<?php
namespace MazlanHalim\IntelliLanz\Graph;

final class Edge implements \JsonSerializable {
    private array $data;

    public function __construct( string $id, string $source, string $target, string $relationship, string $confidence = 'high', array $metadata = array() ) {
        foreach ( array( $id, $source, $target ) as $value ) {
            if ( trim( $value ) === '' ) {
                throw new \InvalidArgumentException( 'Edge identity fields must not be empty.' );
            }
        }
        if ( ! in_array( $relationship, array( 'contains', 'depends_on', 'extends', 'connects_to', 'uses', 'provides', 'child_of', 'integrates_with' ), true ) ) {
            throw new \InvalidArgumentException( 'Invalid relationship.' );
        }
        if ( ! in_array( $confidence, array( 'high', 'medium', 'low' ), true ) ) {
            throw new \InvalidArgumentException( 'Invalid confidence.' );
        }
        $this->data = compact( 'id', 'source', 'target', 'relationship', 'confidence' );
        if ( $metadata !== array() ) { $this->data['metadata'] = $metadata; }
    }

    public function getId(): string { return $this->data['id']; }
    public function getSource(): string { return $this->data['source']; }
    public function getTarget(): string { return $this->data['target']; }
    public function jsonSerialize(): array { return $this->data; }
}