class SwitchShortcutSet

class SwitchShortcutSet extends FormBase {
    
    /**
     * The account the shortcut set is for.
     *
     * @var \Drupal\user\UserInterface
     */
    protected $user;
    
    /**
     * The shortcut set storage.
     *
     * @var \Drupal\shortcut\ShortcutSetStorageInterface
     */
    protected $shortcutSetStorage;
    
    /**
     * Constructs a SwitchShortcutSet object.
     *
     * @param \Drupal\shortcut\ShortcutSetStorageInterface $shortcut_set_storage
     *   The shortcut set storage.
     */
    public function __construct(ShortcutSetStorageInterface $shortcut_set_storage) {
        $this->shortcutSetStorage = $shortcut_set_storage;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('entity_type.manager')
            ->getStorage('shortcut_set'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFormId() {
        return 'shortcut_set_switch';
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildForm(array $form, FormStateInterface $form_state, ?UserInterface $user = NULL) {
        $account = $this->currentUser();
        $this->user = $user;
        // Prepare the list of shortcut sets.
        $options = array_map(function (ShortcutSet $set) {
            return $set->label();
        }, $this->shortcutSetStorage
            ->loadMultiple());
        $current_set = $this->shortcutSetStorage
            ->getDisplayedToUser($this->user);
        // Only administrators can add shortcut sets.
        $add_access = $account->hasPermission('administer shortcuts');
        if ($add_access) {
            $options['new'] = $this->t('New set');
        }
        $account_is_user = $this->user
            ->id() == $account->id();
        if (count($options) > 1) {
            $form['set'] = [
                '#type' => 'radios',
                '#title' => $account_is_user ? $this->t('Choose a set of shortcuts to use') : $this->t('Choose a set of shortcuts for this user'),
                '#options' => $options,
                '#default_value' => $current_set->id(),
            ];
            $form['label'] = [
                '#type' => 'textfield',
                '#title' => $this->t('Label'),
                '#description' => $this->t('The new set is created by copying links from your default shortcut set.'),
                '#access' => $add_access,
                '#states' => [
                    'visible' => [
                        ':input[name="set"]' => [
                            'value' => 'new',
                        ],
                    ],
                    'required' => [
                        ':input[name="set"]' => [
                            'value' => 'new',
                        ],
                    ],
                ],
            ];
            $form['id'] = [
                '#type' => 'machine_name',
                '#machine_name' => [
                    'exists' => [
                        $this,
                        'exists',
                    ],
                    'replace_pattern' => '[^a-z0-9-]+',
                    'replace' => '-',
                ],
                // This ID could be used for menu name.
'#maxlength' => 23,
                '#states' => [
                    'required' => [
                        ':input[name="set"]' => [
                            'value' => 'new',
                        ],
                    ],
                ],
                '#required' => FALSE,
            ];
            if (!$account_is_user) {
                $default_set = $this->shortcutSetStorage
                    ->getDefaultSet($this->user);
                $form['new']['#description'] = $this->t('The new set is created by copying links from the %default set.', [
                    '%default' => $default_set->label(),
                ]);
            }
            $form['actions'] = [
                '#type' => 'actions',
            ];
            $form['actions']['submit'] = [
                '#type' => 'submit',
                '#value' => $this->t('Change set'),
            ];
        }
        else {
            // There is only 1 option, so output a message in the $form array.
            $form['info'] = [
                '#markup' => '<p>' . $this->t('You are currently using the %set-name shortcut set.', [
                    '%set-name' => $current_set->label(),
                ]) . '</p>',
            ];
        }
        return $form;
    }
    
    /**
     * Determines if a shortcut set exists already.
     *
     * @param string $id
     *   The set ID to check.
     *
     * @return bool
     *   TRUE if the shortcut set exists, FALSE otherwise.
     */
    public function exists($id) {
        return (bool) $this->shortcutSetStorage
            ->getQuery()
            ->condition('id', $id)
            ->execute();
    }
    
    /**
     * {@inheritdoc}
     */
    public function validateForm(array &$form, FormStateInterface $form_state) {
        if ($form_state->getValue('set') == 'new') {
            // Check to prevent creating a shortcut set with an empty title.
            if (trim($form_state->getValue('label')) == '') {
                $form_state->setErrorByName('label', $this->t('The new set label is required.'));
            }
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function submitForm(array &$form, FormStateInterface $form_state) {
        $account = $this->currentUser();
        $account_is_user = $this->user
            ->id() == $account->id();
        if ($form_state->getValue('set') == 'new') {
            // Save a new shortcut set with links copied from the user's default set.
            
            /** @var \Drupal\shortcut\Entity\ShortcutSet $set */
            $set = $this->shortcutSetStorage
                ->create([
                'id' => $form_state->getValue('id'),
                'label' => $form_state->getValue('label'),
            ]);
            $set->save();
            $replacements = [
                '%user' => $this->user
                    ->label(),
                '%set_name' => $set->label(),
                ':switch-url' => Url::fromRoute('<current>')->toString(),
            ];
            if ($account_is_user) {
                // Only administrators can create new shortcut sets, so we know they have
                // access to switch back.
                $this->messenger()
                    ->addStatus($this->t('You are now using the new %set_name shortcut set. You can edit it from this page or <a href=":switch-url">switch back to a different one.</a>', $replacements));
            }
            else {
                $this->messenger()
                    ->addStatus($this->t('%user is now using a new shortcut set called %set_name. You can edit it from this page.', $replacements));
            }
            $form_state->setRedirect('entity.shortcut_set.customize_form', [
                'shortcut_set' => $set->id(),
            ]);
        }
        else {
            // Switch to a different shortcut set.
            
            /** @var \Drupal\shortcut\Entity\ShortcutSet $set */
            $set = $this->shortcutSetStorage
                ->load($form_state->getValue('set'));
            $replacements = [
                '%user' => $this->user
                    ->getDisplayName(),
                '%set_name' => $set->label(),
            ];
            $this->messenger()
                ->addStatus($account_is_user ? $this->t('You are now using the %set_name shortcut set.', $replacements) : $this->t('%user is now using the %set_name shortcut set.', $replacements));
        }
        // Assign the shortcut set to the provided user account.
        $this->shortcutSetStorage
            ->assignUser($set, $this->user);
    }
    
    /**
     * Checks access for the shortcut set switch form.
     *
     * @param \Drupal\user\UserInterface $user
     *   (optional) The owner of the shortcut set.
     *
     * @return \Drupal\Core\Access\AccessResultInterface
     *   The access result.
     */
    public function checkAccess(?UserInterface $user = NULL) {
        return shortcut_set_switch_access($user);
    }

}