[DRAFT] Synchronization between legacy inventory data and MSI

Synchronization from MSI to LegacyCatalogInventory

Quantity and stock status

In MSI status field of \Magento\InventoryApi\Api\Data\SourceItemInterface is only one of condition for is_salable concept

But in legacy catalog inventory is_in_stock field of \Magento\CatalogInventory\Api\Data\StockItemInterface is aggregation of few rules related to quantity

In order for the old indexation to work correctly, we need to follow the same rules during synhronization

\Magento\InventoryCatalog\Plugin\InventoryApi\SetDataToLegacyCatalogInventoryAtSourceItemsSavePlugin
...
/** @var \Magento\CatalogInventory\Api\Data\StockItemInterface $legacyStockItem */
$legacyStockItem = $this->getLegacyStockItemBySku($sourceItem->getSku());
$legacyStockItem->setIsInStock((int)$sourceItem->getStatus());
$legacyStockItem->setQty($sourceItem->getQuantity());

/** \Magento\CatalogInventory\Model\Spi\StockStateProviderInterface::verifyStock */
$isInStock = $legacyStockItem->getManageStock() && $this->stockStateProvider->verifyStock($legacyStockItem);

$this->setDataToLegacyStockItem->execute(
    $sourceItem->getSku(),
    (float)$sourceItem->getQuantity(),
    (int)$isInStock
);

Indexation

Since the proper date has been set on previous step, we can use legacy reindexation mechanism

\Magento\InventoryCatalog\Plugin\InventoryApi\SetDataToLegacyCatalogInventoryAtSourceItemsSavePlugin
...
$indexer = $this->indexerRegistry->get('cataloginventory_stock');
if (false === $indexer->isScheduled()) {
    $indexer->reindexList($productIds);
}

Complex products

Introduce chain of data synchronization objects (composite pattern)

$this->dataSynchronizationProcessor->execute($sourceItems);

Configuration

<type name="Magento\InventoryCatalog\Model\DataSynchronizationProcessorChain">
        <arguments>
            <argument name="processors" xsi:type="array">
		<item name="configurable" xsi:type="array">
                    <item name="sort_order" xsi:type="number">20</item>
                    <item name="object" xsi:type="object">Magento\InventoryConfigurableProduct\Model\ConfigurableDataSynchronizationProcessor</item>
                </item>
            </argument>
        </arguments>
    </type>

Complex products processor should be executed after simple products processor

$parentProductIds = $this->configurable->getParentIdsByChild($productIds);
$indexer = $this->indexerRegistry->get('cataloginventory_stock');
if (false === $indexer->isScheduled()) {
    $indexer->reindexList($productIds);
}

2. Synchronization from LegacyCatalogInventory to MSI \Magento\InventoryCatalog\Plugin\CatalogInventory\UpdateSourceItemAtLegacyStockItemSavePlugin::aroundSave

Synchronization from LegacyCatalogInventory to MSI

Plugin on Magento\CatalogInventory\Model\ResourceModel\Stock\Item

\Magento\InventoryCatalog\Plugin\CatalogInventory\UpdateSourceItemAtLegacyStockItemSavePlugin::aroundSave
...
// need to save configuration
$proceed($legacyStockItem);

$typeId = $this->getTypeId($legacyStockItem);
if ($this->isSourceItemsAllowedForProductType->execute($typeId)) {
    $this->updateSourceItemBasedOnLegacyStockItem->execute($legacyStockItem);
}

\Magento\InventoryCatalog\Model\UpdateSourceItemBasedOnLegacyStockItem::execute
...
$sourceItem->setQuantity((float)$legacyStockItem->getQty());
$sourceItem->setStatus((int)$legacyStockItem->getIsInStock());
$this->sourceItemsSave->execute([$sourceItem]);

Synchronization at Import

Synchronization should not execute at Import process

Plugins on implementation???

Testcases

Work with new Inventory interfaces

Data: qty=0, stock_status=1

Steps:

1. $sourceItemsSave->execute($sourceItems);
2. \Magento\InventoryCatalog\Plugin\InventoryApi\SetDataToLegacyCatalogInventoryAtSourceItemsSavePlugin::afterExecute

Result: SourceItems has qty=0, stock_status=1. LegacyStockItem has qty=0, stock_status=0.

The same after full reindexation

Work with legacy Inventory interfaces

Data: qty=0, stock_status=1

Steps:

1. $stockItemsRepository->save($legacyStockItem);
2. \Magento\InventoryCatalog\Plugin\CatalogInventory\UpdateSourceItemAtLegacyStockItemSavePlugin::aroundSave
3. \Magento\InventoryCatalog\Plugin\InventoryApi\SetDataToLegacyCatalogInventoryAtSourceItemsSavePlugin::afterExecute (chain is broken due to SetDataToLegacyCatalogInventoryAtSourceItemsSavePlugin updates via diret SQL queries)

Results: SourceItems has qty=0, stock_status=0. LegacyStockItem has qty=0, stock_status=0. The same after full reindexation