<?php

declare(strict_types=1);

namespace Sarcio\WordPress\Assistant;

use Sarcio\WordPress\StyleRules;

final class StyleRuleAbilities
{
    /** @return array<int,Ability> */
    public static function abilities(): array
    {
        $allowed = static fn (array $args): bool => current_user_can('edit_theme_options');
        $rule = [
            'properties' => [
                'property' => ['enum' => StyleRules::PROPERTIES, 'type' => 'string'],
                'selector' => ['maxLength' => StyleRules::MAX_SELECTOR, 'minLength' => 1, 'type' => 'string'],
                'value' => ['maxLength' => StyleRules::MAX_VALUE, 'minLength' => 1, 'type' => 'string'],
            ],
            'required' => ['selector', 'property', 'value'],
            'type' => 'object',
        ];
        return [
            new Ability(
                'sarcio/style-rules-list',
                __('Look at the style rules', 'sarcio'),
                Ability::READ,
                'The style rules Sarcio keeps for this site: each one a CSS selector, one property and its value, printed on every page after the theme’s styles.',
                ['properties' => [], 'type' => 'object'],
                $allowed,
                static fn (array $args): array => ['rules' => array_values(StyleRules::all(Stage::active() ? Stage::overlay()->option(StyleRules::OPTION, []) : null))],
            ),
            new Ability(
                'sarcio/style-rule-set',
                __('Set a style rule', 'sarcio'),
                Ability::WRITE,
                'Set one property for elements matching a CSS selector (e.g. selector ".site-header .button", property "background-color", value "#1f6f4a"). One property per rule; setting the same selector and property again replaces the value. Values are plain CSS values: no url(), no !important, no semicolons or braces. Prefer the site styles for colours, fonts and spacing that apply site-wide; use a rule for one element the site styles cannot reach.',
                $rule,
                $allowed,
                static fn (array $args): array => self::write(self::withRule(StyleRules::all(), $args), $args),
                null,
                static fn (array $before, array $after): array => self::restore($before),
                false,
                static fn (array $args, Overlay $overlay): array => self::stage(self::withRule(StyleRules::all($overlay->option(StyleRules::OPTION, [])), $args), $overlay, $args),
            ),
            new Ability(
                'sarcio/style-rule-remove',
                __('Remove a style rule', 'sarcio'),
                Ability::WRITE,
                'Remove the style rule for a selector and property, as style-rules-list shows them.',
                [
                    'properties' => [
                        'property' => ['maxLength' => 40, 'minLength' => 1, 'type' => 'string'],
                        'selector' => ['maxLength' => StyleRules::MAX_SELECTOR, 'minLength' => 1, 'type' => 'string'],
                    ],
                    'required' => ['selector', 'property'],
                    'type' => 'object',
                ],
                $allowed,
                static fn (array $args): array => self::write(self::withoutRule(StyleRules::all(), $args), $args),
                null,
                static fn (array $before, array $after): array => self::restore($before),
                false,
                static fn (array $args, Overlay $overlay): array => self::stage(self::withoutRule(StyleRules::all($overlay->option(StyleRules::OPTION, [])), $args), $overlay, $args),
            ),
        ];
    }

    /**
     * @param array<string,array{selector:string,property:string,value:string}> $rules
     * @param array<string,mixed> $args
     * @return array{rules:array<string,array{selector:string,property:string,value:string}>,before:array<string,array{selector:string,property:string,value:string}>}|array{error:string}
     */
    private static function withRule(array $rules, array $args): array
    {
        $checked = StyleRules::check((string) ($args['selector'] ?? ''), (string) ($args['property'] ?? ''), (string) ($args['value'] ?? ''));
        if (is_string($checked)) {
            return ['error' => $checked];
        }
        $before = $rules;
        $id = StyleRules::id($checked['selector'], $checked['property']);
        if (!isset($rules[$id]) && count($rules) >= StyleRules::MAX_RULES) {
            return ['error' => __('The site has as many style rules as it can keep. Remove one first.', 'sarcio')];
        }
        $rules[$id] = $checked;
        return ['before' => $before, 'rules' => $rules];
    }

    /**
     * @param array<string,array{selector:string,property:string,value:string}> $rules
     * @param array<string,mixed> $args
     */
    private static function withoutRule(array $rules, array $args): array
    {
        $selector = trim(preg_replace('~\s+~', ' ', (string) ($args['selector'] ?? '')) ?? '');
        $id = StyleRules::id($selector, strtolower(trim((string) ($args['property'] ?? ''))));
        if (!isset($rules[$id])) {
            return ['error' => __('There is no style rule for that selector and property.', 'sarcio')];
        }
        $before = $rules;
        unset($rules[$id]);
        return ['before' => $before, 'rules' => $rules];
    }

    /** @param array<string,mixed> $change @param array<string,mixed> $args */
    private static function write(array $change, array $args): array
    {
        if (isset($change['error'])) {
            return ['error' => $change['error']];
        }
        if ($change['rules'] === $change['before']) {
            return ['error' => __('Nothing would change.', 'sarcio')];
        }
        update_option(StyleRules::OPTION, array_values($change['rules']), true);
        return [
            'journal' => [
                'after' => ['rules' => array_values($change['rules'])],
                'before' => ['rules' => array_values($change['before'])],
                'summary' => self::summary($change, $args),
                'target' => 'style_rules',
            ],
            'saved' => true,
        ];
    }

    /** @param array<string,mixed> $change @param array<string,mixed> $args */
    private static function stage(array $change, Overlay $overlay, array $args): array
    {
        if (isset($change['error'])) {
            return ['error' => $change['error']];
        }
        if ($change['rules'] === $change['before']) {
            return ['error' => __('Nothing would change.', 'sarcio')];
        }
        $overlay->options[StyleRules::OPTION] = array_values($change['rules']);
        return [
            'after' => StyleRules::css($change['rules']),
            'before' => StyleRules::css($change['before']),
            'summary' => self::summary($change, $args),
        ];
    }

    /** @param array<string,mixed> $before */
    private static function restore(array $before): array
    {
        update_option(StyleRules::OPTION, array_values(StyleRules::all($before['rules'] ?? [])), true);
        return ['restored' => true];
    }

    /** @param array<string,mixed> $change @param array<string,mixed> $args */
    private static function summary(array $change, array $args): string
    {
        $selector = (string) ($args['selector'] ?? '');
        $property = (string) ($args['property'] ?? '');
        return count($change['rules']) < count($change['before'])
            /* translators: 1: a CSS property, 2: a CSS selector. */
            ? sprintf(__('Removed the %1$s style rule for %2$s', 'sarcio'), $property, $selector)
            /* translators: 1: a CSS property, 2: a CSS selector, 3: the value. */
            : sprintf(__('Set %1$s on %2$s to %3$s', 'sarcio'), $property, $selector, (string) ($args['value'] ?? ''));
    }
}