#include <stdio.h>

unsigned char sram[0x8000];
unsigned char sram_new[0x8000];

void generate_new_sav();
int read_file(char * filename);
void write_file(char * filename);

#define offset(BANK,ADRESS) \
	((BANK*0x2000)+(ADRESS&0x1fff))

main(int argc, char *argv[]) {
	char filename[200];

	if(argc!=2) {
		printf("use this program to patch LSDj .sav files to v2.4.4\n\n");
		printf("usage: patchsav244 savfile\n");
		return 0;
	}
	read_file(argv[1]);
	generate_new_sav();

	strcpy(filename, argv[1]);
	strcat(filename, ".new");

	write_file(filename);
	return 1;
}

void write_file(char * filename) {
	FILE *out;

	out=fopen(filename, "wb");
	fwrite(sram_new,0x8000,1,out);
	if(ferror(out)) {
		printf("file error %d",ferror(out));
		exit(1);
	}
	fclose(out);
	printf("wrote file '%s' successfully",filename);
}

void generate_new_sav() {
	int src,dst;

	//copy old sram
	for(dst=offset(0,0); dst!=offset(4,0); dst++) {
		sram_new[dst]=sram[dst];
	}

	//----- clear new areas -----
	//instr->names
	for(dst=offset(0,0xbe7a); dst!=offset(0,0xbfba); dst++) {
		sram_new[dst]=0;
	}
	//instr->alloc
	for(dst=offset(1,0xa040); dst!=offset(1,0xa080); dst++) {
		sram_new[dst]=0;
	}
	//instr->param
	for(dst=offset(1,0xb080); dst!=offset(1,0xb480); dst++) {
		sram_new[dst]=0;
	}
	//init new instr params
#define INSTR_OFFSET offset(1,0xb080)
	//envelope=0xa8
	for(dst=INSTR_OFFSET+0x201;dst!=INSTR_OFFSET+0x401;dst+=0x10) {
		sram_new[dst]=0xa8;
	}
	//sweep=0xff
	for(dst=INSTR_OFFSET+0x204;dst!=INSTR_OFFSET+0x404;dst+=0x10) {
		sram_new[dst]=0xff;
	}
	//pan on
	for(dst=INSTR_OFFSET+0x207;dst!=INSTR_OFFSET+0x407;dst+=0x10) {
		sram_new[dst]=3;
	}
	//dist=clip
	for(dst=INSTR_OFFSET+0x20a;dst!=INSTR_OFFSET+0x40a;dst+=0x10) {
		sram_new[dst]=0xd0;
	}

	//----- move stuff -----
	//instr->names
	src=offset(0,0xaff0);
	for(dst=offset(0,0xbe7a); dst!=offset(0,0xbfba); dst++) {
		sram_new[dst]=sram[src++];
	}
	//table->env
	src=offset(1,0xb280);
	for(dst=offset(0,0xb690); dst!=offset(0,0xb890); dst++) {
		sram_new[dst]=sram[src++];
	}
	//instr->param
	src=offset(0,0xb690);
	for(dst=offset(1,0xb080); dst!=offset(1,0xb280); dst++) {
		sram_new[dst]=sram[src++];
	}
	//instr->alloc
	src=offset(1,0xa000);
	for(dst=offset(1,0xa040); dst!=offset(1,0xa060); dst++) {
		sram_new[dst]=sram[src++];
	}
	
	//change phrase->instr 0x20 to 0x40
	for(dst=offset(3,0xb000); dst!=offset(3,0xbff0); dst++) {
		if(sram_new[dst]==0x20) {
			sram_new[dst]=0x40;
		}
	}
}

int read_file(char *filename) {
	FILE *in;
	int read;

	in=fopen(filename,"rb");

	if(in==NULL) {
		printf("error: can't open file '%s'", filename);
		exit(1);
	}

	read=fread(sram,1,32768,in);
	
	if(ferror(in)) {
		printf("file error %d",ferror(in));
		exit(1);
	}
	if(read!=32768) {
		printf("error: wrong file size! (.sav should be 32 kB)");
		exit(1);
	}

	fclose(in);

	return 1;
}