Envelope

Message.php

<?php

/**
 * @psalm-immutable
 * @template TResult
 */
interface Message
{
}

/**
 * @psalm-immutable
 */
interface Stamp
{
}

/**
 * @psalm-immutable
 * @template TResult
 * @template TMessage of Message<TResult>
 */
final class Envelope
{
    /**
     * @param TMessage $message
     * @param array<class-string<Stamp>, Stamp> $stamps
     */
    private function __construct(
        public readonly Message $message,
        public readonly array $stamps,
    ) {
    }

    /**
     * @psalm-pure
     * @template TTResult
     * @template TTMessage of Message<TTResult>
     * @param TTMessage $message
     * @return self<TTResult, TTMessage>
     */
    public static function wrap(Message $message, Stamp ...$stamps): self
    {
        $stampsByClass = [];

        foreach ($stamps as $stamp) {
            $stampsByClass[$stamp::class] = $stamp;
        }

        return new self($message, $stampsByClass);
    }

    /**
     * @template TTMessage of Message
     * @param TTMessage $message
     * @return self<TResult, TTMessage>
     */
    public function withMessage(Message $message): self
    {
        return new self($message, $this->stamps);
    }

    /**
     * @template TStamp of Stamp
     * @param class-string<TStamp> $class
     */
    public function hasStamp(string $class): bool
    {
        return isset($this->stamps[$class]);
    }

    /**
     * @template TStamp of Stamp
     * @param class-string<TStamp> $class
     * @return TStamp
     */
    public function stamp(string $class): Stamp
    {
        return $this->stampOrNull($class) ?? throw new \RuntimeException(sprintf(
            'Stamp "%s" is not set on the envelope with message "%s".',
            $class,
            $this->message::class,
        ));
    }

    /**
     * @template TStamp of Stamp
     * @param class-string<TStamp> $class
     * @return ?TStamp
     */
    public function stampOrNull(string $class): ?Stamp
    {
        /** @var ?TStamp */
        return $this->stamps[$class] ?? null;
    }

    /**
     * @return self<TResult, TMessage>
     */
    public function withStamps(Stamp ...$stamps): self
    {
        $mergedStamps = $this->stamps;

        foreach ($stamps as $stamp) {
            $mergedStamps[$stamp::class] = $stamp;
        }

        return new self($this->message, $mergedStamps);
    }

    /**
     * @param class-string<Stamp> ...$classes
     * @return self<TResult, TMessage>
     */
    public function withoutStamps(string ...$classes): self
    {
        $stamps = $this->stamps;

        foreach ($classes as $class) {
            unset($stamps[$class]);
        }

        return new self($this->message, $stamps);
    }
}