<?php
namespace Clusterlane\Core;

if ( ! defined( 'ABSPATH' ) ) exit;

/**
 * Thumbs — small featured-image URLs for article lists (search, Articles to
 * review, cluster members, Text Match / link rows, graph tooltips).
 *
 * One batch per list: post meta and the attachment posts are primed first,
 * so a list of 50 articles costs a couple of queries, not 100.
 * Setting show_thumbnails (Settings → General) turns them off everywhere:
 * urls() then returns '' for every ID and the lists show no image at all.
 */
final class Thumbs {

    public static function enabled(): bool {
        $s = Settings::get_instance();
        return $s ? (bool) $s->get( 'show_thumbnails', true ) : true;
    }

    /**
     * @param  int[] $post_ids
     * @return array<int,string> post ID → thumbnail URL ('' when none / disabled)
     */
    public static function urls( array $post_ids ): array {
        $ids = array_values( array_unique( array_filter( array_map( 'intval', $post_ids ) ) ) );
        $out = array_fill_keys( $ids, '' );
        if ( ! $ids || ! self::enabled() ) return $out;

        update_meta_cache( 'post', $ids );
        $att = [];
        foreach ( $ids as $id ) {
            $a = (int) get_post_meta( $id, '_thumbnail_id', true );
            if ( $a ) $att[ $id ] = $a;
        }
        if ( ! $att ) return $out;
        if ( function_exists( '_prime_post_caches' ) ) _prime_post_caches( array_values( $att ), false, true );
        foreach ( $att as $id => $a ) {
            $url = wp_get_attachment_image_url( $a, 'thumbnail' );
            $out[ $id ] = $url ? (string) $url : '';
        }
        return $out;
    }

    /** One URL (for single-post responses). */
    public static function url( int $post_id ): string {
        return self::urls( [ $post_id ] )[ $post_id ] ?? '';
    }

    /**
     * Add a thumbnail field to each row of a list, reading the post ID from $id_key.
     * Works for arrays of arrays and arrays of objects.
     */
    public static function add( array $rows, string $id_key = 'id', string $field = 'thumb' ): array {
        $ids = [];
        foreach ( $rows as $r ) $ids[] = (int) ( is_array( $r ) ? ( $r[ $id_key ] ?? 0 ) : ( $r->$id_key ?? 0 ) );
        $urls = self::urls( $ids );
        foreach ( $rows as $k => $r ) {
            $id = (int) ( is_array( $r ) ? ( $r[ $id_key ] ?? 0 ) : ( $r->$id_key ?? 0 ) );
            if ( is_array( $r ) ) $rows[ $k ][ $field ] = $urls[ $id ] ?? '';
            else $rows[ $k ]->$field = $urls[ $id ] ?? '';
        }
        return $rows;
    }
}