<?php

/**
 * DI with high granularity, every side-effect is its own class.
 * Each side-effect class would be its own mock/stub or anonymous class in the unit-test code.
 */
class PushOrderToRemoteAPICommand
{
    public function __construct(
        FileLogEffect $fileLog,
        FetchDbLogByIdEffect $fetchDbLog,
        UpdateDbLogEffect $updateDbLog,
        FetchApiConfigEffect $fetchApiConf,
        FetchCustomerAddressEffect $fetchCustAdr,
        FetchClerkByIdEffect $fetchStaff,
        FetchCreditCardDataEffect $fetchCredCard,
        FetchWarehouseIdEffect $fetchWareId,
        FetchTranslationsEffect $fetchTrans,
        PostCurlEffect $postCurl,
        DeleteOnHoldReceiptEffect $delHold,
        SetNewOrderIdEffect $setOrd,
        Registry $registry,
    ) {
    }

    public function __invoke()
    {
        $dbLog = $this->fetchDbLog($id);
        $dbLog->status = 'in_progress';
        $this->updateDbLog($dbLog);
        // ...
    }
}

/**
 * Low granularity.
 * Leads to complex mocking where you have to setup precise method calls 
 * to the db connections.
 */
class PushOrderToRemoteAPICommand
{
    public function __construct(
        Connection $db1,
        Connection $db2,
        Logger $logger,
        Curl $curl,
        Registry $registry,
    ) {
    }

    public function __invoke()
    {
        $dbLog = DbLog::fetchById($this->db1, $id);
        $dbLog->status = 'in_progress';
        $dbLog->update($this->db1);
        // ...
    }
}

/**
 * "Normal" granularity? Inject repository objects.
 * Lots of mocks.
 */
class PushOrderToRemoteAPICommand
{
    public function __construct(
        DbLogRepository $dblogrep,
        CustomerRepository $custrep,
        ClerkRepository $clerkrep,
        ApiSettingsRepository $apirep,
        TranslationRepository $transrep,
        OrderRepository $orderrep,
        Logger $logger,
        Curl $curl,
        Registry $registry,
    ) {
    }

    public function __invoke()
    {
        $dbLog = $this->dblogrep->fetchById($id);
        $dbLog->status = 'in_progress';
        $this->dblogrep->update($dbLog);
        // ...
    }
}

/**
 * DI where all side-effects are gathered in a separate environmental facade. See below.
 * Environment facade would be an anonymous class in the test code.
 */
class PushOrderToRemoteAPICommand
{
    public function __construct(
        PushOrderToRemoteAPIEnv $env,
        Registry $registry,
    ) {
    }

    public function __invoke()
    {
        $dbLog = $env->fetchDbLogEntry($id);
        $dbLog->status = 'in_progress';
        $env->updateDbLogEntry($dbLog);
        // ...
    }
}

/**
 * Environment facade that wraps all side-effects.
 */
class PushOrderToRemoteAPIEnv 
{
    public function __construct(
        Connection $db1,
        Connection $db2,
        Curl $curl,
        Registry $registry,
        Logger $logger,
    ) {
    }

    public function traceLog() {}
    public function criticalLog() {}
    public function fetchDbLogEntry() {}
    public function updateDbLogEntry() {}
    public function fetchApiKey() {}
    public function fetchCreditCardData() {}
    public function fetchWarehouseId() {}
    public function fetchTranslations() {}
    public function fetchCustomerById() {}
    public function fetchClerkId() {}
    public function postCurl() {}
    public function setOrderId() {}
    public function deleteOnHold() {}
}

// Small wrapper around Fiber::suspend
function perform(Effect $e): mixed
{
    return Fiber::suspend($e);
}

/**
 * No injection, but use a separate command handler which runs the command as a fiber.
 * Each effect is its own class, but used as algebraic effect instead.
 * One can also use generators instead of fibers, but then you'd have to propagate the effect manually through the call stack.
 */
class PushOrderToRemoteAPICommand
{
    public function __construct(
        Registry $registry,
    ) {
    }

    public function __invoke()
    {
        $dbLog = perform(new FetchDbLogByIdEffect($id));
        $dbLog->status = 'in_progress';
        perform(new UpdateDbLogEffect($dbLog));
        // ...
    }
}

class AlgebraicEffectCommandHandler
{
    public function __construct(Registry $registry)
    {
    }

    public function setEffectHandler(EffectHandler $h) {}

	public function run(): mixed
	{
		$fiber = new Fiber(new PushOrderToRemoteAPICommand($this->registry));
		$data = [
			'foo' => 'bar'
		];
		$effect = $fiber->start($data);
		$db1 = OpenDatabase1();
		$db2 = OpenDatabase2();
		while (!$fiber->isTerminated()) {
			$data = null;
			if ($effect instanceof Effect) {
                // NB: This should be factored out to separate effect handlers, which then are injected.
				if ($effect instanceof FetchCustomerAddressEffect) {
					$data = $db->select($effect->sql);
				} else {
					throw new RuntimeException('Unsupported effect class');
				}
			} else {
				// Other Fiber usage?
			}
			if ($data) {
				$effect = $fiber->resume($data);
			}
		}
		return $fiber->getReturn();
	}
}