<?php

namespace App\Services\Parts;

use App\Entity\Parts\Part;
use App\Entity\Parts\PartLot;

class PartLotWithdrawAddHelper
{
    /**
     * Checks whether the given part can
     * @param  PartLot  $partLot
     * @return bool
     */
    public function canAdd(PartLot $partLot): bool
    {
        //We cannot add or withdraw parts from lots with unknown instock value.
        if($partLot->isInstockUnknown()) {
            return false;
        }

        //So far all other restrictions are defined at the storelocation level
        if($partLot->getStorageLocation() === null) {
            return true;
        }

        //We can not add parts if the storage location of the lot is marked as full
        if($partLot->getStorageLocation()->isFull()) {
            return false;
        }

        return true;
    }

    public function canWithdraw(PartLot $partLot): bool
    {
        //We cannot add or withdraw parts from lots with unknown instock value.
        if ($partLot->isInstockUnknown()) {
            return false;
        }

        return true;
    }

    /**
     * Withdraw the specified amount of parts from the given part lot.
     * Please note that the changes are not flushed to DB yet, you have to do this yourself
     * @param  PartLot  $partLot The partLot from which the instock should be taken (which value should be decreased)
     * @param  float  $amount The amount of parts that should be taken from the part lot
     * @param  string|null  $comment The optional comment describing the reason for the withdrawal
     * @return PartLot The modified part lot
     */
    public function withdraw(PartLot $partLot, float $amount, ?string $comment = null): PartLot
    {
        //Ensure that amount is positive
        if ($amount <= 0) {
            throw new \InvalidArgumentException('Amount must be positive');
        }

        $part = $partLot->getPart();

        //Check whether we have to round the amount
        if (!$part->useFloatAmount()) {
            $amount = round($amount);
        }

        //Ensure that we can withdraw from the part lot
        if (!$this->canWithdraw($partLot)) {
            throw new \RuntimeException("Cannot withdraw from this part lot!");
        }

        //Ensure that there is enough stock to withdraw
        if ($amount > $partLot->getAmount()) {
            throw new \RuntimeException('Not enough stock to withdraw!');
        }

        //Subtract the amount from the part lot
        $partLot->setAmount($partLot->getAmount() - $amount);

        return $partLot;
    }

    /**
     * Add the specified amount of parts to the given part lot.
     * Please note that the changes are not flushed to DB yet, you have to do this yourself
     * @param  PartLot  $partLot The partLot from which the instock should be taken (which value should be decreased)
     * @param  float  $amount The amount of parts that should be taken from the part lot
     * @param  string|null  $comment The optional comment describing the reason for the withdrawal
     * @return PartLot The modified part lot
     */
    public function add(PartLot $partLot, float $amount, ?string $comment = null): PartLot
    {
        if ($amount <= 0) {
            throw new \InvalidArgumentException('Amount must be positive');
        }

        $part = $partLot->getPart();

        //Check whether we have to round the amount
        if (!$part->useFloatAmount()) {
            $amount = round($amount);
        }

        //Ensure that we can add to the part lot
        if (!$this->canAdd($partLot)) {
            throw new \RuntimeException("Cannot add to this part lot!");
        }

        //Subtract the amount from the part lot
        $partLot->setAmount($partLot->getAmount() + $amount);

        return $partLot;
    }

    /**
     * Move the specified amount of parts from the given source part lot to the given target part lot.
     * Please note that the changes are not flushed to DB yet, you have to do this yourself
     * @param  PartLot  $origin The part lot from which the parts should be taken
     * @param  PartLot  $target The part lot to which the parts should be added
     * @param  float  $amount The amount of parts that should be moved
     * @param  string|null  $comment A comment describing the reason for the move
     * @return void
     */
    public function move(PartLot $origin, PartLot $target, float $amount, ?string $comment = null): void
    {
        if ($amount <= 0) {
            throw new \InvalidArgumentException('Amount must be positive');
        }

        $part = $origin->getPart();

        //Ensure that both part lots belong to the same part
        if($origin->getPart() !== $target->getPart()) {
            throw new \RuntimeException("Cannot move instock between different parts!");
        }

        //Check whether we have to round the amount
        if (!$part->useFloatAmount()) {
            $amount = round($amount);
        }

        //Ensure that we can withdraw from origin and add to target
        if (!$this->canWithdraw($origin) || !$this->canAdd($target)) {
            throw new \RuntimeException("Cannot move instock between these part lots!");
        }

        //Ensure that there is enough stock to withdraw
        if ($amount > $origin->getAmount()) {
            throw new \RuntimeException('Not enough stock to withdraw!');
        }

        //Subtract the amount from the part lot
        $origin->setAmount($origin->getAmount() - $amount);
        //And add it to the target
        $target->setAmount($target->getAmount() + $amount);
    }
}