<?php
if ( ! defined( 'ABSPATH' ) ) exit;

class WMW_Search {

    public function init() {
        add_action( 'save_post_wmw_article', array( $this, 'index_article' ), 10, 2 );
        add_action( 'delete_post',           array( $this, 'remove_from_index' ) );
    }

    /**
     * Einen Artikel in den Suchindex schreiben.
     */
    public function index_article( $post_id, $post ) {
        global $wpdb;
        if ( $post->post_status !== 'publish' ) return;

        $wiki_id  = (int) get_post_meta( $post_id, '_wmw_wiki_id', true );
        $keywords = wp_strip_all_tags( $post->post_title . ' ' . $post->post_content . ' ' . $post->post_excerpt );

        $wpdb->replace(
            $wpdb->prefix . 'wmw_search_index',
            array(
                'article_id' => $post_id,
                'wiki_id'    => $wiki_id,
                'keywords'   => $keywords,
            ),
            array( '%d', '%d', '%s' )
        );
    }

    /**
     * Artikel aus dem Index entfernen.
     */
    public function remove_from_index( $post_id ) {
        global $wpdb;
        $wpdb->delete( $wpdb->prefix . 'wmw_search_index', array( 'article_id' => $post_id ), array( '%d' ) );
    }

    /**
     * Alle vorhandenen Artikel in den Index aufnehmen.
     * Wird aufgerufen wenn der Index leer ist (z.B. nach Gitea-Import).
     */
    public static function reindex_all() {
        global $wpdb;

        $articles = get_posts( array(
            'post_type'      => 'wmw_article',
            'post_status'    => 'publish',
            'posts_per_page' => -1,
        ) );

        foreach ( $articles as $post ) {
            $wiki_id  = (int) get_post_meta( $post->ID, '_wmw_wiki_id', true );
            $keywords = wp_strip_all_tags( $post->post_title . ' ' . $post->post_content . ' ' . $post->post_excerpt );

            $wpdb->replace(
                $wpdb->prefix . 'wmw_search_index',
                array(
                    'article_id' => $post->ID,
                    'wiki_id'    => $wiki_id,
                    'keywords'   => $keywords,
                ),
                array( '%d', '%d', '%s' )
            );
        }

        return count( $articles );
    }

    /**
     * Artikel suchen.
     * 1. Versucht den schnellen Custom-Index.
     * 2. Fällt auf WP_Query zurück, wenn der Index leer ist (z.B. nach Gitea-Import).
     * 3. Baut den Index automatisch auf, wenn er leer war.
     */
    public static function search( $query, $wiki_id = 0, $limit = 20 ) {
        global $wpdb;

        $table = $wpdb->prefix . 'wmw_search_index';
        $like  = '%' . $wpdb->esc_like( $query ) . '%';

        // ── Prüfen ob der Index überhaupt Einträge hat ────────────────────
        $index_count = (int) $wpdb->get_var( "SELECT COUNT(*) FROM $table" );

        $ids = array();

        if ( $index_count > 0 ) {
            // ── Custom-Index nutzen ───────────────────────────────────────
            if ( $wiki_id ) {
                $rows = $wpdb->get_results( $wpdb->prepare(
                    "SELECT article_id FROM $table WHERE wiki_id = %d AND keywords LIKE %s LIMIT %d",
                    $wiki_id, $like, $limit
                ) );
            } else {
                $rows = $wpdb->get_results( $wpdb->prepare(
                    "SELECT article_id FROM $table WHERE keywords LIKE %s LIMIT %d",
                    $like, $limit
                ) );
            }
            $ids = wp_list_pluck( $rows, 'article_id' );
        }

        // ── Fallback: WP_Query (wenn Index leer oder keine Treffer) ───────
        if ( empty( $ids ) ) {
            $args = array(
                'post_type'      => 'wmw_article',
                'post_status'    => 'publish',
                'posts_per_page' => $limit,
                's'              => $query,
                'orderby'        => 'relevance',
            );

            if ( $wiki_id ) {
                $args['meta_query'] = array(
                    array(
                        'key'   => '_wmw_wiki_id',
                        'value' => $wiki_id,
                    ),
                );
            }

            $fallback = get_posts( $args );

            // Index war leer → jetzt automatisch aufbauen (im Hintergrund)
            if ( $index_count === 0 ) {
                self::reindex_all();
            }

            foreach ( $fallback as &$post ) {
                $excerpt          = $post->post_excerpt ?: wp_trim_words( $post->post_content, 25 );
                $post->wmw_excerpt = self::highlight( $excerpt, $query );
                $post->wmw_title   = self::highlight( $post->post_title, $query );
            }

            return $fallback;
        }

        // ── Artikel-Objekte aus IDs laden ─────────────────────────────────
        $posts = get_posts( array(
            'post_type'      => 'wmw_article',
            'post_status'    => 'publish',
            'post__in'       => $ids,
            'posts_per_page' => $limit,
            'orderby'        => 'post_title',
            'order'          => 'ASC',
        ) );

        foreach ( $posts as &$post ) {
            $excerpt          = $post->post_excerpt ?: wp_trim_words( $post->post_content, 25 );
            $post->wmw_excerpt = self::highlight( $excerpt, $query );
            $post->wmw_title   = self::highlight( $post->post_title, $query );
        }

        return $posts;
    }

    /**
     * Suchtreffer hervorheben.
     */
    public static function highlight( $text, $query ) {
        $words = explode( ' ', preg_quote( trim( $query ), '/' ) );
        foreach ( $words as $word ) {
            if ( strlen( $word ) < 2 ) continue;
            $text = preg_replace( '/(' . $word . ')/iu', '<mark class="wmw-highlight">$1</mark>', $text );
        }
        return $text;
    }
}