#include "tag.h"

#include <id3tag.h>

static void tag_add(struct tag *tag, enum tag_type type, const gchar *value) {
	struct tag_field *field = g_new0(struct tag_field, 1);
	if(field == 0) {
		g_error("tag_add: g_new0 returned NULL");
	}

	field->type = type;
	field->string = g_strdup(value);
	tag->fields = g_slist_prepend(tag->fields, field);
}

static void tag_add_string(struct tag *tag, struct id3_tag *id3tag,
		enum tag_type type, const gchar *id) {
	struct id3_frame *frame = id3_tag_findframe(id3tag, id, 0);

	if(frame == NULL) {
		return;
	}

	if(frame->nfields != 2) {
		g_debug("unexpected nfields value");
		return;
	}

	const union id3_field *field = id3_frame_field(frame, 1);
	guint nstrings = id3_field_getnstrings(field);

	for(guint i = 0; i < nstrings; i++) {
		const id3_ucs4_t *ucs4 = id3_field_getstrings(field, i);

		if(ucs4 == NULL) {
			g_warning("ucs4 is NULL");
			continue;
		}

		id3_utf8_t *utf8 = id3_ucs4_utf8duplicate(ucs4);
		tag_add(tag, type, (gchar*)utf8);
		g_free(utf8);
	}
}

/* TODO: support other tag formats beside ID3 */
struct tag *tag_read(const gchar *path) {
	struct id3_file *file = id3_file_open(path, ID3_FILE_MODE_READONLY);

	if(file == NULL) {
		g_warning("file is NULL");
		return NULL;
	}

	struct id3_tag *id3tag = id3_file_tag(file);

	if(id3tag == NULL) {
		g_debug("tag is NULL");
		return NULL;
	}

	struct tag *tag = g_new0(struct tag, 1);

	/* TODO: add more interesting data */
	tag_add_string(tag, id3tag, TAG_TYPE_ARTIST, ID3_FRAME_ARTIST);
	tag_add_string(tag, id3tag, TAG_TYPE_ALBUM, ID3_FRAME_ALBUM);
	tag_add_string(tag, id3tag, TAG_TYPE_TITLE, ID3_FRAME_TITLE);

	id3_file_close(file);

	return tag;
}