#!/usr/bin/env python
#-*-coding:utf-8-*-
#
# $Id: deldupes,v 0.4 2009/10/07 18:34:14 stef Exp $
#
# Find duplicates (files with matching MD5 hashes) in a directory and
# optionally delete all except one of the duplicates.
#
# Copyright (c) Stefan Pettersson 2009, http://www.bigpointyteeth.se/
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
#

import os, sys
import hashlib

me = os.path.basename(sys.argv[0])

def usage():
    print "Usage: %s FILE ..." % me
    sys.exit(1)


def getyesno(question):
    """
    Displays the question string to the user and expects a yes/no answer.
    Returns True if yes, False if no."""
    answer = "a"
    while True:
        if answer.lower() in ("yes", "y"):
            return True
        elif answer.lower() in ("no", "n"):
            return False
        else:
            answer = raw_input(question + " (yes/no) ")


def choose(msg, choices):
    """
    Take a message string and a list of strings (filenames) as input. Print
    all the filenames with numbers to console and wait for a numbered input
    from the user.

    Return the number given, or if "x" is chosen (none), return -1.
    """

    # list them in alphabetical order
    choices.sort()

    for i in range(len(choices)):
        print "(%d) %s" % (i, choices[i])
    print "(x) all of them"
    answer = -1
    while True:
        answer = raw_input(msg + " ")
        try:
            answer = int(answer)
        except ValueError:
            if answer == "x":
                return -1
            continue
        if 0 <= answer and answer <= len(choices)-1:
            return choices[int(answer)]

if len(sys.argv) < 2:
    usage()

# key   => filename string
# value => file's cryptographic hash
hashes = {}

# key   => hash 
# value => list of names with the same hash
duplicates = {}

# files to delete
delete = []

try:
    # get filenames from command line
    filenames = sys.argv[1:]

    # calculate hashes for all files
    for file in filenames:
        try: F = open(file, "r")
        except IOError: continue
        S = F.read()
        hashes[file] = hashlib.md5(S).hexdigest()
        F.close()

    # check for duplicates and populate duplicates dictionary
    while hashes:
        name, hash = hashes.popitem()
        duplicates[hash] = [name]
        for pair in hashes.items():
            if hash == pair[1]:
                # found duplicate, add to duplicates, remove from files
                duplicates[pair[1]].append(pair[0])
                hashes.pop(pair[0])

    # go through the list of duplicates and choose which to keep
    for key, values in duplicates.items():
        if len(values) > 1:
            keep = choose("Which one do you want to keep?", values)
            if keep == -1:
                # the user wants to keep all the files
                continue
            for value in values:
                # store any file names that are to be deleted
                if value != keep:
                    delete.append(value)

    # did we find any duplicates?
    # where any of them chosen for deletion?
    if len(delete) < 1:
        print "Done. Nothing removed."
        sys.exit(0)

    print ""

    # print the files that are to be deleted
    for file in delete:
        print file

    if getyesno("Delete these files?"):
        for file in delete:
            os.remove(file)
            pass
        print "Done. %d files removed." % len(delete)
        sys.exit(0)
    else:
        print "Done. Nothing removed."
        sys.exit(0)

except KeyboardInterrupt:
    print "\nUser-abort."
    sys.exit(1)

# EOF