// Copyright 1993 Nildram Software. All rights reserved.
// May not be copied, except for backup purposes, without express written
// permission from Nildram Software

#include "stdafx.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "isammgr.h"

IsamMgr::IsamMgr(char *dfName, int dSize, int isMode) :
	FileMgr(dfName, dSize, caNoCache, isMode)
{
	curidx = 0;
	idxfname = "Invalid Index";
    m_lBlockRecNum = -1;
}

IsamMgr::~IsamMgr(void)
{
	for (int x = 0; x < noidxs; x++)
		delete ifile[x];
	delete buffer;
}

void IsamMgr::rebuild_idxs(void)
{
	for (int x = 0; x < noidxs; x++)
	{
		long count = 0;
		m_lBlockRecNum = -1;
		while (FileMgr::next() != -1)
		{
			fill_buffer(x, m_lBlockRecNum);
			if (ifile[x]->insert(m_lBlockRecNum, buffer) == noDuplicate)
			{
				AfxMessageBox("Error rebuilding Index: Duplicate Key!");
                ASSERT(FALSE);
				exit(0);
			}
			//if ((++count % 10) == 0)
            //{
            //    if (count == 10)
            //        IsamInitProgress(idxfname, idxname[x]);
            //    IsamProgress(count);
			//}
		}

        //if ((count % 10) != 0 && count > 10)
        //{
        //    IsamProgress(count);
		//	IsamEndProgress();
		//}
	}
}

int IsamMgr::insert(void)
{
	FileMgr::insert();
	for (int x = 0; x < noidxs; x++)
	{
		fill_buffer(x, m_lBlockRecNum);
		if (ifile[x]->insert(m_lBlockRecNum, buffer) == noDuplicate)
		{
			for (int y = x - 1; y >= 0; y--)
				ifile[y]->erase();
			FileMgr::erase();
			return -1;
		}
	}
	return 0;
}

int IsamMgr::next(int no_recs)
{
	long block;
	if (curidx == -1) 
	{
		int retval;
		for (; no_recs > 0; no_recs--)
		{
			retval = FileMgr::next();
			if (retval == -1)
				return -1;
		}
		return retval;
	}
	do  {
		m_lBlockRecNum = -1;
		//FileMgr::unlock();
		if ((block = ifile[curidx]->next(no_recs)) == -1)
			return -1;
		//FileMgr::lock(block);
		FileMgr::read(block);
		no_recs = 1;
	} while (ifile[curidx]->retrieve() != block);
	return 0;
}

int IsamMgr::prev(int no_recs)
{
	long block;
	do  {
		//FileMgr::unlock();
		m_lBlockRecNum = -1;
		if ((block = ifile[curidx]->prev(no_recs)) == -1)
			return -1;
		//FileMgr::lock(block);
		FileMgr::read(block);
		no_recs = 1;
	} while (ifile[curidx]->retrieve() != block);
	return 0;
}

void IsamMgr::rew(void)
{
	m_lBlockRecNum = -1;
	if (curidx != -1)
		ifile[curidx]->rew();
	//FileMgr::unlock();
}

void IsamMgr::ffwd(void)
{
	m_lBlockRecNum = -1;
	if (curidx != -1)
		ifile[curidx]->ffwd();
	//FileMgr::unlock();
}

int IsamMgr::find(void)
{
	long block;
	do {
		//FileMgr::unlock();
		m_lBlockRecNum = -1;
		fill_buffer(curidx, 0);
		if ((block = ifile[curidx]->find(buffer)) == -1)
				return -1;
		//FileMgr::lock(block);
		FileMgr::read(block);
	} while (ifile[curidx]->retrieve() != block);
	return 0;
}

int IsamMgr::retrieve(void)
{
	long block;
	m_lBlockRecNum = -1;
	if ((block = ifile[curidx]->retrieve()) == -1)
		return -1;
	//FileMgr::lock(block);
	FileMgr::read(block);
	return 0;
}

int IsamMgr::erase(void)
{
	if (m_lBlockRecNum == -1)
		return -1;
	for (int x = 0; x < noidxs; x++)
	{
		fill_buffer(x, m_lBlockRecNum);
		if (ifile[x]->find(buffer) != -1)
			ifile[x]->erase();
	}
	FileMgr::erase();
	//FileMgr::unlock();
	return 0;
}

int IsamMgr::amend(void)
{
	if (m_lBlockRecNum == -1)
		return -1;
	char *block = new char[FileMgr::m_nRecSize];
	char *block2 = new char[FileMgr::m_nRecSize];
	write_data(block);

	FileMgr::read(m_lBlockRecNum);
	write_data(block2);
	for (int x = 0; x < noidxs; x++)
	{
		fill_buffer(x, m_lBlockRecNum);
		ifile[x]->find(buffer);
	}

	read_data(block);
	int xchg[MAXIDXS];

	for (x = 0; x < noidxs; x++)
	{
		xchg[x] = 0;
		fill_buffer(x, m_lBlockRecNum);
		if (ifile[x]->compare(buffer) != 0)
		{
			xchg[x] = 1;
			if (ifile[x]->insert(m_lBlockRecNum, buffer) == noDuplicate)
			{
				for (int y = x - 1; y >= 0; y--)
					if (xchg[y])
						ifile[y]->erase();
				
				read_data(block2);
				fill_buffer(curidx, m_lBlockRecNum);
				ifile[curidx]->find(buffer);
	
				read_data(block);
				delete block;
				delete block2;
				return -1;
			}
		}
	}

	FileMgr::amend();
	
	read_data(block2);
	for (x = 0; x < noidxs; x++)
		if (xchg[x])
		{
			long block;
			fill_buffer(x, m_lBlockRecNum);
			block = ifile[x]->find(buffer);
			if (block == m_lBlockRecNum)
				ifile[x]->erase();
		}

	read_data(block);
	fill_buffer(curidx, m_lBlockRecNum);
	ifile[curidx]->find(buffer);

	delete block;
	delete block2;
	return 0;
}

void IsamMgr::set_idx(const char *name)
{
	for (int x = 0; x < noidxs; x++)
		if (strcmp(idxname[x], name) == 0)
		{
			curidx = x;
			return;
		}
	AfxMessageBox("Invalid Index Name");
	ASSERT(FALSE);
	exit(0);
}

void IsamMgr::set_idx(int idxno)
{
	 if (idxno > noidxs || idxno < -1)
		AfxMessageBox("Invalid Index No");
	 curidx = idxno;
}

void IsamMgr::close(void)
{
	if (m_nFileHandle == -1)
		return;
	m_lBlockRecNum = -1;
	FileMgr::close_file();
	for (int x = 0; x < noidxs; x++)
		ifile[x]->close_file();
}

void IsamMgr::open(void)
{
	if (m_nFileHandle != -1)
		return;
	FileMgr::open_file();
	ifile[0]->open_file();
	for (int x = 0; x < noidxs; x++)
		ifile[x]->set_fd(ifile[0]->get_fd());
}