/*
    * SymmetricDS is an open source database synchronization solution.
    *   
    * Copyright (C) Chris Henson <chenson42@users.sourceforge.net>
    *
    * This library is free software; you can redistribute it and/or
    * modify it under the terms of the GNU Lesser General Public
    * License as published by the Free Software Foundation; either
    * version 3 of the License, or (at your option) any later version.
   *
   * This library 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
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, see
   * <http://www.gnu.org/licenses/>.
   */
  
  package org.jumpmind.symmetric.db.mysql;
  
  import java.sql.Connection;
  import java.sql.SQLException;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.jumpmind.symmetric.Version;
  import org.jumpmind.symmetric.db.AbstractDbDialect;
  import org.jumpmind.symmetric.db.BinaryEncoding;
  import org.jumpmind.symmetric.db.IDbDialect;
  import org.jumpmind.symmetric.model.Trigger;
  import org.jumpmind.symmetric.model.TriggerHistory;
  
  public class MySqlDbDialect extends AbstractDbDialect implements IDbDialect {
  
      static final Log logger = LogFactory.getLog(MySqlDbDialect.class);
  
      static final String TRANSACTION_ID_FUNCTION_NAME = "fn_transaction_id";
  
      static final String SYNC_TRIGGERS_DISABLED_USER_VARIABLE = "@sync_triggers_disabled";
      
      static final String SYNC_TRIGGERS_DISABLED_NODE_VARIABLE = "@sync_node_disabled";
  
      private boolean supportsTransactionId = false;
  
      protected void initForSpecificDialect() {
          int[] versions = Version.parseVersion(getProductVersion());
          if (getMajorVersion() == 5
                  && (getMinorVersion() == 0 || (getMinorVersion() == 1 && versions[2] < 23))) {
              logger.info("Enabling transaction ID support");
              supportsTransactionId = true;
          }
      }
  
      @Override
      protected void createRequiredFunctions() {
          String[] functions = sqlTemplate.getFunctionsToInstall();
          for (String funcName : functions) {
              if (! funcName.equals("fn_transaction_id") || supportsTransactionId) {
                  if (jdbcTemplate.queryForInt(sqlTemplate.getFunctionInstalledSql(funcName)) == 0) {
                      jdbcTemplate.update(sqlTemplate.getFunctionSql(funcName));
                      logger.info("Just installed " + funcName);
                  }
              }
          }
      }
  
      @Override
      protected boolean doesTriggerExistOnPlatform(String catalog, String schema, String tableName, String triggerName) {
          catalog = catalog == null ? (getDefaultCatalog() == null ? null : getDefaultCatalog()) : catalog;
          String checkCatalogSql = (catalog != null && catalog.length() > 0) ? " and trigger_schema='" + catalog + "'"
                  : "";
          return jdbcTemplate.queryForInt(
                  "select count(*) from information_schema.triggers where trigger_name like ? and event_object_table like ?"
                          + checkCatalogSql, new Object[] { triggerName, tableName }) > 0;
      }
  
      // TODO this belongs in SqlTemplate
      public void removeTrigger(String catalogName, String schemaName, String triggerName, String tableName, TriggerHistory oldHistory) {
          catalogName = catalogName == null ? "" : (catalogName + ".");
          try {
              jdbcTemplate.update("drop trigger " + catalogName + triggerName);
          } catch (Exception e) {
              logger.warn("Trigger does not exist");
          }
      }
  
      public void disableSyncTriggers(String nodeId) {
          jdbcTemplate.update("set " + SYNC_TRIGGERS_DISABLED_USER_VARIABLE + "=1");
          if (nodeId != null) {
              jdbcTemplate.update("set " + SYNC_TRIGGERS_DISABLED_NODE_VARIABLE + "='" + nodeId + "'");
          }
      }
  
      public void enableSyncTriggers() {
          jdbcTemplate.update("set " + SYNC_TRIGGERS_DISABLED_USER_VARIABLE + "=null");
          jdbcTemplate.update("set " + SYNC_TRIGGERS_DISABLED_NODE_VARIABLE + "=null");
      }
 
     public String getSyncTriggersExpression() {
         return SYNC_TRIGGERS_DISABLED_USER_VARIABLE + " is null";
     }
 
     // Mister CHenson, what is this non-sense?
     public String getTransactionTriggerExpression(Trigger trigger) {
         if (supportsTransactionId) {
             String defaultCatalog = "";
             if (trigger.getSourceCatalogName() != null) {
                 defaultCatalog = this.getDefaultCatalog() + ".";
             }
             return defaultCatalog + TRANSACTION_ID_FUNCTION_NAME + "()";
         }
         return "null";
     }
 
     public boolean supportsTransactionId() {
         return supportsTransactionId;
     }
 
     public String getSelectLastInsertIdSql(String sequenceName) {
         return "select last_insert_id()";
     }
 
     public boolean isCharSpacePadded() {
         return false;
     }
 
     public boolean isCharSpaceTrimmed() {
         return true;
     }
 
     public boolean isEmptyStringNulled() {
         return false;
     }
 
     public void purge() {
     }
 
     public String getDefaultSchema() {
         return null;
     }
 
     public String getDefaultCatalog() {
         return (String) jdbcTemplate.queryForObject("select database()", String.class);
     }
 
     protected String switchCatalogForTriggerInstall(String catalog, Connection c) throws SQLException {
         if (catalog != null) {
             String previousCatalog = c.getCatalog();
             c.setCatalog(catalog);
             return previousCatalog;
         } else {
             return null;
         }
     }
 
     /***
      * According to the documentation (and experience) the jdbc driver for mysql
      * requires the fetch size to be as follows.
      */
     @Override
     public int getStreamingResultsFetchSize() {
         return Integer.MIN_VALUE;
     }
 
     public BinaryEncoding getBinaryEncoding() {
         return BinaryEncoding.HEX;
     }
     
     public String getIdentifierQuoteString()
     {
         return "`";
     }
 
 }