#! /usr/bin/env python3
"""cmp.py: compare two files. Replace cmp because standard cmp cannot compare
large files.
"""

import sys, os

if sys.argv[1] in ("-h", "--help"):
   print("Broytman cmp.py 1.0, Copyright (C) 2003-2023 PhiloSoft Design")
   print("Usage: cmp.py [-h|--help|-V|--version] [-i] file1 file2")
   sys.exit()
elif sys.argv[1] in ("-V", "--version"):
   print("Broytman cmp.py 1.0, Copyright (C) 2003-2023 PhiloSoft Design")
   sys.exit()
elif sys.argv[1] == "-i":
   show_pbar = False
   fname1 = sys.argv[2]
   fname2 = sys.argv[3]
else:
   show_pbar = sys.stderr.isatty()
   fname1 = sys.argv[1]
   fname2 = sys.argv[2]

if show_pbar:
   try:
      from m_lib.pbar.tty_pbar import ttyProgressBar
   except ImportError:
      show_pbar = 0

if show_pbar:
   try:
      size = os.path.getsize(fname1)
   except:
      print(filename, ": no such file")
      sys.exit(1)

if show_pbar:
   pbar = ttyProgressBar(0, size)

file1 = open(fname1, 'rb')
file2 = open(fname2, 'rb')

M = 1024*1024
diff = False
count = 0


def report():
   if show_pbar:
      global pbar
      del pbar
   sys.stderr.write("Files differ at %d megabayte block\n" % count)
   global diff
   diff = True


while True:
   block1 = file1.read(M)
   block2 = file2.read(M)

   if show_pbar:
      pbar.display(file1.tell())

   if block1 and block2:
      if len(block1) != len(block2):
         report()
         break
   elif block1:
      report()
      break
   elif block2:
      report()
      break
   else:
      break

   if block1 != block2:
      report()
      break

   count += 1

if show_pbar and not diff:
   del pbar

file1.close()
file2.close()

if diff:
   sys.exit(1)