<?php
namespace DayTidy\DisplayViews;

use DayTidy\Config as DayTidyConfig;
use DayTidy\Db;
use DayTidy\Forms\CustomFields;
use DayTidy\Forms\Fields\Agreement;
use DayTidy\Forms\Fields\Checkboxes;
use DayTidy\Forms\Fields\Number;
use DayTidy\Posts\Offering;
use Webilia\WP\Interfaces\Entity\Post;

class OfferingDataIndexer
{
    const KEY_PREFIX = 'daytidy_offering_field_';
    const VERSION_OPTION = 'daytidy_offering_field_index_version';
    const OFFSET_OPTION = 'daytidy_offering_field_index_offset';
    const CRON_HOOK = 'daytidy_views_reindex_offering_data';
    const BATCH_SIZE = 25;

    public function init(): void
    {
        add_action('DayTidy/A__DayTidy/Posts/Offering__store/data', [$this, 'indexStoredOffering'], 30, 1);
        add_action('DayTidy/A__DayTidy/Modules/Features/Dashboard/Handlers/AjaxHandlerOfferingSave__perform/data', [$this, 'indexOffering'], 30, 1);
        add_action('admin_init', [$this, 'maybeScheduleBackfill']);
        add_action(self::CRON_HOOK, [$this, 'backfillBatch']);
    }

    public static function key(string $field_id, bool $numeric = false): string
    {
        return self::KEY_PREFIX . sanitize_key($field_id) . ($numeric ? '_num' : '');
    }

    public function indexStoredOffering(Post $entity): void
    {
        $this->indexOffering($entity->id());
    }

    public function indexOffering(int $offering_id): void
    {
        if ($offering_id <= 0 || get_post_type($offering_id) !== Offering::PT) return;

        $fields = $this->fields();
        $values = get_post_meta($offering_id, \DayTidy\Modules\Offering\Core\Module::OFFERING_FIELDS_META, true);
        if (!is_array($values)) $values = [];

        $this->deleteIndex($offering_id);

        foreach ($fields as $field_id => $field)
        {
            if (!array_key_exists($field_id, $values)) continue;

            $type = (string) ($field['type'] ?? '');
            $value = $values[$field_id];

            if ($type === Number::TYPE)
            {
                if (is_numeric($value)) add_post_meta($offering_id, self::key((string) $field_id, true), (string) $value, false);
                continue;
            }

            if ($type === Agreement::TYPE)
            {
                add_post_meta($offering_id, self::key((string) $field_id), $value ? '1' : '0', false);
                continue;
            }

            if ($type === Checkboxes::TYPE && is_array($value))
            {
                foreach ($value as $item)
                {
                    $item = sanitize_text_field((string) $item);
                    if ($item !== '') add_post_meta($offering_id, self::key((string) $field_id), $item, false);
                }

                continue;
            }

            if (is_array($value)) $value = implode(' ', array_map('sanitize_text_field', $value));
            $value = sanitize_text_field((string) $value);
            if ($value !== '') add_post_meta($offering_id, self::key((string) $field_id), $value, false);
        }
    }

    public function maybeScheduleBackfill(): void
    {
        $version = $this->fieldsVersion();
        if (get_option(self::VERSION_OPTION, '') === $version) return;
        if (wp_next_scheduled(self::CRON_HOOK)) return;

        update_option(self::OFFSET_OPTION, 0, false);
        wp_schedule_single_event(time() + 5, self::CRON_HOOK);
    }

    public function backfillBatch(): void
    {
        $offset = absint(get_option(self::OFFSET_OPTION, 0));
        $ids = get_posts([
            'post_type' => Offering::PT,
            'post_status' => 'any',
            'fields' => 'ids',
            'posts_per_page' => self::BATCH_SIZE,
            'offset' => $offset,
            'orderby' => 'ID',
            'order' => 'ASC',
        ]);

        foreach ($ids as $id)
        {
            $this->indexOffering((int) $id);
        }

        if (count($ids) === self::BATCH_SIZE)
        {
            update_option(self::OFFSET_OPTION, $offset + self::BATCH_SIZE, false);
            wp_schedule_single_event(time() + 5, self::CRON_HOOK);
            return;
        }

        update_option(self::VERSION_OPTION, $this->fieldsVersion(), false);
        delete_option(self::OFFSET_OPTION);
    }

    private function deleteIndex(int $offering_id): void
    {
        $db = new Db();

        $db->query($db->prepare(
            "DELETE FROM {$db->table('postmeta')} WHERE post_id = %d AND meta_key LIKE %s",
            $offering_id,
            $db->escLike(self::KEY_PREFIX) . '%'
        ));
    }

    /**
     * @return mixed[]
     */
    private function fields(): array
    {
        $config = DayTidyConfig::module('offering/core');
        $fields = isset($config['fields']) && is_array($config['fields']) ? $config['fields'] : [];

        return CustomFields::normalize($fields);
    }

    private function fieldsVersion(): string
    {
        return md5((string) wp_json_encode($this->fields()));
    }
}