<?php

declare(strict_types=1);

namespace OpenTelemetry\SDK\Trace;

use OpenTelemetry\API\Trace as API; /** @phan-suppress-current-line PhanUnreferencedUseNormal */
use OpenTelemetry\SDK\Common\Future\CancellationInterface;
use OpenTelemetry\SDK\Resource\ResourceInfo;
use OpenTelemetry\SDK\Trace\SpanProcessor\MultiSpanProcessor;
use OpenTelemetry\SDK\Trace\SpanProcessor\NoopSpanProcessor;

/**
 * Stores shared state/config between all {@see API\TracerInterface} created via the same {@see API\TracerProviderInterface}.
 */
final class TracerSharedState
{
    /** @readonly */
    private IdGeneratorInterface $idGenerator;

    /** @readonly */
    private ResourceInfo $resource;

    /** @readonly */
    private SpanLimits $spanLimits;

    /** @readonly */
    private SamplerInterface $sampler;

    /** @readonly */
    private SpanProcessorInterface $spanProcessor;

    private ?bool $shutdownResult = null;

    public function __construct(
        IdGeneratorInterface $idGenerator,
        ResourceInfo $resource,
        SpanLimits $spanLimits,
        SamplerInterface $sampler,
        array $spanProcessors
    ) {
        $this->idGenerator = $idGenerator;
        $this->resource = $resource;
        $this->spanLimits = $spanLimits;
        $this->sampler = $sampler;

        switch (count($spanProcessors)) {
            case 0:
                $this->spanProcessor = NoopSpanProcessor::getInstance();

                break;
            case 1:
                $this->spanProcessor = $spanProcessors[0];

                break;
            default:
                $this->spanProcessor = new MultiSpanProcessor(...$spanProcessors);

                break;
        }
    }

    public function hasShutdown(): bool
    {
        return null !== $this->shutdownResult;
    }

    public function getIdGenerator(): IdGeneratorInterface
    {
        return $this->idGenerator;
    }

    public function getResource(): ResourceInfo
    {
        return $this->resource;
    }

    public function getSpanLimits(): SpanLimits
    {
        return $this->spanLimits;
    }

    public function getSampler(): SamplerInterface
    {
        return $this->sampler;
    }

    public function getSpanProcessor(): SpanProcessorInterface
    {
        return $this->spanProcessor;
    }

    /**
     * Returns `false` is the provider is already shutdown, otherwise `true`.
     */
    public function shutdown(?CancellationInterface $cancellation = null): bool
    {
        return $this->shutdownResult ?? ($this->shutdownResult = $this->spanProcessor->shutdown($cancellation));
    }
}