
#include "installOS.h"
#include "log.h"
#include "extract.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/*
 * Self-Extracting File Structure
 * 
 * |---------------------------|
 * |   Executable Extractor    |
 * |                           |
 * |---------------------------|
 * |       Files Data          |
 * |                           |
 * |---------------------------|
 * |       SFX Header          |
 * |                           |
 * |---------------------------|
 * |     Table Of Contents     |
 * |           (TOC)           |
 * |---------------------------|
 * |       SFX Footer          |
 * |                           |
 * |---------------------------|
 * 
 * 
 *  SFX Header:
 *  12 bytes - SFX signature ( including format version )
 *  4 bytes - number of files
 *  
 *  TOC Entry:
 *  4 bytes - file data offset
 *  4 bytes - file data size
 *  4 bytes - filename length (N)
 *  N bytes - filename
 *
 *  SFX Footer:
 *  4 bytes - SFX header offset
 *  4 bytes - 32-bit complementary checksum
 */

static const char* SIGNATURE = "!SFX.PKG-0.1";
static TOC_ENTRY * toc = NULL;
static unsigned int file_count = 0;

static int doError( int error, _TCHAR* str );

#ifdef MACOSX
#define SWAP32(x)	/* do nothing */
#else
#define SWAP32(x)	(x) = ((x)>>24)|(((x)&0x00FF0000)>>8)|(((x)&0x0000FF00)<<8)|(((x)&0x000000FF)<<24)
#endif

#define BUFFER_SIZE		1024
#define MIN(a,b)		(a)<(b) ? (a) : (b)


#define FLAGS_EXTRACT		(0x00000001)

/*
 * Errors
 */
#define ERROR_READ					(-1)
#define ERROR_INVALID_CONTENT		(-2)
#define ERROR_WRITE					(-3)

/*
 * Read Table Of Contents
 */
static int readTOC( FILE *file )
{
	long filesize = 0;
	unsigned int value = 0;
	unsigned int i;
	char sign[12];
	char * filename;
	TOC_ENTRY* entry;

	/* verify checksum here */
	
	if ( fseek(file, -8, SEEK_END ) != 0 ) return ERROR_READ;
	if ( fread(&value,4,1,file) != 1 ) return ERROR_READ;
	SWAP32(value);
	if ( (filesize = ftell(file)) <= (long)value ) return ERROR_INVALID_CONTENT;

	if ( fseek(file, value, SEEK_SET ) != 0 ) return ERROR_READ;
	if ( fread(sign,sizeof(sign),1,file) != 1 ) return ERROR_READ;
	
	if ( strncmp(SIGNATURE,sign,sizeof(sign)) != 0 ) return ERROR_INVALID_CONTENT;
	if ( fread(&file_count,4,1,file) != 1 ) return ERROR_READ;
	SWAP32(file_count);
	
	toc = entry = calloc(file_count,sizeof(TOC_ENTRY));
	for( i = 0; i < file_count; ++i, ++entry )
	{
		if ( fread(entry,4,3,file) != 3 ) return ERROR_READ;
		if ( fread(&value,4,1,file) != 1 ) return ERROR_READ;
		SWAP32(entry->OFFSET);
		SWAP32(entry->SIZE);
		SWAP32(entry->FLAGS);
		SWAP32(value);
		if ( filesize <= (long)(entry->OFFSET+entry->SIZE) ) return ERROR_INVALID_CONTENT;
		filename = malloc(value+1);
		if ( fread(filename,1,value,file) != value ) return ERROR_READ;		
#ifdef _UNICODE
		{
			WCHAR *wstring = malloc((value + 1) * sizeof(WCHAR));
			value = MultiByteToWideChar(CP_ACP, MB_PRECOMPOSED, filename, value, wstring, value);
			wstring[value] = 0;
			entry->FILENAME = wstring;
			free(filename);
		}
#else
		filename[value] = '\0';
		entry->FILENAME = filename;
#endif
	}
	
	return 0;
}

/*
 * Free TOC resources
 */
static void freeTOC()
{
	if ( toc != NULL )
	{
		unsigned int i;
		TOC_ENTRY* entry = toc;
		for( i = 0; i < file_count; ++i, ++entry )
			free(entry->FILENAME);
		free(toc);
		toc = NULL;
	}
		
}
	
/*
 * Extract all contents to directory
 */
int extract( _TCHAR* fromfile, _TCHAR* todir )
{
	int error = 0;
	unsigned int i;
	TOC_ENTRY* entry;
	_TCHAR * string;
	char * buffer;
	FILE *fout;
	
	FILE *file = _tfopen(fromfile, _T_INSTALL("rb"));
	if (file == NULL)
		return doError(ERROR_READ,fromfile);
	if ( (error = readTOC(file)) != 0 ) {
		fclose(file);
		return doError(error,fromfile);
	}
	entry = toc;
	string = malloc( MAX_PATH * sizeof(_TCHAR) );
	buffer = malloc( BUFFER_SIZE );
	for( i = 0; i < file_count; ++i, ++entry )
	{
		unsigned int size = entry->SIZE;	
		if ( (entry->FLAGS & FLAGS_EXTRACT ) == 0 ) continue;
		if ( entry->CREATED) continue;	
		_tcscpy(string, todir);
		_tcscat(string,entry->FILENAME);
		logFormatS(_T_INSTALL("[i] Extracting file %s"),string);
		fout = _tfopen(string, _T_INSTALL("wb"));
		if (fout == NULL) { error = doError(ERROR_WRITE,string); break; }
		if ( fseek(file, entry->OFFSET, SEEK_SET ) != 0 ) { error = doError(ERROR_READ,fromfile); fclose(fout); break; }
		
		while( size > 0 )
		{
			unsigned int n = MIN(size,BUFFER_SIZE);
			if ( fread(buffer,n,1,file) != 1 ) { error = doError(ERROR_READ,fromfile); fclose(fout); break; }
			if ( fwrite(buffer,n,1,fout) != 1 ) { error = doError(ERROR_WRITE,string); fclose(fout); break; }
			size -= n;
		}
		if ( error != 0 ) break;		
		fclose(fout);
		entry->FILENAME = _tcsdup(string);
		entry->CREATED = 1;
	}
	if ( error != 0 )
	{
		logFormatI(_T_INSTALL("[i] Total %i files extracted"),file_count);	
	}
	free(buffer);
	free(string);	
	fclose(file);
	return error;
}

/*
 * Extract splash file to directory
 */
int extractFile( _TCHAR* fromfile, _TCHAR* todir, _TCHAR* fileName )
{
	int error = 0;
	unsigned int i;
	TOC_ENTRY* entry;
	_TCHAR * string;
	char * buffer;
	FILE *fout;
	
	FILE *file = _tfopen(fromfile, _T_INSTALL("rb"));
	if (file == NULL)
		return doError(ERROR_READ,fromfile);
	if ( (error = readTOC(file)) != 0 ) {
		fclose(file);
		return doError(error,fromfile);
	}
	entry = toc;
	string = malloc( MAX_PATH * sizeof(_TCHAR) );
	buffer = malloc( BUFFER_SIZE );
	for( i = 0; i < file_count; ++i, ++entry )
	{
		
		unsigned int size = entry->SIZE;	
		if ( (entry->FLAGS & FLAGS_EXTRACT ) == 0 ) continue;
		if(_tcscmp(entry->FILENAME,fileName)!=0) continue;
		_tcscpy(string, todir);
		_tcscat(string,entry->FILENAME);
		
		logFormatS(_T_INSTALL("[i] Extracting file %s"),string);
		fout = _tfopen(string, _T_INSTALL("wb"));
		if (fout == NULL) { error = doError(ERROR_WRITE,string); break; }
		if ( fseek(file, entry->OFFSET, SEEK_SET ) != 0 ) { error = doError(ERROR_READ,fromfile); fclose(fout); break; }
		
		while( size > 0 )
		{
			unsigned int n = MIN(size,BUFFER_SIZE);
			if ( fread(buffer,n,1,file) != 1 ) { error = doError(ERROR_READ,fromfile); fclose(fout); break; }
			if ( fwrite(buffer,n,1,fout) != 1 ) { error = doError(ERROR_WRITE,string); fclose(fout); break; }
			size -= n;
		}
		if ( error != 0 ) break;		
		fclose(fout);
		entry->FILENAME = _tcsdup(string);
		entry->CREATED = 1;
	}
	if ( error != 0 )
	{
		logFormatI(_T_INSTALL("[i] Total %i files extracted"),file_count);	
	}
	free(buffer);
	free(string);	
	fclose(file);
	return error;
}


/*
 * Delete all extracted contents
 */
void cleanup()
{
	unsigned int i;
	TOC_ENTRY* entry = toc;
	if ( toc == NULL ) return;
	for( i = 0; i < file_count; ++i, ++entry )
	{
		if ( entry->CREATED )
		{
			logFormatS(_T_INSTALL("[i] Deleting file %s"),entry->FILENAME);
			_tremove(entry->FILENAME);
		}
	}
	freeTOC();
}

static int doError( int error, _TCHAR* str )
{
	switch( error ) {
		case ERROR_READ:
			writeLog(_T_INSTALL("[x] Error reading INSTALL_FILE"));
			break;
		case ERROR_INVALID_CONTENT:
			writeLog(_T_INSTALL("[x] File INSTALL_FILE has no valid SFX signature or its content corrupted"));
			break;
		case ERROR_WRITE:
			logFormatS(_T_INSTALL("[x] Error writing to file %s"),str);
			break;
	}
	return error;
}



/* EOF */