#!/usr/bin/env python

# Author: Sean McLean
# License: GPLv2
#
# Requires: pyid3lib

import pyid3lib, optparse, sys, os

# file extension mime mappings
mimes = {"jpg": "image/jpeg",
	 "jpeg": "image/jpeg",
	 "png": "image/png"}	 

# set up option parser
usage = "%prog [options] [cover art file] [target MP3 file]"
opts = optparse.OptionParser(usage = usage)
opts.add_option('-f','--force',action='store_true',dest='force',help='force overwriting of existing images')
opts.add_option('-l','--listtypes', action='store_true',dest='listtypes',help='list image types')
opts.add_option('-t','--type', action='store',dest='imgtype',help='image type (use -l to list types)')
opts.add_option('-d','--description', action='store',dest='description',help='image description')

options,files = opts.parse_args()


# print image types if selected
if options.listtypes:
    print """ID3 Image Types:
    01 - 32x32 pixels 'file icon' (PNG only)
    02 - Other file icon
    03 - Cover (front)   ***Default***
    04 - Cover (back)
    05 - Leaflet page
    06 - Media (e.g. label side of CD)
    07 - Lead artist/lead performer/soloist
    08 - Artist/performer
    09 - Conductor
    10 - Band/Orchestra
    11 - Composer
    12 - Lyricist/text writer
    13 - Recording Location
    14 - During recording
    15 - During performance
    16 - Movie/video screen capture
    17 - A bright coloured fish
    18 - Illustration
    19 - Band/artist logotype
    20 - Publisher/Studio logotype"""
    sys.exit()
    
    
# validate file arguments
if len(files) != 2:
    print "Invalid parameter count.\n"
    opts.print_help()
    sys.exit()
    

# get file extension
fileext = os.path.splitext(files[0])[1][1:].lower()

# validate image file
if not mimes.has_key(fileext):
    print "The image file you specified is invalid; images must be in jpg or png format.\n"
    opts.print_help()
    sys.exit()
else:
    mimetype = mimes[fileext]
    
# load tags for mp3 file
id3 = pyid3lib.tag(files[1])

# open image file
tcf = open(files[0], 'rb')

# picture type
if options.imgtype:
    picturetype = options.imgtype
else:
    picturetype = 3

# description
if options.description:
    description = options.description
else:
    description = 'None'

# loop through all frames
i=0
while i < len(id3):
    
    # if this is an apic frame, and its the picture type we wanted
    if id3[i]['frameid'] == 'APIC' and int(id3[i]['picturetype']) == int(picturetype):
	
	# if we were told to force, then force
	if not options.force:
	    print 'An image already exists with type '+str(picturetype)+'.  Enable force mode (-f) to overwrite it.'
	    sys.exit()
	else:
	    print 'An image already exists with type '+str(picturetype)+', but force is enabled, overwriting.'
	    del id3[i]
	    
    # next frame.
    i += 1
	    
# create new id3 frame
picframe = { 'frameid': 'APIC',
	     'mimetype': mimetype,
	     'description': description,
	     'picturetype': int(picturetype),
	     'data': tcf.read() }

# close image file
tcf.close()
    
# add image frame
id3.append(picframe)

# update tags
id3.update()

# output    
print files[0], "added to", files[1], "with type", str(picturetype)