Implement a customer approval process based on a generic state machine

<?php

namespace Pyz\Zed\CustomerApproveProcess\Business;

use Generated\Shared\Transfer\CustomerApproveProcessItemTransfer;
use Generated\Shared\Transfer\CustomerTransfer;
use Generated\Shared\Transfer\StateMachineItemTransfer;

interface CustomerApproveProcessFacadeInterface
{
    /**
     * Retrieves all our approve process items. Used for Zed UI presentation.
     *
     * @return \Generated\Shared\Transfer\CustomerApproveProcessItemTransfer[]
     */
    public function getAllCustomerApproveProcessItems(): array;

    /**
     * Retrieves approve process items by state ids. Used in `StateMachineHandlerPlugin`.
     *
     * @param int[] $stateIds
     *
     * @return \Generated\Shared\Transfer\CustomerApproveProcessItemTransfer[]
     */
    public function getCustomerApproveProcessItemsByStateIds(array $stateIds = []): array;

    /**
     * Creates `SpyCustomerApproveProcessItem` entity based on `CustomerTransfer` (only customer ID is used) and saves it into DB.
     *
     * @param \Generated\Shared\Transfer\CustomerTransfer $customerTransfer
     *
     * @return \Generated\Shared\Transfer\CustomerApproveProcessItemTransfer
     */
    public function createCustomerApproveProcessStateMachineItem(CustomerTransfer $customerTransfer): CustomerApproveProcessItemTransfer;

    /**
     * Updates `SpyCustomerApproveProcessItem` entity and saves it into DB. Used when we moving item through state machine.
     *
     * @param \Generated\Shared\Transfer\StateMachineItemTransfer $stateMachineItemTransfer
     *
     * @return \Generated\Shared\Transfer\CustomerApproveProcessItemTransfer
     */
    public function updateCustomerApproveProcessStateMachineItem(StateMachineItemTransfer $stateMachineItemTransfer): CustomerApproveProcessItemTransfer;

    /**
     * Deletes `SpyCustomerApproveProcessItem` entity from DB.
     *
     * @param int $customerApproveProcessItemId
     *
     * @return void
     */
    public function deleteCustomerApproveProcessStateMachineItem(int $customerApproveProcessItemId): void;
}

<?php

namespace Pyz\Zed\CustomerApproveProcess\Communication\Plugin;

use Generated\Shared\Transfer\StateMachineItemTransfer;
use Pyz\Zed\CustomerApproveProcess\Communication\Plugin\Command\CustomerApproveProcessCommandPlugin;
use Pyz\Zed\CustomerApproveProcess\Communication\Plugin\Condition\CustomerApproveProcessConditionPlugin;
use Spryker\Zed\Kernel\Communication\AbstractPlugin;
use Spryker\Zed\StateMachine\Dependency\Plugin\StateMachineHandlerInterface;

/**
 * @method \Pyz\Zed\CustomerApproveProcess\Business\CustomerApproveProcessFacadeInterface getFacade()
 */
class CustomerApproveProcessStateMachineHandlerPlugin extends AbstractPlugin implements StateMachineHandlerInterface
{
    /**
     * List of command plugins for this state machine for all processes.
     *
     * @return \Spryker\Zed\StateMachine\Dependency\Plugin\CommandPluginInterface[]
     */
    public function getCommandPlugins(): array
    {
        return [
            'CustomerApproveProcess/CustomerApproveProcessCommand' => new CustomerApproveProcessCommandPlugin(),
        ];
    }

    /**
     * List of condition plugins for this state machine for all processes.
     *
     * @return \Spryker\Zed\StateMachine\Dependency\Plugin\ConditionPluginInterface[]
     */
    public function getConditionPlugins(): array
    {
        return [
            'CustomerApproveProcess/CustomerApproveProcessCondition' => new CustomerApproveProcessConditionPlugin(),
        ];
    }

    /**
     * Name of state machine used by this handler.
     *
     * @return string
     */
    public function getStateMachineName(): string
    {
        return 'CustomerApproveProcess';
    }

    /**
     * List of active processes used for this state machine
     *
     * @return string[]
     */
    public function getActiveProcesses(): array
    {
        return [
            'Process01',
        ];
    }

    /**
     * Provide initial state name for item when state machine initialized. Using process name.
     *
     * @param string $processName
     *
     * @throws \InvalidArgumentException
     *
     * @return string
     */
    public function getInitialStateForProcess($processName): string
    {
        return 'new';
    }

    /**
     * This method is called when state of item was changed, client can create custom logic for example update it's related table with new state id/name.
     * StateMachineItemTransfer:identifier is ID of entity from implementor.
     *
     * @param \Generated\Shared\Transfer\StateMachineItemTransfer $stateMachineItemTransfer
     *
     * @return bool
     */
    public function itemStateUpdated(StateMachineItemTransfer $stateMachineItemTransfer): bool
    {
        $customerApproveProcessItemTransfer = $this->getFacade()
            ->updateCustomerApproveProcessStateMachineItem($stateMachineItemTransfer);

        if ($customerApproveProcessItemTransfer->getIdCustomerApproveProcessItem()) {
            return true;
        }

        return false;
    }

    /**
     * This method returns all list of StateMachineItemTransfer, with (identifier, IdStateMachineProcess, IdItemState)
     *
     * @param array $stateIds
     *
     * @return \Generated\Shared\Transfer\StateMachineItemTransfer[]
     */
    public function getStateMachineItemsByStateIds(array $stateIds = []): array
    {
        $customerApproveProcessItems = $this->getFacade()->getCustomerApproveProcessItemsByStateIds($stateIds);
        $stateMachineItems = [];
        foreach ($customerApproveProcessItems as $customerApproveProcessItem) {
            $stateMachineItems[] = $customerApproveProcessItem->getStateMachineItem();
        }

        return $stateMachineItems;
    }
}

<?php

namespace Pyz\Zed\CustomerApproveProcess\Communication\Controller;

use Generated\Shared\Transfer\CustomerTransfer;
use Spryker\Zed\Kernel\Communication\Controller\AbstractController;
use Spryker\Zed\StateMachine\Business\StateMachineFacadeInterface;
use Symfony\Component\HttpFoundation\RedirectResponse;
use Symfony\Component\HttpFoundation\Request;

/**
 * @method \Pyz\Zed\CustomerApproveProcess\Communication\CustomerApproveProcessCommunicationFactory getFactory()
 * @method \Pyz\Zed\CustomerApproveProcess\Business\CustomerApproveProcessFacadeInterface getFacade()
 */
class StateMachineItemsController extends AbstractController
{
    /**
     * @return array
     */
    public function listAction(): array
    {
        $customerApproveProcessStateItems = $this->getFacade()
            ->getAllCustomerApproveProcessItems();

        $processedStateMachineItems = $this->getStateMachineFacade()
            ->getProcessedStateMachineItems(
                $this->getStateMachineItems($customerApproveProcessStateItems)
            );

        $manualEvents = $this->getStateMachineFacade()
            ->getManualEventsForStateMachineItems($processedStateMachineItems);

        return [
            'customerApproveProcessItems' => $customerApproveProcessStateItems,
            'manualEvents' => $manualEvents,
            'stateMachineItems' => $this->createCustomerApproveProcessItemsLookupTable($processedStateMachineItems),
        ];
    }

    /**
     * @return \Symfony\Component\HttpFoundation\RedirectResponse
     */
    public function addItemAction(): RedirectResponse
    {
        $customerTransfer = (new CustomerTransfer())
            ->setIdCustomer(mt_rand(1, 26));

        $this->getFacade()->createCustomerApproveProcessStateMachineItem($customerTransfer);

        return $this->redirectResponse('/customer-approve-process/state-machine-items/list');
    }

    /**
     * @param \Symfony\Component\HttpFoundation\Request $request
     *
     * @return \Symfony\Component\HttpFoundation\RedirectResponse
     */
    public function deleteItemAction(Request $request): RedirectResponse
    {
        $idCustomerApproveProcessItem = $this->castId($request->query->get('id'));
        $this->getFacade()->deleteCustomerApproveProcessStateMachineItem($idCustomerApproveProcessItem);

        return $this->redirectResponse('/customer-approve-process/state-machine-items/list');
    }

    /**
     * @param \Generated\Shared\Transfer\CustomerApproveProcessItemTransfer[] $customerApproveProcessStateItems
     *
     * @return \Generated\Shared\Transfer\StateMachineItemTransfer[]
     */
    protected function getStateMachineItems(array $customerApproveProcessStateItems): array
    {
        $stateMachineItems = [];
        foreach ($customerApproveProcessStateItems as $customerApproveProcessStateItem) {
            $stateMachineItems[] = $customerApproveProcessStateItem->getStateMachineItem();
        }

        return $stateMachineItems;
    }

    /**
     * @param \Generated\Shared\Transfer\StateMachineItemTransfer[] $stateMachineItems
     *
     * @return \Generated\Shared\Transfer\StateMachineItemTransfer[]
     */
    protected function createCustomerApproveProcessItemsLookupTable(array $stateMachineItems): array
    {
        $lookupIndex = [];
        foreach ($stateMachineItems as $stateMachineItemTransfer) {
            $lookupIndex[$stateMachineItemTransfer->getIdentifier()] = $stateMachineItemTransfer;
        }

        return $lookupIndex;
    }

    /**
     * @return \Spryker\Zed\StateMachine\Business\StateMachineFacadeInterface
     */
    protected function getStateMachineFacade(): StateMachineFacadeInterface
    {
        return $this->getFactory()->getStateMachineFacade();
    }
}