#include "unalf.h"
#include "addrs.h"

int bad_checksum, bad_checksum_count = 0;
int new_file = 0;
unsigned int bytes_written = 0;
char *out_filename;

void dpoke(int addr, u16 value) {
	mem[addr] = value & 0xff;
	mem[addr + 1] = value >> 8;
}

u16 dpeek(int addr) {
	return mem[addr] | (mem[addr + 1] << 8);
}

static void bad_atari_filename(const char *msg) {
	char fn[50] = "";
	char xbuf[5];
	int i;
	u8 c;

	for(i = 0; (c = (u8)out_filename[i]) && i < 12; i++) {
		if(c < ' ' || c > '|') {
			/* not printable, insert a hex escape */
			sprintf(xbuf, "$%02X", c);
			strcat(fn, xbuf);
		} else {
			strncat(fn, (char *)&c, 1);
		}
	}

	fprintf(stderr, "%s: bad Atari filename \"%s\": %s\n", self, fn, msg);
}

/* note to self: it's tempting to use isalpha(), isprint(), etc
	from ctype.h... but those are locale-aware. we want ASCII-only
	versions. */
static void sanity_check_filename(void) {
	u8 c;
	unsigned int i, bad = 0, dots = 0, uscore = 0;

	c = out_filename[0];
	if(!c) {
		bad_atari_filename("empty! corrupt ALF file?");
		return;
	} else if(c < 'A' || c > 'Z') {
		bad_atari_filename("does not begin with A-Z");
	}

	for(i = 0; (c = out_filename[i]) && i < 12; i++) {
		if(c >= 'A' && c <= 'Z')
			continue;
		if(c >= '0' && c <= '9')
			continue;
		if(c == '_') {
			uscore++;
			continue;
		}
		if(c == '.') {
			dots++;
			continue;
		}
		bad++;
	}

	if(!dots) {
		bad_atari_filename("no \".\"");
	} else if(dots > 1) {
		bad_atari_filename("more than one \".\"");
	}

	if(bad)
		bad_atari_filename("invalid characters. corrupt ALF file?");
	else if(uscore)
		fprintf(stderr, "%s: filename has underscore, OK on Sparta/MyDOS, not Atari DOS 2.x\n", self);
}

void fix_filename(void) {
	char *p;

	if(!out_filename) return;

	if(strlen(out_filename) > 12) {
		fprintf(stderr, "%s: filename in ALF header not null-terminated, fixing.\n", self);
		out_filename[12] = '\0';
	}

	sanity_check_filename();

	if(opts.lowercase) {
		for(p = out_filename; *p; p++)
			*p = tolower(*p);
	}

	if(!opts.keepdot) {
		for(p = out_filename; *p; p++)
			if(p[0] == '.' && !p[1])
				*p = '\0';
	}
}

void make_backup(void) {
	/* up to 12-char FILENAME.EXT, plus a ~, plus null terminator = 14 */
	char backup[14];

	strncpy(backup, out_filename, 13);
	strncat(backup, "~", 13);

	/* silently ignore errors! */
	rename(out_filename, backup);
}

void extract_alf(void) {
	/* get ready to call fake 6502 stuff. set up memory like the Atari. */
	dpoke(MEMTOP, 0xbc1f);

	while(read_alf_header()) {
		out_filename = (char *)(mem + alf_hdr_filename);

		fix_filename();

		if(!file_wanted(out_filename)) {
			if(fseek(in_file, getquad(alf_hdr_compsize0), SEEK_CUR) != 0) {
				fprintf(stderr, "%s: fatal: seek failed on input!\n", self);
				exit(1);
			}
			out_filename = 0;
			continue;
		}

		if(!opts.quiet) {
			printf("%s %s\n", opts.testonly ? "Testing" : "Uncrunching", out_filename);
		}

		if(opts.extract_to_stdout) {
			out_file = stdout;
		} else {
			char *realname = out_filename;

			if(opts.testonly) {
				out_filename = "/dev/null";
			} else if(!opts.overwrite) {
				make_backup();
			}

			if(!(out_file = fopen(out_filename, "wb"))) {
				fprintf(stderr, "%s: fatal:  ", self);
				perror(out_filename);
				exit(1);
			}

			out_filename = realname;
		}

		bad_checksum = bytes_written = 0;
		new_file = 1;
		uncrunch_file();
		if(bad_checksum) bad_checksum_count++;
		if(bytes_written != getquad(alf_hdr_origsize0))
			fprintf(stderr, "%s: %s should be %u bytes, but extracted to %u.\n",
					self, out_filename, getquad(alf_hdr_origsize0), bytes_written);

		if(!opts.extract_to_stdout) fclose(out_file);
		out_filename = 0;
	}

	if(opts.testonly && !opts.quiet) {
		if(bad_checksum_count)
			printf("%d file%s with bad checksum!\n",
					bad_checksum_count,
					bad_checksum_count == 1 ? "" : "s");
		else
			printf("All files OK.\n");
	}
}

void chksum_err(void) {
	bad_checksum = 1;
	fprintf(stderr, "%s: checksum error on %s\n", self, out_filename);
}

void unknown_err(void){
	fprintf(stderr, "%s: fatal: unknown error (L7712)\n", self);
	exit(1);
}

void stack_underrun(void){
	fprintf(stderr, "%s: fatal: stack underrun\n", self);
	exit(1);
}

void stack_overrun(void){
	fprintf(stderr, "%s: fatal: stack overrun\n", self);
	exit(1);
}