<?php

namespace Drupal\views_ui;

use Drupal\Core\Form\FormStateInterface;
use Drupal\views\Plugin\views\wizard\WizardPluginBase;
use Drupal\views\Plugin\views\wizard\WizardException;
use Drupal\views\Plugin\ViewsPluginManager;
use Drupal\views\ViewsFormAjaxHelperTrait;
use Symfony\Component\DependencyInjection\ContainerInterface;
use Drupal\Core\Extension\ModuleHandlerInterface;

/**
 * Form controller for the Views add form.
 *
 * @internal
 */
class ViewAddForm extends ViewFormBase {

  use ViewsFormAjaxHelperTrait;

  /**
   * The wizard plugin manager.
   *
   * @var \Drupal\views\Plugin\ViewsPluginManager
   */
  protected $wizardManager;

  /**
   * The module handler service.
   *
   * @var \Drupal\Core\Extension\ModuleHandlerInterface
   */
  protected $moduleHandler;

  /**
   * Constructs a new ViewAddForm object.
   *
   * @param \Drupal\views\Plugin\ViewsPluginManager $wizard_manager
   *   The wizard plugin manager.
   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
   *   The module handler service.
   */
  public function __construct(ViewsPluginManager $wizard_manager, ModuleHandlerInterface $module_handler) {
    $this->wizardManager = $wizard_manager;
    $this->moduleHandler = $module_handler;
  }

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container) {
    return new static(
      $container->get('plugin.manager.views.wizard'),
      $container->get('module_handler')
    );
  }

  /**
   * {@inheritdoc}
   */
  protected function prepareEntity() {
    // Do not prepare the entity while it is being added.
  }

  /**
   * {@inheritdoc}
   */
  public function form(array $form, FormStateInterface $form_state) {
    $form['#attached']['library'][] = 'views_ui/views_ui.admin';
    $form['#attributes']['class'] = ['views-admin'];

    $form['name'] = [
      '#type' => 'fieldset',
      '#title' => $this->t('View basic information'),
      '#attributes' => ['class' => ['fieldset-no-legend']],
    ];

    $form['name']['label'] = [
      '#type' => 'textfield',
      '#title' => $this->t('View name'),
      '#required' => TRUE,
      '#size' => 32,
      '#default_value' => '',
      '#maxlength' => 255,
    ];
    $form['name']['id'] = [
      '#type' => 'machine_name',
      '#maxlength' => 128,
      '#machine_name' => [
        'exists' => '\Drupal\views\Views::getView',
        'source' => ['name', 'label'],
      ],
      '#description' => $this->t('A unique machine-readable name for this View. It must only contain lowercase letters, numbers, and underscores.'),
    ];

    $form['name']['description_enable'] = [
      '#type' => 'checkbox',
      '#title' => $this->t('Description'),
    ];
    $form['name']['description'] = [
      '#type' => 'textfield',
      '#title' => $this->t('Provide description'),
      '#title_display' => 'invisible',
      '#size' => 64,
      '#default_value' => '',
      '#states' => [
        'visible' => [
          ':input[name="description_enable"]' => ['checked' => TRUE],
        ],
      ],
    ];

    // Create a wrapper for the entire dynamic portion of the form. Everything
    // that can be updated by AJAX goes somewhere inside here. For example, this
    // is needed by "Show" dropdown (below); it changes the base table of the
    // view and therefore potentially requires all options on the form to be
    // dynamically updated.
    $form['displays'] = [];

    // Create the part of the form that allows the user to select the basic
    // properties of what the view will display.
    $form['displays']['show'] = [
      '#type' => 'fieldset',
      '#title' => $this->t('View settings'),
      '#tree' => TRUE,
      '#attributes' => ['class' => ['container-inline']],
    ];

    // Create the "Show" dropdown, which allows the base table of the view to be
    // selected.
    $wizard_plugins = $this->wizardManager->getDefinitions();
    $options = [];
    foreach ($wizard_plugins as $key => $wizard) {
      $options[$key] = $wizard['title'];
    }
    $form['displays']['show']['wizard_key'] = [
      '#type' => 'select',
      '#title' => $this->t('Show'),
      '#options' => $options,
      '#sort_options' => TRUE,
    ];
    $show_form = &$form['displays']['show'];
    $default_value = $this->moduleHandler->moduleExists('node') ? 'node' : 'users';
    $show_form['wizard_key']['#default_value'] = WizardPluginBase::getSelected($form_state, ['show', 'wizard_key'], $default_value, $show_form['wizard_key']);
    // Changing this dropdown updates the entire content of $form['displays']
    // via AJAX.
    $this->addAjaxTrigger($show_form, 'wizard_key', ['displays']);

    // Build the rest of the form based on the currently selected wizard plugin.
    $wizard_key = $show_form['wizard_key']['#default_value'];
    $wizard_instance = $this->wizardManager->createInstance($wizard_key);
    $form = $wizard_instance->buildForm($form, $form_state);

    return $form;
  }

  /**
   * {@inheritdoc}
   */
  protected function actions(array $form, FormStateInterface $form_state) {
    $actions = parent::actions($form, $form_state);
    $actions['submit']['#value'] = $this->t('Save and edit');
    // Remove EntityFormController::save() form the submission handlers.
    $actions['submit']['#submit'] = [[$this, 'submitForm']];
    $actions['cancel'] = [
      '#type' => 'submit',
      '#value' => $this->t('Cancel'),
      '#submit' => ['::cancel'],
      '#limit_validation_errors' => [],
    ];
    return $actions;
  }

  /**
   * {@inheritdoc}
   */
  public function validateForm(array &$form, FormStateInterface $form_state) {
    $wizard_type = $form_state->getValue(['show', 'wizard_key']);
    $wizard_instance = $this->wizardManager->createInstance($wizard_type);
    $form_state->set('wizard', $wizard_instance->getPluginDefinition());
    $form_state->set('wizard_instance', $wizard_instance);

    $path = &$form_state->getValue(['page', 'path']);
    if (!empty($path)) {
      // @todo https://www.drupal.org/node/2423913 Views should expect and store
      //   a leading /.
      $path = ltrim($path, '/ ');
    }
    $errors = $wizard_instance->validateView($form, $form_state);

    foreach ($errors as $display_errors) {
      foreach ($display_errors as $name => $message) {
        $form_state->setErrorByName($name, $message);
      }
    }
  }

  /**
   * {@inheritdoc}
   */
  public function submitForm(array &$form, FormStateInterface $form_state) {
    try {
      /** @var \Drupal\views\Plugin\views\wizard\WizardInterface $wizard */
      $wizard = $form_state->get('wizard_instance');
      $this->entity = $wizard->createView($form, $form_state);
    }
    // @todo Figure out whether it really makes sense to throw and catch exceptions on the wizard.
    catch (WizardException $e) {
      $this->messenger()->addError($e->getMessage());
      $form_state->setRedirect('entity.view.collection');
      return;
    }
    $this->entity->save();
    $this->messenger()->addStatus($this->t('The view %name has been saved.', ['%name' => $form_state->getValue('label')]));
    $form_state->setRedirectUrl($this->entity->toUrl('edit-form'));
  }

  /**
   * Form submission handler for the 'cancel' action.
   *
   * @param array $form
   *   An associative array containing the structure of the form.
   * @param \Drupal\Core\Form\FormStateInterface $form_state
   *   The current state of the form.
   */
  public function cancel(array $form, FormStateInterface $form_state) {
    $form_state->setRedirect('entity.view.collection');
  }

}
