<?php
namespace MazlanHalim\IntelliLanz\Graph;

use MazlanHalim\IntelliLanz\Detection\DetectorRegistry;

final class GraphBuilder {
    private DetectorRegistry $registry;
    private ?RelationshipResolver $resolver;
    private ?\MazlanHalim\IntelliLanz\Health\HealthEvaluator $health;
    private ?SnapshotCache $cache;
    private array $lastBuildInfo = array( 'cache_enabled' => false, 'cache_hit' => false, 'generated_at' => null );

    public function __construct( DetectorRegistry $registry, ?RelationshipResolver $resolver = null, ?\MazlanHalim\IntelliLanz\Health\HealthEvaluator $health = null, ?SnapshotCache $cache = null ) {
        $this->registry = $registry;
        $this->resolver = $resolver;
        $this->health = $health;
        $this->cache = $cache;
        $this->lastBuildInfo['cache_enabled'] = $cache !== null;
    }

    public function build( bool $refresh = false ): Graph {
        if ( $this->cache !== null ) {
            if ( $refresh ) { $this->cache->invalidate(); }
            $cached = $this->cache->get();
            if ( $cached !== null ) {
                $this->lastBuildInfo = array( 'cache_enabled' => true, 'cache_hit' => true, 'generated_at' => $cached['generated_at'] );
                return $cached['graph'];
            }
        }
        $graph = new Graph();
        $edges = array();
        foreach ( $this->registry->all() as $detector ) {
            $result = $detector->detect();
            if ( ! isset( $result['nodes'], $result['edges'] ) || ! is_array( $result['nodes'] ) || ! is_array( $result['edges'] ) ) {
                throw new \UnexpectedValueException( 'Detectors must return nodes and edges arrays.' );
            }
            foreach ( $result['nodes'] as $node ) {
                if ( ! $node instanceof Node ) {
                    throw new \UnexpectedValueException( 'Detector nodes must be Node objects.' );
                }
                $graph->addNode( $node );
            }
            foreach ( $result['edges'] as $edge ) {
                if ( ! $edge instanceof Edge ) {
                    throw new \UnexpectedValueException( 'Detector edges must be Edge objects.' );
                }
                $edges[] = $edge;
            }
        }
        foreach ( $edges as $edge ) {
            $graph->addEdge( $edge );
        }
        if ( $this->resolver !== null ) {
            foreach ( $this->resolver->resolve( $graph ) as $edge ) {
                $graph->addEdge( $edge );
            }
        }
        $graph = $this->health !== null ? $this->health->evaluate( $graph ) : $graph;
        $generated_at = $this->cache !== null ? $this->cache->set( $graph ) : time();
        $this->lastBuildInfo = array( 'cache_enabled' => $this->cache !== null, 'cache_hit' => false, 'generated_at' => $generated_at );
        return $graph;
    }

    public function getLastBuildInfo(): array {
        return $this->lastBuildInfo;
    }
}