#!/usr/bin/env python

from argparse import ArgumentParser
from math import ceil, floor
from random import randrange, choice
from reportlab.pdfgen import canvas
from reportlab.lib.pagesizes import A4
from reportlab.graphics.shapes import Drawing 
from reportlab.graphics.barcode.qr import QrCodeWidget 
from reportlab.graphics import renderPDF
from urllib.parse import urljoin

def generate_random_username(female_nouns, male_nouns, adjectives, used_usernames):
    random_username = None
    while True:
        nouns = choice([female_nouns, male_nouns])
        random_username = f"{adjectives[randrange(len(adjectives)-1)]}{'' if nouns is female_nouns else 'r'}-{nouns[randrange(len(nouns)-1)].lower()}"
        if random_username not in used_usernames:
            used_usernames.add(random_username)
            print(random_username)
            return random_username

if __name__ == "__main__":
    parser = ArgumentParser(description="Generates a QR code PDF with random usernames and prints the names to stdout.")
    parser.add_argument("url", help="Base URL, e.g. 'https://url.com'.")
    parser.add_argument("-n", "--number", type=int, help="Amount of requested usernames, defaults to 50.", default=50)
    parser.add_argument("-o", "--output", type=str, help="Output file, defaults to 'qrcodes.pdf'.", default="qrcodes.pdf")
    parser.add_argument("-s", "--size", type=int, help="QR code size, defaults to 45.", default=45)

    args = parser.parse_args()

    adjectives = set()
    female_nouns = set()
    male_nouns = set()
    with open('adjektive-weiblich.txt', 'r') as file:
        for line in file:
            adjectives.add(line.strip())
    with open('nomen-weiblich.txt', 'r') as file:
        for line in file:
            female_nouns.add(line.strip())
    with open('nomen-maennlich.txt', 'r') as file:
        for line in file:
            male_nouns.add(line.strip()) 
    adjectives = list(adjectives)
    female_nouns = list(female_nouns)
    male_nouns = list(male_nouns)

    pdf = canvas.Canvas(args.output, pagesize=A4)
    page_width, page_height = A4
    used_usernames = set()

    codes_per_row = floor(page_width/args.size)
    codes_per_col = floor(page_height/args.size)
    if codes_per_col == 0 or codes_per_row == 0:
        raise Exception(f"There is not enough space on A4 page to fit a QR code of size {args.size}x{args.size}!")
    codes_per_page = codes_per_row*codes_per_col
    required_pages = ceil(args.number/codes_per_page)
    generated_codes = 0

    for page in range(required_pages):
        for y in range(codes_per_col):
            for x in range(codes_per_row):
                qr_code = QrCodeWidget(urljoin(args.url, generate_random_username(female_nouns, male_nouns, adjectives, used_usernames)))
                bounds = qr_code.getBounds()

                code_width = bounds[2] - bounds[0]
                code_height = bounds[3] - bounds[1]

                drawing = Drawing(args.size, args.size, transform=[args.size/code_width, 0, 0, args.size/code_height, 0, 0]) 
                drawing.add(qr_code)

                renderPDF.draw(drawing, pdf, args.size*(x%codes_per_row), args.size*(y%codes_per_col))
                generated_codes += 1
                if generated_codes >= args.number:
                    pdf.save()
                    exit()
        pdf.showPage()

    pdf.save()