<?php
namespace MazlanHalim\IntelliLanz\Graph;

final class ConnectionsResolver {
    private const LIMIT = 20;

    public function resolve( Graph $graph, string $node_id ): ?array {
        $data = $graph->jsonSerialize();
        $nodes = array();
        foreach ( $data['nodes'] as $node ) { $nodes[ $node['id'] ] = $node; }
        if ( ! isset( $nodes[ $node_id ] ) ) { return null; }
        $out = array( 'node' => $nodes[ $node_id ], 'depends_on' => array(), 'depended_on_by' => array(), 'truncated' => false );
        foreach ( $data['edges'] as $edge ) {
            $key = $edge['source'] === $node_id ? 'depends_on' : ( $edge['target'] === $node_id ? 'depended_on_by' : null );
            if ( $key === null ) { continue; }
            $other = $key === 'depends_on' ? $edge['target'] : $edge['source'];
            if ( ! isset( $nodes[ $other ] ) ) { continue; }
            if ( count( $out[ $key ] ) >= self::LIMIT ) { $out['truncated'] = true; continue; }
            $out[ $key ][] = array( 'node' => $nodes[ $other ], 'relationship' => $edge['relationship'], 'confidence' => $edge['confidence'] );
        }
        return $out;
    }
}