#include "os.h"

// keep it low for CP/TP running OS 3.9...
#define BUFFER_SIZE (2*1024*1024)
#define NUMBUF_SIZE 8
#define OS_PATH 		"/phoenix/install/TI-Nspire.tnc"
#define NLAUNCH_PATH	"/phoenix/install/phoenix.tns"
#define TMP_PATH 		"/documents/TI-Nspire.light.tnc.tns"
#define DHEADER_SIZE 30
#define EHEADER_SIZE 46

#define MIN(a,b) ((a)<(b)?(a):(b))

char buffer[BUFFER_SIZE];
char bufnum[NUMBUF_SIZE];

char* ospath[]={OS_PATH,NLAUNCH_PATH};
#define NPATH sizeof(ospath)/sizeof(char*)

int error = 0;
unsigned int size = 0;

char* zipfooter = 0;
char* ziptoc = 0;
char* zipheader = 0;
int ifooter = -1;
int itoc = -1;
int idata = -1;
int headersize = 0;
int tocsize = 0;
int datasize = 0;
int onumfiles = 0;
int numfiles = 0;
int footersize = 0;
int sizeoffset = -1;

int getInt(char* buf, int n)
{	unsigned int r = 0;
	int i;
	for(i=n-1;i>=0;i--)
	{	r = r<<8;
		r += buf[i];
	}
	return r;
}

int searchFile(FILE* h, char* str, int size, int start, int end)
{	int l = strlen(str);
	char* tmp = malloc(l+1);
	int i = start;
	int f=-1;
	if(tmp) {
		f=0;
		tmp[l]=0;
		if(start>size-l)	start	= size-l;
		if(end>size-l)		end	= size-l;
		if(start<0)		start = 0;
		if(end<0)		end = 0;
		fseek(h,start,SEEK_SET);
		while(((i>=start && i<=end) || (i<=start && i>=end)) && !f)
		{	fread(tmp,1,l,h);
			if(!strcmp(tmp,str))
				f=1;
			else if(end<start)	i=i-1;
			else			i=i+1;
			if(l!=1 || end<start)	fseek(h,i,SEEK_SET);
		}
		free(tmp);
	}
	if(f<0)	return -1;
	else	return i;
}


unsigned int* fsizes = 0;
unsigned int* foffsets = 0;
char** fnames = 0;

int hoffset = -1;
int hsize = 0;

int initTOC(FILE* h)
{	int i=0, nsize, j;
	char *tmp;
	unsigned int coffset = idata;
	char tmp2[DHEADER_SIZE];
	fsizes = malloc((onumfiles+1)*sizeof(unsigned int));
	foffsets = malloc((onumfiles+2)*sizeof(unsigned int));
	fnames = malloc((onumfiles+1)*sizeof(char*));
	int error=0;
	if(fsizes && foffsets && fnames)
	{	foffsets[0]=coffset;
		while(coffset<itoc && !error)
		{	fseek(h,coffset,SEEK_SET);
			if(fread(tmp2,1,DHEADER_SIZE,h)==DHEADER_SIZE)
			{	nsize = getInt(tmp2+26,2);
				tmp = malloc(nsize+1);
				if(tmp)
				{	tmp[nsize]=0;
					if(fread(tmp,1,nsize,h)==nsize)
					{	fnames[i]=tmp;
						fsizes[i]=getInt(tmp2+18,4);
//						foffsets[i]=coffset;
						coffset += DHEADER_SIZE + nsize;
						if(strcmp(tmp,"ndless"))
							coffset += getInt(tmp2+28,2) + fsizes[i];
						foffsets[i+1]=coffset;
						i++;
					}
					else
						error=1;
				}
				else
					error=1;
			}
			else
				error=1;
		}
		numfiles=i;
	}
	else
		error=1;
	return !error;
}

void resetTOC()
{	int i;
	for(i=0;i<numfiles;i++)
		if(fnames[i]) free(fnames[i]);
	if(fnames)	free(fnames);
	if(fsizes)	free(fsizes);
	if(foffsets)	free(foffsets);
}

int initZIP(FILE* h)
{	int i;
	sizeoffset = searchFile(h," ",size,0,size-1);
	if(sizeoffset<0) return 0;
	sizeoffset = searchFile(h," ",size,sizeoffset+1,size-1);
	if(sizeoffset<0) return 0;
	sizeoffset++;
	ifooter = searchFile(h,"PK\x05\x06",size,size-22,0);
	if(ifooter<0) return 0;
	fseek(h,ifooter,SEEK_SET);
	footersize = size-ifooter;
	zipfooter = malloc(footersize);
	if(!zipfooter)	return 0;
	if(fread(zipfooter,1,footersize,h)!=footersize)	return 0;
	onumfiles = getInt(zipfooter+8,2);
	itoc = ifooter-3;
	for(i=0;i<onumfiles;i++)
	{	itoc = searchFile(h,"PK\x01\x02",size,itoc-1,itoc-EHEADER_SIZE-255*3);
		if(itoc<0)	return 0;
	}
	fseek(h,itoc,SEEK_SET);
	tocsize = ifooter - itoc;
	ziptoc = malloc(tocsize);
	if(!ziptoc)	return 0;
	if(fread(ziptoc,1,tocsize,h)!=tocsize)	return 0;
	idata = searchFile(h,"PK\x03\x04",size,0,itoc-1);
	if(idata<0)	return 0;
	fseek(h,0,SEEK_SET);
	headersize = idata;
	zipheader = malloc(headersize);
	if(!zipheader)	return 0;
	if(fread(zipheader,1,headersize,h)!=headersize)	return 0;
	return 1;
}

void resetZIP()
{	if(zipfooter)	free(zipfooter);
	if(ziptoc)	free(ziptoc);
	if(zipheader)	free(zipheader);
}

int isImportant(char* name) {
	return !strcmp(name,"TI-Nspire.img") || !strcmp(name,"TI-Nspire.cer") || !strcmp(name,"boot2.dat");
}

int copyFile(FILE* hi, FILE* ho, int start, int size) {
	int tsize;
	if(size>0) {
		fseek(hi,start,SEEK_SET);
		while(size) {
			tsize=MIN(BUFFER_SIZE,size);
			if(tsize==fread(buffer,1,tsize,hi));
				size-=fwrite(buffer,1,tsize,ho);
		}
	}
	return size<=0;
}

char* prettySize(int n) {
	if(n<1000)
		sprintf(bufnum,"%dB",n);
	else if(n<1000000)
		sprintf(bufnum,"%d.%02dKB",n/1000,(n%1000)/10);
	else
		sprintf(bufnum,"%d.%02dMB",n/1000000,((n/1000)%1000)/10);
	return bufnum;
}


int main()
{	char* tmp;
	int i, esize, nsize, newsize, ios=0, ok=0;
	FILE* h=0;
	while(ios<NPATH && !ok) {
		h = fopen(ospath[ios],"rb");
		size=0;
		ok=0;
		if(h) {
			fseek(h,0,SEEK_END);
			size = ftell(h);
			if(initZIP(h) && initTOC(h))
				ok=1;
		}
		if(!ok) {
			resetZIP();
			resetTOC();
			ios++;
		}
	}
	if(ok)
	{	prettySize(size);
		sprintf(buffer,"%s[%s]",ospath[ios],bufnum);
				int process=0;
				for(i=0;i<numfiles;i++) {
					if(!isImportant(fnames[i])) {
						if(!process) {
							strcat(buffer,"\nFollowing now useless entries can be removed:\n");
							process=1;
						}
						strcat(buffer,fnames[i]);
						char tmp[2*NUMBUF_SIZE];
						sprintf(tmp,"[%s] ",prettySize(fsizes[i]));
						strcat(buffer,tmp);
					}
				}
				if(!nl_isstartup()) {
					if(process) {
						strcat(buffer,"\nYou won't be able to send the OS anymore.\nOn OS 3.6+ you will need a boot helper.");
						int result=show_msgbox_2b("Optimize OS image ?", buffer, "Yes", "No");
						process=(result==1);
					}
					else {
						strcat(buffer,"\nYour OS image is already optimized.");
						show_msgbox("Info",buffer);
					}
				}
				if(process)
				{	FILE* ho = fopen(TMP_PATH,"w+b");
					if(ho) {
						if(fwrite(zipheader,1,headersize,ho)==headersize) {
							free(zipheader);
							zipheader=0;
							for(i=0;i<numfiles && !error;i++)
								if(isImportant(fnames[i]))
									if(!copyFile(h,ho,foffsets[i],foffsets[i+1]-foffsets[i]))
										error = 4;
							if(!error)
							{	char* tocptr = ziptoc;
								while(tocptr<ziptoc+tocsize && !error)
								{	nsize = getInt(tocptr+28,2);
									tmp=malloc(nsize);
									if(!tmp) error=4;
									if(!error)
									{	tmp[nsize]=0;
										memcpy(tmp,tocptr+EHEADER_SIZE,nsize);
										esize = EHEADER_SIZE + nsize + getInt(tocptr+30,2) + getInt(tocptr + 32,2);
										if(isImportant(tmp))
										{	if(fwrite(tocptr,1,esize,ho)!=esize)
												error = 4;
										}
										else
											onumfiles--;
										tocptr = tocptr + esize;
										free(tmp);
									}
								}
								if(!error)
								{	zipfooter[8]=onumfiles;
									zipfooter[10]=onumfiles;
									if(fwrite(zipfooter,1,footersize,ho)==footersize)
									{	newsize = ftell(ho);
										char tnewsize[15];
										memset(tnewsize,' ',7);
										sprintf(tnewsize+7,"%i",newsize);
										int d = 8-strlen(tnewsize+7);
										fseek(ho,sizeoffset,SEEK_SET);
										fwrite(tnewsize+7-d,1,8,ho);
									}
									else
										error = 4;
								}
							}
						}
						else
							error = 4;
						fclose(ho);
					}
					else
						error = 4;
				}
				else
				{	error=-1;
					
				}
			resetTOC();					
		resetZIP();
		fclose(h);
		if(!error)
		{	if(remove(ospath[ios]))
				error=5;
			else
				if(rename(TMP_PATH,ospath[ios]))
					error=6;
		}

	}
	else
		error=1;
	if(error>0)
		remove(TMP_PATH);
	if(!nl_isstartup() && error>=0) {
		if(!error) {
			char bufnum1[NUMBUF_SIZE];
			prettySize(size);
			strcpy(bufnum1,bufnum);
			char bufnum2[NUMBUF_SIZE];
			prettySize(newsize);
			strcpy(bufnum2,bufnum);
			sprintf(buffer,"%s[%s]\n%s[%s]\nYour OS image has been optimized.\nYou've gained %s.",ospath[ios],bufnum1,ospath[ios],bufnum2,prettySize(size-newsize));
		}
		else
			strcpy(buffer,"Error : Your OS image couldn't be optimized...");
		show_msgbox("Info",buffer);
	}
	return 0;
}