#ifndef ID3_H
#define ID3_H

#include <string.h>
#include <ctype.h>
#include <fcntl.h>

#define NR_GENRES 148

/* all data is private */
struct id3 {
	struct {
		char tag[3];
		char title[30];
		char artist[30];
		char album[30];
		char year[4];
		union {
			struct {
				char comment[30];
			} v1_0;
			struct {
				char comment[28];
				char zero;
				char track;
			} v1_1;
		} u;
		unsigned char genre;
	} tag;
	int fd;
	int has_tag;
	enum { ID3_V1_0, ID3_V1_1 } version;
};

extern const char *genres[];

extern int id3_open(struct id3 *id3, const char *filename, int wr);
extern int id3_save(struct id3 *id3);
extern void id3_close(struct id3 *id3);
extern void id3_clear_tags(struct id3 *id3);
extern void __id3_buf_to_str(char *str, const char *buf, int buf_size);

static inline void id3_set_title(struct id3 *id3, const char *title)
{
	strncpy(id3->tag.title, title, sizeof(id3->tag.title));
}

static inline void id3_set_artist(struct id3 *id3, const char *artist)
{
	strncpy(id3->tag.artist, artist, sizeof(id3->tag.artist));
}

static inline void id3_set_album(struct id3 *id3, const char *album)
{
	strncpy(id3->tag.album, album, sizeof(id3->tag.album));
}

static inline void id3_set_year(struct id3 *id3, unsigned int year)
{
	if (year == 0) {
		id3->tag.year[0] = 0;
		id3->tag.year[1] = 0;
		id3->tag.year[2] = 0;
		id3->tag.year[3] = 0;
	} else {
		id3->tag.year[3] = year % 10 + '0'; year /= 10;
		id3->tag.year[2] = year % 10 + '0'; year /= 10;
		id3->tag.year[1] = year % 10 + '0'; year /= 10;
		id3->tag.year[0] = year % 10 + '0';
	}
}

static inline void id3_set_comment(struct id3 *id3, const char *comment)
{
	if (id3->version == ID3_V1_1) {
		strncpy(id3->tag.u.v1_1.comment, comment,
				sizeof(id3->tag.u.v1_1.comment));
	} else {
		strncpy(id3->tag.u.v1_0.comment, comment,
				sizeof(id3->tag.u.v1_0.comment));
	}
}

static inline void id3_set_track(struct id3 *id3, unsigned int track)
{
	if (track == 0) {
		if (id3->version == ID3_V1_1) {
			id3->tag.u.v1_1.track = 0;
			id3->version = ID3_V1_0;
		}
	} else {
		id3->tag.u.v1_1.zero = 0;
		id3->tag.u.v1_1.track = track;
		id3->version = ID3_V1_1;
	}
}

static inline void id3_set_genre(struct id3 *id3, unsigned int genre)
{
	if (genre < NR_GENRES) {
		id3->tag.genre = genre;
	} else {
		id3->tag.genre = 0xff;
	}
}

static inline void id3_get_title(struct id3 *id3, char *title)
{
	__id3_buf_to_str(title, id3->tag.title, sizeof(id3->tag.title));
}

static inline void id3_get_artist(struct id3 *id3, char *artist)
{
	__id3_buf_to_str(artist, id3->tag.artist, sizeof(id3->tag.artist));
}

static inline void id3_get_album(struct id3 *id3, char *album)
{
	__id3_buf_to_str(album, id3->tag.album, sizeof(id3->tag.album));
}

static inline int id3_get_year(struct id3 *id3)
{
	int i, year = 0;

	for (i = 0; i < 4; i++) {
		if (!isdigit(id3->tag.year[i]))
			return -1;
		year *= 10;
		year += id3->tag.year[i] - '0';
	}
	return year;
}

static inline void id3_get_comment(struct id3 *id3, char *comment)
{
	if (id3->version == ID3_V1_1) {
		__id3_buf_to_str(comment, id3->tag.u.v1_1.comment,
				sizeof(id3->tag.u.v1_1.comment));
	} else {
		__id3_buf_to_str(comment, id3->tag.u.v1_0.comment,
				sizeof(id3->tag.u.v1_0.comment));
	}
}

static inline int id3_get_track(struct id3 *id3)
{
	if (id3->version == ID3_V1_1)
		return id3->tag.u.v1_1.track;
	return -1;
}

static inline int id3_get_genre(struct id3 *id3)
{
	if (id3->tag.genre == 0xff)
		return -1;
	return id3->tag.genre;
}

static inline int id3_has_tag(struct id3 *id3)
{
	return id3->has_tag;
}

static inline int id3_version(struct id3 *id3)
{
	return id3->version;
}

#endif