#!/usr/bin/env python

from __future__ import unicode_literals, division, absolute_import, with_statement, print_function

import os
import re

from datetime import datetime
from optparse import OptionParser
from os import path

def add(arr):
    return arr[0] + arr[1]
assert add([1, 2]) == 3

def mul(arr):
    return arr[0] * arr[1]
assert mul([2, 3]) == 6

def echo(arg):
    print(arg)
    return arg

def compose(*funcs):
    return lambda arg = None: reduce(lambda val, func: func(val), funcs, arg)

test_compose = compose(lambda _: [2, 3], mul, lambda x: [x, 3], mul, lambda x: [x, 1], add)
# 2 * 3 = 6 * 3 = 18 + 1 = 19
assert test_compose() == 19

date_reg_ex = re.compile("\d{4}-\d{2}-\d{2}_")
doesnt_start_with_date = lambda string: date_reg_ex.search(string, 0, 11) is None
assert doesnt_start_with_date("1234-56-78_") == False
assert doesnt_start_with_date("a1234-56-78_")
assert doesnt_start_with_date("1234-56-78")
assert doesnt_start_with_date("1234-56-78_ sdfsakdsdf fjalsdjhfaskj  ldfh") == False

def prop(key):
    def obj(dic):
        return dic[key]
    return obj
assert prop('key')({'key': 1}) == 1

def path_join(directory):
    def do_join(file_name):
        return path.join(directory, file_name)
    return do_join

def mk_dir_map(ret, directory):
    is_file = compose(path_join(directory), path.isfile)
    files = filter(is_file, os.listdir(directory))
    not_with_date = filter(doesnt_start_with_date, files)
    ret[directory] = map(lambda x: {'original': x}, not_with_date)
    return ret

def add_date(ret, directory):
    original = prop('original')
    add_dir_name = path_join(directory)
    def list_date(file_obj):
        date_from_obj = compose(
            original,
            add_dir_name,
            path.getctime,
            datetime.fromtimestamp
        )
        date = date_from_obj(file_obj)
        file_obj['new'] = date.strftime('%Y-%m-%d_{0}'.format(original(file_obj)))
        return file_obj

    ret[directory] = map(list_date, ret[directory])
    return ret

def rename(ret, directory):
    original = compose(
        prop('original'),
        path_join(directory),
    )
    new = compose(
        prop('new'),
        path_join(directory),
    )
    def do_rename(file_obj):
        os.rename(original(file_obj), new(file_obj))
        return echo("mv -v {0} {1}".format(original(file_obj), new(file_obj)))
    map(do_rename, ret[directory])
    return ret

def main(options, directories):
    real_directories = filter(path.isdir, directories)
    file_tree = reduce(mk_dir_map, real_directories, {})
    file_tree = reduce(add_date, file_tree, file_tree)
    file_tree = reduce(rename, file_tree, file_tree)

if __name__ == '__main__':
    parser = OptionParser()
    parser.add_option("-f", "--file", dest="filename",
                              help="write report to FILE", metavar="FILE")
    parser.add_option("-q", "--quiet",
                              action="store_false", dest="verbose", default=True,
                                                help="don't print status messages to stdout")

    (options, args) = parser.parse_args()
    main(options, args)

