import string
from urllib.request import urlopen

from PIL import Image, ImageDraw, ImageFont
from sys import argv
import random
import requests
import os

def getRandomFont(apiKey: str, usedFont: list=None) -> str:
    """
    Function to fetch a random font from a list of available fonts
    provided by Google Font
    :param apiKey: API Key used to connect to Google Fonts.
    :param usedFont: List of already used fonts. Set to none by default
    :return: Link to the ttf file
    """
    if usedFont is None:
        usedFont = []
    url = f"https://www.googleapis.com/webfonts/v1/webfonts?key={apiKey}"
    response = requests.get(url)
    if response.status_code != 200:
        raise Exception(f"Failed to fetch fonts: {response.status_code} - {response.reason}")

    fonts_data = response.json()
    if "items" not in fonts_data:
        raise Exception("No fonts found in the API response.")
    available_fonts = fonts_data["items"]
    unused_fonts = [font for font in available_fonts if usedFont is None or font["family"] not in usedFont]

    if not unused_fonts:
        raise Exception("No unused fonts available to select from.")
    chosen_font = random.choice(unused_fonts)

    usedFont.append(chosen_font["family"])

    font_files = chosen_font.get("files", {})
    ttf_link = font_files.get("regular") or next(iter(font_files.values()), None)

    if not ttf_link:
        raise Exception(f"No TTF link found for the font: {chosen_font['family']}")

    print(f"Selected font: {chosen_font['family']}")
    return ttf_link


def create_letter_image(letter, output_path, font):
    """
    Function to create an image for a letter passed as an argument
    :param letter: the letter
    :param output_path: the path to save the image
    :param font: font to be used (should be an online Font URL)
    :return: print a message and save the image
    """
    width, height = 13, 13
    font_size = 12

    image = Image.new('L', (width, height), color=255)  # Fond blanc
    draw = ImageDraw.Draw(image)

    try:
        font = ImageFont.truetype(urlopen(font), font_size)
    except IOError:
        raise Exception("Cannot open font URL")

    bbox = draw.textbbox((0, 0), letter, font=font)
    text_width, text_height = bbox[2] - bbox[0], bbox[3] - bbox[1]

    text_x = (width - text_width) // 2
    text_y = (height - text_height) // 2

    draw.text((text_x, text_y), letter, fill=0, font=font)  # Texte noir

    image.save(output_path)
    print(f"Image saved at {output_path}")

def createImageForEachLetter(output_folder, font, index=0):
    """
    Function to create an image for each of the letters passed as an argument
    :param output_folder: the folder where to save the image
    :param font: Google Font URL
    :param index: the current index of the iteration (default to 0 if there is no iteration)
    :return: Save the image into the correct subfolder
    """
    alphabet = string.ascii_letters
    if not os.path.exists(output_folder):
        os.makedirs(output_folder)
    for element in alphabet:
        if not os.path.exists(os.path.join(output_folder, element)):
            os.makedirs(os.path.join(output_folder, element))
        create_letter_image(element, f"{output_folder}/{element}/{element}-{index}.png", font)


if __name__ == "__main__":
    if len(argv) < 3:
        raise Exception("Usage: " + argv[0] + " <number-of-letter> <api-key>")
    if input(f"This script will generate {argv[1]} images for each letter in the alphabet. Continue? Y/n ") != "Y":
        print("Exiting...")
        exit(0)
    usedFont = []
    for i in range(int(argv[1])):
        createImageForEachLetter("dataset", getRandomFont(argv[2], usedFont), i)