#!/usr/bin/env python2

import os
import sys
import qrcode

'''
Converts a file to a pdf filled with QR codes.
Depends on:
    - qrcode
    - pillow
    - reportlab
'''

# pdf generation

from reportlab.pdfgen import canvas
from reportlab.lib.units import inch, cm
from reportlab.lib.pagesizes import A4

redundancy = qrcode.constants.ERROR_CORRECT_L
tmp_name   = '/tmp/qr.jpg'

def to_qr(data):
    qr = qrcode.QRCode(
        version=1,
        error_correction=redundancy,
        box_size=4,
        border=4,
    )
    qr.add_data(data)
    qr.make(fit=True)
    return qr.make_image()

def to_page(c, images):
    assert len(images) <= 6
    images = iter(images)
    for row in range(3):
        for col in range(2):
            try:
                img = images.next()
                img.save(tmp_name)
                x = 10.5 * col + 0.25
                y = 19.5 - (9.5 * row)
                print row, col, x, y
                c.drawImage(tmp_name, x * cm, y * cm, 10*cm, 10*cm)
            except StopIteration:
                return

# main program

if __name__ == '__main__':
    if len(sys.argv) != 3:
        print 'usage:', sys.argv[0], '[input file]', '[output pdf]'
        exit(-1)
    _, fin, fout = sys.argv

    # open output
    c = canvas.Canvas(fout, pagesize=A4)

    with open(fin, 'r') as f:
        while 1:
            # read chunks for this page
            chunks = []
            for _ in range(6):
                data = f.read(512)
                if len(data) > 0:
                    print 'store:', data.encode('hex')
                    chunks.append(data)
                if len(data) < 512:
                    break

            # write qr to page
            if len(chunks) > 0:
                chunks = map(to_qr, chunks)
                to_page(c, chunks)
                c.showPage()
            if len(chunks) < 6:
                break
    c.save()
    print 'done'