#!/usr/bin/python
import os
import sys
import getopt
import shutil
from mutagen.id3 import ID3
from mutagen.flac import FLAC
from mutagen.oggvorbis import OggVorbis

#encoders and decoders
MP3_ENCODER = "lame --silent -r -x --vbr-new -m s -V 7 --tt $TITLE$ --ta $ARTIST$ --tl $ALBUM$ --ty $DATE$ --tn $TRACK$ --tg $GENRE$ - $FILE$ 2>/dev/null"
OGGVORBIS_ENCODER = "oggenc -Q -r -q 3 -t $TITLE$ -a $ARTIST$ -l $ALBUM$ -d $DATE$ -N $TRACK$ -G $GENRE$ - -o $FILE$ 2>/dev/null"
FLAC_DECODER = "flac -s -d --force-raw-format --sign=signed --endian=little $FILE$ -o - 2>/dev/null"
OGGVORBIS_DECODER = "oggdec -Q -s 1 -e 0 -R $FILE$ 2>/dev/null"
MP3_DECODER = "madplay -q -o raw:- $FILE$ 2>/dev/null"

#associated formats
FLAC_FORMAT = "flac"
OGGVORBIS_FORMAT = "ogg"
MP3_FORMAT = "mp3"
SUPPORTED_TARGETS = [MP3_FORMAT,OGGVORBIS_FORMAT]
SUPPORTED_SOURCES = [MP3_FORMAT,OGGVORBIS_FORMAT,FLAC_FORMAT]

#set option defaults
target_format = MP3_FORMAT
target_encoder = MP3_ENCODER
source = os.getcwd()
target = os.getcwd()
verbose = False

def reencode(source_file,target_file):
  if (verbose):
    print("Found "+source_file);
  source_format = source_file.split(".").pop()
  target_file = target_file.replace(source_format,target_format)
  #if the file exists at the destination already we'll skip it
  if (os.path.isfile(target_file)):
    if (verbose):
      print("Target exists.");
    return
  if (source_format in SUPPORTED_SOURCES):
    #if the formats are the same, why reencode?
    if ((target_format in SUPPORTED_TARGETS) and (source_format == target_format)):
      shutil.copyfile(source_file,target_file)
      if (verbose):
        print("Copying to "+target_file);
      return
    #retrieve the metadata and set the decoder appropriately
    if (source_format == FLAC_FORMAT):
      audio = FLAC(source_file)
      source_decoder = FLAC_DECODER
    if (source_format == MP3_FORMAT):
      audio = ID3(source_file)
      source_decoder = MP3_DECODER
    if (source_format == OGGVORBIS_FORMAT):
      audio = OggVorbis(source_file)
      source_decoder = OGGVORBIS_DECODER
      
    command = target_encoder.replace("$FILE$","\""+target_file+"\"")
    command = command.replace("$TITLE$","\""+audio["title"].pop()+"\"")
    command = command.replace("$ARTIST$","\""+audio["artist"].pop()+"\"")
    command = command.replace("$ALBUM$","\""+audio["album"].pop()+"\"")
    command = command.replace("$GENRE$","\""+audio["genre"].pop()+"\"")
    command = command.replace("$DATE$","\""+audio["date"].pop()+"\"")
    command = command.replace("$TRACK$","\""+audio["tracknumber"].pop()+"\"")
    command = source_decoder.replace("$FILE$","\""+source_file+"\"")+" | "+command

    if (verbose):
      print("Reencoding to "+target_file);
    os.popen(command)
  else:
    if (verbose):
      print("Unsupported format.");

#recursively walk through directories, in turn walking through
#subdirectories and processing files accordingly
def recursive_walk(running_directory=""):
  subfolders = os.listdir(os.path.join(source,running_directory))
  subfolders.sort(key=str.lower)
  for abstract_source_object in subfolders:
    source_object = os.path.join(os.path.join(source,running_directory),abstract_source_object)
    if os.path.isfile(source_object):
      reencode(source_object,os.path.join(os.path.join(target,running_directory),abstract_source_object))
    else:
      if os.path.isdir(source_object):
        target_directory = os.path.join(os.path.join(target,running_directory),abstract_source_object)
        if not (os.access(target_directory,os.F_OK+os.W_OK+os.X_OK)):
          os.mkdir(target_directory,0755)
        recursive_walk(os.path.join(running_directory,abstract_source_object))

#get arguments and set options
try:                                
  opts, args = getopt.getopt(sys.argv[1:], "s:d:t:v", ["source=", "destination=","target=","verbose"])
  for opt,arg in opts:
    if (opt in ("-v","--verbose")):
      verbose = True
    if (opt in ("-s","--source")):
      source = arg
    if (opt in ("-d","--destination")):
      target = arg
    if (opt in ("-t","--target")):
      target_format = arg
      #set the encoder
      if (target_format == FLAC_FORMAT):
        target_encoder = FLAC_ENCODER
      if (target_format == MP3_FORMAT):
        target_encoder = MP3_ENCODER
      if (target_format == OGGVORBIS_FORMAT):
        target_encoder = OGGVORBIS_ENCODER
except getopt.GetoptError:
  sys.exit(str(getopt.GetoptError))

#check to make sure the directories we're going to use are OK
if not (os.access(source,os.F_OK+os.R_OK+os.X_OK)):
  sys.exit("Source directory doesn't exist or isn't accesible!")
if not (os.access(target,os.F_OK+os.W_OK+os.X_OK)):
  sys.exit("Destination directory doesn't exist or isn't accesible!")
if not (target_format in SUPPORTED_TARGETS):
  sys.exit("Invalid target format!") 

#start our walk
recursive_walk()