/**
    * Copyright 2004-2012 The Kuali Foundation
    *
    * Licensed under the Educational Community License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    * http://www.opensource.org/licenses/ecl2.php
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.kuali.db;
  
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.PrintStream;
  import java.io.Reader;
  import java.sql.Connection;
  import java.sql.ResultSet;
  import java.sql.ResultSetMetaData;
  import java.sql.SQLException;
  import java.sql.SQLWarning;
  import java.sql.Statement;
  import java.util.ArrayList;
  import java.util.Enumeration;
  import java.util.List;
  import java.util.StringTokenizer;
  import java.util.Vector;
  
  import org.apache.commons.lang.StringEscapeUtils;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import static org.apache.commons.io.IOUtils.*;
  import static org.kuali.db.JDBCUtils.*;
  
  /**
   * Executes SQL statements
   */
  public class SQLExecutor {
  	private static final Log log = LogFactory.getLog(SQLExecutor.class);
  
  	/**
  	 * Call {@link #setOnError(String)} with this value to abort SQL command execution if an error is found.
  	 */
  	public static final String ON_ERROR_ABORT = "abort";
  
  	/**
  	 * Call {@link #setOnError(String)} with this value to continue SQL command execution until all commands have been
  	 * attempted, then abort the build if an SQL error occurred in any of the commands.
  	 */
  	public static final String ON_ERROR_ABORT_AFTER = "abortAfter";
  
  	/**
  	 * Call {@link #setOnError(String)} with this value to continue SQL command execution if an error is found.
  	 */
  	public static final String ON_ERROR_CONTINUE = "continue";
  
  	Vector<Transaction> transactions;
  	boolean keepFormat = true;
  	String delimiterType = "row";
  	String delimiter = "/";
  	boolean printResultSet = false;;
  	String onError = ON_ERROR_ABORT;
  	boolean showheaders = true;
  	String outputDelimiter = ",";
  	int totalStatements;
  	int successfulStatements;
  	Connection conn;
  	Statement statement;
  	boolean autocommit = false;
  	boolean escapeProcessing = true;
  	boolean skipOnConnectionError;
  	boolean connectionError;
  	boolean append = false;
  	List<DatabaseListener> listeners = new ArrayList<DatabaseListener>();
  
  	public void addListener(DatabaseListener listener) {
  		listeners.add(listener);
  	}
  
  	protected void fireMessageLogged(String message) {
  		fireMessageLogged(message, MessagePriority.INFO);
  	}
  
  	protected void fireMessageLogged(String message, MessagePriority priority) {
  		DatabaseEvent event = new DatabaseEvent(message, priority);
  		for (DatabaseListener listener : listeners) {
  			listener.messageLogged(event);
  		}
  	}
  
  	protected void fireBeginTransaction(Transaction transaction) {
  		DatabaseEvent event = new DatabaseEvent();
  		event.setTransaction(transaction);
 		for (DatabaseListener listener : listeners) {
 			listener.beginTransaction(event);
 		}
 	}
 
 	protected void fireFinishTransaction(Transaction transaction) {
 		DatabaseEvent event = new DatabaseEvent();
 		event.setTransaction(transaction);
 		for (DatabaseListener listener : listeners) {
 			listener.finishTransaction(event);
 		}
 	}
 
 	protected DatabaseEvent getExecuteSQLEvent(int totalStatements, String sql) {
 		DatabaseEvent event = new DatabaseEvent();
 		event.setSql(sql);
 		event.setTotalStatements(totalStatements);
 		return event;
 	}
 
 	protected void fireBeforeExecuteSQL(int totalStatements, String sql) {
 		for (DatabaseListener listener : listeners) {
 			listener.beforeExecuteSQL(getExecuteSQLEvent(totalStatements, sql));
 		}
 	}
 
 	protected void fireAfterExecuteSQL(int totalStatements, String sql) {
 		for (DatabaseListener listener : listeners) {
 			listener.afterExecuteSQL(getExecuteSQLEvent(totalStatements, sql));
 		}
 	}
 
 	protected void fireAfterProcessingSQLResults(int totalStatements, int successfulStatements, int updateCountTotal, String sql) {
 		DatabaseEvent event = getExecuteSQLEvent(totalStatements, sql);
 		event.setSuccessfulStatements(successfulStatements);
 		event.setUpdateCountTotal(updateCountTotal);
 		for (DatabaseListener listener : listeners) {
 			listener.afterExecuteSQL(event);
 		}
 	}
 
 	public void info(String message) {
 		log.info(message);
 		fireMessageLogged(message);
 	}
 
 	public void debug(String message) {
 		log.debug(message);
 		fireMessageLogged(message, MessagePriority.DEBUG);
 	}
 
 	public void error(Throwable throwable, String message) {
 		if (throwable == null) {
 			log.error(message);
 		} else {
 			log.error(message, throwable);
 		}
 		DatabaseEvent event = new DatabaseEvent(message, MessagePriority.ERROR);
 		event.setException(throwable);
 		for (DatabaseListener listener : listeners) {
 			listener.messageLogged(event);
 		}
 	}
 
 	public void error(String message) {
 		error(null, message);
 	}
 
 	public void executeSql(String sql) throws SQLException {
 		Transaction transaction = new Transaction();
 		transaction.setSqlCommand(sql);
 		executeTransaction(transaction);
 	}
 
 	public void executeTransaction(Transaction transaction) throws SQLException {
 		this.transactions = new Vector<Transaction>();
 		transactions.add(transaction);
 		execute();
 	}
 
 	public void execute() throws SQLException {
 		try {
 			statement = conn.createStatement();
 			statement.setEscapeProcessing(escapeProcessing);
 
 			// Process all transactions
 			for (Enumeration<Transaction> e = transactions.elements(); e.hasMoreElements();) {
 				Transaction t = (Transaction) e.nextElement();
 
 				fireBeginTransaction(t);
 				runTransaction(t, System.out);
 				fireFinishTransaction(t);
 
 				if (!autocommit) {
 					debug("Committing transaction");
 					conn.commit();
 				}
 			}
 		} catch (IOException e) {
 			throw new SQLException(e);
 		} catch (SQLException e) {
 			if (!autocommit && ON_ERROR_ABORT.equalsIgnoreCase(getOnError())) {
 				rollbackQuietly(conn);
 			}
 			throw e;
 		} finally {
 			closeQuietly(statement, conn);
 		}
 
 		log.info(getSuccessfulStatements() + " of " + getTotalStatements() + " SQL statements executed successfully");
 
 		if (ON_ERROR_ABORT_AFTER.equalsIgnoreCase(getOnError()) && totalStatements != successfulStatements) {
 			throw new SQLException("Some SQL statements failed to execute");
 		}
 	}
 
 	protected void runTransaction(Transaction t, PrintStream out) throws IOException, SQLException {
 		Reader in = null;
 		try {
 			in = t.getReader();
 			runStatements(in, out);
 		} finally {
 			closeQuietly(in);
 		}
 	}
 
 	/**
 	 * Exec the sql statement.
 	 * 
 	 * @param sql
 	 *            query to execute
 	 * @param out
 	 *            the outputstream
 	 */
 	protected void execSQL(String sql, PrintStream out) throws SQLException {
 		// Check and ignore empty statements
 		if ("".equals(sql.trim())) {
 			return;
 		}
 
 		ResultSet resultSet = null;
 		try {
 			totalStatements++;
 			debug("SQL: " + sql);
 
 			boolean ret;
 			int updateCountTotal = 0;
 
 			fireBeforeExecuteSQL(totalStatements, sql);
 			ret = statement.execute(sql);
 			fireAfterExecuteSQL(totalStatements, sql);
 			do {
 				if (!ret) {
 					int updateCount = statement.getUpdateCount();
 					if (updateCount != -1) {
 						updateCountTotal += updateCount;
 					}
 				} else {
 					resultSet = statement.getResultSet();
 					if (printResultSet) {
 						printResultSet(resultSet, out);
 					}
 				}
 				ret = statement.getMoreResults();
 			} while (ret);
 
 			debug(updateCountTotal + " rows affected");
 
 			if (printResultSet) {
 				StringBuffer line = new StringBuffer();
 				line.append(updateCountTotal).append(" rows affected");
 				out.println(line);
 			}
 
 			SQLWarning warning = conn.getWarnings();
 			while (warning != null) {
 				debug(warning + " sql warning");
 				warning = warning.getNextWarning();
 			}
 			conn.clearWarnings();
 			successfulStatements++;
 			fireAfterProcessingSQLResults(totalStatements, successfulStatements, updateCountTotal, sql);
 		} catch (SQLException e) {
 			error("Failed to execute: " + sql + "\n\n" + e.getMessage());
 			if (ON_ERROR_ABORT.equalsIgnoreCase(getOnError())) {
 				throw e;
 			}
 		} finally {
 			closeQuietly(resultSet);
 		}
 	}
 
 	/**
 	 * read in lines and execute them
 	 * 
 	 * @param reader
 	 *            the reader
 	 * @param out
 	 *            the outputstream
 	 * @throws SQLException
 	 * @throws IOException
 	 */
 	protected void runStatements(Reader reader, PrintStream out) throws SQLException, IOException {
 		String line;
 
 		StringBuffer sql = new StringBuffer();
 
 		BufferedReader in = new BufferedReader(reader);
 
 		while ((line = in.readLine()) != null) {
 			if (!keepFormat) {
 				line = line.trim();
 			}
 
 			if (!keepFormat) {
 				if (line.startsWith("//")) {
 					continue;
 				}
 				if (line.startsWith("--")) {
 					continue;
 				}
 				StringTokenizer st = new StringTokenizer(line);
 				if (st.hasMoreTokens()) {
 					String token = st.nextToken();
 					if ("REM".equalsIgnoreCase(token)) {
 						continue;
 					}
 				}
 			}
 
 			if (!keepFormat) {
 				sql.append(" ").append(line);
 			} else {
 				sql.append("\n").append(line);
 			}
 
 			// SQL defines "--" as a comment to EOL
 			// and in Oracle it may contain a hint
 			// so we cannot just remove it, instead we must end it
 			if (!keepFormat) {
 				if (SqlSplitter.containsSqlEnd(line, delimiter) == SqlSplitter.NO_END) {
 					sql.append("\n");
 				}
 			}
 
 			if ((delimiterType.equals(DelimiterType.NORMAL) && SqlSplitter.containsSqlEnd(line, delimiter) > 0) || (delimiterType.equals(DelimiterType.ROW) && line.trim().equals(delimiter))) {
 				execSQL(sql.substring(0, sql.length() - delimiter.length()), out);
 				sql.setLength(0); // clean buffer
 			}
 		}
 
 		// Catch any statements not followed by ;
 		if (!sql.toString().equals("")) {
 			execSQL(sql.toString(), out);
 		}
 	}
 
 	/**
 	 * print any results in the result set.
 	 * 
 	 * @param rs
 	 *            the resultset to print information about
 	 * @param out
 	 *            the place to print results
 	 * @throws SQLException
 	 *             on SQL problems.
 	 */
 	protected void printResultSet(ResultSet rs, PrintStream out) throws SQLException {
 		if (rs == null) {
 			return;
 		}
 		debug("Processing new result set.");
 		ResultSetMetaData md = rs.getMetaData();
 		int columnCount = md.getColumnCount();
 		StringBuffer line = new StringBuffer();
 		if (showheaders) {
 			boolean first = true;
 			for (int col = 1; col <= columnCount; col++) {
 				String columnValue = md.getColumnName(col);
 
 				if (columnValue != null) {
 					columnValue = columnValue.trim();
 
 					if (",".equals(outputDelimiter)) {
 						columnValue = StringEscapeUtils.escapeCsv(columnValue);
 					}
 				}
 
 				if (first) {
 					first = false;
 				} else {
 					line.append(outputDelimiter);
 				}
 				line.append(columnValue);
 			}
 			out.println(line);
 			line = new StringBuffer();
 		}
 		while (rs.next()) {
 			boolean first = true;
 			for (int col = 1; col <= columnCount; col++) {
 				String columnValue = rs.getString(col);
 				if (columnValue != null) {
 					columnValue = columnValue.trim();
 
 					if (",".equals(outputDelimiter)) {
 						columnValue = StringEscapeUtils.escapeCsv(columnValue);
 					}
 				}
 
 				if (first) {
 					first = false;
 				} else {
 					line.append(outputDelimiter);
 				}
 				line.append(columnValue);
 			}
 			out.println(line);
 			line = new StringBuffer();
 		}
 		out.println();
 	}
 
 	public boolean isKeepFormat() {
 		return keepFormat;
 	}
 
 	public void setKeepFormat(boolean keepFormat) {
 		this.keepFormat = keepFormat;
 	}
 
 	public String getDelimiterType() {
 		return delimiterType;
 	}
 
 	public void setDelimiterType(String delimiterType) {
 		this.delimiterType = delimiterType;
 	}
 
 	public String getDelimiter() {
 		return delimiter;
 	}
 
 	public void setDelimiter(String delimiter) {
 		this.delimiter = delimiter;
 	}
 
 	public boolean isPrintResultSet() {
 		return printResultSet;
 	}
 
 	public void setPrintResultSet(boolean printResultSet) {
 		this.printResultSet = printResultSet;
 	}
 
 	public String getOnError() {
 		return onError;
 	}
 
 	public void setOnError(String onError) {
 		this.onError = onError;
 	}
 
 	public boolean isShowheaders() {
 		return showheaders;
 	}
 
 	public void setShowheaders(boolean showheaders) {
 		this.showheaders = showheaders;
 	}
 
 	public String getOutputDelimiter() {
 		return outputDelimiter;
 	}
 
 	public void setOutputDelimiter(String outputDelimiter) {
 		this.outputDelimiter = outputDelimiter;
 	}
 
 	public int getTotalStatements() {
 		return totalStatements;
 	}
 
 	public void setTotalStatements(int totalStatements) {
 		this.totalStatements = totalStatements;
 	}
 
 	public int getSuccessfulStatements() {
 		return successfulStatements;
 	}
 
 	public void setSuccessfulStatements(int successfulStatements) {
 		this.successfulStatements = successfulStatements;
 	}
 
 	public Connection getConn() {
 		return conn;
 	}
 
 	public void setConn(Connection conn) {
 		this.conn = conn;
 	}
 
 	public Statement getStatement() {
 		return statement;
 	}
 
 	public void setStatement(Statement statement) {
 		this.statement = statement;
 	}
 
 	public boolean isAutocommit() {
 		return autocommit;
 	}
 
 	public void setAutocommit(boolean autocommit) {
 		this.autocommit = autocommit;
 	}
 
 	public boolean isEscapeProcessing() {
 		return escapeProcessing;
 	}
 
 	public void setEscapeProcessing(boolean escapeProcessing) {
 		this.escapeProcessing = escapeProcessing;
 	}
 
 	public boolean isAppend() {
 		return append;
 	}
 
 	public void setAppend(boolean append) {
 		this.append = append;
 	}
 
 	public boolean isSkipOnConnectionError() {
 		return skipOnConnectionError;
 	}
 
 	public void setSkipOnConnectionError(boolean skipOnConnectionError) {
 		this.skipOnConnectionError = skipOnConnectionError;
 	}
 
 	public boolean isConnectionError() {
 		return connectionError;
 	}
 
 	public void setConnectionError(boolean connectionError) {
 		this.connectionError = connectionError;
 	}
 
 	public List<DatabaseListener> getListeners() {
 		return listeners;
 	}
 
 	public void setListeners(List<DatabaseListener> listeners) {
 		this.listeners = listeners;
 	}
 
 	public Vector<Transaction> getTransactions() {
 		return transactions;
 	}
 
 	public void setTransactions(Vector<Transaction> transactions) {
 		this.transactions = transactions;
 	}
 }