#!/usr/bin/env python

import os,sys

if (sys.hexversion<0x3000000):
  # PYTHON 2.X FUNCTIONS
  def binary(text): return(text)
  def text(binary): return(binary)
  def byte(value): return(chr(value))
else:
  # PYTHON 3.X FUNCTIONS
  def binary(text): return(text.encode("latin-1"))
  def text(binary): return(binary.decode("latin-1"))
  def byte(value): return(value)

if (len(sys.argv)!=2): print("You must provide the path to the YASARA executable as first argument")
else:
  yasara=open(sys.argv[1],"rb").read()
  oldurl=binary("cftp.rcsb.org")
  idx=yasara.find(oldurl)
  # DOWNLOAD SERVER IS PRESENT AS A SECOND STRING http://"PDB_DOWNLOADSERVER"/view FOR ALIGNMENTS */
  if (idx!=-1 and yasara[idx-7:idx]==binary("http://")): idx=yasara.find(oldurl,idx+1)
  if (idx==-1):
    if (yasara.find(binary("files.rcsb.org"))!=-1): print("This YASARA executable has already been patched")
    else: print("The file %s is not a YASARA executable"%sys.argv[1])
  else:
    for i in range(40):
      if (yasara[idx+14+i]==byte(0)): break
    print("Replacing RCSB URL, damaging the string '%s'"%text(yasara[idx+14:idx+14+i]))
    yasara=yasara[:idx]+binary("files.rcsb.org\0")+yasara[idx+15:]
    open(sys.argv[1],"wb").write(yasara)
    print("Patch completed")