#include <stdio.h>
#include <sys/stat.h>
#include <unistd.h>

/*#define DEBUG*/
#define VERSION "0.01"
#define AUTHOR "Mishiki Sakana"
#define MYMAIL "osakana@ofo.jp"

void showUsage(char *filename){
	fprintf (stderr, "\"%s\" Ver. %s by %s <%s>\nUsage: %s FILE(.sue)\n\t(if you omit FILE, assumes \"_THUMBNL.SUE\" is specified)\n\n",filename, VERSION, AUTHOR, MYMAIL, filename);
	return;
}

int getFileSize(FILE *fp){
	long filesize;
	fseek(fp,0L,SEEK_END);
	filesize=ftell(fp);
	rewind(fp);
	return(filesize);
}

void padnullbyte(FILE *fp, int padlong){
	int i=0;
	while (i++<padlong){
		fputc (0,fp);
	}
}

int checkSuecatSig(FILE *fp){
	rewind(fp);
	if ( fgetc(fp) != 'S' || fgetc(fp) != 'U' || fgetc(fp) != 'E' || fgetc(fp) != 'C' || fgetc(fp) != 'A' || fgetc(fp) != 'T') {
		return (0);
	}
	return (1);
}

void skipSuecatHeader(FILE *fp){
	int c;
	while ((c = getc(fp)) != EOF) {
		if (c == 0xf2 && fgetc(fp) == 0xf7 && fgetc(fp) == 0){
			return;
		}
	}
	fprintf(stderr,"Cannot find header end.\n");
	exit(1);
}

int main(int argc, char **argv){
	FILE *fp, *fb;
	char dbfilename[255];
	char dirname[255];

	strcpy (dbfilename,"_THUMBNL.SUE");

	if (argv[1]){
		if (strcmp(argv[1],"-h")==0 || strcmp(argv[1],"--help")==0){
			showUsage(argv[0]);
			exit(1);
		}
		strcpy (dbfilename,argv[1]);
	}
	strcpy (dirname,".thumbnl");

	if ((fp = fopen (dbfilename, "rb")) == NULL){
		showUsage(argv[0]);
		fprintf (stderr, "Cannot open file: \"%s\".\n",dbfilename);
		exit (1);
	}
	long filesize=getFileSize(fp);

	if (!checkSuecatSig(fp)) {

		fprintf (stderr, "Not a SUECAT file.\n");
		exit (1);
	}


	skipSuecatHeader(fp);

#ifdef DEBUG
	printf ("Scanning SUECAT starts at %d...\n",ftell(fp));
#endif

	long chunklong=0;
	unsigned int icontype=0;
	unsigned int bitdepth=0;
	int imgwidth=0;
	int imgheight=0;
	unsigned long timestamp=0;
	unsigned int filenamelong=0;
	unsigned int fpstartat=0;

	mkdir(dirname,0777);	//mingw32 では、マスクが通らない悪寒。
	if (chdir(dirname)!=0){
		fprintf (stderr, "Cannot access the .thumbnl directory.\n");
		exit;
	}

	while(filesize > ftell(fp)+10){

#ifdef DEBUG
		printf("getting each icon chunk length...\n");
#endif

		fpstartat = ftell(fp);
		fread (&chunklong,4,1,fp);

#ifdef DEBUG
		printf("\tchunklength : %d(fp : %d)\n",chunklong,ftell(fp));
#endif

		fread (&icontype,1,1,fp);

#ifdef DEBUG
		printf ("\ticontype : %d (fp : %d)\n",icontype,ftell(fp));
#endif

		if (icontype!=1){
			fseek(fp,(fpstartat+chunklong),SEEK_SET);
		}
		else {

#ifdef DEBUG
			printf("OK, icontype is :%d!!\nNow Reading headers...(fp : %d)\n",icontype,ftell(fp));
#endif

			fread (&bitdepth,1,1,fp);
			fread (&imgwidth,2,1,fp);
			fread (&imgheight,2,1,fp);
			fread (&timestamp,4,1,fp);
			fread (&filenamelong,1,1,fp);

			char filename[filenamelong+16];

			fgets (filename,filenamelong+1,fp);
#ifdef DEBUG
			printf("Done.\n\tchunklong : %d\n\tbitdepth : %d\n\twidth : %d\n\theight : %d\n\ttimestamp : %d\n\tnamelong : %d\n\tfilename : %s\n",chunklong, bitdepth, imgwidth,imgheight,timestamp, filenamelong, filename);
#endif

			fseek(fp,(ftell(fp)),SEEK_SET);

#ifdef DEBUG
			printf("\t\t(fp is : %d)\n",ftell(fp));
#endif


			char ext[8];
			strcpy (ext, ".bmp");
			strcat (filename,ext);


			long padbitwidth=0;
			long realbitwidth=0;
			int diff=0;
			realbitwidth = imgwidth*bitdepth/8;

			if (realbitwidth%4){
	padbitwidth = (realbitwidth/4+1)*4;
	diff = padbitwidth - realbitwidth;
			}

#ifdef DEBUG
			printf ("\trealwidth : %d\n\tpadded to : %d\n\tdiff : %d\n\n\n",realbitwidth,padbitwidth,diff);
			printf ("Writing a new BMP file...\n");
#endif


			//fb = fopen (filename,"wb");
			if ((fb = fopen (filename, "wb")) == NULL){
	fprintf (stderr, "Cannot open file : %s.\n",filename);
	exit (1);
			}

			fputc ('B',fb);fputc ('M',fb);
			long headeroffset = 54;
			long filelong = 0;
			long realfilelong = 0;

			filelong = realbitwidth*imgheight;
			realfilelong = (padbitwidth)?(padbitwidth*imgheight):(filelong);
			realfilelong +=headeroffset;

#ifdef DEBUG
			printf ("\tdatalong : %d\n\trealfilelong : %d\n",filelong, realfilelong);
#endif

			fwrite (&realfilelong,4,1,fb);

#ifdef DEBUG
			printf("\nchunklong is : %d\nnow, fp is : %d\nfilelong is : %d\n",chunklong,ftell(fp),filelong);
#endif

			padnullbyte(fb,4);


			fwrite (&headeroffset,4,1,fb);
			long headersize = 40;
			fwrite (&headersize,4,1,fb);
			fwrite (&imgwidth,4,1,fb);
			fwrite (&imgheight,4,1,fb);
			fputc (1,fb);
			fputc (0,fb);
			fwrite (&bitdepth,2,1,fb);


			padnullbyte(fb,4);

			fwrite (&filelong,4,1,fb);


			padnullbyte(fb,16);


			//printf("\nnow, fp is : %d\nfilelong is : %d\n",ftell(fp),filelong);


			unsigned short filebit;

			unsigned short rval=0;
			unsigned short gval=0;
			unsigned short bval=0;

			int i=0;
			int j=realbitwidth;
			int k=0;

			while ((ftell(fp))<(fpstartat+chunklong)){
	i++;
	if (padbitwidth){
		if (i>j){
			k=0;
			while(k++<diff){
				//printf("%d\n",i);
				fputc(0,fb);
				i++;
			}
			j+=padbitwidth;
		}
	}
	if (bitdepth!=16){
		fputc (fgetc(fp) ,fb);
	}
	else {

		filebit = fgetc(fp) << 8;
		filebit = filebit + fgetc(fp);

		bval = filebit >> 11;

		gval = filebit << 5;
		gval = gval >> 11;
		gval = gval << 5;

		rval = filebit << 11;
					rval =	rval >> 1;

		filebit = gval + bval + rval;

		fwrite (&filebit,2,1,fb);
		i++;
	}
			}


			fclose (fb);
		}
		fseek(fp,(fpstartat+chunklong),SEEK_SET);
	}
	fclose (fp);
}