#! /usr/bin/env python

"""mmv: Multiple move.
A small utility designed to rename files in the current working directory both matching against, and transforming the matches via python regular expressions."""

import re,os,os.path,sys,optparse

class OptParser(optparse.OptionParser):
    def format_epilog(self,formatter):
        return self.epilog

parser = OptParser(usage="%prog [OPTIONS] $regex_match [$lambda | $str_method | $regex_sub]",version="%prog 0.9.7.1")
parser.set_description(__doc__) 

parser.add_option("-l","--lambda",action="store_true",default=False,dest="_lambda",help="Use a lambda expression. Match file names against $regex_match, transform with eval('lambda fname:' + $lambda).")
parser.add_option("-r","--regex",action="store_true",default=True,dest="_regex",help="(Default) Use regexs. Match file names with $regex_match, transform with $regex_sub.")
parser.add_option("-s","--string",action="store",default=False,dest="_string",help="Use a python string method to transform file names.")
parser.add_option("-t","--test",action="store_true",default=False,dest="_test",help="Test. Display all output but do not commit new filenames.")
parser.add_option("-v","--verbose",action="store_true",default=False,dest="_verbose",help="Verbose. Display output, implied by -t")

parser.epilog = """Examples:
    mmv -t "mmmv" "mmv"                                                                     #convert all cases of 'mmmv' to 'mmv'
    mmv -tl "." "'%s.%s' % ('.'.join(fname.split('.')[:-1]),fname.split('.')[1:].upper())"  #capitalize file extensions
    mmv -tl "open(fname,'r').readline().replace(' ','_')"                                   #use first line of the file for new filename
    mmv -t --string upper                                                                   #return uppercase filenames
    mmv -t -l "*" "fname[1:]+fname[0]+'ay'"                                                 #pig latin
"""

(options,args) = parser.parse_args()

try:
    regex = re.compile(args[0])
except Exception as E:
    parser.error("Missing or malformed filename matching regex")
    raise

if options._test:
    mmv = lambda src,dst: "testing:%s:\t%s" % (src,dst)     #dummy
    options._verbose = True                                 #always dump testing output
else:
    mmv = lambda src,dst: os.rename(src,dst)                #default behavior
if options._lambda:                                         #user supplied func. uses eval; treat with care
    trans = eval('lambda fname: %s' % args[1])
elif options._string:
    trans = lambda src: getattr(src,options._string)()
else:
    trans = lambda src: regex.sub(args[1],src)              #default, simple regex sub

for ix in os.listdir('./'):                                 #cwd only
    if regex.search(ix):
        try:
            dst = trans(ix)
            result = mmv(ix,dst)
            if result == None:
                result = "%s:\t%s" % (ix,dst)
        except Exception as e:
            result = e.__doc__
        if options._verbose:
            print(result)