"""Render a weight sweep and compare variable endpoints against static references."""

import hashlib
import json
from pathlib import Path

from fontTools.ttLib import TTFont
from fontTools.varLib.instancer import instantiateVariableFont
from PIL import Image, ImageChops, ImageDraw, ImageFont, ImageStat

from render import ROOT, code_mask


def main():
    output = ROOT / 'build/variable'
    path = ROOT / 'build/TTF/iocgnMono-Variable.ttf'
    sweep = Image.new('RGB', (2200, 3640), '#fafafa')
    rows = [('Hno mWw r g 0O1Il| \'"`', 110, 165),
            ('comment format com rma minimum WWWW wwww mmmm', 48, 255),
            ('const row = `${name}: ${count}`; // + - = * < > ()[]{}', 42, 325),
            ('if (value != null && count >= 0) { return "airport"; }', 42, 385),
            ('aopqnr mWw 6G9g 8B @#%& \'quoted\' "double" `grave`', 24, 455)]
    report = {'font': {'path': str(path.relative_to(ROOT)), 'sha256': hashlib.sha256(path.read_bytes()).hexdigest()},
              'weights': [200, 300, 400, 550, 700, 750, 800], 'em_pixels': [110, 48, 42, 24], 'endpoints': {}}
    with TTFont(path) as variable:
        for i, weight in enumerate(report['weights']):
            font = instantiateVariableFont(variable, {'wght': weight, 'ital': 0}, inplace=False)
            panel = Image.new('RGB', (2200, 520), '#fafafa')
            panel.paste('#171c22', (0, 0), code_mask(font, rows, panel.size))
            ImageDraw.Draw(panel).text((38, 20), f'iocgn Mono / wght {weight}', fill='#58616d', font=ImageFont.load_default(size=28))
            sweep.paste(panel, (0, i * 520))
            font.close()
        for style, weight in [('ExtraLight', 200), ('Regular', 400), ('Bold', 700), ('ExtraBold', 800)]:
            font = instantiateVariableFont(variable, {'wght': weight, 'ital': 0}, inplace=False)
            directory = ROOT / 'build/native'
            with TTFont(directory / f'iocgnMono-{style}.ttf') as static:
                grid = [(''.join(chr(cp) for cp in range(start, min(start + 13, 127))), 256, 240 + i * 300)
                        for i, start in enumerate(range(33, 127, 13))]
                masks = [code_mask(f, grid, (1800, 2450)) for f in (static, font)]
                difference = ImageChops.difference(*masks)
                pixel_error = sum(ImageStat.Stat(difference).sum)
                ink = sum(ImageStat.Stat(masks[0]).sum)
                report['endpoints'][style] = {'absolute_raster_difference_over_ink': pixel_error / ink,
                                              'em_pixels': 256}
                assert pixel_error / ink < .025, (style, pixel_error / ink)
                overlay = Image.merge('RGB', (masks[1], masks[0], ImageChops.lighter(*masks)))
                overlay.save(output / f'endpoint-{style.lower()}.png')
            font.close()
        charset = Image.new('RGB', (6000, 1650), '#fafafa')
        grid = [(''.join(chr(cp) for cp in range(start, min(start + 13, 127))), 160, 210 + i * 180)
                for i, start in enumerate(range(33, 127, 13))]
        for column, weight in enumerate((200, 400, 550, 700, 800)):
            font = instantiateVariableFont(variable, {'wght': weight, 'ital': 0}, inplace=False)
            panel = Image.new('RGB', (1200, 1650), '#fafafa')
            panel.paste('#171c22', (0, 0), code_mask(font, grid, panel.size))
            ImageDraw.Draw(panel).text((38, 20), f'wght {weight}', fill='#58616d', font=ImageFont.load_default(size=28))
            charset.paste(panel, (column * 1200, 0))
            panel.save(output / f'charset-{weight}.png')
            font.close()
        charset.save(output / 'charset.png')
    sweep.save(output / 'weight-sweep.png')
    template = ROOT / 'tools/variable-demo.html'
    (output / 'index.html').write_bytes(template.read_bytes())
    report['demo_sha256'] = hashlib.sha256(template.read_bytes()).hexdigest()
    report['renderer_sha256'] = hashlib.sha256(Path(__file__).read_bytes()).hexdigest()
    (output / 'render-manifest.json').write_text(json.dumps(report, indent=2) + '\n')
    print(output / 'weight-sweep.png')
    print('Endpoint raster differences:', report['endpoints'])


if __name__ == '__main__':
    main()