/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2008, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This 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 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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 software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.ejb.plugins.cmp.jdbc.metadata;

import java.io.IOException;
import java.io.StringReader;
import java.util.ArrayList;

import org.jboss.deployment.DeploymentException;
import org.jboss.metadata.MetaData;
import org.w3c.dom.Element;

public final class JDBCFunctionMappingMetaData
{
   private final String functionName;
   private String[] sqlChunks;
   private int[] parameters;

   public JDBCFunctionMappingMetaData(String functionName, String[] sqlChunks, int[] parameters)
   {
      this.functionName = functionName;
      this.sqlChunks = sqlChunks;
      this.parameters = parameters;
   }

   public JDBCFunctionMappingMetaData(Element element) throws DeploymentException
   {
      functionName = MetaData.getUniqueChildContent(element, "function-name");

      String sql = MetaData.getUniqueChildContent(element, "function-sql");
      initFromString(sql);
   }

   public JDBCFunctionMappingMetaData(String functionName, String sql) throws DeploymentException
   {
      this.functionName = functionName;
      initFromString(sql);
   }

   private void initFromString(String sql) throws DeploymentException
   {
      ArrayList chunkList = new ArrayList();
      ArrayList parameterList = new ArrayList();

      // add a dummy chunk so we can be assured that the sql started with chunk before a number
      if(sql.charAt(0) == '?')
      {
         chunkList.add("");
      }
      // break the sql into chunks and parameters
      StringBuffer chunk = new StringBuffer();
      StringReader reader = new StringReader(sql);
      try
      {
         for(int c = reader.read(); c >= 0; c = reader.read())
         {
            if(c != '?')
            {
               chunk.append((char)c);
            }
            else
            {
               chunkList.add(chunk.toString());
               chunk = new StringBuffer();

               // read the number
               StringBuffer number = new StringBuffer();
               for(int digit = reader.read(); digit >= 0; digit = reader.read())
               {
                  if(Character.isDigit((char)digit))
                  {
                     number.append((char)digit);
                  }
                  else
                  {
                     if(digit >= 0)
                     {
                        chunk.append((char)digit);
                     }
                     break;
                  }
               }
               if(number.length() == 0)
               {
                  throw new DeploymentException("Invalid parameter in function-sql: " + sql);
               }
               Integer parameter;
               try
               {
                  parameter = new Integer(number.toString());
               }
               catch(NumberFormatException e)
               {
                  throw new DeploymentException("Invalid parameter number in function-sql: number=" + number + " sql=" + sql);
               }
               parameterList.add(parameter);
            }
         }
      }
      catch(IOException e)
      {
         // will never happen because io is in memory, but required by the interface
         throw new DeploymentException("Error parsing function-sql: " + sql);
      }
      chunkList.add(chunk.toString());

      // save out the chunks
      sqlChunks = new String[chunkList.size()];
      chunkList.toArray(sqlChunks);

      // save out the parameter order
      parameters = new int[parameterList.size()];
      for(int i = 0; i < parameters.length; i++)
      {
         parameters[i] = ((Integer)parameterList.get(i)).intValue() - 1;
      }
   }

   public String getFunctionName()
   {
      return functionName;
   }

   public StringBuffer getFunctionSql(Object[] args, StringBuffer buf)
   {
      for(int i = 0; i < sqlChunks.length; i++)
      {
         if(i < parameters.length)
         {
            // the logic is that if there is a parameter
            // than append its chunck unless the parameter is null
            // FIXME: I am not sure it's ok for any kind of template.
            Object arg = args[parameters[i]];
            if(arg != null)
            {
               buf.append(sqlChunks[i]);
               buf.append(arg);
            }
         }
         else
         {
            // this is tail
            buf.append(sqlChunks[i]);
         }
      }
      return buf;
   }
}