#!/usr/bin/env python

# This program transcode-syncs SRCDIR to DSTDIR. Basic algorithm:
#
# For every subpath+filename in SRCDIR:
#   If no equivalent (transcoded or linked) exists in DSTDIR:
#     Execute the appropriate command to transcode or link the subpath into SRCDIR
# For every subpath+filename in DSTDIR:
#   If no equivalent exists in SRCDIR:
#     Remove the subpath from DSTDIR
#
# SRCDIR is never written to, only read. The resulting DSTDIR is a copy of SRCDIR that can
# be read by the PS3 (or whatever) and has minimal size. 
# Transcode commands can be adapted in the transcoders list. Currently, MKVs get transcoded
# into MPEG2 VOBs giving a copy of the original, everything else is just linked.
#
# To use this, you need the command line tools referenced in TRANSCODERS. For me, this is 
# currently mencoder and plain old ln :-)

import os, sys, shutil

SRCDIR="/Volumes/Data/Movies"
DSTDIR="/Volumes/Data/Movies PS3"

# Adapt TRANSCODERS to do what you want. The format is:
# Key: InputFileSuffix
# Value: Tuple (OutputFileSuffix, ShellCommandToGetThere)
# If InputFileSuffix is equal to OutputFileSuffix, the name of the output file will be the
# same as that of the input file. If not, the output file will be called 
#   "InputFileName.OutputFileSuffix"
# I.e. in the example below, a file named "SRCDIR/test/dummy.mkv" will be transcoded by
# mencoder into "DSTDIR/test/dummy.mkv.vob".

TRANSCODERS = {
  "mkv": ("vob", 'mencoder -oac lavc -of mpeg -lavfopts format=asf -mpegopts format=mpeg2:muxrate=500000:vbuf_size=1194:abuf_size=64 -ovc lavc -lavcopts autoaspect=1:vcodec=mpeg2video:keyint=3:vqscale=2:vqmin=3 -subcp cp1252 -subfont /System/Library/Frameworks/JavaVM.framework/Versions/1.5.0/Home/lib/fonts/LucidaSansRegular.ttf -subfont-text-scale 3 -subfont-outline 1 -subfont-blur 1 -subpos 98 -subdelay 20000 -mc 0 -noskip "%s" -o "%s"'),
  "avi": ("avi", 'ln -s "%s" "%s"'),
  "vob": ("vob", 'ln -s "%s" "%s"')
  }


def mkfile_if_not_exist(srcfname, dstfname):
  try:
    suffix = srcfname.split(".")[-1]
    dstsuffix, command = TRANSCODERS[suffix]
  except:
    print "Ignoring '"+srcfname+"' (unknown suffix)."
    return
  if suffix != dstsuffix:
    dstfname = dstfname + "." + dstsuffix

  if os.path.exists(dstfname):
    print "Ignoring '"+srcfname+"' ('"+dstfname+"' exists)."
    return

  if os.path.exists(dstfname + ".LOG"):
    print "Error: '"+dstfname+".LOG' exists!"
    return

  print "Making '"+dstfname+"' from '"+srcfname+"'"
  
  # make lock(log)file
  logfname = dstfname+".LOG"
  open(logfname, "w").close()
  
  # fork here
  cmdstr = command % (srcfname, dstfname) + ' > "%s" 2>&1' % logfname
  print "Executing '"+cmdstr+"'"
    
  retval = os.system(cmdstr)
  if retval == 0:
    print "OK"
    os.remove(logfname)
  else:
    print "Error"
      
def rmfile_if_not_exist(srcfname, dstfname):
  if dstfname.endswith(".LOG"):
    print "'"+dstfname+"' is a log file. Not touching it."
    return
  print "Checking for '"+dstfname+"'..."
  # Are the filenames equal and source is still there? Bail.
  if os.path.exists(srcfname):
    print "\t'"+srcfname+"' still exists. Bail."
    return

  # Let's see how the original filename might look
  for suffix in TRANSCODERS.keys():
    dstsuffix, command = TRANSCODERS[suffix]
    if suffix != dstsuffix:
      srcfname2 = srcfname[:-len(dstsuffix)-1]
      if os.path.exists(srcfname2):
        print "\t'"+srcfname2+"' still exists. Bail."
        return

  print "\tNo good equivalent found. Removing it."
  os.remove(dstfname)
  try:
    os.remove(dstfname+".LOG")
  except:
    pass
    
      
# provide (link or transcode) files that are in SRCDIR but not (yet) in DSTDIR
print "\nPROVIDE\n-------\n"
for (srcpath, dirnames, filenames) in os.walk(SRCDIR):
  # create subpath of SRCDIR under DSTDIR if it doesn't exist yet
  dstpath = DSTDIR + srcpath[len(SRCDIR):]
  if not os.path.exists(dstpath):
    print "Making '"+dstpath+"'"
    os.mkdir(dstpath)

  # provide files (link or transcode)
  for fname in filenames:
    dstfname = dstpath + "/" + fname
    srcfname = srcpath + "/" + fname
    mkfile_if_not_exist(srcfname, dstfname)

print "\nCLEANUP\n-------\n"
# cleanup files and directories that are in DSTDIR but not (anymore) in SRCDIR
for (dstpath, dirnames, filenames) in os.walk(DSTDIR):
  
  # cleanup entire subpaths that don't exist anymore
  srcpath = SRCDIR + dstpath[len(DSTDIR):]
  if not os.path.exists(srcpath):
    print "'"+srcpath+"' has gone away, removing '"+dstpath+"'"
    shutil.rmtree(dstpath)
  
  # cleanup files
  for fname in filenames:
    dstfname = dstpath + "/" + fname
    srcfname = srcpath + "/" + fname
    rmfile_if_not_exist(srcfname, dstfname)