<?php

namespace AOP\App;

use AOP\App\Database\PageRepository;
use AOP\App\Frontend\PublicFields;

/**
 * The options of the fields of all pages. `aop_option_names` is a cache of what the stored pages say, rebuilt
 * after every write, so it can not drift away from the pages (uninstall and the import preview read it).
 */
final class OptionNames
{
    /**
     * The option names of all fields of all stored pages, without duplicates and without layout fields.
     *
     * @return array<int, string>
     */
    public static function fromPages(): array
    {
        $names = [];

        foreach (PageRepository::pageValueRows() as $row) {
            foreach (PageRepository::decode($row->page_value)['pages'] ?? [] as $page) {
                foreach ($page['fields'] ?? [] as $field) {
                    if (!empty($field['field_name'])) {
                        $names[] = $field['field_name'];
                    }
                }
            }
        }

        return array_values(array_unique($names));
    }

    /**
     * Rebuild `aop_option_names`, and the list of fields for the shortcode and the blocks, from the stored pages.
     */
    public static function sync(): void
    {
        update_option(Plugin::PREFIX_ . 'option_names', self::fromPages());
        PublicFields::rebuild();
    }

    /**
     * A page was created: give every option of its fields its default value, with the autoload of the field.
     * Options that already exist keep their value.
     *
     * @param array $pageValue The stored page value.
     */
    public static function createFor(array $pageValue): void
    {
        foreach (self::fieldsWithDefaults($pageValue) as $field) {
            $autoload = ($field['toggle_autoload'] ?? 'yes') === 'no' ? 'no' : 'yes';

            add_option($field['field_name'], $field['default_value'], '', $autoload);
        }
    }

    /**
     * A page was saved again: make sure every option exists (a new field) and follows the autoload setting of its
     * field. The value of an existing option is kept, also when it is empty or 0.
     *
     * @param array $pageValue The stored page value.
     */
    public static function updateFor(array $pageValue): void
    {
        $missing = '__aop_missing__';

        foreach (self::fieldsWithDefaults($pageValue) as $field) {
            $autoload = isset($field['toggle_autoload']) ? $field['toggle_autoload'] : 'yes';
            $current = get_option($field['field_name'], $missing);

            Plugin::updateOption($field['field_name'], $current === $missing ? $field['default_value'] : $current, $autoload);
        }
    }

    /**
     * @return array<int, array> The stored fields that have an option and a default value.
     */
    private static function fieldsWithDefaults(array $pageValue): array
    {
        $fields = [];

        foreach ($pageValue['pages'] ?? [] as $page) {
            foreach ($page['fields'] ?? [] as $field) {
                if (isset($field['default_value']) && isset($field['field_name'])) {
                    $fields[] = $field;
                }
            }
        }

        return $fields;
    }
}