<?php

namespace Tests\Feature;

use Tests\TestCase;

/**
 * Light secondary buttons get their own theme colours: 'secondary' is a dark colour in some
 * themes (vegetable, yellow), which made x-jetstream.secondary-button unreadable there.
 */
class ThemeButtonColorsTest extends TestCase
{
    private function vars(string $theme): array
    {
        config(['themes.active' => $theme]);
        preg_match_all('/(--[\w-]+): ([^;]+);/', theme_css_vars(), $matches);

        return array_combine($matches[1], $matches[2]);
    }

    /** Relative luminance (WCAG) of an "r g b" CSS variable value. */
    private function luminance(string $rgb): float
    {
        $channels = array_map(function ($value) {
            $c = ((int) $value) / 255;
            return $c <= 0.03928 ? $c / 12.92 : (($c + 0.055) / 1.055) ** 2.4;
        }, explode(' ', trim($rgb)));

        return 0.2126 * $channels[0] + 0.7152 * $channels[1] + 0.0722 * $channels[2];
    }

    public function test_every_theme_has_readable_secondary_buttons(): void
    {
        foreach (array_keys(config('themes.themes')) as $theme) {
            $vars = $this->vars($theme);
            $this->assertArrayHasKey('--color-button-secondary', $vars, $theme);
            $this->assertArrayHasKey('--color-button-secondary-text', $vars, $theme);

            $light = $this->luminance($vars['--color-button-secondary']);
            $dark = $this->luminance($vars['--color-button-secondary-text']);
            $contrast = (max($light, $dark) + 0.05) / (min($light, $dark) + 0.05);
            $this->assertGreaterThanOrEqual(4.5, $contrast, "$theme: secondary button text contrast is $contrast");
        }
    }

    public function test_default_theme_keeps_its_look(): void
    {
        $vars = $this->vars('timebank_cc');

        $this->assertSame($vars['--color-secondary'], $vars['--color-button-secondary']);
        $this->assertSame($vars['--color-text-primary'], $vars['--color-button-secondary-text']);
    }

    public function test_theme_without_button_colours_falls_back_to_secondary(): void
    {
        $custom = config('themes.themes.timebank_cc');
        unset($custom['colors']['button-secondary'], $custom['colors']['button-secondary-text']);
        $custom['colors']['secondary'] = '#123456';
        config(['themes.themes.custom' => $custom]);

        $vars = $this->vars('custom');

        $this->assertSame('18 52 86', $vars['--color-button-secondary']);
        $this->assertSame($vars['--color-text-primary'], $vars['--color-button-secondary-text']);
    }
}