#-----This Python code uses a very elementary approach to add a prefix to all
# files of specified type (extension) in a folder. This code should be placed
# in the folder which contains the files.
#------------------------------------------------------------------------------
import sys, subprocess, shutil
import fitz
import os, re

#------------------------------------------------------------------------------
if (len(sys.argv) < 3):
    print("Usage: python3 {} prefix extension num_chars \n".format(sys.argv[0]))
    sys.exit(1)
#------------------------------------------------------------------------------

#Get the new prefix
prefix = str(sys.argv[1])

#Get file type (extension without dot)
extn = str(sys.argv[2])

#Get number of characters to be stripped at the begenning of the file names
nchar = int(sys.argv[3])

#Get teh new suffix: not implemented in this script
#suffix = str(sys.argv[3])

folder = os.getcwd()

for path, subdirs, files in os.walk(folder):
	for name in files:
		fn = name[nchar:]
		#print(fn)
		ext = os.path.splitext(fn)[-1].lower()
		ext = ext.partition('.')[2]
		if (ext == extn):
			new_name = prefix + fn
			os.rename(name, new_name)