<?php

namespace App\Yr\Forecast\Tabular\Time;

/**
 * Time-object entity should inherit this
 */
abstract class AbstractUnit implements DiffInterface {
    const DEFAULT_VARIANCE = 2;

    private $value = 0;
    private $unit;

    /**
     * @param float The value
     * @param float The unit
     */
    public function __construct(float $value, string $unit) {
        $this->value = $value;
        $this->unit = $unit;
    }

    private function canOperate(AbstractUnit $with, bool $throw = false): bool {
        if ($with instanceof $this || $with instanceof CustomUnit)
            return true;

        if ($this instanceof CustomUnit && $with instanceof AbstractUnit)
            return true;

        if ($throw)
            throw new \InvalidArgumentException(sprintf(
                "Invalid type <%s>, expected of type \"%s\" or \"%s\"",
                get_class($with), get_class($this), CustomUnit::class
            )); 

        return false;
    }

    protected function transformClass(CustomUnit $cu): self {
        return unserialize(preg_replace(
            '/^O:\d+:"[^"]++"/',
            sprintf('O:%d:"%s"', strlen(static::class), static::class),
            serialize($cu)
        ));
    }

    /**
     * Addition method
     *
     * @param AbstractUnit $with Unit to add with
     * @thows \InvalidArgumentException
     * */
    public function add(AbstractUnit $with): self {
        $this->canOperate($with, true);
        return $this->transformClass(
            new CustomUnit($this->getValue() + $with->getValue(), $with->getUnit())
        );
    }

    /**
     * Multiplication method
     *
     * @param AbstractUnit $with Unit to multiply with
     * @thows \InvalidArgumentException
     * */
    public function mul(AbstractUnit $with): self {
        $this->canOperate($with, true);
        return $this->transformClass(
            new CustomUnit($this->getValue() * $with->getValue(), $with->getUnit())
        );
    }

    /**
     * Divide method
     *
     * @param AbstractUnit $with Unit to divide with
     * @thows \InvalidArgumentException
     * */
    public function div(AbstractUnit $with): self {
        $this->canOperate($with, true);
        return $this->transformClass(
            new CustomUnit($this->getValue() / $with->getValue(), $with->getUnit())
        );
    }

    /**
     * Get the value
     *
     * @return float
     */
    public function getValue(): float {
        return $this->value;
    }

    /**
     * Return the unit (e.g «degree»)
     *
     * @return string
     */
    public function getUnit(): string {
        return $this->unit;
    }

    /**
     * {@inheritDoc}
     */
    public function diff(DiffInterface $d): int {
        if ($d instanceof $this)
            return $this->value - $d->getValue();

        return 0;
    }

    public function __toString(): string {
        return sprintf(
            "%s: %f %s", basename(str_replace(
                '\\', DIRECTORY_SEPARATOR, get_class($this)
            )), $this->value, $this->unit);
    }
}