<?php


namespace App\Komma\Kms\Core\Sequence\Parts;

/**
 * Class abstractPart
 *
 * All Parts must extend this class
 *
 * @package App\Komma\Kms\Core\Sequence\Parts
 */
abstract class AbstractPart
{
    /** @var string The current value of the part */
    protected $currentValue = null;

    /** @var string The value to start "nexting" from */
    protected $startingAtValue = null;

    /** @var string The name of the part */
    protected $name = '';

    /** @var string Must answer the question: Why did it overflow? When it did overflow*/
    protected $overflownBecause = '';

    /** @var int The length of the part in characters */
    protected $length;

    /**
     * AbstractPart constructor.
     *
     * @param int $length
     */
    public function __construct(int $length)
    {
        if($length == 0) throw new \InvalidArgumentException('AbstractPart: The length parameter must be bigger than 0. But 0 was given');
        $this->length = $length;
    }

    /**
     * Calculate the next value
     */
    abstract public function next(): AbstractPart;

    /**
     * Initialize the part with (a part of) the given value.
     *
     * @param string $value
     * @param bool $mayOverflow This value determines if the given value must be limited to the length of the part
     * @return AbstractPart
     */
    abstract public function startingAt(string $value, $mayOverflow = false): AbstractPart;

    /**
     * Return the current value of the part
     *
     * @return string
     */
    abstract public function getValue():string;

    /**
     * Describes in human language what the part consists of.
     * End the description with a dot, not followed by a space.
     *
     * @return string
     */
    abstract public function describe():string;

    /**
     * Return the name of the part
     */
    abstract public function getName():string;

    /**
     * @return string An indication on why this value overflowed. If it is an empty string, it did not overflow.
     */
    public function overflownBecause(): string
    {
        return $this->overflownBecause;
    }
}