#include "tag.h"

char *filename;

void
warn(char *msg, ...)
{
	char buf[1024], *p;
	va_list args;

	p = seprint(buf, buf+sizeof(buf), "%s %s: ", argv0, filename);
	va_start(args, msg);
	p = vseprint(p, buf+sizeof(buf), msg, args);
	p = seprint(p, buf+sizeof(buf), "\n");
	va_end(args);
	write(2, buf, p-buf);
}

void
usage(void)
{
	fprint(2, "usage: %s [file]\n", argv0);
	exits("usage");
}

void
main(int argc, char **argv)
{
	int fd;
	Biobuf bin, bout;
	uchar buf[1024], *p;
	Header hdr;
	Rechdr rhdr;
	int rtype;
	char err[ERRMAX];

	ARGBEGIN {
	default:
		usage();
	} ARGEND

	switch(argc) {
	case 0:
		fd = 0;
		filename = "<stdin>";
		break;
	case 1:
		if((fd = open(argv[0], OREAD)) < 0)
			sysfatal("open %s: %r", argv[0]);
		filename = argv[0];
		break;
	default:
		usage();
		SET(fd);
	}

	quotefmtinstall();
	Binit(&bin, fd, OREAD);
	Binit(&bout, 1, OWRITE);

	readrec(&bin, buf, sizeof buf, HeaderSize, "header");
	p = buf;

	gheader(&p, &hdr);
	if(strcmp(hdr.magic, "ID3") != 0)
		sysfatal("bad magic: %s", hdr.magic);
	if(hdr.version < 2 || hdr.version > 4)
		sysfatal("unrecognized version: %d", hdr.version);
	if(hdr.flags) {
		if(hdr.flags == 1<<7)
			warn("unsynchronized tag");	// FIXME -- actually implement this
		else
			sysfatal("unknown header flag: %.8b", hdr.flags);
	}

	while(Boffset(&bin) < HeaderSize + hdr.length) {
		readrec(&bin, buf, sizeof buf, hdr.version == 2 ? 6 : RecHdrSize, "rhdr");	// FIXME
		p = buf;

		grechdr(&p, &rhdr, &hdr);
		if(strcmp(rhdr.id, "") == 0)	/* detect padding */
			exits(nil);
		if(rhdr.length == 0) {
			// FIXME -- record parsers should handle this case
			warn("%s: discarding: zero-length record", rhdr.id);
			continue;
		}

		if((rtype = rectype(rhdr.id)) < 0) {
			warn("%s: discarding: unknown record type", rhdr.id);
			if(Bseek(&bin, rhdr.length, 1) < 0)
				sysfatal("seek: %r");
			continue;
		}

		if(rhdr.length > sizeof buf) {
			warn("%s: discarding: too big for buffer: %ld/%ld", rhdr.id, rhdr.length, sizeof buf);
			if(Bseek(&bin, rhdr.length, 1) < 0)
				sysfatal("seek: %r");
			continue;
		}

		readrec(&bin, buf, sizeof buf, rhdr.length, "record");
		p = buf;

		switch(rtype) {
		case Rcomment: {
				Comment cmnt;

				if(gcomment(&p, &cmnt, rhdr.length) < 0) {
					rerrstr(err, sizeof err);
					if(strncmp(err, "discarding", 10) == 0) {
						warn("%s: %r", rhdr.id);
						break;
					}
					sysfatal("%s: %r", rhdr.id);
				}
				Bprint(&bout, "%s	%q	%q %q\n",
					rhdr.id, cmnt.language, cmnt.description, cmnt.comment);
				free(cmnt.description);
				free(cmnt.comment);
			}
			break;
		case Rtext: {
				Text txt;
				char **s;

				if(gtext(&p, &txt, rhdr.length) < 0) {
					rerrstr(err, sizeof err);
					if(strncmp(err, "discarding", 10) == 0) {
						warn("%s: %r", rhdr.id);
						break;
					}
					sysfatal("%s: %r", rhdr.id);
				}
				Bprint(&bout, "%s", rhdr.id);
				for(s = txt.strings; *s != nil; s++) {
					Bprint(&bout, "	%q", *s);
					free(*s);
				}
				Bprint(&bout, "\n");
			}
			break;
		case Runimplemented:
			warn("%s: discarding: umimplemented", rhdr.id);
			break;
		default:
			abort();
		}
	}
	exits(nil);
}
// FIXME -- put filename in sysfatal