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package convwatch;

import java.io.File;
import java.io.RandomAccessFile;
import java.util.ArrayList;

/**
   Helper class to give a simple API to read/write windows like ini files
 */
/* public */ // is only need, if we need this class outside package convwatch
class IniFile
{
    /**
     * internal representation of the ini file content.
     * Problem, if ini file changed why other write something difference, we don't realise this.
     */
    String m_sFilename;
    ArrayList m_aList;
    boolean m_bListContainUnsavedChanges = false;

    /**
       open a ini file by it's name
       @param _sFilename string a filename, if the file doesn't exist, a new empty ini file will create.
       write back to disk only if there are really changes.
     */
    public IniFile(String _sFilename)
        {
            m_sFilename = _sFilename;
            m_aList = loadLines();
        }

    ArrayList loadLines()
        {
            File aFile = new File(m_sFilename);
            ArrayList aLines = new ArrayList();
            if (! aFile.exists())
            {
                GlobalLogWriter.get().println("couldn't find file " + m_sFilename);
                // DebugHelper.exception(BasicErrorCode.SbERR_FILE_NOT_FOUND, "");
                // m_bListContainUnsavedChanges = false;
                return aLines;
            }
            RandomAccessFile aReader = null;
            try
            {
                aReader = new RandomAccessFile(aFile,"r");
                String aLine = "";
                while (aLine != null)
                {
                    aLine = aReader.readLine();
                    if (aLine != null)
                    {
                        aLines.add(aLine);
                        }
                    }
                }
            catch (java.io.FileNotFoundException fne)
            {
                GlobalLogWriter.get().println("couldn't open file " + m_sFilename);
                GlobalLogWriter.get().println("Message: " + fne.getMessage());
                // DebugHelper.exception(BasicErrorCode.SbERR_FILE_NOT_FOUND, "");
            }
            catch (java.io.IOException ie)
            {
                GlobalLogWriter.get().println("Exception occurs while reading from file " + m_sFilename);
                GlobalLogWriter.get().println("Message: " + ie.getMessage());
                // DebugHelper.exception(BasicErrorCode.SbERR_INTERNAL_ERROR, ie.getMessage());
            }
            try
            {
                aReader.close();  
            }
            catch (java.io.IOException ie)
            {
                GlobalLogWriter.get().println("Couldn't close file " + m_sFilename);
                GlobalLogWriter.get().println("Message: " + ie.getMessage());
                // DebugHelper.exception(BasicErrorCode.SbERR_INTERNAL_ERROR, ie.getMessage());
            }
            return aLines;
        }

    /**
     * @return true, if the ini file contain some readable data
     */
    public boolean is()
        {
            return m_aList.size() > 1 ? true : false;
        }

    // -----------------------------------------------------------------------------
    
    boolean isRemark(String _sLine)
        {
            if ( ((_sLine.length() < 2) ) ||
                 ( _sLine.startsWith("#")) || 
                 ( _sLine.startsWith(";")) )
            {
                return true;
            }
            return false;
        }
    
    String getItem(int i)
        {
            return (String)m_aList.get(i);
        }

    String buildSectionName(String _sSectionName)
        {
            String sFindSection = "[" + _sSectionName + "]";
            return sFindSection;
        }
    String toLowerIfNeed(String _sName)
        {
            return _sName.toLowerCase();
        }
    
    // return the number where this section starts
    int findSection(String _sSection)
        {
            String sFindSection = toLowerIfNeed(buildSectionName(_sSection));
            // ----------- find _sSection ---------------
            int i;
            for (i=0; i<m_aList.size();i++)
            {
                String sLine = toLowerIfNeed(getItem(i).trim());
                if (isRemark(sLine))
            {
                    continue;
                }
                if (sFindSection.equals("[]"))
                {
                    // special case, empty Section.
                    return i - 1;
                }
                if (sLine.startsWith(sFindSection))
                {
                    return i;
                }
            }
            return -1;
        }
    
    // return the line number, where the key is found.
    int findKey(String _sSection, String _sKey)
        {
            int i = findSection(_sSection);
            if (i == -1)
            {
                // Section not found, therefore the value can't exist
                return -1;
            }
            return findKeyFromKnownSection(i, _sKey);
        }
    
    // i must be the index in the list, where the well known section starts
    int findKeyFromKnownSection(int _nSectionIndex, String _sKey)
        {
            _sKey = toLowerIfNeed(_sKey);
            for (int j=_nSectionIndex + 1; j<m_aList.size();j++)
            {
                String sLine = getItem(j).trim();
                
                if (isRemark(sLine))
                {
                    continue;
                }
                
                if (sLine.startsWith("[") /* && sLine.endsWith("]") */)
                {
                    // found end.
                    break;
                }
                
                int nEqual = sLine.indexOf("=");
                if (nEqual >= 0)
                {
                    String sKey = toLowerIfNeed(sLine.substring(0, nEqual).trim());
                    if (sKey.equals(_sKey))
                    {
                        return j;
                    }
            }
            }
            return -1;
        }
            
    // i must be the index in the list, where the well known section starts
    int findLastKnownKeyIndex(int _nSectionIndex, String _sKey)
        {
            _sKey = toLowerIfNeed(_sKey);
            int i = _nSectionIndex + 1;
            for (int j=i; j<m_aList.size();j++)
            {
                String sLine = getItem(j).trim();
                
                if (isRemark(sLine))
                {
                    continue;
                }

                if (sLine.startsWith("[") /* && sLine.endsWith("]") */)
                {
                    // found end.
                    return j;
                }
                
                int nEqual = sLine.indexOf("=");
                if (nEqual >= 0)
                {
                    String sKey = toLowerIfNeed(sLine.substring(0, nEqual).trim());
                    if (sKey.equals(_sKey))
                    {
                        return j;
                    }
                }
            }
            return i;
        }
    
    String getValue(int _nIndex)
        {
            String sLine = getItem(_nIndex).trim();
            if (isRemark(sLine))
            {
                return "";
            }
            int nEqual = sLine.indexOf("=");
            if (nEqual >= 0)
            {
                String sKey =   sLine.substring(0, nEqual).trim();
                String sValue = sLine.substring(nEqual + 1).trim();
                return sValue;
                    }
            return "";
                }

    /**
       @param _sSection string 
       @param _sKey string
       @return the value found in the inifile which is given by the section and key parameter 
    */
    public String getValue(String _sSection, String _sKey)
        {
            String sValue = "";
            int i = findKey(_sSection, _sKey);
            if (i == -1)
            {
                // Section not found, therefore the value can't exist
                return "";
            }

            sValue = getValue(i);
            
            return sValue;
        }

    /**
       write back the ini file to the disk, only if there exist changes
    */
    public void store() 
        {
            if (m_bListContainUnsavedChanges == false)
            {
                // nothing has changed, so no need to store
                return;
            }
            
            File aFile = new File(m_sFilename);
            if (aFile.exists())
            {
                // System.out.println("couldn't find file " + m_sFilename);
                aFile.delete();
                if (aFile.exists())
                {
                    GlobalLogWriter.get().println("Couldn't delete the file " + m_sFilename);
                    return;
                    // DebugHelper.exception(BasicErrorCode.SbERR_INTERNAL_ERROR, "Couldn't delete the file " + m_sFilename);
                }
            }
            // if (! aFile.canWrite())
            // {
            //    System.out.println("Couldn't write to file " + m_sFilename);
            //    DebugHelper.exception(BasicErrorCode.SbERR_INTERNAL_ERROR, "");
            // }
            try
            {
                RandomAccessFile aWriter = new RandomAccessFile(aFile, "rw");
                for (int i=0; i<m_aList.size();i++)
                {
                    String sLine = getItem(i);
                    aWriter.writeBytes(sLine);
                    aWriter.writeByte((int)'\n');
                }
                aWriter.close();
            }
            
            catch (java.io.FileNotFoundException fne)
            {
                GlobalLogWriter.get().println("couldn't open file for writing " + m_sFilename);
                GlobalLogWriter.get().println("Message: " + fne.getMessage());
                // DebugHelper.exception(BasicErrorCode.SbERR_FILE_NOT_FOUND, "");
            }
            catch(java.io.IOException ie)
            {
                GlobalLogWriter.get().println("Exception occurs while writing to file " + m_sFilename);
                GlobalLogWriter.get().println("Message: " + ie.getMessage());
                // DebugHelper.exception(BasicErrorCode.SbERR_INTERNAL_ERROR, ie.getMessage());
            }
        }
    
    
    
    /**
       insert a value
       there are 3 cases
       1. section doesn't exist, goto end and insert a new section, insert a new key value pair
       2. section exist but key not, search section, search key, if key is -1 get last known key position and insert new key value pair there
       3. section exist and key exist, remove the old key and insert the key value pair at the same position
    */
    public void insertValue(String _sSection, String _sKey, String _sValue) 
        {
            int i = findSection(_sSection);
            if (i == -1)
            {
                // case 1: section doesn't exist
                String sFindSection = buildSectionName(_sSection);

                m_aList.add(sFindSection);
                String sKeyValuePair = _sKey + "=" + _sValue;
                m_aList.add(sKeyValuePair);
                m_bListContainUnsavedChanges = true;
                return;
            }
            int j = findKeyFromKnownSection(i, _sKey);
            if (j == -1)
            {
                // case 2: section exist, but not the key
                j = findLastKnownKeyIndex(i, _sKey);
                String sKeyValuePair = _sKey + "=" + _sValue;
                m_aList.add(j, sKeyValuePair);
                m_bListContainUnsavedChanges = true;
                return;
            }
            else
            {
                // case 3: section exist, and also the key
                String sKeyValuePair = _sKey + "=" + _sValue;
                m_aList.set(j, sKeyValuePair);
                m_bListContainUnsavedChanges = true;
            }
        }
    // -----------------------------------------------------------------------------
    // String replaceEvaluatedValue(String _sSection, String _sValue)
    //     {
    //         String sValue = _sValue;
    //         int nIndex = 0;
    //         while (( nIndex = sValue.indexOf("$(", nIndex)) >= 0)
    //         {
    //             int nNextIndex = sValue.indexOf(")", nIndex);
    //             if (nNextIndex >= 0)
    //             {
    //                 String sKey = sValue.substring(nIndex + 2, nNextIndex);
    //                 String sNewValue = getValue(_sSection, sKey);
    //                 if (sNewValue != null && sNewValue.length() > 0)
    //                 {
    //                     String sRegexpKey = "\\$\\(" + sKey + "\\)";
    //                     sValue = sValue.replaceAll(sRegexpKey, sNewValue);
    //                 }
    //                 nIndex = nNextIndex;
    //             }
    //             else
    //             {
    //                 nIndex += 2;
    //             }
    //         }
    //         return sValue;
    //     }
    // -----------------------------------------------------------------------------

    // public String getLocalEvaluatedValue(String _sSection, String _sKey)
    //     {
    //         String sValue = getValue(_sSection, _sKey);
    //         sValue = replaceEvaluatedValue(_sSection, sValue);
    //         return sValue;
    //     }

    // -----------------------------------------------------------------------------

    // this is a special behaviour.
    // public String getGlobalLocalEvaluatedValue(String _sSection, String _sKey)
    //     {
    //         String sGlobalValue = getKey("global", _sKey);
    //         String sLocalValue = getKey(_sSection, _sKey);
    //         if (sLocalValue.length() == 0)
    //         {
    //             sGlobalValue = replaceEvaluatedKey(_sSection, sGlobalValue);
    //             sGlobalValue = replaceEvaluatedKey("global", sGlobalValue);
    //             return sGlobalValue;
    //         }
    //         sLocalValue = replaceEvaluatedKey(_sSection, sLocalValue);
    //         sLocalValue = replaceEvaluatedKey("global", sLocalValue);
    //     
    //         return sLocalValue;
    //     }

    
    /**
     * some tests for this class
     */
//    public static void main(String[] args)
//        {
//            IniFile aIniFile = new IniFile("/tmp/inifile");
//            String sValue = aIniFile.getValue("Section","Key");
//            // insert a new value to a already exist section
//            aIniFile.insertValue("Section","Key2","a new value in a existing section");
//            // replace a value
//            aIniFile.insertValue("Section","Key","replaced value");
//            // create a new value
//            aIniFile.insertValue("New Section", "Key", "a new key value pair");
//
//            String sValue2 = aIniFile.getValue("Section2","Key");
//            aIniFile.store();
//        }
}