package org.jtheque.core.managers.schema;

 import org.jtheque.core.managers.Managers;

 import org.jtheque.core.managers.log.ILoggingManager;

 import org.jtheque.utils.StringUtils;

 import org.jtheque.utils.io.FileUtils;

 import java.io.File;

 import java.io.FileInputStream;

 import java.io.FileNotFoundException;

 import java.nio.channels.FileChannel;

 import java.util.ArrayList;

 import java.util.Collection;

 import java.util.Scanner;

 /*

  * This file is part of JTheque.

  *

  * JTheque is free software: you can redistribute it and/or modify

  * it under the terms of the GNU General Public License as published by

  * the Free Software Foundation, either version 3 of the License.

  *

  * JTheque is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  * GNU General Public License for more details.

  *

  * You should have received a copy of the GNU General Public License

  * along with JTheque.  If not, see <http://www.gnu.org/licenses/>.

  */

 /**

  * A reader for HSQL Script file and log files.

  *

  * @author Baptiste Wicht

  */

 final class HSQLFileReader {

     /**

      * Utility class, cannot be instantiated.

      */

     private HSQLFileReader() {

         super();

     }

     /**

      * Read the file and get off all the inserts.

      *

      * @param file The file to parse.

      * @return The List of all the inserts of the file.

      */

     public static Collection<Insert> readFile(File file) {

         Collection<Insert> inserts = new ArrayList<Insert>(100);

         FileChannel in = null;

         try {

             in = new FileInputStream(file).getChannel();

             Scanner scanner = new Scanner(in);

             while (scanner.hasNextLine()) {

                 String line = scanner.nextLine().trim();

                 if (line.startsWith("INSERT INTO")) {

                     inserts.add(readInsert(line));

                 }

             }

         } catch (FileNotFoundException e) {

             Managers.getManager(ILoggingManager.class).getLogger(HSQLFileReader.class).error(e);

         } finally {

             FileUtils.close(in);

         }

         return inserts;

     }

     /**

      * Read the insert.

      *

      * @param line The line to read the insert from.

      * @return The read Insert.

      */

     private static Insert readInsert(String line) {

         Insert insert = new Insert();

         insert.setTable(line.substring(12, line.indexOf(" VALUES(")));

         insert.setValues(extractValues(line));

         return insert;

     }

     /**

      * Extract The values from the line.

      *

      * @param line The line to read.

      * @return A collection containing all the values.

      */

     private static Collection<String> extractValues(String line) {

         String valuesStr = line.substring(line.indexOf('(') + 1, line.lastIndexOf(')') + 1);

         valuesStr = valuesStr.replace(",'',", ",NULL,");

         return parseStrValues(valuesStr);

     }

     /**

      * Parse the values string to a Collection of values.

      *

      * @param valuesStr The String values.

      * @return A collection containing all the values.

      */

     private static Collection<String> parseStrValues(String valuesStr) {

         Collection<String> values = new ArrayList<String>(10);

         StringBuilder current = new StringBuilder(100);

         boolean surroundStart = false;

         char last = ' ';

         for (char c : valuesStr.toCharArray()) {

             if (isEndOfValue(surroundStart, c)) {

                 values.add(StringUtils.removeUnicode(current.toString()));

                 current.setLength(0);

             } else if (isEscapedChar(last, c)) {

                 current.append('\'');

                 surroundStart ^= true;

             } else if (c == '\'') {

                 surroundStart ^= true;

             } else {

                 current.append(c);

             }

             last = c;

         }

         return values;

     }

     /**

      * Indicate if the two chars form an escaped char or not.

      *

      * @param last The last char.

      * @param c    The current char.

      * @return true if the two chars form an escaped char else false.

      */

     private static boolean isEscapedChar(char last, char c) {

         return last == '\'' && c == '\'';

     }

     /**

      * Indicate if the char c indicate the end of the current value or not.

      *

      * @param surroundStart Indicate the surround started or not.

      * @param c             The current char.

      * @return true if this is the end of the value else false.

      */

     private static boolean isEndOfValue(boolean surroundStart, char c) {

         return !surroundStart && (c == ',' || c == ')');

     }

 }