#!/usr/bin/env python3

import argparse
import os
import random
import string
from hashlib import sha512 as hashfunc


def create_rand_name(size=None):
    """ Create rand name using alphanumeric char.
        Param size: size of str name.
        Type size: int.
        Return: random name.
        Rtype: str.
    """
    if not size:
        size = random.randint(5, 15)
    name = ''
    for x in range(size):
        name += random.choice(string.hexdigits)
    return name


def create_rand_folder(directory):
    """ Create rand folder in directory.
        Param directory: folder where create new rand folder.
        Type directory: str.
        Return: path with new directory.
        Rtype: str.
    """
    new_dir = os.path.join(directory, create_rand_name())
    if not os.path.exists(new_dir):
        os.makedirs(new_dir)
    else:
        new_dir = create_rand_folder(directory)
    return new_dir


def create_rand_cad(size=1024):
    """ Create rand str using hexadecimal char and hash sha512.
        Param size: size in byte of str for generate.
        Type size: int.
        Return: random name.
        Rtype: str.
    """
    cads = [hashfunc(create_rand_name().encode('utf-8')).hexdigest()]
    last = cads[0]
    for i in range(int(size / 128)):
        last = hashfunc(last[:8].encode('utf-8')).hexdigest()
        cads.append(last)
    return ''.join(cads)[:size]


def create_file(path, size):
    """ Get rand name using alphanumeric char.
        Param size: size of str name.
        Type size: int.
        Return: random name.
        Rtype: str.
    """
    filename = create_rand_name()
    new_file = os.path.join(path, filename)
    if not os.path.exists(new_file):
        with open(new_file, 'w') as f:
            f.write(create_rand_cad(size))
        return new_file
    else:
        return create_file(path, size)


def generate_list_sizes(nfile, size, distribute_size):
    """ Generate list of size for use it with create_files.
        Param nfile: .
        Type nfile: .
        Param size: .
        Type size: .
        Param distribute_size: .
        Type distribute_size: .
        Return: .
        Rtype: .
    """
    list_sizes = []
    aux_size = size
    normal_size = int(size / nfile)
    var = max(1, int(normal_size - normal_size * distribute_size / 100))
    for s in range(nfile):
        if aux_size <= 0:
            list_sizes.append(0)
            continue
        tmp_size = random.randint(normal_size - var, normal_size + var)
        aux_size -= tmp_size
        if tmp_size < 0:
            list_sizes.append(tmp_size + aux_size)
        else:
            list_sizes.append(tmp_size)
    return list_sizes


def get_files_per_folder(nfile, ndir, distribute_files):
    """ Get numbers of files for each folder.
        Param nfile: .
        Type nfile: .
        Param ndir: .
        Type ndir: .
        Param distribute_files: .
        Type distribute_files: .
        Return: List of numbers.
        Rtype: list(int).
    """
    list_files = []
    aux_files = nfile
    f_per_dir = int(nfile / ndir)
    f_remainder = int(nfile % ndir)
    for d in range(ndir):
        if (aux_files <= 0):
            list_files.append(0)
            continue
        files = 0
        if (f_per_dir > 0):
            var = max(1, int(f_per_dir - f_per_dir * distribute_files / 100))
            files += random.randint(f_per_dir - var, f_per_dir + var)
        var = f_remainder - f_remainder * distribute_files // 100
        files += random.randint(f_remainder - var, f_remainder + var)
        aux_files -= files
        if (aux_files <= 0):
            list_files.append(files + aux_files)
            continue
        list_files.append(files)
    if (aux_files > 0):
        list_files[-1] += aux_files
    return list_files


def main(args = None):
    parser = argparse.ArgumentParser(description='Wgeneration option. ')
    parser.add_argument('--seed', type=int, action='store', help='Seed. ')
    parser.add_argument('--ndir', type=int, action='store',
            help='Number of directories for create. ')
    parser.add_argument('--deep', type=int, action='store',
            help='Percent for distribute deep.')
    parser.add_argument('--nfile', type=int, action='store',
            help='Number of files for create. ')
    parser.add_argument('--size', type=int, action='store',
            help='Total size of files (MB) ')
    parser.add_argument('--distribute_files', type=int, action='store',
            help='Percent for distribute files. ')
    parser.add_argument('--distribute_size', type=int, action='store',
            help='Percent to distribute size of files. ')
    parser.add_argument('--path', action='store', help='Path to generate. ')

    if not args:
        parsed_args = parser.parse_args()
    else:
        parsed_args = parser.parse_args(args)

    if parsed_args.seed is not None:
        seed = parsed_args.seed
    else:
        seed = random.randint(0, 1000000000)
    random.seed(seed)
    if parsed_args.ndir is not None:
        ndir = parsed_args.ndir
    else:
        ndir = random.randint(0, 50000)
    if parsed_args.deep is not None:
        deep = parsed_args.deep
    else:
        deep = random.randint(0, 100)
    if parsed_args.nfile:
        nfile = parsed_args.nfile
    else:
        nfile = random.randint(1, 500000)
    if parsed_args.size:
        size = parsed_args.size * 1024 * 1024 # MB to byte
    else:
        size = random.randint(1, 5000)
        size = size * 1024 * 1024 # MB to byte
    if parsed_args.distribute_files is not None:
        distribute_files = parsed_args.distribute_files
    else:
        distribute_files = random.randint(0, 100)
    if parsed_args.distribute_size is not None:
        distribute_size = parsed_args.distribute_size
    else:
        distribute_size = random.randint(0, 100)
    if parsed_args.path:
        path = os.path.abspath(parsed_args.path)
        if not os.path.exists(path):
            os.makedirs(path)
    else:
        path = os.getcwd()

    print("Using seed %d: " % seed)
    print("Generate %d folders with %d%% of deep." % (ndir, deep))
    print("Generate %d files with total size %d MB." % (nfile,
            size / 1024 / 1024))
    print("\tDistribute (files, size): (%d%%, %d%%)." % (distribute_files,
            distribute_size))

    list_dir = [[path, ndir, nfile]]
    list_sizes = generate_list_sizes(nfile, size, distribute_size)
    list_files = get_files_per_folder(nfile, ndir, distribute_files)

    while ndir > 0:
        new_dir = create_rand_folder(list_dir[0][0])
        ndir -= 1
        for i in range(list_files[0]):
            create_file(new_dir, list_sizes[i])
        del list_sizes[:list_files[0]]
        del list_files[0]
        current_ndir = list_dir[0][1] - 1
        if (current_ndir == 0):
            del list_dir[0]
        else:
            ndir_deep = current_ndir * deep / 100
            ndir_path = current_ndir - ndir_deep
            if (ndir_deep > 0):
                list_dir.append([new_dir, ndir_deep])
            if (ndir_path > 0):
                list_dir[0][1] = ndir_path
            else:
                del list_dir[0]
    return seed


if __name__ == "__main__":
    main()