<?php

/*
 * @copyright   Copyright (C) 2010-2025 Combodo SARL
 * @license     http://opensource.org/licenses/AGPL-3.0
 */

namespace Combodo\iTop\Forms\FormBuilder;

use Combodo\iTop\Forms\Block\AbstractFormBlock;
use Combodo\iTop\Forms\Block\AbstractTypeFormBlock;
use Combodo\iTop\Forms\Block\Base\FormBlock;
use Combodo\iTop\Forms\Block\FormBlockException;
use Exception;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\Form\FormError;
use Symfony\Component\Form\FormEvent;
use Symfony\Component\Form\FormEvents;
use Symfony\Component\Form\FormInterface;

/**
 * Handler responsible for form blocks dependencies.
 *
 * @package Combodo\iTop\Forms\FormBuilder
 * @since 3.3.0
 */
class DependencyHandler
{
	public static array $aDependencyHandlers = [];

	/** @var DependencyMap dependencies map */
	private DependencyMap $oDependenciesMap;

	/** @var array events */
	private array $aEvents = [];
	private readonly FormBuilder $oFormBuilder;
	private readonly FormBlock $oFormBlock;
	private readonly array $aDependentBlocks;

	/**
	 * Constructor.
	 *
	 * @param FormBuilder $oFormBuilder The form builder
	 * @param FormBlock $oFormBlock The block attached to the builder
	 * @param array $aDependentBlocks Dependants blocks
	 */
	public function __construct(FormBuilder $oFormBuilder, FormBlock $oFormBlock, array $aDependentBlocks)
	{
		$this->aDependentBlocks = $aDependentBlocks;
		$this->oFormBuilder = $oFormBuilder;
		$this->oFormBlock = $oFormBlock;

		// dependencies map
		$this->oDependenciesMap = new DependencyMap($aDependentBlocks);

		// Add form ready listener
		$this->AddFormReadyListener();

		// Check the dependencies (handle internal binding)
		$this->CheckDependencies($this->oFormBuilder);

		// Store the dependency handler (debug purpose)
		self::$aDependencyHandlers[] = $this;
	}

	/**
	 * Get the form name.
	 *
	 * @return string
	 */
	public function GetName(): string
	{
		return $this->oFormBuilder->getName();
	}

	/**
	 * Get the debug data.
	 *
	 * @return array
	 */
	public function GetDebugData(): array
	{
		return $this->aEvents;
	}

	/**
	 * Get the dependencies map.
	 *
	 * @return DependencyMap
	 */
	public function GetMap(): DependencyMap
	{
		return $this->oDependenciesMap;
	}

	/**
	 * Add form ready listener.
	 *
	 * Listen the form PRE_SET_DATA
	 * First event from Symfony framework, we know that the form is built at this step.
	 *
	 * @return void
	 */
	private function AddFormReadyListener(): void
	{
		// Initialize the dependencies listeners once the form is built
		$this->oFormBuilder->addEventListener(FormEvents::PRE_SET_DATA, function (FormEvent $event) {

			/** Iterate throw blocks impacting other but without dependencies */
			foreach ($this->oDependenciesMap->GetImpactingBlocksWithoutDependencies() as $sOutputBlockName) {

				// Add event
				$this->AddEvent('form.listen', $sOutputBlockName);

				// Listen the output block POST_SET_DATA & POST_SUBMIT
				$this->oFormBuilder->get($sOutputBlockName)->addEventListener(FormEvents::POST_SET_DATA, $this->GetEventListeningCallback());
				$this->oFormBuilder->get($sOutputBlockName)->addEventListener(FormEvents::POST_SUBMIT, $this->GetEventListeningCallback());
			}
		});
	}

	/**
	 * Get the listening callback.
	 *
	 * @return callable
	 */
	private function GetEventListeningCallback(): callable
	{
		return function (FormEvent $oEvent) {

			// Get the event type
			$sEventType = FormHelper::GetEventType($oEvent);

			// Add event
			$this->AddEvent($sEventType, $oEvent->getForm()->getName(), $oEvent->getData());

			// Get the form
			$oForm = $oEvent->getForm();

			// Get the form block
			$oFormBlock = $this->oFormBlock->Get($oForm->getName());

			// Compute the block outputs with the data
			try {
				$oFormBlock->ComputeOutputs($sEventType, $oForm->getData());
			} catch (Exception $e) {
				$oForm->addError(new FormError($e->getMessage()));
			}

			// Check dependencies
			$this->CheckDependencies($oForm->getParent(), $oForm->getName(), $sEventType);
		};

	}

	/**
	 * @param FormInterface|FormBuilderInterface $oForm
	 * @param string|null $sOutputBlock
	 * @param string|null $sEventType
	 *
	 * @return void
	 * @throws FormBlockException
	 */
	private function CheckDependencies(FormInterface|FormBuilderInterface $oForm, string $sOutputBlock = null, string $sEventType = null): void
	{
		$aImpactedBlocks = $this->aDependentBlocks;
		if ($sOutputBlock !== null) {
			$aImpactedBlocks = $this->oDependenciesMap->GetBlocksImpactedBy($sOutputBlock, function (AbstractFormBlock $oBlock) use ($sEventType) {
				return $oBlock instanceof AbstractTypeFormBlock;
			});
		}

		/** Iterate throw dependencies... @var AbstractFormBlock $oDependentBlock */
		foreach ($aImpactedBlocks as $oDependentBlock) {
			if (!$oDependentBlock instanceof AbstractTypeFormBlock) {
				continue;
			}

			// When dependencies met, add the dependent field if not already done or options changed
			if ($oDependentBlock->IsVisible($sEventType) && $oDependentBlock->IsInputsDataReady($sEventType)) {

				// Get the Symfony options
				$aOptions = $oDependentBlock->GetOptions();

				// Add the listener callback to the dependent field if it is also a dependency for another field
				if ($this->oDependenciesMap->HasBlocksImpactedBy($oDependentBlock->getName())) {

					// Pass the listener call back to be registered by the dependency form builder
					$aOptions = array_merge($aOptions, [
						'builder_listener' => $this->GetEventListeningCallback(),
					]);
				}

				if ($oDependentBlock->AllowAdd($sEventType)) {

					// Add events
					$this->AddEvent('form.add', $oDependentBlock->getName());
					if (array_key_exists('builder_listener', $aOptions)) {
						$this->AddEvent('form.listen.after', $oDependentBlock->getName());
					}

					// Mark the dependency as added
					$oDependentBlock->SetAdded(true);

					// Add the dependent field to the form
					$oForm->add($oDependentBlock->GetName(), $oDependentBlock->GetFormType(), $aOptions);

				}

			}

			if ($oDependentBlock->IsAdded() && (!$oDependentBlock->IsVisible($sEventType) || !$oDependentBlock->IsInputsDataReady($sEventType))) {
				$oForm->remove($oDependentBlock->GetName());
				$oDependentBlock->SetAdded(false);

				// Add event
				$this->AddEvent('form.remove', $oDependentBlock->getName());
			}
		}
	}

	/**
	 * Add a debug event.
	 *
	 * @param string $sEvent
	 * @param string $sForm
	 * @param mixed $oValue
	 *
	 * @return void
	 */
	private function AddEvent(string $sEvent, string $sForm, mixed $oValue = 'NA'): void
	{
		$this->aEvents[] = [
			'builder' => $this->oFormBuilder->getName(),
			'event'   => $sEvent,
			'form'    => $sForm,
			'value'   => $oValue,
		];
	}
}