#!/usr/bin/env python3 

import argparse 
parser = argparse.ArgumentParser(
    prog='pdf2book',
    description='pdf2book rearranges pages for signature printing ',
    epilog='AQOABA')

#parser.add_argument('pdf-file')           # positional argument
parser.add_argument('pages', type=int)           # positional argument
#parser.add_argument('-s', '--signature')      # option that takes a value
parser.add_argument('-v', '--verbose', action='store_true')  # on/off flag
parser.add_argument('-s', '--signature', 
    dest='signature', 
    type=int,
    action='store',
    default=1,
    help='')
args = parser.parse_args()

s=args.signature
if s < 0 : 
#    print("signature size must be greater than 0!")
    print("signature size must be positive integer!")
    exit(1)
pages=args.pages
#print(pages)

lst=[]

def get_reorder(page_number: int, signature_size: int):
    panu=page_number
    sisi=signature_size

    #  s|  1 |  2 |  3 |  4 | 
    #-----------------------
    #p  |    |    |    | 
    # 1 |  4 |  8 | 12 | 16 | 
    # 2 |  4 |  8 | 12 | 16 |
    # 3 |  4 |  8 | 12 | 16 |
    # 4 |  4 |  8 | 12 | 16 |
    # 5 |  8 |  8 | 12 | 16 |
    # 6 |  8 |  8 | 12 | 16 |
    # 7 |  8 |  8 | 12 | 16 |
    # 8 |  8 |  8 | 12 | 16 |
    # 9 | 12 | 16 | 12 | 16 |
    #10 | 12 | 16 | 12 | 16 |
    #11 | 12 | 16 | 12 | 16 |
    #12 | 12 | 16 | 12 | 16 |
    #13 | 16 | 16 | 24 | 16 |
          
    p=page_number
    s=signature_size
    if s == 0:
        s=1
        pages_filled= ( int((p-1)/(4*s)) +1 )*4*s
        s=int(pages_filled/4)
    pages_filled= ( int((p-1)/(4*s)) +1 )*4*s
          
    signature_count=int( pages_filled/s/4 )
    #print(signature_count)
    for i in range(signature_count):
    #    print("i=",i)
        down=(i+1)*4*s
    #    print("down=",down)
        up=  (i*4*s)+1
    #    print("up",up)
        for count in range(s):
    #        print("count=",count)
            lst.append(down); down -= 1
            lst.append(up);   up   += 1 
            lst.append(up);   up   += 1 
            lst.append(down); down -= 1
    #        print(lst)
    #print(lst)
    #print(len(lst))
    return lst
def print_signatures(lst: list,s: int):
    if s==0: s=1
    for i in range( len( lst ) ):
        if ( (i+1) % (4*s) == 0 ):
            print(lst[i])
        elif ( (i+1) % (4) == 0 ):
            print(lst[i], end=' ')
        else:
            print(lst[i],end='.')
lst=get_reorder(args.pages, args.signature)
print_signatures(lst,s)