"""Compose the boot splash: chroma-keyed mascot plus VT323 "Mat Games" lettering.

The raw mascot comes from an image generator on a flat magenta background (generators
do not emit real alpha). This script keys that background to transparency, removes
magenta spill, then draws the title with the OFL-licensed VT323 font and saves a
transparent PNG ready for application/boot_splash/image.
"""
import argparse
import hashlib
import json
import pathlib
from PIL import Image, ImageDraw, ImageFilter, ImageFont

parser = argparse.ArgumentParser()
parser.add_argument('raw', type=pathlib.Path, help='raw generated image (magenta background)')
parser.add_argument('--title', default='MatGames')
parser.add_argument('--canvas', type=int, default=1024)
parser.add_argument('--title-height', type=int, default=190)
parser.add_argument('--bottom-fade', type=int, default=50,
                    help='soften the generator frame cut at the bottom of the bust')
parser.add_argument('--colors', type=int, default=256,
                    help='palette colors for the shipped PNG; 0 keeps 32-bit RGBA')
parser.add_argument('--generated-from', type=pathlib.Path, default=None,
                    help='pre-edit generation this file was derived from, for provenance')
args = parser.parse_args()
args.raw = args.raw.resolve()
root = pathlib.Path(__file__).resolve().parents[1]
branding = root / 'assets/branding'
branding.mkdir(parents=True, exist_ok=True)
source_tools = root / 'tools/branding'
font_path = source_tools / 'fonts/VT323-Regular.ttf'

# ---------------------------------------------------------------- chroma key
source = Image.open(args.raw).convert('RGB')
corners = [source.getpixel(p) for p in
           [(2, 2), (source.width - 3, 2), (2, source.height - 3), (source.width - 3, source.height - 3)]]
background = tuple(sorted(channel)[1] for channel in zip(*corners))  # median per channel
T0, T1 = 55, 130
alpha = Image.new('L', source.size)
spill = Image.new('L', source.size)
pixels = source.load()
alpha_pixels = alpha.load()
spill_pixels = spill.load()
for y in range(source.height):
    for x in range(source.width):
        r, g, b = pixels[x, y]
        distance = ((r - background[0]) ** 2 + (g - background[1]) ** 2 + (b - background[2]) ** 2) ** 0.5
        alpha_pixels[x, y] = max(0, min(255, round((distance - T0) / (T1 - T0) * 255)))
        # Magenta contamination raises both red and blue above green.
        spill_pixels[x, y] = max(0, min(r, b) - g)
mask = alpha.filter(ImageFilter.MedianFilter(3))
fixed = Image.new('RGB', source.size)
fixed_pixels = fixed.load()
for y in range(source.height):
    for x in range(source.width):
        r, g, b = pixels[x, y]
        amount = spill_pixels[x, y]
        fixed_pixels[x, y] = (max(0, r - amount), g, max(0, b - amount))
mascot = fixed.convert('RGBA')
mascot.putalpha(mask)
mascot = mascot.crop(mascot.getbbox())
if args.bottom_fade > 0:
    fade = min(args.bottom_fade, mascot.height)
    ramp = Image.new('L', (1, fade))
    for y in range(fade):
        ramp.putpixel((0, y), round(255 * (1.0 - y / fade)))
    band = mascot.crop((0, mascot.height - fade, mascot.width, mascot.height))
    band.putalpha(Image.composite(band.getchannel('A'), Image.new('L', band.size, 0), ramp.resize((1, fade)).resize(band.size, Image.NEAREST)))
    mascot.paste(band, (0, mascot.height - fade))

# ---------------------------------------------------------------- composition
canvas_width = args.canvas
title_area = args.title_height
scale = (canvas_width - 2 * 40) / mascot.width
mascot = mascot.resize((round(mascot.width * scale), round(mascot.height * scale)), Image.LANCZOS)
height = mascot.height + title_area
canvas = Image.new('RGBA', (canvas_width, height), (0, 0, 0, 0))
canvas.alpha_composite(mascot, ((canvas_width - mascot.width) // 2, 0))

font_size = int(title_area * 0.95)
font = ImageFont.truetype(str(font_path), font_size)
text = args.title
while font.getbbox(text)[2] - font.getbbox(text)[0] > canvas_width - 60 and font_size > 8:
    font_size -= 2
    font = ImageFont.truetype(str(font_path), font_size)
box = font.getbbox(text)
text_width = box[2] - box[0]
position = ((canvas_width - text_width) // 2 - box[0], mascot.height + (title_area - box[3]) // 2 - box[1])
glow = Image.new('RGBA', canvas.size, (0, 0, 0, 0))
ImageDraw.Draw(glow).text(position, text, font=font, fill=(255, 150, 20, 190))
glow = glow.filter(ImageFilter.GaussianBlur(9))
canvas.alpha_composite(glow)
ImageDraw.Draw(canvas).text(position, text, font=font, fill=(255, 196, 64, 255))

out = branding / 'boot_splash.png'
if args.colors > 0:
    # Flat cartoon art tolerates a palette well; keeps ~95 alpha levels for edges.
    canvas = canvas.quantize(colors=args.colors, method=Image.FASTOCTREE, dither=Image.Dither.NONE)
canvas.save(out, optimize=True)
manifest = json.loads((source_tools / 'manifest.json').read_text()) if (source_tools / 'manifest.json').exists() else {}
manifest.update({
    'boot_splash': {'file': str(out.relative_to(root)), 'size': list(canvas.size), 'mode': canvas.mode,
                    'palette_colors': args.colors,
                    'sha256': hashlib.sha256(out.read_bytes()).hexdigest()},
    'mascot_source': {'file': str(args.raw.relative_to(root)),
                      'sha256': hashlib.sha256(args.raw.read_bytes()).hexdigest()},
    'generator': {
        'tool': 'agy_generate (Antigravity direct API)',
        'model': 'gemini-3.1-flash-image',
        'date': '2026-10-11',
        'prompt': ('single cartoon zombie head-and-bust mascot, unsettling wide grin, thumbs up, '
                   '2D cartoon style with bold outlines, flat magenta chroma-key background, '
                   'no text and no logo; then edited to a bald scalp with a sparse hair fringe '
                   'on the sides only'),
        'terms_note': ('generated from no third-party source material; the provider terms do not claim '
                       'ownership of the output. The generator emits no real alpha channel, so the '
                       'background is keyed out locally by this script.'),
    },
    'chroma_key': {'background_rgb': list(background), 'transparent_below': T0, 'opaque_above': T1},
    'title': {'text': args.title, 'font': 'tools/branding/fonts/VT323-Regular.ttf',
              'license': 'SIL Open Font License 1.1 (tools/branding/fonts/OFL.txt)'},
    'bottom_fade_px': args.bottom_fade,
})
if args.generated_from is not None:
    chain = manifest.get('mascot_derived_from', [])
    manifest['mascot_derived_from'] = chain + [{
        'file': str(args.generated_from.resolve().relative_to(root)),
        'sha256': hashlib.sha256(args.generated_from.read_bytes()).hexdigest(),
        'edit': 'AI edit (agy_edit): keep face, grin, thumbs up, shirt, pose and flat background; '
                'change the hair to a bald scalp with a sparse fringe on the sides only',
    }]
(source_tools / 'manifest.json').write_text(json.dumps(manifest, indent=2) + '\n')
print(out, canvas.size, canvas.mode, 'mascot', mascot.size)