<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\widgets;

use Yii;
use yii\base\Component;
use yii\base\ErrorHandler;
use yii\helpers\ArrayHelper;
use yii\helpers\Html;
use yii\base\Model;
use yii\web\JsExpression;

/**
 * ActiveField represents a form input field within an [[ActiveForm]].
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 */
class ActiveField extends Component
{
    /**
     * @var ActiveForm the form that this field is associated with.
     */
    public $form;
    /**
     * @var Model the data model that this field is associated with
     */
    public $model;
    /**
     * @var string the model attribute that this field is associated with
     */
    public $attribute;
    /**
     * @var array the HTML attributes (name-value pairs) for the field container tag.
     * The values will be HTML-encoded using [[Html::encode()]].
     * If a value is null, the corresponding attribute will not be rendered.
     * The following special options are recognized:
     *
     * - tag: the tag name of the container element. Defaults to "div".
     *
     * If you set a custom `id` for the container element, you may need to adjust the [[$selectors]] accordingly.
     *
     * @see \yii\helpers\Html::renderTagAttributes() for details on how attributes are being rendered.
     */
    public $options = ['class' => 'form-group'];
    /**
     * @var string the template that is used to arrange the label, the input field, the error message and the hint text.
     * The following tokens will be replaced when [[render()]] is called: `{label}`, `{input}`, `{error}` and `{hint}`.
     */
    public $template = "{label}\n{input}\n{hint}\n{error}";
    /**
     * @var array the default options for the input tags. The parameter passed to individual input methods
     * (e.g. [[textInput()]]) will be merged with this property when rendering the input tag.
     *
     * If you set a custom `id` for the input element, you may need to adjust the [[$selectors]] accordingly.
     *
     * @see \yii\helpers\Html::renderTagAttributes() for details on how attributes are being rendered.
     */
    public $inputOptions = ['class' => 'form-control'];
    /**
     * @var array the default options for the error tags. The parameter passed to [[error()]] will be
     * merged with this property when rendering the error tag.
     * The following special options are recognized:
     *
     * - tag: the tag name of the container element. Defaults to "div".
     * - encode: whether to encode the error output. Defaults to true.
     *
     * If you set a custom `id` for the error element, you may need to adjust the [[$selectors]] accordingly.
     *
     * @see \yii\helpers\Html::renderTagAttributes() for details on how attributes are being rendered.
     */
    public $errorOptions = ['class' => 'help-block'];
    /**
     * @var array the default options for the label tags. The parameter passed to [[label()]] will be
     * merged with this property when rendering the label tag.
     * @see \yii\helpers\Html::renderTagAttributes() for details on how attributes are being rendered.
     */
    public $labelOptions = ['class' => 'control-label'];
    /**
     * @var array the default options for the hint tags. The parameter passed to [[hint()]] will be
     * merged with this property when rendering the hint tag.
     * The following special options are recognized:
     *
     * - tag: the tag name of the container element. Defaults to "div".
     *
     * @see \yii\helpers\Html::renderTagAttributes() for details on how attributes are being rendered.
     */
    public $hintOptions = ['class' => 'hint-block'];
    /**
     * @var boolean whether to enable client-side data validation.
     * If not set, it will take the value of [[ActiveForm::enableClientValidation]].
     */
    public $enableClientValidation;
    /**
     * @var boolean whether to enable AJAX-based data validation.
     * If not set, it will take the value of [[ActiveForm::enableAjaxValidation]].
     */
    public $enableAjaxValidation;
    /**
     * @var boolean whether to perform validation when the value of the input field is changed.
     * If not set, it will take the value of [[ActiveForm::validateOnChange]].
     */
    public $validateOnChange;
    /**
     * @var boolean whether to perform validation when the input field loses focus.
     * If not set, it will take the value of [[ActiveForm::validateOnBlur]].
     */
    public $validateOnBlur;
    /**
     * @var boolean whether to perform validation while the user is typing in the input field.
     * If not set, it will take the value of [[ActiveForm::validateOnType]].
     * @see validationDelay
     */
    public $validateOnType;
    /**
     * @var integer number of milliseconds that the validation should be delayed when the user types in the field
     * and [[validateOnType]] is set true.
     * If not set, it will take the value of [[ActiveForm::validationDelay]].
     */
    public $validationDelay;
    /**
     * @var array the jQuery selectors for selecting the container, input and error tags.
     * The array keys should be "container", "input", and/or "error", and the array values
     * are the corresponding selectors. For example, `['input' => '#my-input']`.
     *
     * The container selector is used under the context of the form, while the input and the error
     * selectors are used under the context of the container.
     *
     * You normally do not need to set this property as the default selectors should work well for most cases.
     */
    public $selectors = [];
    /**
     * @var array different parts of the field (e.g. input, label). This will be used together with
     * [[template]] to generate the final field HTML code. The keys are the token names in [[template]],
     * while the values are the corresponding HTML code. Valid tokens include `{input}`, `{label}` and `{error}`.
     * Note that you normally don't need to access this property directly as
     * it is maintained by various methods of this class.
     */
    public $parts = [];


    /**
     * PHP magic method that returns the string representation of this object.
     * @return string the string representation of this object.
     */
    public function __toString()
    {
        // __toString cannot throw exception
        // use trigger_error to bypass this limitation
        try {
            return $this->render();
        } catch (\Exception $e) {
            ErrorHandler::convertExceptionToError($e);
            return '';
        }
    }

    /**
     * Renders the whole field.
     * This method will generate the label, error tag, input tag and hint tag (if any), and
     * assemble them into HTML according to [[template]].
     * @param string|callable $content the content within the field container.
     * If null (not set), the default methods will be called to generate the label, error tag and input tag,
     * and use them as the content.
     * If a callable, it will be called to generate the content. The signature of the callable should be:
     *
     * ~~~
     * function ($field) {
     *     return $html;
     * }
     * ~~~
     *
     * @return string the rendering result
     */
    public function render($content = null)
    {
        if ($content === null) {
            if (!isset($this->parts['{input}'])) {
                $this->parts['{input}'] = Html::activeTextInput($this->model, $this->attribute, $this->inputOptions);
            }
            if (!isset($this->parts['{label}'])) {
                $this->parts['{label}'] = Html::activeLabel($this->model, $this->attribute, $this->labelOptions);
            }
            if (!isset($this->parts['{error}'])) {
                $this->parts['{error}'] = Html::error($this->model, $this->attribute, $this->errorOptions);
            }
            if (!isset($this->parts['{hint}'])) {
                $this->parts['{hint}'] = '';
            }
            $content = strtr($this->template, $this->parts);
        } elseif (!is_string($content)) {
            $content = call_user_func($content, $this);
        }

        return $this->begin() . "\n" . $content . "\n" . $this->end();
    }

    /**
     * Renders the opening tag of the field container.
     * @return string the rendering result.
     */
    public function begin()
    {
        if ($this->form->enableClientScript) {
            $clientOptions = $this->getClientOptions();
            if (!empty($clientOptions)) {
                $this->form->attributes[] = $clientOptions;
            }
        }

        $inputID = Html::getInputId($this->model, $this->attribute);
        $attribute = Html::getAttributeName($this->attribute);
        $options = $this->options;
        $class = isset($options['class']) ? [$options['class']] : [];
        $class[] = "field-$inputID";
        if ($this->model->isAttributeRequired($attribute)) {
            $class[] = $this->form->requiredCssClass;
        }
        if ($this->model->hasErrors($attribute)) {
            $class[] = $this->form->errorCssClass;
        }
        $options['class'] = implode(' ', $class);
        $tag = ArrayHelper::remove($options, 'tag', 'div');

        return Html::beginTag($tag, $options);
    }

    /**
     * Renders the closing tag of the field container.
     * @return string the rendering result.
     */
    public function end()
    {
        return Html::endTag(isset($this->options['tag']) ? $this->options['tag'] : 'div');
    }

    /**
     * Generates a label tag for [[attribute]].
     * @param string|boolean $label the label to use. If null, the label will be generated via [[Model::getAttributeLabel()]].
     * If false, the generated field will not contain the label part.
     * Note that this will NOT be [[Html::encode()|encoded]].
     * @param array $options the tag options in terms of name-value pairs. It will be merged with [[labelOptions]].
     * The options will be rendered as the attributes of the resulting tag. The values will be HTML-encoded
     * using [[Html::encode()]]. If a value is null, the corresponding attribute will not be rendered.
     * @return static the field object itself
     */
    public function label($label = null, $options = [])
    {
        if ($label === false) {
            $this->parts['{label}'] = '';
            return $this;
        }

        $options = array_merge($this->labelOptions, $options);
        if ($label !== null) {
            $options['label'] = $label;
        }
        $this->parts['{label}'] = Html::activeLabel($this->model, $this->attribute, $options);

        return $this;
    }

    /**
     * Generates a tag that contains the first validation error of [[attribute]].
     * Note that even if there is no validation error, this method will still return an empty error tag.
     * @param array|boolean $options the tag options in terms of name-value pairs. It will be merged with [[errorOptions]].
     * The options will be rendered as the attributes of the resulting tag. The values will be HTML-encoded
     * using [[Html::encode()]]. If a value is null, the corresponding attribute will not be rendered.
     *
     * The following options are specially handled:
     *
     * - tag: this specifies the tag name. If not set, "div" will be used.
     *
     * If this parameter is false, no error tag will be rendered.
     *
     * If you set a custom `id` for the error element, you may need to adjust the [[$selectors]] accordingly.
     *
     * @return static the field object itself
     */
    public function error($options = [])
    {
        if ($options === false) {
            $this->parts['{error}'] = '';
            return $this;
        }
        $options = array_merge($this->errorOptions, $options);
        $this->parts['{error}'] = Html::error($this->model, $this->attribute, $options);

        return $this;
    }

    /**
     * Renders the hint tag.
     * @param string $content the hint content. It will NOT be HTML-encoded.
     * @param array $options the tag options in terms of name-value pairs. These will be rendered as
     * the attributes of the hint tag. The values will be HTML-encoded using [[Html::encode()]].
     *
     * The following options are specially handled:
     *
     * - tag: this specifies the tag name. If not set, "div" will be used.
     *
     * @return static the field object itself
     */
    public function hint($content, $options = [])
    {
        $options = array_merge($this->hintOptions, $options);
        $tag = ArrayHelper::remove($options, 'tag', 'div');
        $this->parts['{hint}'] = Html::tag($tag, $content, $options);

        return $this;
    }

    /**
     * Renders an input tag.
     * @param string $type the input type (e.g. 'text', 'password')
     * @param array $options the tag options in terms of name-value pairs. These will be rendered as
     * the attributes of the resulting tag. The values will be HTML-encoded using [[Html::encode()]].
     *
     * If you set a custom `id` for the input element, you may need to adjust the [[$selectors]] accordingly.
     *
     * @return static the field object itself
     */
    public function input($type, $options = [])
    {
        $options = array_merge($this->inputOptions, $options);
        $this->adjustLabelFor($options);
        $this->parts['{input}'] = Html::activeInput($type, $this->model, $this->attribute, $options);

        return $this;
    }

    /**
     * Renders a text input.
     * This method will generate the "name" and "value" tag attributes automatically for the model attribute
     * unless they are explicitly specified in `$options`.
     * @param array $options the tag options in terms of name-value pairs. These will be rendered as
     * the attributes of the resulting tag. The values will be HTML-encoded using [[Html::encode()]].
     *
     * The following special options are recognized:
     *
     * - maxlength: integer|boolean, when `maxlength` is set true and the model attribute is validated
     *   by a string validator, the `maxlength` option will take the value of [[\yii\validators\StringValidator::max]].
     *   This is available since version 2.0.3.
     *
     * Note that if you set a custom `id` for the input element, you may need to adjust the value of [[selectors]] accordingly.
     *
     * @return static the field object itself
     */
    public function textInput($options = [])
    {
        $options = array_merge($this->inputOptions, $options);
        $this->adjustLabelFor($options);
        $this->parts['{input}'] = Html::activeTextInput($this->model, $this->attribute, $options);

        return $this;
    }

    /**
     * Renders a hidden input.
     *
     * Note that this method is provided for completeness. In most cases because you do not need
     * to validate a hidden input, you should not need to use this method. Instead, you should
     * use [[\yii\helpers\Html::activeHiddenInput()]].
     *
     * This method will generate the "name" and "value" tag attributes automatically for the model attribute
     * unless they are explicitly specified in `$options`.
     * @param array $options the tag options in terms of name-value pairs. These will be rendered as
     * the attributes of the resulting tag. The values will be HTML-encoded using [[Html::encode()]].
     *
     * If you set a custom `id` for the input element, you may need to adjust the [[$selectors]] accordingly.
     *
     * @return static the field object itself
     */
    public function hiddenInput($options = [])
    {
        $options = array_merge($this->inputOptions, $options);
        $this->adjustLabelFor($options);
        $this->parts['{input}'] = Html::activeHiddenInput($this->model, $this->attribute, $options);

        return $this;
    }

    /**
     * Renders a password input.
     * This method will generate the "name" and "value" tag attributes automatically for the model attribute
     * unless they are explicitly specified in `$options`.
     * @param array $options the tag options in terms of name-value pairs. These will be rendered as
     * the attributes of the resulting tag. The values will be HTML-encoded using [[Html::encode()]].
     *
     * If you set a custom `id` for the input element, you may need to adjust the [[$selectors]] accordingly.
     *
     * @return static the field object itself
     */
    public function passwordInput($options = [])
    {
        $options = array_merge($this->inputOptions, $options);
        $this->adjustLabelFor($options);
        $this->parts['{input}'] = Html::activePasswordInput($this->model, $this->attribute, $options);

        return $this;
    }

    /**
     * Renders a file input.
     * This method will generate the "name" and "value" tag attributes automatically for the model attribute
     * unless they are explicitly specified in `$options`.
     * @param array $options the tag options in terms of name-value pairs. These will be rendered as
     * the attributes of the resulting tag. The values will be HTML-encoded using [[Html::encode()]].
     *
     * If you set a custom `id` for the input element, you may need to adjust the [[$selectors]] accordingly.
     *
     * @return static the field object itself
     */
    public function fileInput($options = [])
    {
        // https://github.com/yiisoft/yii2/pull/795
        if ($this->inputOptions !== ['class' => 'form-control']) {
            $options = array_merge($this->inputOptions, $options);
        }
        $this->adjustLabelFor($options);
        $this->parts['{input}'] = Html::activeFileInput($this->model, $this->attribute, $options);

        return $this;
    }

    /**
     * Renders a text area.
     * The model attribute value will be used as the content in the textarea.
     * @param array $options the tag options in terms of name-value pairs. These will be rendered as
     * the attributes of the resulting tag. The values will be HTML-encoded using [[Html::encode()]].
     *
     * If you set a custom `id` for the textarea element, you may need to adjust the [[$selectors]] accordingly.
     *
     * @return static the field object itself
     */
    public function textarea($options = [])
    {
        $options = array_merge($this->inputOptions, $options);
        $this->adjustLabelFor($options);
        $this->parts['{input}'] = Html::activeTextarea($this->model, $this->attribute, $options);

        return $this;
    }

    /**
     * Renders a radio button.
     * This method will generate the "checked" tag attribute according to the model attribute value.
     * @param array $options the tag options in terms of name-value pairs. The following options are specially handled:
     *
     * - uncheck: string, the value associated with the uncheck state of the radio button. If not set,
     *   it will take the default value '0'. This method will render a hidden input so that if the radio button
     *   is not checked and is submitted, the value of this attribute will still be submitted to the server
     *   via the hidden input. If you do not want any hidden input, you should explicitly set this option as null.
     * - label: string, a label displayed next to the radio button. It will NOT be HTML-encoded. Therefore you can pass
     *   in HTML code such as an image tag. If this is coming from end users, you should [[Html::encode()|encode]] it to prevent XSS attacks.
     *   When this option is specified, the radio button will be enclosed by a label tag. If you do not want any label, you should
     *   explicitly set this option as null.
     * - labelOptions: array, the HTML attributes for the label tag. This is only used when the "label" option is specified.
     *
     * The rest of the options will be rendered as the attributes of the resulting tag. The values will
     * be HTML-encoded using [[Html::encode()]]. If a value is null, the corresponding attribute will not be rendered.
     *
     * If you set a custom `id` for the input element, you may need to adjust the [[$selectors]] accordingly.
     *
     * @param boolean $enclosedByLabel whether to enclose the radio within the label.
     * If true, the method will still use [[template]] to layout the checkbox and the error message
     * except that the radio is enclosed by the label tag.
     * @return static the field object itself
     */
    public function radio($options = [], $enclosedByLabel = true)
    {
        if ($enclosedByLabel) {
            $this->parts['{input}'] = Html::activeRadio($this->model, $this->attribute, $options);
            $this->parts['{label}'] = '';
        } else {
            if (isset($options['label']) && !isset($this->parts['{label}'])) {
                $this->parts['{label}'] = $options['label'];
                if (!empty($options['labelOptions'])) {
                    $this->labelOptions = $options['labelOptions'];
                }
            }
            unset($options['labelOptions']);
            $options['label'] = null;
            $this->parts['{input}'] = Html::activeRadio($this->model, $this->attribute, $options);
        }
        $this->adjustLabelFor($options);

        return $this;
    }

    /**
     * Renders a checkbox.
     * This method will generate the "checked" tag attribute according to the model attribute value.
     * @param array $options the tag options in terms of name-value pairs. The following options are specially handled:
     *
     * - uncheck: string, the value associated with the uncheck state of the radio button. If not set,
     *   it will take the default value '0'. This method will render a hidden input so that if the radio button
     *   is not checked and is submitted, the value of this attribute will still be submitted to the server
     *   via the hidden input. If you do not want any hidden input, you should explicitly set this option as null.
     * - label: string, a label displayed next to the checkbox. It will NOT be HTML-encoded. Therefore you can pass
     *   in HTML code such as an image tag. If this is coming from end users, you should [[Html::encode()|encode]] it to prevent XSS attacks.
     *   When this option is specified, the checkbox will be enclosed by a label tag. If you do not want any label, you should
     *   explicitly set this option as null.
     * - labelOptions: array, the HTML attributes for the label tag. This is only used when the "label" option is specified.
     *
     * The rest of the options will be rendered as the attributes of the resulting tag. The values will
     * be HTML-encoded using [[Html::encode()]]. If a value is null, the corresponding attribute will not be rendered.
     *
     * If you set a custom `id` for the input element, you may need to adjust the [[$selectors]] accordingly.
     *
     * @param boolean $enclosedByLabel whether to enclose the checkbox within the label.
     * If true, the method will still use [[template]] to layout the checkbox and the error message
     * except that the checkbox is enclosed by the label tag.
     * @return static the field object itself
     */
    public function checkbox($options = [], $enclosedByLabel = true)
    {
        if ($enclosedByLabel) {
            $this->parts['{input}'] = Html::activeCheckbox($this->model, $this->attribute, $options);
            $this->parts['{label}'] = '';
        } else {
            if (isset($options['label']) && !isset($this->parts['{label}'])) {
                $this->parts['{label}'] = $options['label'];
                if (!empty($options['labelOptions'])) {
                    $this->labelOptions = $options['labelOptions'];
                }
            }
            unset($options['labelOptions']);
            $options['label'] = null;
            $this->parts['{input}'] = Html::activeCheckbox($this->model, $this->attribute, $options);
        }
        $this->adjustLabelFor($options);

        return $this;
    }

    /**
     * Renders a drop-down list.
     * The selection of the drop-down list is taken from the value of the model attribute.
     * @param array $items the option data items. The array keys are option values, and the array values
     * are the corresponding option labels. The array can also be nested (i.e. some array values are arrays too).
     * For each sub-array, an option group will be generated whose label is the key associated with the sub-array.
     * If you have a list of data models, you may convert them into the format described above using
     * [[ArrayHelper::map()]].
     *
     * Note, the values and labels will be automatically HTML-encoded by this method, and the blank spaces in
     * the labels will also be HTML-encoded.
     * @param array $options the tag options in terms of name-value pairs. The following options are specially handled:
     *
     * - prompt: string, a prompt text to be displayed as the first option;
     * - options: array, the attributes for the select option tags. The array keys must be valid option values,
     *   and the array values are the extra attributes for the corresponding option tags. For example,
     *
     * ~~~
     * [
     *     'value1' => ['disabled' => true],
     *     'value2' => ['label' => 'value 2'],
     * ];
     * ~~~
     *
     * - groups: array, the attributes for the optgroup tags. The structure of this is similar to that of 'options',
     *   except that the array keys represent the optgroup labels specified in $items.
     *
     * The rest of the options will be rendered as the attributes of the resulting tag. The values will
     * be HTML-encoded using [[Html::encode()]]. If a value is null, the corresponding attribute will not be rendered.
     *
     * If you set a custom `id` for the input element, you may need to adjust the [[$selectors]] accordingly.
     *
     * @return static the field object itself
     */
    public function dropDownList($items, $options = [])
    {
        $options = array_merge($this->inputOptions, $options);
        $this->adjustLabelFor($options);
        $this->parts['{input}'] = Html::activeDropDownList($this->model, $this->attribute, $items, $options);

        return $this;
    }

    /**
     * Renders a list box.
     * The selection of the list box is taken from the value of the model attribute.
     * @param array $items the option data items. The array keys are option values, and the array values
     * are the corresponding option labels. The array can also be nested (i.e. some array values are arrays too).
     * For each sub-array, an option group will be generated whose label is the key associated with the sub-array.
     * If you have a list of data models, you may convert them into the format described above using
     * [[\yii\helpers\ArrayHelper::map()]].
     *
     * Note, the values and labels will be automatically HTML-encoded by this method, and the blank spaces in
     * the labels will also be HTML-encoded.
     * @param array $options the tag options in terms of name-value pairs. The following options are specially handled:
     *
     * - prompt: string, a prompt text to be displayed as the first option;
     * - options: array, the attributes for the select option tags. The array keys must be valid option values,
     *   and the array values are the extra attributes for the corresponding option tags. For example,
     *
     * ~~~
     * [
     *     'value1' => ['disabled' => true],
     *     'value2' => ['label' => 'value 2'],
     * ];
     * ~~~
     *
     * - groups: array, the attributes for the optgroup tags. The structure of this is similar to that of 'options',
     *   except that the array keys represent the optgroup labels specified in $items.
     * - unselect: string, the value that will be submitted when no option is selected.
     *   When this attribute is set, a hidden field will be generated so that if no option is selected in multiple
     *   mode, we can still obtain the posted unselect value. If you do not want any hidden input,
     *   you should explicitly set this option as null.
     *
     * The rest of the options will be rendered as the attributes of the resulting tag. The values will
     * be HTML-encoded using [[Html::encode()]]. If a value is null, the corresponding attribute will not be rendered.
     *
     * If you set a custom `id` for the input element, you may need to adjust the [[$selectors]] accordingly.
     *
     * @return static the field object itself
     */
    public function listBox($items, $options = [])
    {
        $options = array_merge($this->inputOptions, $options);
        $this->adjustLabelFor($options);
        $this->parts['{input}'] = Html::activeListBox($this->model, $this->attribute, $items, $options);

        return $this;
    }

    /**
     * Renders a list of checkboxes.
     * A checkbox list allows multiple selection, like [[listBox()]].
     * As a result, the corresponding submitted value is an array.
     * The selection of the checkbox list is taken from the value of the model attribute.
     * @param array $items the data item used to generate the checkboxes.
     * The array values are the labels, while the array keys are the corresponding checkbox values.
     * Note that the labels will NOT be HTML-encoded, while the values will.
     * @param array $options options (name => config) for the checkbox list. The following options are specially handled:
     *
     * - unselect: string, the value that should be submitted when none of the checkboxes is selected.
     *   By setting this option, a hidden input will be generated. If you do not want any hidden input,
     *   you should explicitly set this option as null.
     * - separator: string, the HTML code that separates items.
     * - item: callable, a callback that can be used to customize the generation of the HTML code
     *   corresponding to a single item in $items. The signature of this callback must be:
     *
     * ~~~
     * function ($index, $label, $name, $checked, $value)
     * ~~~
     *
     * where $index is the zero-based index of the checkbox in the whole list; $label
     * is the label for the checkbox; and $name, $value and $checked represent the name,
     * value and the checked status of the checkbox input.
     * @return static the field object itself
     */
    public function checkboxList($items, $options = [])
    {
        $this->adjustLabelFor($options);
        $this->parts['{input}'] = Html::activeCheckboxList($this->model, $this->attribute, $items, $options);

        return $this;
    }

    /**
     * Renders a list of radio buttons.
     * A radio button list is like a checkbox list, except that it only allows single selection.
     * The selection of the radio buttons is taken from the value of the model attribute.
     * @param array $items the data item used to generate the radio buttons.
     * The array values are the labels, while the array keys are the corresponding radio values.
     * Note that the labels will NOT be HTML-encoded, while the values will.
     * @param array $options options (name => config) for the radio button list. The following options are specially handled:
     *
     * - unselect: string, the value that should be submitted when none of the radio buttons is selected.
     *   By setting this option, a hidden input will be generated. If you do not want any hidden input,
     *   you should explicitly set this option as null.
     * - separator: string, the HTML code that separates items.
     * - item: callable, a callback that can be used to customize the generation of the HTML code
     *   corresponding to a single item in $items. The signature of this callback must be:
     *
     * ~~~
     * function ($index, $label, $name, $checked, $value)
     * ~~~
     *
     * where $index is the zero-based index of the radio button in the whole list; $label
     * is the label for the radio button; and $name, $value and $checked represent the name,
     * value and the checked status of the radio button input.
     * @return static the field object itself
     */
    public function radioList($items, $options = [])
    {
        $this->adjustLabelFor($options);
        $this->parts['{input}'] = Html::activeRadioList($this->model, $this->attribute, $items, $options);

        return $this;
    }

    /**
     * Renders a widget as the input of the field.
     *
     * Note that the widget must have both `model` and `attribute` properties. They will
     * be initialized with [[model]] and [[attribute]] of this field, respectively.
     *
     * If you want to use a widget that does not have `model` and `attribute` properties,
     * please use [[render()]] instead.
     *
     * For example to use the [[MaskedInput]] widget to get some date input, you can use
     * the following code, assuming that `$form` is your [[ActiveForm]] instance:
     *
     * ```php
     * $form->field($model, 'date')->widget(\yii\widgets\MaskedInput::className(), [
     *     'mask' => '99/99/9999',
     * ]);
     * ```
     *
     * If you set a custom `id` for the input element, you may need to adjust the [[$selectors]] accordingly.
     *
     * @param string $class the widget class name
     * @param array $config name-value pairs that will be used to initialize the widget
     * @return static the field object itself
     */
    public function widget($class, $config = [])
    {
        /* @var $class \yii\base\Widget */
        $config['model'] = $this->model;
        $config['attribute'] = $this->attribute;
        $config['view'] = $this->form->getView();
        $this->parts['{input}'] = $class::widget($config);

        return $this;
    }

    /**
     * Adjusts the "for" attribute for the label based on the input options.
     * @param array $options the input options
     */
    protected function adjustLabelFor($options)
    {
        if (isset($options['id']) && !isset($this->labelOptions['for'])) {
            $this->labelOptions['for'] = $options['id'];
        }
    }

    /**
     * Returns the JS options for the field.
     * @return array the JS options
     */
    protected function getClientOptions()
    {
        $attribute = Html::getAttributeName($this->attribute);
        if (!in_array($attribute, $this->model->activeAttributes(), true)) {
            return [];
        }

        $enableClientValidation = $this->enableClientValidation || $this->enableClientValidation === null && $this->form->enableClientValidation;
        $enableAjaxValidation = $this->enableAjaxValidation || $this->enableAjaxValidation === null && $this->form->enableAjaxValidation;

        if ($enableClientValidation) {
            $validators = [];
            foreach ($this->model->getActiveValidators($attribute) as $validator) {
                /* @var $validator \yii\validators\Validator */
                $js = $validator->clientValidateAttribute($this->model, $attribute, $this->form->getView());
                if ($validator->enableClientValidation && $js != '') {
                    if ($validator->whenClient !== null) {
                        $js = "if (({$validator->whenClient})(attribute, value)) { $js }";
                    }
                    $validators[] = $js;
                }
            }
        }

        if (!$enableAjaxValidation && (!$enableClientValidation || empty($validators))) {
            return [];
        }

        $options = [];

        $inputID = Html::getInputId($this->model, $this->attribute);
        $options['id'] = $inputID;
        $options['name'] = $this->attribute;

        $options['container'] = isset($this->selectors['container']) ? $this->selectors['container'] : ".field-$inputID";
        $options['input'] = isset($this->selectors['input']) ? $this->selectors['input'] : "#$inputID";
        if (isset($this->selectors['error'])) {
            $options['error'] = $this->selectors['error'];
        } elseif (isset($this->errorOptions['class'])) {
            $options['error'] = '.' . implode('.', preg_split('/\s+/', $this->errorOptions['class'], -1, PREG_SPLIT_NO_EMPTY));
        } else {
            $options['error'] = isset($this->errorOptions['tag']) ? $this->errorOptions['tag'] : 'span';
        }

        $options['encodeError'] = !isset($this->errorOptions['encode']) || $this->errorOptions['encode'];
        if ($enableAjaxValidation) {
            $options['enableAjaxValidation'] = true;
        }
        foreach (['validateOnChange', 'validateOnBlur', 'validateOnType', 'validationDelay'] as $name) {
            $options[$name] = $this->$name === null ? $this->form->$name : $this->$name;
        }

        if (!empty($validators)) {
            $options['validate'] = new JsExpression("function (attribute, value, messages, deferred, \$form) {" . implode('', $validators) . '}');
        }

        // only get the options that are different from the default ones (set in yii.activeForm.js)
        return array_diff_assoc($options, [
            'validateOnChange' => true,
            'validateOnBlur' => true,
            'validateOnType' => false,
            'validationDelay' => 500,
            'encodeError' => true,
            'error' => '.help-block',
        ]);
    }
}