/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * lyric_viewer.c              (c) 2008 smoking gnu
 *
 * Copyright (C) 2002 Björn Stenberg
 *
 * All files in this archive are subject to the GNU General Public License.
 * See the file COPYING in the source tree root for full license agreement.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 
 * This plugin is my first rockbox project, so please don't expect it to be perfect ;)
 * I guess the "lyric-finding" part of this plugin could be handled by the rockbox core metadata parser, but this works too...
 
 *Update: 
 *Now it checks how long the ID3 tag is before it searches for the lyric tag - therefore it doesn't have to search the 
 *whole file if there's no lyric tag at all. 
 
 * This plugin will NOT work when some other ID3-tag (e.g. Artist, Title etc) contains the string "USLT".
 
 ****************************************************************************/
#include "plugin.h"
#define BUF_SIZE 5000	/*Size of the lyrics buffer - 5k should be way enough*/

static struct plugin_api* rb;
static int  line_count, fd;
static struct gui_synclist gui_lyrics;
static unsigned char lyr_buffer[BUF_SIZE];

PLUGIN_HEADER

char* get_lyric_line(int selected_line, void *data, char *buffer, size_t buf_len)
{
	
	int i=0, start=0, stop;
	(void) data;
	
	rb->strcpy(buffer,"Couldn't read line!"); /*Just in case something goes wrong*/
	
	for (i=0; i<selected_line; i++)           /*go to the beginning of the line*/			
	{
		while (lyr_buffer[start]!= '\n')
		{
			if (start<BUF_SIZE) start++;
			else break;
		}
		start++;
	}
	
	stop=start;
	while (lyr_buffer[stop]!= '\n')           /*Find out how long the line is*/
	{
		if (stop<BUF_SIZE) stop++;
		else break;
	}
	
	rb->snprintf(buffer, stop-start, "%s", &lyr_buffer[start]);

    return buffer;
}

int show_lyrics(void)
{
	/*a standard gui_list*/
	rb->gui_synclist_init(&gui_lyrics, &get_lyric_line, NULL, false, 1, NULL);
	rb->gui_synclist_set_nb_items(&gui_lyrics, line_count+1);
	rb->gui_synclist_limit_scroll(&gui_lyrics, false);
	rb->gui_synclist_select_item(&gui_lyrics, 0);
	rb->gui_synclist_draw(&gui_lyrics);

	int button;
	while (true) 
	{
		rb->gui_syncstatusbar_draw(rb->statusbars, true);
		button = rb->get_action(CONTEXT_LIST,TIMEOUT_BLOCK);
		if (rb->gui_synclist_do_button(&gui_lyrics, &button, LIST_WRAP_UNLESS_HELD)) 
		{
			continue;
		}
		if (button==ACTION_STD_CANCEL) return 0;
	}
}
	
int find_lyr_tag(void)
{

	int pos=0, eof_check, tag_pos=0, i, id3_length=0;
	char lyr_tag[5], temp;

	rb->strcpy(lyr_tag, "USLT");
	
	eof_check=rb->read(fd, lyr_buffer, 6);
	if (eof_check==0) return 0;	
        
    if (lyr_buffer[0]!='I' || lyr_buffer[1]!='D' || lyr_buffer[2]!='3')	
		return 0;				/*check whether there's an ID3 tag*/
        
    for (i=0; i<4; i++)        /*get its length*/
    {
        id3_length<<=8;
		
        eof_check=rb->read(fd, &temp, 1);
		if (eof_check==0) return 0;	
		
        id3_length+=temp; 
    } 
	
	for (i=0; i< id3_length; i++) /*... and finally search for the tag*/
	{
	
        eof_check=rb->read(fd, &temp, 1);
		if (eof_check==0) return 0;	
        
		pos++;
		
        if (temp==lyr_tag[tag_pos])
        {
            if ((unsigned int)tag_pos < (rb->strlen(lyr_tag)-1))
            {
                tag_pos++;
            }
            else
            {
                return pos;                       
            }
        }
        else tag_pos=0;
    }
	return 0;
}

int get_lyr_len(void)
{
	int eof_check, pos=0, lyr_len=0, i;
	unsigned char temp;

	/*get the length of the lyrics*/
	for (i=0; i<4; i++)
    {
        lyr_len<<=8;
		
        eof_check=rb->read(fd, &temp, 1);
		if (eof_check==0) return 0;	
		
        lyr_len+=temp; 
    }          
	
    /*go to the beginning of the lyrics*/
	temp=0;
    while(temp==0)
    {
        eof_check=rb->read(fd, &temp, 1);
		if (eof_check==0) return 0;
        pos++;
    }            
    while(temp!=0)
    {
        eof_check=rb->read(fd, &temp, 1);
		if (eof_check==0) return 0;
        pos++;
    }  
	return lyr_len-pos+2;
}

int save_lyrics(int len)
{
	int eof_check, pos;
	unsigned char temp;
	
	/*just copy the whole lyric block to lyr_buffer[]   */
	for (pos=0; pos<len; pos++)	
    {
		eof_check=rb->read(fd, &temp, 1);
		if (eof_check==0) return 0;
		if (pos==BUF_SIZE) return -1;
			
		lyr_buffer[pos]=temp;
		if (temp=='\n') line_count++;
	}
	lyr_buffer[pos+1]=0;
	return 1;
}

enum plugin_status plugin_start(struct plugin_api* api, void* parameter)
{

    int lyr_len=0; 
  
    rb = api;
    fd=rb->open((char*)parameter, O_RDONLY);
	line_count=0;

	
    if (fd>=0)
    {     	
        if (find_lyr_tag())						/*check whether there is a USLT lyric tag */
        {
            lyr_len=get_lyr_len();  			/*get length of the lyrics */
			save_lyrics(lyr_len);				/*read lyrics and save them to the buffer */	
			
			show_lyrics();						/*show us those lyrics! */
        }
        else rb->splash(HZ*2, "No Lyric tag found!");

        rb->close(fd);  
		
    }
	else rb->splash(HZ*2, "Could not open file '%s'!", (char*) parameter);
	 
    return PLUGIN_OK;
}