from PIL import Image, ImageDraw, ImageFont
import sys

# fonts are defined here
fonts = {
    "r": "fonts/F25_Bank_Printer.ttf",
    "b": "fonts/F25_Bank_Printer_Bold.ttf",
}

if len(sys.argv) == 1:
    print("please specify a path to a shirtfile")
    exit(1)

# parse shirtfile into list of tuples
#
# shirtfile syntax:
#   a shirtfile is a plain-text file made up of lines in the following format
#     {alignment}:{font}:{size} {text}
#   where:
#     - alignment can be: 
#       * 'm' for centered text
#       * 'l' for left aligned text
#       * 'r' for right aligned text
#     - font can be one of the configured fonts above, included per default are:
#       * 'r' for F25 Bank Printer (regular)
#       * 'b' for F25 Bank Printer Bold
#     - size is either 'fill' to automatically calculate a font size to fill the width of the canvas
#       or a font size in pixels
#     - text is your desired line of text (with no line breaks)
#   the shirtfile parser treats lines starting with # as comments and ignores empty lines
#
texts = []
with open(sys.argv[1], "r") as f:
    lines = f.readlines()

    for line in lines:
        # skip comments and empyt lines
        if line.startswith("#") or len(line.strip()) == 0:
            continue

        parts = line.strip().split(" ", 1)
        texts.append(tuple(parts[0].split(":")) + (parts[1],))

# create transparent 5000x5000 image
im = Image.new("RGBA", (5000, 5000), (0, 0, 0, 0))

# quick maths
# calculate appropriate text sizes and bounding box sizes for positioning later
p_texts = []
total_height = 0
for text in texts:
    font_size = 50
    font_path = fonts[text[1]]
    bbox_size = (0, 0)
    font = None

    if text[2] == "fill":
        # dynamic font size calc is hell
        # reload font at increasing size until we fill out the whole canvas width
        while bbox_size[0] < (im.size[0] - 5):
            font = ImageFont.truetype(font_path, font_size)
            bbox = font.getbbox(text[3], anchor=f"{text[0]}b")
            bbox_size = (bbox[2] - bbox[0], bbox[3] - bbox[1])
            font_size += 5
    else:
        # load font for configured size and do bbox calculation
        font_size = int(text[2])
        font = ImageFont.truetype(font_path, font_size)
        bbox = font.getbbox(text[3], anchor=f"{text[0]}b")
        bbox_size = (bbox[2] - bbox[0], bbox[3] - bbox[1])

    print(f"selected font size {font_size}")

    total_height += bbox[1]
    p_texts.append(text + (font, bbox_size))

# account for padding
total_height += (len(texts) - 1) * 20

# draw the text
draw = ImageDraw.Draw(im)
y_offset = 0
for text in p_texts:
    # set x location dependent on alignment
    loc_x = 0
    if text[0] == "m":
        loc_x = (im.size[0]/2)
    elif text[0] == "r":
        loc_x = im.size[0]

    # calculate y location based on total height of all text + current line height to
    # center all text together in the center of the canvas
    loc_y = (im.size[1]/2 + total_height / 2) + text[5][1] + y_offset

    draw.text((loc_x, loc_y), text[3], font=text[4], anchor=f"{text[0]}b")

    # add height of this line to offset
    y_offset += text[5][1] + 20

# crop to content and save
im = im.crop(im.getbbox())
filename = sys.argv[1].removesuffix(".shirt")
im.save(f"{filename}.png", 'PNG')