<?php

declare(strict_types=1);

namespace Sarcio\WordPress\Assistant;

/**
 * WordPress's own revisions as a way back: "put the About page back to how
 * it was on Tuesday". A restore is journaled with what the page held just
 * before it, so even the restore can be undone.
 */
final class RevisionAbilities
{
    /** @return array<int,Ability> */
    public static function abilities(): array
    {
        $id = ['minimum' => 1, 'type' => 'integer'];
        return [
            new Ability(
                'sarcio/revisions-list',
                __('Look at a page’s earlier versions', 'sarcio'),
                Ability::READ,
                'The saved revisions of a page, post or product, newest first: id, date, who saved it and the first words. Use a revision id with revision-restore.',
                ['properties' => ['id' => $id, 'limit' => ['maximum' => 50, 'minimum' => 1, 'type' => 'integer']], 'required' => ['id'], 'type' => 'object'],
                static fn (array $args): bool => isset($args['id']) && self::canEdit((int) $args['id']),
                static fn (array $args): array => self::list($args),
            ),
            new Ability(
                'sarcio/styles-revisions-list',
                __('Look at earlier versions of the site styles', 'sarcio'),
                Ability::READ,
                'The saved revisions of the block theme’s site styles (colours, fonts, spacing set in the Site Editor), newest first, with the id to use with revision-restore and the id of the styles themselves.',
                ['properties' => ['limit' => ['maximum' => 50, 'minimum' => 1, 'type' => 'integer']], 'required' => [], 'type' => 'object'],
                static fn (array $args): bool => current_user_can('edit_theme_options'),
                static fn (array $args): array => self::stylesList($args),
            ),
            new Ability(
                'sarcio/revision-restore',
                __('Put a page back to an earlier version', 'sarcio'),
                Ability::WRITE,
                'Restore a page, post or product to one of its saved revisions (title, content and excerpt). Made when the person confirms; undo puts back what the page held just before.',
                ['properties' => ['id' => $id, 'revisionId' => $id], 'required' => ['id', 'revisionId'], 'type' => 'object'],
                static fn (array $args): bool => isset($args['id']) && self::canEdit((int) $args['id']),
                static fn (array $args): array => self::restore($args),
                null,
                static fn (array $before, array $after): array => self::undo($before),
            ),
        ];
    }

    private static function canEdit(int $id): bool
    {
        $post = get_post($id);
        if ($post !== null && (string) $post->post_type === 'wp_global_styles') {
            return current_user_can('edit_theme_options');
        }
        return current_user_can('edit_post', $id);
    }

    public static function globalStylesId(): int
    {
        return class_exists('\WP_Theme_JSON_Resolver') && method_exists('\WP_Theme_JSON_Resolver', 'get_user_global_styles_post_id') ? (int) \WP_Theme_JSON_Resolver::get_user_global_styles_post_id() : 0;
    }

    /** @param array<string,mixed> $args */
    private static function stylesList(array $args): array
    {
        $id = self::globalStylesId();
        if ($id <= 0) {
            return ['error' => __('This theme keeps no site styles to go back to (only a block theme does).', 'sarcio')];
        }
        return self::list(['id' => $id, 'limit' => $args['limit'] ?? 20]) + ['stylesId' => $id];
    }

    /** @param array<string,mixed> $args */
    private static function list(array $args): array
    {
        $post = get_post((int) $args['id']);
        if ($post === null) {
            return ['error' => __('There is no page or post with that id.', 'sarcio')];
        }
        $revisions = wp_get_post_revisions((int) $args['id'], ['posts_per_page' => (int) ($args['limit'] ?? 20)]);
        $out = [];
        foreach (is_array($revisions) ? $revisions : [] as $revision) {
            $author = function_exists('get_userdata') ? get_userdata((int) $revision->post_author) : null;
            $out[] = [
                'author' => is_object($author) && isset($author->display_name) ? (string) $author->display_name : '',
                'date' => (string) $revision->post_date,
                'excerpt' => mb_substr(ContentAbilities::readable((string) $revision->post_content), 0, 200),
                'id' => (int) $revision->ID,
                'title' => (string) $revision->post_title,
            ];
        }
        return ['current' => ['date' => (string) $post->post_modified, 'title' => (string) $post->post_title], 'revisions' => $out];
    }

    /** @param array<string,mixed> $args */
    private static function restore(array $args): array
    {
        $post = get_post((int) $args['id']);
        $revision = get_post((int) $args['revisionId']);
        if ($post === null || $revision === null || (string) $revision->post_type !== 'revision' || (int) $revision->post_parent !== (int) $post->ID) {
            return ['error' => __('That revision does not belong to that page.', 'sarcio')];
        }
        $before = ['content' => (string) $post->post_content, 'excerpt' => (string) $post->post_excerpt, 'id' => (int) $post->ID, 'title' => (string) $post->post_title];
        $result = wp_restore_post_revision((int) $revision->ID);
        if (!$result) {
            return ['error' => __('WordPress could not restore that revision.', 'sarcio')];
        }
        return [
            'journal' => [
                'after' => ['id' => (int) $post->ID, 'revisionId' => (int) $revision->ID, 'title' => (string) $revision->post_title],
                'before' => $before,
                'summary' => sprintf(
                    /* translators: 1: the page title, 2: the revision date. */
                    __('Put “%1$s” back to its version of %2$s', 'sarcio'),
                    (string) $post->post_title,
                    (string) $revision->post_date,
                ),
                'target' => 'post:' . $post->ID,
            ],
            'restored' => (int) $revision->ID,
        ];
    }

    /** @param array<string,mixed> $before */
    private static function undo(array $before): array
    {
        $id = (int) ($before['id'] ?? 0);
        if ($id <= 0 || get_post($id) === null) {
            return ['error' => __('That page no longer exists.', 'sarcio')];
        }
        $result = wp_update_post(['ID' => $id, 'post_content' => (string) ($before['content'] ?? ''), 'post_excerpt' => (string) ($before['excerpt'] ?? ''), 'post_title' => (string) ($before['title'] ?? '')], true);
        return is_wp_error($result) ? ['error' => sanitize_text_field($result->get_error_message())] : ['id' => $id, 'restored' => true];
    }
}