(3).toString());
		}
		rs.close();
		return result;
	}

	/**
	 * WICHTIG: Einige Methoden werden nicht für SuperX aber für Joolap benötigt,
	 * daher nicht einfach entfernen.
	 * 
	 * @param sql
	 * @return List in LIst!!
	 * @throws SQLException
	 */
	public List getResultList(String sql) throws SQLException {
		List result = new LinkedList();
		ResultSet rs = executeQuery(sql);
		result = DbUtils.toResultList(rs);
		rs.close();
		return result;
	}

	/**
	 * Hsql needs uppercase!
	 * WICHTIG: Einige Methoden werden nicht für SuperX aber für Joolap benötigt, daher nicht einfach entfernen.
	 * @throws SQLException
	 */
	public int getColumnType(String tablename, String colname) throws SQLException {
		int result = -9999;
		if (!hasTable(tablename))
			throw new RuntimeException("Database doesn't contain table " + tablename);
		if (!hasColumn(tablename, colname))
			throw new RuntimeException("Table " + tablename + " doesn't have column:" + colname);
		ResultSet rs = con.getMetaData().getColumns(null, null, tablename.toUpperCase(), colname.toUpperCase());
		while (rs.next()) {
			result = rs.getInt(5);
		}
		rs.close();
		return result;
	}

	/*
	 * WICHTIG: Einige Methoden werden nicht für SuperX aber für Joolap benötigt, daher nicht einfach entfernen.
	 */
	public int getColumnCount(String tablename) throws SQLException {
		int result = 0;
		if (!hasTable(tablename))
			throw new RuntimeException("Database doesn't contain table " + tablename);
		ResultSet rs = con.getMetaData().getColumns(null, null, tablename.toUpperCase(), null);
		while (rs.next()) {
			result++;
		}
		rs.close();
		return result;
	}

	/**
	 * Hsql needs uppercase!
	 * WICHTIG: Einige Methoden werden nicht für SuperX aber für Joolap benötigt, daher nicht einfach entfernen.
	 * @throws SQLException
	 */
	public List getColumnNames(String tablename) throws SQLException {
		List result = new LinkedList();
		if (!hasTable(tablename))
			throw new RuntimeException("Database doesn't contain table " + tablename);
		ResultSet rs = con.getMetaData().getColumns(null, null, tablename.toUpperCase(), null);
		while (rs.next()) {
			result.add(rs.getObject(4).toString());
		}
		rs.close();
		return result;
	}

	/**
	 * Method executeAndCheckUpdate1Row.
	 * WICHTIG: Einige Methoden werden nicht für SuperX aber für Joolap benötigt, daher nicht einfach entfernen.
	 * @param string
	 * @throws SQLException
	 */
	public void executeAndCheckUpdate1Row(String sql) throws SQLException {
		int updateRowCount = execute(sql);
		if (updateRowCount != 1)
			throw new IllegalStateException("Es wurde nicht 1 Zeile geupdated, sondern " + updateRowCount);
	}

	/**
	 * Sets a property in the properties table of a db WICHTIG: Einige Methoden
	 * werden nicht für SuperX aber für Joolap benötigt, daher nicht einfach
	 * entfernen.
	 * 
	 * @param key
	 * @param value
	 * @throws SQLException
	 */
	public void setProperty(String key, String value) throws SQLException {
		if (key == null || value == null)
			throw new IllegalArgumentException("no nulls allowed in properties table");
		execute("delete from properties where name='key';insert into properties (name,value) values('" + key + "','"
				+ value + "');");
	}

	/**
	 * Gets a property from the properties table WICHTIG: Einige Methoden werden
	 * nicht für SuperX aber für Joolap benötigt, daher nicht einfach entfernen.
	 * 
	 * @param key
	 * @return String - null if nothing found
	 * @throws SQLException
	 */
	public String getProperty(String key) throws SQLException {
		return getString("select value from properties where name='" + key + "'");
	}

	/**
	 * creates a java.util.List with NamedIDObjects from a table in the database
	 * WICHTIG: Einige Methoden werden nicht für SuperX aber für Joolap benötigt,
	 * daher nicht einfach entfernen.
	 * 
	 * @param tablename   - name of the source table
	 * @param idColName   - name of the ID column in the table (e.g. tid)
	 * @param nameColName - name of the name column in the table (e.g. name or text)
	 * @param restriction - optionally a restriction like "where id>2" may be null
	 * @return NamedIdObjectList
	
	 */
	public NamedIdObjectList getNamedIdObjectList(String tablename, String idColName, String nameColName,
			String restriction, String orderby, Class targetClass)
			throws SecurityException, NoSuchMethodException, IllegalArgumentException, InstantiationException,
			IllegalAccessException, InvocationTargetException, SQLException {
		NamedIdObjectList result = new NamedIdObjectList();
		if (restriction == null)
			restriction = "";
		Object id;
		String name;
		List rawList = getResultList(
				"select " + idColName + "," + nameColName + " from " + tablename + " " + restriction + " " + orderby);
		Class[] constparams = { Object.class, String.class };
		Object[] data = new Object[2];
		Constructor constr = targetClass.getConstructor(constparams);
		for (Iterator it = rawList.iterator(); it.hasNext();) {
			List row = (List) it.next();
			id = row.get(0);
			name = "";
			if (row.get(1) != null)
				name = row.get(1).toString();
			data[0] = id;
			data[1] = name;
			Object o = constr.newInstance(data);
			result.add(o);
		}
		return result;
	}

	/**
	 * WICHTIG: Einige Methoden werden nicht für SuperX aber für Joolap benötigt,
	 * daher nicht einfach entfernen.
	 * 
	 * @param tablename
	 * @param idColName
	 * @param nameColName
	 * @param restriction
	 * @param orderby
	
	 */
	public NamedIdObjectList getNamedIdObjectList(String tablename, String idColName, String nameColName,
			String restriction, String orderby) throws IllegalArgumentException, SQLException, SecurityException,
			NoSuchMethodException, InstantiationException, IllegalAccessException, InvocationTargetException {
		NamedIdObjectList result = null;
		result = getNamedIdObjectList(tablename, idColName, nameColName, restriction, orderby, NamedIdObject.class);
		return result;
	}

	public NamedIdObjectWithParentList getNamedIdObjectWithParentList(String tablename, String idColName,
			String nameColName, String restriction) throws KeyParentEqualException, SQLException {
		NamedIdObjectWithParentList result = new NamedIdObjectWithParentList();
		if (restriction == null)
			restriction = "";
		Object id;
		String name;
		Object parentKey;
		NamedIdObjectWithParent one;
		List rawList = getResultList(
				"select " + idColName + "," + nameColName + ",parent from " + tablename + " " + restriction);
		for (Iterator it = rawList.iterator(); it.hasNext();) {
			List row = (List) it.next();
			id = row.get(0);
			name = "";
			if (row.get(1) != null)
				name = row.get(1).toString();
			parentKey = row.get(2);
			one = new NamedIdObjectWithParent(id, name, parentKey);
			result.add(one);
		}
		return result;
	}

	public void execute(StringBuffer sql) throws SQLException {
		execute(sql.toString());
	}
}