#!/usr/bin/env python

import empty

rep = lambda s, i, c: s[ : i ] + c + s[ i + 1 : ]

def enc(s, lst):
	lst = list( filter( lambda c2: c2[ 0 ] in s, lst ) )

	e = empty.new()
	e.s = s

	def cvt(c2):
		(c_s, c_d) = c2
		ps = []
		while c_s in e.s:
			i = e.s.index( c_s )
			e.s = rep( e.s, i, c_d )
			ps.append( i )

		ps = '_'.join( map( str, ps ) )
		return '/'.join( [ 's', c_d, str( ord( c_s ) ), ps ] )

	h = '/'.join( map( cvt, reversed( lst ) ) )
	return h + ' ' + e.s

def dec(s):
	if ' ' not in s:
		return s

	def get_hs(s):
		i = s.index( ' ' )
		(h, s) = ( s[ : i ], s[ i + 1 : ] )
		if '/' not in h:
			return None
		h = h.split( '/' )
		if len( h ) % 4 != 0:
			return None
		return empty.new( h=h, s=s )

	e = get_hs( s )
	if not e:
		return s

	def cvt(cmd, c_d, c_s, ps):
		if cmd != 's':
			return False
		c_s = chr( int( c_s ) )
		ps = list( map( int, ps.split( '_' ) ) )
		for i in ps:
			if e.s[ i ] != c_d:
				return False
			e.s = rep( e.s, i, c_s )
		return True

	while e.h:
		(h4, e.h) = ( e.h[ : 4 ], e.h[ 4 : ] )
		if not cvt( * h4 ):
			return s
	return e.s

def sample():
	s = 'abc.FOO.xyz/KONDOH_bar'
	lst = [ 'b.', 'O_' ]
	s_e = enc( s, lst )
	s_d = dec( s_e )
	print( s )
	print( s_e )
	print( s_d )

if __name__ == "__main__":
	sample()
# EOF