#!/usr/bin/python3

import sys, re, os

errortxt = " mydirectory\nRenames _all_ strange filenames in a given directory. No other options, edit the source."
count = 0

# Check for one single commandlineparameter
try:
    dirname = sys.argv[1]
except:
    sys.exit(sys.argv[0] + errortxt)

# Regex to eliminate everything not belonging into a filename
# Ey, this is not zombiecode!
# whitelist="[^a-z.A-Z0-9äöüÄÖÜß_+-]"    # All trash eliminate
# whitelist="[^a-z.A-Z0-9äöüÄÖÜß_+-][^a-z.A-Z0-9äöüÄÖÜß_+-]*" # Reduce trash to "-"
whitelist = "[^a-z.A-Z0-9äöüÄÖÜß_+-][^a-z.A-Z0-9äöüÄÖÜß_+-]*"
cutminus = "^-+"

# Open first commandline parameter as a directory
if os.path.isdir(dirname):
    for filename in os.listdir(dirname):
        tmpfilename = re.sub(whitelist, "-", filename)
        # repair leading "-" and prepend a "0"
        newfilename = re.sub(cutminus, "0-", tmpfilename)
        # Test for already existing target
        if os.path.exists(dirname + "/" + newfilename) == False:
            # show what is happening
            print("moving ", filename, " to ", newfilename)
            os.rename(dirname + "/" + filename, dirname + "/" + newfilename)
            count += 1
        else:
            print("Not overwriting existing file: ", newfilename)
# Not a directory - exit and say someting nasty
else:
    sys.exit(sys.argv[0] + errortxt)

# Give a summary.
print("\n", count, " files renamed\n")