<?php
namespace MazlanHalim\IntelliLanz\Graph;

final class Graph implements \JsonSerializable {
    private array $nodes = array();
    private array $edges = array();

    public function addNode( Node $node ): void {
        if ( isset( $this->nodes[ $node->getId() ] ) ) {
            throw new \InvalidArgumentException( 'Duplicate node ID.' );
        }
        $this->nodes[ $node->getId() ] = $node;
    }

    public function addEdge( Edge $edge ): void {
        if ( isset( $this->edges[ $edge->getId() ] ) ) {
            throw new \InvalidArgumentException( 'Duplicate edge ID.' );
        }
        if ( ! isset( $this->nodes[ $edge->getSource() ], $this->nodes[ $edge->getTarget() ] ) ) {
            throw new \InvalidArgumentException( 'Edge endpoints must exist.' );
        }
        $this->edges[ $edge->getId() ] = $edge;
    }

    public function jsonSerialize(): array {
        return array(
            'nodes' => array_map( static function ( Node $node ) { return $node->jsonSerialize(); }, array_values( $this->nodes ) ),
            'edges' => array_map( static function ( Edge $edge ) { return $edge->jsonSerialize(); }, array_values( $this->edges ) ),
        );
    }
}