import os
import sys
import copy
import struct

###########################################################################
### String that acts something like a streaming file (read, tell, close)

class stryle:
  def __init__(self,s):
    self.buffer=s
    self.__tell=long(0)

  def read(self,n):
    self.__tell += n
    return self.buffer[self.__tell-n:self.__tell]

  def tell(self):
    return self.__tell

  def close(self):
    return


###########################################################################
### Riff class

class Riff:

  def __init__(self,fn=None,fyleArg=None,parentArg=None):
    if fyleArg is None:
      self.fn = fn
      self.sz = os.stat(fn).st_size
      fyle = open(fn)
    else:
      self.fn = None
      self.sz = 0
      fyle = fyleArg

    self.parent=parentArg

    eight = fyle.read(8)
    tell0 = fyle.tell()
    
    self.ID = eight[:4]
    self.Length=struct.unpack('<l', eight[4:])[0]

    self.subChunks = dict(idList=[])
    self.subID = ''
    self.Data = None

    if self.ID in ['RIFF','LIST']:
      self.subID = fyle.read(4)
      while fyle.tell()<(tell0+self.Length):
        next = Riff(fyleArg=fyle,parentArg=self)
        if not (next.ID in self.subChunks): self.subChunks[next.ID] = []
        self.subChunks['idList'] += [ (next.ID,len(self.subChunks[next.ID])) ]
        self.subChunks[next.ID] += [next]
    else:
      self.Data = fyle.read(self.Length)
      if (self.Length%2): fyle.read(1)
      if self.ID == 'fmt ':
        wFormatTag ,wChannels ,dwSamplesPerSec ,dwAvgBytesPerSec \
        ,wBlockAlign ,wBitePerSample = struct.unpack( '<hhllhh', self.Data)
        self.fmt = dict(
          wFormatTag       = wFormatTag
        , wChannels        = wChannels
        , dwSamplesPerSec  = dwSamplesPerSec
        , dwAvgBytesPerSec = dwAvgBytesPerSec
        , wBlockAlign      = wBlockAlign
        , wBitePerSample   = wBitePerSample
        , )

    if self.sz > 0 and fyle.tell()==self.sz: fyle.close()

  def changeLength(self,deltaLength):
    self.Length += deltaLength
    if self.parent:
      self.parent.changeLength(deltaLength)

  def addData(self,moreData):
    self.Data += moreData
    self.changeLength(len(moreData))

  def reParent(self,parent):
    self.parent = parent
    for id,idx in self.subChunks['idList']: self.subChunks[id][idx].reParent(self)

  def deepcopy(self,parent=None):
    newSelf=copy.deepcopy(self)
    newSelf.reParent(parent)
    return newSelf
    
  def replaceSubChunk( self, newRiff, idx=0):
    ID = newRiff.ID[:]
    oldLength = 0+self.subChunks[ID][idx].Length
    self.subChunks[ID][idx] = newRiff.deepcopy(self)
    self.changeLength( newRiff.Length - oldLength)

  def pout(self, indent='', dataShow=0):
    if self.Data: lenData=len(self.Data)
    elif self.Data is None: lenData=-1
    else: lenData=0
    d = dict(ID=self.ID,fn=self.fn,sz=self.sz,Length=self.Length,subID=self.subID,lenData=lenData,parent=self.parent)
    if dataShow > 0:
      if self.Data is None:  d['show']=None
      else                :  d['show']=self.Data[:dataShow]
    print( indent + str(d) )
    if self.ID=='fmt ': print( indent + '  ' + str(dict(fmt=self.fmt)) )
    for id,idx in self.subChunks['idList']: self.subChunks[id][idx].pout( indent='  '+indent,dataShow=dataShow)


if __name__=='__main__':
  for av in sys.argv[1:]:
    riff=Riff(fn=av)
    print( riff)
    riff.pout(dataShow=4)

    if 'RIFFADD' in os.environ:
      id_data=os.environ['RIFFADD']
      if riff.subID:
        riff.subChunks[id_data[:4]][0].addData(id_data[4:])
      else:
        riff.addData(id_data)
      riff.pout(indent='  ADDED DATA>  ')

    if 'RIFFREPLACE' in os.environ and riff.subID:
      id_data=os.environ['RIFFREPLACE']
      ID,newData = id_data[:4],id_data[4:]
      if ID in riff.subChunks:
        cpy = copy.deepcopy(riff.subChunks[ID][0])
        cpy.parent = None
        cpy.pout(indent='  COPY>')
        riff.subChunks[ID][0].pout(indent='  ORIG>')
        cpy.addData(newData)
        riff.replaceSubChunk( cpy)
        print( '  '+str(riff))
        riff.pout(indent='  REPLACED DATA>  ')