/*
 * Slightly modified version of the com.ibatis.common.jdbc.ScriptRunner class
 * from the iBATIS Apache project. Only removed dependency on Resource class
 * and a constructor
 */
/*
 *  Copyright 2004 Clinton Begin
 *
 *  Licensed under the Apache 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.apache.org/licenses/LICENSE-2.0
 *
 *  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 com.cloud.utils.db;

import java.io.IOException;
import java.io.LineNumberReader;
import java.io.Reader;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;

import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.LogManager;

/**
 * Tool to run database scripts
 */
public class ScriptRunner {
    private static Logger LOGGER = LogManager.getLogger(ScriptRunner.class);

    private static final String DEFAULT_DELIMITER = ";";

    private Connection connection;

    private boolean stopOnError;
    private boolean autoCommit;
    private boolean verbosity = true;

    private String delimiter = DEFAULT_DELIMITER;
    private boolean fullLineDelimiter = false;

    private StringBuffer _logBuffer = new StringBuffer();

    /**
     * Default constructor
     */
    public ScriptRunner(Connection connection, boolean autoCommit, boolean stopOnError) {
        this.connection = connection;
        this.autoCommit = autoCommit;
        this.stopOnError = stopOnError;
    }

    public ScriptRunner(Connection connection, boolean autoCommit, boolean stopOnError, boolean verbosity) {
        this.connection = connection;
        this.autoCommit = autoCommit;
        this.stopOnError = stopOnError;
        this.verbosity = verbosity;
    }

    public void setDelimiter(String delimiter, boolean fullLineDelimiter) {
        this.delimiter = delimiter;
        this.fullLineDelimiter = fullLineDelimiter;
    }

    /**
     * Runs an SQL script (read in using the Reader parameter)
     *
     * @param reader
     *            - the source of the script
     */
    public void runScript(Reader reader) throws IOException, SQLException {
        try {
            boolean originalAutoCommit = connection.getAutoCommit();
            try {
                if (originalAutoCommit != this.autoCommit) {
                    connection.setAutoCommit(this.autoCommit);
                }
                runScript(connection, reader);
            } finally {
                connection.setAutoCommit(originalAutoCommit);
            }
        } catch (IOException e) {
            throw e;
        } catch (SQLException e) {
            throw e;
        } catch (Exception e) {
            throw new RuntimeException("Error running script.  Cause: " + e, e);
        }
    }

    /**
     * Runs an SQL script (read in using the Reader parameter) using the
     * connection passed in
     *
     * @param conn
     *            - the connection to use for the script
     * @param reader
     *            - the source of the script
     * @throws SQLException
     *             if any SQL errors occur
     * @throws IOException
     *             if there is an error reading from the Reader
     */
    private void runScript(Connection conn, Reader reader) throws IOException, SQLException {
        StringBuffer command = null;
        try {
            LineNumberReader lineReader = new LineNumberReader(reader);
            String line = null;
            while ((line = lineReader.readLine()) != null) {
                if (command == null) {
                    command = new StringBuffer();
                }
                String trimmedLine = line.trim();
                if (trimmedLine.startsWith("--")) {
                    println(trimmedLine);
                } else if (trimmedLine.length() < 1 || trimmedLine.startsWith("//")) {
                    // Do nothing
                } else if (trimmedLine.length() < 1 || trimmedLine.startsWith("--")) {
                    // Do nothing
                } else if (trimmedLine.length() < 1 || trimmedLine.startsWith("#")) {
                    // Do nothing
                } else if (!fullLineDelimiter && trimmedLine.endsWith(getDelimiter()) || fullLineDelimiter && trimmedLine.equals(getDelimiter())) {
                    command.append(line.substring(0, line.lastIndexOf(getDelimiter())));
                    command.append(" ");
                    try (Statement statement = conn.createStatement();) {
                        println(command);
                        boolean hasResults = false;
                        if (stopOnError) {
                            hasResults = statement.execute(command.toString());
                        } else {
                            try {
                                statement.execute(command.toString());
                            } catch (SQLException e) {
                                e.fillInStackTrace();
                                printlnError("Error executing: " + command);
                                printlnError(e);
                            }
                        }
                        if (autoCommit && !conn.getAutoCommit()) {
                            conn.commit();
                        }
                        try(ResultSet rs = statement.getResultSet();) {
                            if (hasResults && rs != null) {
                                ResultSetMetaData md = rs.getMetaData();
                                int cols = md.getColumnCount();
                                for (int i = 0; i < cols; i++) {
                                    String name = md.getColumnLabel(i);
                                    print(name + "\t");
                                }
                                println("");
                                while (rs.next()) {
                                    for (int i = 1; i <= cols; i++) {
                                        String value = rs.getString(i);
                                        print(value + "\t");
                                    }
                                    println("");
                                }
                            }
                            command = null;
                            Thread.yield();
                        }
                    }
                } else {
                    int idx = line.indexOf("--");
                    if (idx != -1)
                        command.append(line.substring(0, idx));
                    else
                        command.append(line);
                    command.append(" ");
                }
            }
            if (!autoCommit) {
                conn.commit();
            }
        } catch (SQLException e) {
            e.fillInStackTrace();
            printlnError("Error executing: " + command);
            printlnError(e);
            throw e;
        } catch (IOException e) {
            e.fillInStackTrace();
            printlnError("Error executing: " + command);
            printlnError(e);
            throw e;
        } finally {
            conn.rollback();
            flush();
        }
    }

    private String getDelimiter() {
        return delimiter;
    }

    private void print(Object o) {
        _logBuffer.append(o);
    }

    private void println(Object o) {
        _logBuffer.append(o);
        if (verbosity)
            LOGGER.debug(_logBuffer.toString());
        _logBuffer = new StringBuffer();
    }

    private void printlnError(Object o) {
        LOGGER.error("" + o);
    }

    private void flush() {
        if (_logBuffer.length() > 0) {
            LOGGER.debug(_logBuffer.toString());
            _logBuffer = new StringBuffer();
        }
    }
}
