<?php

declare(strict_types=1);

namespace Zhineng\Snowflake;

abstract class Field implements Component
{
    /**
     * The bit offset.
     */
    private int $offset = 0;

    public function __construct(
        public readonly string $name,
        public readonly int $bits,
    ) {
        if ($bits < 1 || $bits > 63) {
            throw new \InvalidArgumentException('Bits must be between 1 and 63.');
        }
    }

    /**
     * The bit size.
     */
    public function bits(): int
    {
        return $this->bits;
    }

    /**
     * The maximum value based on the number of bits.
     */
    public function maxValue(): int
    {
        return (1 << $this->bits) - 1;
    }

    /**
     * Set the bit offset.
     */
    public function setOffset(int $offset): static
    {
        $this->offset = $offset;

        return $this;
    }

    /**
     * The bit offset.
     */
    public function offset(): int
    {
        return $this->offset;
    }

    abstract public function value(): int;
}