/*
 $Id: kwdsstorage.cc 5795 2010-10-23 01:18:03Z abehm $
 
 Copyright (C) 2010 by The Regents of the University of California
 
 Redistribution of this file is permitted under
 the terms of the BSD license.
 
 Date: 08/19/2010
 Author: Sattam Alsubaiee <salsubai (at) ics.uci.edu>
*/

#include "kwdsstorage.h"

KeywordsFile::KeywordsFile(string fileName)
{
	keywordsFileName = fileName;
	buffer = 0;
}

void KeywordsFile::readIndex(string indexFileName, bool newFile)
{
  	fstream indexFile;
	
	if(newFile)
	{
		indexFile.open(indexFileName.c_str(), ios_base::in | ios_base::out | ios_base::binary | ios_base::trunc);
	}
	else
	{
		indexFile.open(indexFileName.c_str(), ios_base::in | ios_base::out | ios_base::binary);
		if(indexFile.is_open())
		{
			indexFile.seekg(0, ios_base::end);
			if(indexFile.tellg() / sizeof(IndexNode) > 0)
			{
				indexFile.seekg(0, ios_base::beg);
				IndexNode irec;
				while(!indexFile.eof())
				{
					indexFile.read((char *)&irec, sizeof(irec));
					indexMap[irec.id] = irec;
				}
			}
			indexFile.close();
		}
	}
}

void KeywordsFile::writeIndex()
{
  	fstream indexFile;
	IndexNode irec;
	indexFile.open((keywordsFileName + ".idx").c_str(), ios_base::in | ios_base::out | ios_base::binary | ios_base::trunc);
	if(indexFile.is_open())
	{
		unordered_map <unsigned, IndexNode>::iterator it; 
		for (it = indexMap.begin(); it != indexMap.end(); ++it) 
		{
			irec = (*it).second;
            indexFile.write((char *)&irec, sizeof(irec));
		}
		indexFile.close();
	}
}

IndexNode KeywordsFile::getIndexNode(unsigned id)
{
	return indexMap[id];
}

bool KeywordsFile::open(bool newFile)
{
	if(newFile)
	{
		keywordsFile.open((keywordsFileName + ".dat").c_str(), ios_base::in | ios_base::out | ios_base::binary | ios_base::trunc);
	}
	else
	{
		keywordsFile.open((keywordsFileName + ".dat").c_str(), ios_base::in | ios_base::out | ios_base::binary);
	}
	readIndex(keywordsFileName + ".idx", newFile);
	return keywordsFile.is_open();
}


KeywordsFile::~KeywordsFile()
{
	if(keywordsFile.is_open())
	{
		close();
	}
}

unordered_map <unsigned, IndexNode>::iterator KeywordsFile::begin()
{
	return indexMap.begin();
}

unordered_map <unsigned, IndexNode>::iterator KeywordsFile::end()
{
	return indexMap.end();
}

void KeywordsFile::close()
{
	writeIndex();
	keywordsFile.close();
	keywordsFile.clear();
	indexMap.clear();
}

bool KeywordsFile::write(string text, unsigned id, unsigned numKeywords)
{
    bool result = true;
	IndexNode irec;
	
	try
	{	
		unordered_map<unsigned, IndexNode>::iterator it;
		it = indexMap.find(id);
		
		if(it != indexMap.end())
		{
			indexMap.erase(it);
			keywordsFile.seekp((it->second).position);
			irec.position = keywordsFile.tellp();
			irec.size = text.length();
			irec.id = id;
			irec.numKeywords = numKeywords;
			indexMap[id] = irec;
			keywordsFile.write(text.c_str(), (std::streamsize)text.length());
			keywordsFile.seekp(0, ios_base::end);
		}
		else 
		{
			irec.position = keywordsFile.tellp();
			irec.size = text.length();
			irec.id = id;
			irec.numKeywords = numKeywords;
			indexMap[id] = irec;
			keywordsFile.write(text.c_str(), (std::streamsize)text.length());
		}
	}
	catch(char *ex)
	{
		cout << "Problem writing " << ex << endl;
		result = false;
	}
    
	return (result); 
}

string KeywordsFile::read(unsigned id)
{
	IndexNode irec = indexMap[id];
	if(buffer)
	{
		delete [] buffer;
	}
	buffer = new char[irec.size + 1];
	keywordsFile.seekg(irec.position, ios_base::beg);
	keywordsFile.read(buffer, irec.size);
	buffer[irec.size] = '\0';
	return (string)buffer;
}

unsigned KeywordsFile::getRecordCount()
{
	return (unsigned)indexMap.size();
}