#! /usr/bin/env python
# -*- coding: utf-8 -*-
import os, tempfile, shlex, subprocess
from argparse import ArgumentParser
from random import shuffle

####
# Arguments
# TODO: add example to description
####
p = ArgumentParser(description='Script converts 8 images (jpg or png) from a given directory into a single page 4x2 imposition. Example: python imposition.py --dir imgs/  --size a3 --order random ')
p.add_argument("--dir", metavar='', default='', required=True, help="Image directory, which stores the source images for the imposition")
p.add_argument("--size", metavar='', default="A4", choices=['A4','a4','A3','a3'], help="Size of the printing sheet: A4 or A3. Default:A4")
p.add_argument("--order", metavar='', default="alphabet", choices=["alphabet", "reverse", "random"], help="Image distribution Order in the imposition. Possible Values: alphabet (alphabetically) , reverse (reverse alphabetically), random. Default: alphabet")
p.add_argument("--output", metavar='' ,default="output.pdf", help="Output file. Can either be a pdf, jpg or png. Default: output.pdf")
args = p.parse_args()

temp_dir = tempfile.mkdtemp()

# dimensions
args.size = (args.size).upper()
global size_sheet
if args.size == 'A4':
    size_sheet = (3508, 2480) #landscape: widthxheight in px
elif args.size == 'A3':
    size_sheet = (4960, 3508) #landscape: widthxheight in px
size_pages =  (size_sheet[0]/4,size_sheet[1]/2 )# size of each of the pages which makes up the printing sheet

# image selection
listdir = os.listdir( os.path.abspath(args.dir))
listdir = [f for f in listdir if any (x in f for x in ['.jpeg','.jpg','.png','.JPEG','.JPG','.PNG', '.Jpg', '.Jpeg','.Png']) ] #only bitmaps allowed

# create list of 8 ordered images
global listdir_order
if args.order == 'alphabet':
    listdir.sort()        
    listdir_order = listdir
elif args.order == 'reverse':
    listdir.sort()
    listdir.reverse()
    listdir_order = listdir
elif args.order == 'random':
    shuffle(listdir)    
    listdir_order = listdir

print listdir_order
listdir_order = listdir_order[0:8]
pagenumbers = [2,5,4,3,1,6,7,0] # from from top left to bottom right ( order in imagemagick creates mosaic)
listdir_order = [listdir_order[n] for n in pagenumbers] # reorder according to pagenumbers
print 'selected files according to pagenumbers:', listdir_order

# image conversion: -extent
tmpfiles =  [ (temp_dir +'/'+ str(n)+'.jpg')  for n, img in enumerate(listdir_order) ]
for n, img in enumerate(listdir_order):
    template_convert = 'convert -background white "{targetimg}" -gravity Center -resize {w}x{h} -extent {w}x{h} {tmpfile}'
    cmd_convert = template_convert.format(targetimg=(os.path.abspath(args.dir))+'/'+img,
                                          w=size_pages[0],
                                          h=size_pages[1],
                                          tmpfile=tmpfiles[n])
    cmd_convert_l = shlex.split(cmd_convert)
    subprocess.call(cmd_convert_l)
    
# montage
## order & rotation
tmpfiles_top =  tmpfiles[0:4] # top row will be rotated in the mosaic
tmpfiles_top = ' '.join(tmpfiles_top)
tmpfiles_bottom = tmpfiles[4:8]
tmpfiles_bottom = ' '.join(tmpfiles_bottom)
tmp_output = (temp_dir +'/'+'output.jpg') 
# command
template_montage = "montage -geometry +1+1 -tile 4x2  \( -rotate 180 {topfiles} \) {bottomfiles}  {output}"
cmd_montage = template_montage.format(topfiles=tmpfiles_top,
                                      bottomfiles=tmpfiles_bottom,
                                      output = tmp_output)
cmd_montage_l = shlex.split(cmd_montage)
subprocess.call(cmd_montage_l)

# resize output
output_f = os.path.abspath('./'+args.output)
template_convert = "convert {input_f} -resize {w}x{h} -units PixelsPerInch -density 300x300 {output}"
cmd_convert = template_convert.format(
    input_f= tmp_output,
    w=size_sheet[0],
    h=size_sheet[1],
    output=output_f)
cmd_convert_l = shlex.split(cmd_convert)
subprocess.call(cmd_convert_l)

print '** imposition save in', output_f, '**'

# garbage collection
cmd_rm = shlex.split( ('rm -rf '+ temp_dir) )
subprocess.call(cmd_rm ) # rm temp dir