<?php

namespace NoNameWeb\LivewireMaterial\Support;

/**
 * The colour scheme as data, for the places CSS custom properties cannot reach: a mail client
 * resolves none, and an error page whose build is missing has no stylesheet to declare them.
 *
 * The data is the JSON `php artisan material:scheme` writes beside the stylesheet
 * (`livewire-material.scheme`, resources/css/material-scheme.json by default). Without that
 * file — or with one that is not a scheme — the package's own default applies, the same one
 * tokens/scheme.css carries. A role the application's file lacks (a scheme generated before
 * the role existed) is taken from the default, and a value that is not a #rrggbb hex is
 * refused, so nothing but a colour ever reaches a stylesheet.
 *
 * Read on every call and never kept: a regenerated scheme applies at once, and a long-running
 * worker holds nothing.
 */
class Scheme
{
    /**
     * @return array{light: array<string, string>, dark: array<string, string>}
     */
    public static function load(?string $path = null): array
    {
        $default = static::read(dirname(__DIR__, 2).'/resources/css/tokens/scheme.json');
        $scheme = static::read($path ?? (string) config('livewire-material.scheme'));

        return [
            'light' => [...$default['light'], ...$scheme['light']],
            'dark' => [...$default['dark'], ...$scheme['dark']],
        ];
    }

    /**
     * The light roles: what a mail wears.
     *
     * @return array<string, string>
     */
    public static function light(?string $path = null): array
    {
        return static::load($path)['light'];
    }

    /**
     * @return array{light: array<string, string>, dark: array<string, string>}
     */
    protected static function read(string $path): array
    {
        $data = is_file($path) ? json_decode((string) file_get_contents($path), true) : null;

        return [
            'light' => static::roles($data['light'] ?? null),
            'dark' => static::roles($data['dark'] ?? null),
        ];
    }

    /**
     * @return array<string, string>
     */
    protected static function roles(mixed $roles): array
    {
        if (! is_array($roles)) {
            return [];
        }

        return array_filter(
            $roles,
            fn (mixed $hex, mixed $role): bool => is_string($role)
                && preg_match('/^[a-z-]+$/', $role) === 1
                && is_string($hex)
                && preg_match('/^#[0-9a-fA-F]{6}$/', $hex) === 1,
            ARRAY_FILTER_USE_BOTH,
        );
    }
}