#!/usr/bin/env python3
""" Script that checks if Pygments styles meet the WCAG color contrast standards """
import sys
import statistics

import pygments.styles
import wcag_contrast_ratio


def hex2rgb(hexstr):
    hexstr = hexstr.lstrip('#')
    r = int(hexstr[:2], 16) / 255
    g = int(hexstr[2:4], 16) / 255
    b = int(hexstr[4:], 16) / 255
    return (r, g, b)


total_wcag_fails = 0
styles = []

for name in pygments.styles.get_all_styles():
    style = pygments.styles.get_style_by_name(name)
    bgcolor = hex2rgb(style.background_color)
    contrasts = [
        (
            wcag_contrast_ratio.rgb(
                bgcolor,
                hex2rgb(style['color'] or '#000000')
                # we default to black because browsers also do
            ),
            ttype,
        )
        for ttype, style in style.list_styles()
    ]
    if len(contrasts) == 0:
        continue

    styles.append(
        (
            statistics.mean([x[0] for x in contrasts]),
            min([x[0] for x in contrasts]),
            name,
        )
    )

    bad_contrasts = [c for c in contrasts if not wcag_contrast_ratio.passes_AA(c[0])]

    print(f'=== {name} ===')
    if len(bad_contrasts) > 0:
        for contrast, ttype in sorted(bad_contrasts):
            print(f'{contrast:.2f} {ttype}')
    else:
        print('meets AA standard')
    print()

    total_wcag_fails += len(bad_contrasts)

if total_wcag_fails:
    print(f'found {total_wcag_fails} contrasts that fail to meet the WCAG AA standard')
    print(
        '''According to WCAG:
     AA contrast is >= 4.5
    AAA contrast is >= 7.0
    '''
    )
    print('=== Styles ranked by contrast ===')
    print(' avg   min  name')
    for contrast, minimum, name in sorted(styles):
        print(f'{contrast:4.1f}  {minimum:4.1f}  {name}')
    sys.exit(1)