/* ScummVM - Scumm Interpreter
 * Copyright (C) 2003 The ScummVM project
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.

 * This program 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 General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * $Header$
 *
 */

#include "stdafx.h"
#include "common/scummsys.h"
#include "common/engine.h"
#include "sky/disk.h"
#include "sky/skydefs.h"
#include "sky/sky.h"
#include "sky/rnc_deco.h"

static const char *dataFilename = "sky.dsk";
static const char *dinnerFilename = "sky.dnr";

SkyDisk::SkyDisk(char *gameDataPath) {
	_prefRoot = NULL;
	_gameDataPath = gameDataPath;

	_dataDiskHandle = new File();
	_dnrHandle = new File();

	uint32 entriesRead;

	_dnrHandle->open(dinnerFilename, _gameDataPath);
	if (_dnrHandle->isOpen() == false)
			error("Could not open %s%s!\n", _gameDataPath, dinnerFilename);

	if (!(_dinnerTableEntries = _dnrHandle->readUint32LE()))
		error("Error reading from sky.dnr!\n"); //even though it was opened correctly?!
	
	debug(1, "Entries in dinner table: %d", _dinnerTableEntries);

	_dinnerTableArea = (uint8 *)malloc(_dinnerTableEntries * 8);
	entriesRead = _dnrHandle->read(_dinnerTableArea, 8 * _dinnerTableEntries) / 8;

	if (entriesRead != _dinnerTableEntries)
		warning("entriesRead != dinnerTableEntries. [%d/%d]\n", entriesRead, _dinnerTableEntries);

	_dataDiskHandle->open(dataFilename, _gameDataPath);
	if (_dataDiskHandle->isOpen() == false) 
		error("Error opening %s%s!\n", _gameDataPath, dataFilename);

	memset(_buildList, 0, 60 * 2);
	memset(_loadedFilesList, 0, 60 * 4);
}

SkyDisk::~SkyDisk(void) {

	PrefFile *fEntry = _prefRoot;
	while (fEntry) {
		free(fEntry->data);
		PrefFile *fTemp = fEntry;
		fEntry = fEntry->next;
		delete fTemp;
	}
	if (_dnrHandle->isOpen()) _dnrHandle->close();
	if (_dataDiskHandle->isOpen()) _dataDiskHandle->close();
	delete _dnrHandle;
	delete _dataDiskHandle;
}

void SkyDisk::flushPrefetched(void) {

	PrefFile *fEntry = _prefRoot;
	while (fEntry) {
		free(fEntry->data);
		PrefFile *fTemp = fEntry;
		fEntry = fEntry->next;
		delete fTemp;
	}
	_prefRoot = NULL;
}

//load in file file_nr to address dest
//if dest == NULL, then allocate memory for this file
uint8 *SkyDisk::loadFile(uint16 fileNr, uint8 *dest) {
	
	uint8 cflag;
	int32 bytesRead;
	uint8 *filePtr, *inputPtr, *outputPtr;
	dataFileHeader fileHeader;

	uint8 *prefData = givePrefetched(fileNr, &_lastLoadedFileSize);
	if (prefData) {
		if (dest == NULL) return prefData;
		else {
			memcpy(dest, prefData, _lastLoadedFileSize);
			free(prefData);
			return dest;
		}
	}

	#ifdef file_order_chk
		warning("File order checking not implemented yet!\n");
	#endif

	_compFile = fileNr;
	debug(2, "load file %d,%d (%d)", (fileNr >> 11), (fileNr & 2047), fileNr); 

	filePtr = getFileInfo(fileNr);
	if (filePtr == NULL) {
		printf("File %d not found!\n", fileNr);
		return NULL;
	}

	_fileFlags = READ_LE_UINT32((filePtr + 5));
	_fileSize = _fileFlags & 0x03fffff;
	_lastLoadedFileSize = _fileSize;
	
	_fileOffset = READ_LE_UINT32((filePtr + 2)) & 0x0ffffff;

	cflag = (uint8)((_fileOffset >> (23)) & 0x1);
	_fileOffset = (((1 << (23)) ^ 0xFFFFFFFF) & _fileOffset);

	if (cflag)
		_fileOffset <<= 4;

	_fixedDest = dest;
	_fileDest = dest;
	_compDest = dest;

	if (dest == NULL) //we need to allocate memory for this file
		_fileDest = (uint8 *)malloc(_fileSize);

	_dataDiskHandle->seek(_fileOffset, SEEK_SET);

	#ifdef file_order_chk
		warning("File order checking not implemented yet!\n");
	#endif

	//now read in the data
	bytesRead = _dataDiskHandle->read(_fileDest, 1 * _fileSize);

	if (bytesRead != (int32)_fileSize)
		printf("ERROR: Unable to read %d bytes from datadisk (%d bytes read)\n", _fileSize, bytesRead);

	cflag = (uint8)((_fileFlags >> (23)) & 0x1);

	//if cflag == 0 then file is compressed, 1 == uncompressed

	if (!cflag) {
		debug(2, "File is compressed...");

		memcpy(&fileHeader, _fileDest, sizeof(struct dataFileHeader));
		if ( (uint8)((FROM_LE_16(fileHeader.flag) >> 7) & 0x1)	 ) {
			debug(2, "with RNC!");

			_decompSize = (FROM_LE_16(fileHeader.flag) & 0xFFFFFF00) << 8;
			_decompSize |= FROM_LE_16((uint16)fileHeader.s_tot_size);

			if (_fixedDest == NULL) // is this valid?
				_compDest = (uint8 *)malloc(_decompSize);

			inputPtr = _fileDest;
			outputPtr = _compDest;

			if ( (uint8)(_fileFlags >> (22) & 0x1) ) //do we include the header?
				inputPtr += sizeof(struct dataFileHeader);
			else {
				memcpy(outputPtr, inputPtr, sizeof(struct dataFileHeader));
				inputPtr += sizeof(struct dataFileHeader);
				outputPtr += sizeof(struct dataFileHeader);
			}

			RncDecoder rncDecoder;
			int32 unPackLen = rncDecoder.unpackM1(inputPtr, outputPtr, 0);

			debug(3, "UnpackM1 returned: %d", unPackLen);

			if (unPackLen == 0) { //Unpack returned 0: file was probably not packed.
				if (_fixedDest == NULL)
					free(_compDest);
			
				return _fileDest;
			}

			if (! (uint8)(_fileFlags >> (22) & 0x1) ) { // include header?
				unPackLen += sizeof(struct dataFileHeader);

				if (unPackLen != (int32)_decompSize) {
					debug(1, "ERROR: invalid decomp size! (was: %d, should be: %d)", unPackLen, _decompSize);
				}
			}

			_lastLoadedFileSize = _decompSize; //including header
			
			if (_fixedDest == NULL)
				free(_fileDest);

		} else
			debug(2, "but not with RNC! (?!)");
	} else
		return _fileDest;

	return _compDest;
}

void SkyDisk::prefetchFile(uint16 fileNr) {

	PrefFile **fEntry = &_prefRoot;
	bool found = false;
	while (*fEntry) {
		if ((*fEntry)->fileNr == fileNr) found = true;
		fEntry = &((*fEntry)->next);
	}
	if (found) {
		debug(1,"SkyDisk::prefetchFile: File %d was already prefetched.\n",fileNr);
		return ;
	}
	uint8 *temp = loadFile(fileNr, NULL);
	*fEntry = new PrefFile;
	(*fEntry)->data = temp;
	(*fEntry)->fileSize = _lastLoadedFileSize;
	(*fEntry)->fileNr = fileNr;
	(*fEntry)->next = NULL;
}

uint8 *SkyDisk::givePrefetched(uint16 fileNr, uint32 *fSize) {
	
	PrefFile **fEntry = &_prefRoot;
	bool found = false;
	while ((*fEntry) && (!found)) {
		if ((*fEntry)->fileNr == fileNr) found = true;
		else fEntry = &((*fEntry)->next);
	}
	if (!found) {
		*fSize = 0;
		return NULL;
	}
	uint8 *retPtr = (*fEntry)->data;
	PrefFile *retStr = *fEntry;
	*fEntry = (*fEntry)->next;
	*fSize = retStr->fileSize;
	delete retStr;
    return retPtr;
}

uint8 *SkyDisk::getFileInfo(uint16 fileNr) {
	
	uint16 i;
	uint16 *dnrTbl16Ptr = (uint16 *)_dinnerTableArea;

	for (i = 0; i < _dinnerTableEntries; i++) {
		if (READ_LE_UINT16(dnrTbl16Ptr + (i * 4)) == fileNr) {
			debug(2, "file %d found!", fileNr);
			return (uint8 *)(dnrTbl16Ptr + (i * 4));
		}
	}

	// if file not found return NULL
	return (uint8 *)NULL;
}

void SkyDisk::fnCacheChip(uint32 list) {

	// fnCacheChip is called after fnCacheFast
	uint16 cnt = 0;
	while (_buildList[cnt]) cnt++;
	uint16 *fList = (uint16*)SkyState::fetchCompact(list);
	uint16 fCnt = 0;
	do {
		_buildList[cnt + fCnt] = fList[fCnt] & 0x7FFFU;
		fCnt++;
	} while (fList[fCnt-1]);
	fnCacheFiles();
}

void SkyDisk::fnCacheFast(uint32 list) {

	if (list == 0) return;
	uint8 cnt = 0;
	uint16 *fList = (uint16*)SkyState::fetchCompact(list);
	do {
		_buildList[cnt] = fList[cnt];
		cnt++;
	} while (fList[cnt-1]);
}

void SkyDisk::fnCacheFiles(void) {

	// call trash_all_fx
	uint16 lCnt, bCnt, targCnt;
	targCnt = lCnt = 0;
	bool found;
	while (_loadedFilesList[lCnt]) {
		bCnt = 0;
		found = false;
		while (_buildList[bCnt] && (!found)) {
			if ((_buildList[bCnt] & 0x7FFFU) == _loadedFilesList[lCnt]) found = true;
			else bCnt++;
		}
		if (found) {
			_loadedFilesList[targCnt] = _loadedFilesList[lCnt];
			targCnt++;
		} else {
			free(SkyState::_itemList[_loadedFilesList[lCnt] & 2047]);
			SkyState::_itemList[_loadedFilesList[lCnt] & 2047] = NULL;
		}
		lCnt++;
	}
	_loadedFilesList[targCnt] = 0; // mark end of list
	bCnt = 0;
	while (_buildList[bCnt]) {
		if ((_buildList[bCnt] & 0x7FF) == 0x7FF) {
			// amiga dummy files
			bCnt++;
			continue;
		}
		lCnt = 0;
		found = false;
		while (_loadedFilesList[lCnt] && (!found)) {
			if (_loadedFilesList[lCnt] == (_buildList[bCnt] & 0x7FFFU)) found = true;
			lCnt++;
		}
		if (found) {
			bCnt++;
			continue;
		}
		// ok, we really have to load the file.
		_loadedFilesList[targCnt] = _buildList[bCnt] & 0x7FFFU;
		targCnt++;
		_loadedFilesList[targCnt] = 0;
		SkyState::_itemList[_buildList[bCnt] & 2047] = (void**)loadFile(_buildList[bCnt] & 0x7FFF, NULL);
		bCnt++;
	}
	_buildList[0] = 0;
}

void SkyDisk::fnMiniLoad(uint16 fileNum) {

	uint16 cnt = 0;
	while (_loadedFilesList[cnt]) {
		if (_loadedFilesList[cnt] == fileNum) return ;
		cnt++;
	}
	_loadedFilesList[cnt] = fileNum;
	_loadedFilesList[cnt + 1] = 0;
	SkyState::_itemList[fileNum & 2047] = (void**)loadFile(fileNum, NULL);
}

void SkyDisk::fnFlushBuffers(void) {

	// dump all loaded sprites
	uint8 lCnt = 0;
	while (_loadedFilesList[lCnt]) {
		free(SkyState::_itemList[_loadedFilesList[lCnt] & 2047]);
		SkyState::_itemList[_loadedFilesList[lCnt] & 2047] = 0;
		lCnt++;
	}
	_loadedFilesList[0] = 0;
}

void SkyDisk::dumpFile(uint16 fileNr) {
	char buf[128];
	File out;
	byte* filePtr;

	filePtr = loadFile(fileNr, NULL);
	sprintf(buf, "dumps/file-%d.dmp", fileNr);
	
	out.open(buf, "", 1);
	if (out.isOpen() == false) {
		out.open(buf, "", 2);
		if (out.isOpen() == false)
			return;
		out.write(filePtr, _lastLoadedFileSize);
	}
	out.close();
	free(filePtr);
}

uint32 SkyDisk::determineGameVersion() {
	//determine game version based on number of entries in dinner table
	switch (_dinnerTableEntries) {
	case 247:	
		//floppy demo (v0.0267)
		return 267;
	case 1404:
		//floppy (v0.0288)
		return 288;
	case 1413:
		//floppy (v0.0303)
		return 303;
	case 1445:
		//floppy (v0.0331)
		return 331;
	case 1711:
		//cd demo (v0.0365)
		return 365;
	case 5099:
		//cd (v0.0368)
		return 368;
	case 5097:
		//cd (v0.0372)
		return 372;
	default:
		//unknown version
		error("Unknown game version!");
		break;
	}
}