DVDoug\BoxPacker\LayerPacker

Complexity

Total Complexity

24

Size/Duplication

Total Lines	188
Duplicated Lines	0 %

Test Coverage

Coverage

98.95%

Importance

Changes	7
Bugs	0	Features	0

7 Methods

Rating	Name	Duplication	Size	Complexity
A	getRemainingWeightAllowed()	0	8	2
A	isSameDimensions()	0	11	2
A	__construct()	0	7	1
B	packLayer()	0	70	9
A	setLogger()	0	4	1
A	setSinglePassMode()	0	4	1
B	packVerticallyInsideItemFootprint()	0	32	8

<?php
/**
 * Box packing (3D bin packing, knapsack problem).
 *
 * @author Doug Wright
 */
declare(strict_types=1);

namespace DVDoug\BoxPacker;

use function max;
use Psr\Log\LoggerAwareInterface;
use Psr\Log\LoggerInterface;
use Psr\Log\NullLogger;

/**
 * Layer packer.
 *
 * @internal
 * @author Doug Wright
 */
class LayerPacker implements LoggerAwareInterface
{
    /**
     * The logger instance.
     *
     * @var LoggerInterface
     */
    private $logger;

    /**
     * Box to pack items into.
     *
     * @var Box
     */
    private $box;

    /**
     * Whether the packer is in single-pass mode.
     *
     * @var bool
     */
    private $singlePassMode = false;

    /**
     * @var OrientatedItemFactory
     */
    private $orientatedItemFactory;

    /**
     * Constructor.
     */
    public function __construct(Box $box)
    {
        $this->box = $box;
        $this->logger = new NullLogger();

        $this->orientatedItemFactory = new OrientatedItemFactory($this->box);
        $this->orientatedItemFactory->setLogger($this->logger);
    }

    /**
     * Sets a logger.
     */
    public function setLogger(LoggerInterface $logger): void
    {
        $this->logger = $logger;
        $this->orientatedItemFactory->setLogger($logger);
    }

    public function setSinglePassMode(bool $singlePassMode): void
    {
        $this->singlePassMode = $singlePassMode;
        $this->orientatedItemFactory->setSinglePassMode($singlePassMode);
    }

    /**
     * Pack items into an individual vertical layer.
     */
    public function packLayer(ItemList &$items, PackedItemList $packedItemList, array $layers, int $z, int $layerWidth, int $lengthLeft, int $depthLeft, int $guidelineLayerDepth): PackedLayer
    {
        $layer = new PackedLayer();
        $prevItem = null;
        $x = $y = $rowLength = 0;
        $skippedItems = [];
        $remainingWeightAllowed = $this->getRemainingWeightAllowed($layers);

        while ($items->count() > 0) {
            $itemToPack = $items->extract();

            //skip items that will never fit e.g. too heavy
            if ($itemToPack->getWeight() > $remainingWeightAllowed) {
                continue;
            }

            $orientatedItem = $this->orientatedItemFactory->getBestOrientation($itemToPack, $prevItem, $items, $layerWidth - $x, $lengthLeft, $depthLeft, $rowLength, $x, $y, $z, $packedItemList);

            if ($orientatedItem instanceof OrientatedItem) {
                $packedItem = PackedItem::fromOrientatedItem($orientatedItem, $x, $y, $z);
                $layer->insert($packedItem);
                $remainingWeightAllowed -= $itemToPack->getWeight();
                $packedItemList->insert($packedItem);

                $rowLength = max($rowLength, $packedItem->getLength());

                //Figure out if we can stack the next item vertically on top of this rather than side by side
                //e.g. when we've packed a tall item, and have just put a shorter one next to it.
                $this->packVerticallyInsideItemFootprint($layer, $packedItem, $packedItemList, $items, $remainingWeightAllowed, $guidelineLayerDepth, $rowLength, $x, $y, $z);
                $x += $packedItem->getWidth();

                $prevItem = $orientatedItem;
                if ($items->count() === 0) {
                    $items = ItemList::fromArray(array_merge($skippedItems, iterator_to_array($items)), true);
                    $skippedItems = [];
                }
                continue;
            }

            if ($items->count() > 0) { // skip for now, move on to the next item
                $this->logger->debug("doesn't fit, skipping for now");
                $skippedItems[] = $itemToPack;
                // abandon here if next item is the same, no point trying to keep going. Last time is not skipped, need that to trigger appropriate reset logic
                while ($items->count() > 1 && static::isSameDimensions($itemToPack, $items->top())) {
                    $skippedItems[] = $items->extract();
                }
                continue;
            }

            if ($x > 0) {
                $this->logger->debug('No more fit in width wise, resetting for new row');
                $lengthLeft -= $rowLength;
                $y += $rowLength;
                $x = $rowLength = 0;
                $skippedItems[] = $itemToPack;
                $items = ItemList::fromArray(array_merge($skippedItems, iterator_to_array($items)), true);
                $skippedItems = [];
                $prevItem = null;
                continue;
            }

            $this->logger->debug('no items fit, so starting next vertical layer');
            $skippedItems[] = $itemToPack;

            $items = ItemList::fromArray(array_merge($skippedItems, iterator_to_array($items)), true);

            return $layer;
        }

        return $layer;
    }

    private function packVerticallyInsideItemFootprint(PackedLayer $layer, PackedItem $packedItem, PackedItemList $packedItemList, ItemList &$items, int &$remainingWeightAllowed, int $guidelineLayerDepth, int $rowLength, int $x, int $y, int $z): void
    {
        $stackableDepth = ($guidelineLayerDepth ?: $layer->getDepth()) - $packedItem->getDepth();
        $stackedZ = $z + $packedItem->getDepth();
        $stackSkippedItems = [];
        $stackedItem = $packedItem->toOrientatedItem();
        while ($stackableDepth > 0 && $items->count() > 0) {
            $itemToTryStacking = $items->extract();

            //skip items that will never fit
            if ($itemToTryStacking->getWeight() > $remainingWeightAllowed) {
                continue;
            }

            $stackedItem = $this->orientatedItemFactory->getBestOrientation($itemToTryStacking, $stackedItem, $items, $packedItem->getWidth(), $packedItem->getLength(), $stackableDepth, $rowLength, $x, $y, $stackedZ, $packedItemList);
            if ($stackedItem) {
                $packedStackedItem = PackedItem::fromOrientatedItem($stackedItem, $x, $y, $stackedZ);
                $layer->insert($packedStackedItem);
                $remainingWeightAllowed -= $itemToTryStacking->getWeight();
                $packedItemList->insert($packedStackedItem);
                $stackableDepth -= $stackedItem->getDepth();
                $stackedZ += $stackedItem->getDepth();
                continue;
            }

            $stackSkippedItems[] = $itemToTryStacking;
            // abandon here if next item is the same, no point trying to keep going
            while ($items->count() > 0 && static::isSameDimensions($itemToTryStacking, $items->top())) {
                $stackSkippedItems[] = $items->extract();
            }
        }
        $items = ItemList::fromArray(array_merge($stackSkippedItems, iterator_to_array($items)), true);
    }

    private function getRemainingWeightAllowed(array $layers): int
    {
        $remainingWeightAllowed = $this->box->getMaxWeight() - $this->box->getEmptyWeight();
        foreach ($layers as $layer) {
            $remainingWeightAllowed -= $layer->getWeight();
        }

        return $remainingWeightAllowed;
    }

    /**
     * Compare two items to see if they have same dimensions.
     */
    private static function isSameDimensions(Item $itemA, Item $itemB): bool
    {
        if ($itemA === $itemB) {
            return true;
        }
        $itemADimensions = [$itemA->getWidth(), $itemA->getLength(), $itemA->getDepth()];
        $itemBDimensions = [$itemB->getWidth(), $itemB->getLength(), $itemB->getDepth()];
        sort($itemADimensions);
        sort($itemBDimensions);

        return $itemADimensions === $itemBDimensions;
    }
}