Automattic/php-push

<?php
declare( strict_types = 1 );

// Keys defined at https://developer.apple.com/documentation/usernotifications/setting_up_a_remote_notification_server/generating_a_remote_notification#2990112
class APNSSound implements JsonSerializable {

    /** @var bool */
    private $is_critical = false;

    /** @var string */
    private $name;

    /** @var float */
    private $volume;

    public function __construct( string $name, float $volume = 1.0, bool $is_critical = false ) {
        $this->name   = $name;
        $this->volume = $volume;
        $this->set_is_critical( $is_critical );
    }

    public static function from_string( string $name ): APNSSound {
        return new APNSSound( $name );
    }

    public function get_is_critical(): bool {
        return $this->is_critical;
    }

    public function set_is_critical( bool $is_critical ): self {
        $this->is_critical = $is_critical;
        return $this;
    }

    public function get_name(): string {
        return $this->name;
    }

    public function set_name( string $name ): self {
        $this->name = $name;
        return $this;
    }

    public function get_volume(): float {
        return $this->volume;
    }

    public function set_volume( float $volume ): self {
        if ( $volume < 0 || $volume > 1.0 ) {
            throw new InvalidArgumentException( 'Invalid sound volume: ' . $volume . '. Valid volume levels are between 0.0 and 1.0' );
        }

        $this->volume = $volume;
        return $this;
    }

    /** @psalm-suppress InvalidReturnType */
    public function jsonSerialize() {

        // If the volume and `critical` flags haven't been modified, we can just send the filename to save space
        if ( 1.0 === $this->volume && false === $this->is_critical ) {
            return $this->name;
        }

        return [
            'critical' => $this->is_critical ? 1 : 0,
            'name'     => $this->name,
            'volume'   => $this->volume,
        ];
    }
}