<?php namespace ProcessWire;

/**
 * Base for selection form inputs, which by default behaves as a regular <select>
 *
 * Serves as the base for Inputfields that provide selection of options (whether single or multi).
 * As a result, this class includes functionality for, and checks for both single-and-multi selection values. 
 * Sublcasses will want to override the render method, but it's not necessary to override processInput().
 * Subclasses that select multiple values should implement the InputfieldHasArrayValue interface. 
 * 
 * @property string|int $defaultValue
 * @property array|string $options Get or set options, array of [value => label], or use options string. 
 * @property array $optionAttributes 
 *
 */
class InputfieldSelect extends Inputfield {

	/**
	 * Options specific to this Select
	 *
	 */
	protected $options = array();

	/**
	 * Attributes for options specific to this select (if applicable)
	 *
	 */
	protected $optionAttributes = array();

	/**
	 * Alternate language labels for options, array of [ languageID => [ optionValue => optionLabel ] ]
	 * 
	 * @var array
	 * 
	 */
	protected $optionLanguageLabels = array();

	/**
	 * Return information about this module
	 *
	 */
	public static function getModuleInfo() {
		return array(
			'title' => __('Select', __FILE__), // Module Title
			'summary' => __('Selection of a single value from a select pulldown', __FILE__), // Module Summary
			'version' => 102,
			'permanent' => true, 
			);
	}

	/**
	 * Construct
	 * 
	 */
	public function __construct() {
		parent::__construct();
		$this->set('defaultValue', ''); 
	}

	/**
	 * Add an option that may be selected
	 *
	 * If you want to add an optgroup, use the $value param as the label, and the label param as an array of options. 
	 * Note that optgroups may not be applicable to other Inputfields that descend from InputfieldSelect.
	 *
	 * @param string $value Value that the option submits (or label of optgroup, if specifying an optgroup)
	 * @param string $label|array Optional label associated with the value (if null, value will be used as the label), or array of optgroup options [value=>label]
	 * @param array $attributes Optional attributes to be associated with this option (i.e. a 'selected' attribute for an <option> tag)
	 * @return $this
	 *
	 */
	public function addOption($value, $label = null, array $attributes = null) {
		if(is_null($label) || (is_string($label) && !strlen($label))) $label = $value; 
		$this->options[$value] = $label; 	
		if(!is_null($attributes)) $this->optionAttributes[$value] = $attributes; 
		return $this; 
	}

	/**
	 * Add multiple options at once
	 *
 	 * @param array $options Array of options to add. It is assumed that array keys are the option value, and array 
	 *   values are the option labels, unless overridden by the $assoc argument.
	 * @param bool $assoc Is $options an associative array? (default=true). Specify false if $options is intended to be
	 *   a regular PHP array, where the array keys/indexes should be ignored, and option value will also be the label.
	 * @return $this
	 *
	 */
	public function addOptions(array $options, $assoc = true) {
		foreach($options as $k => $v) {
			if($assoc) {
				$this->addOption($k, $v);
			} else {
				$this->addOption($v);
			}
		}
		return $this; 
	}

	/**
	 * Set/replace all options
	 *
	 * @param array $options Array of options to add. It is assumed that array keys are the option value, and array
	 *   values are the option labels, unless overridden by the $assoc argument.
	 * @param bool $assoc Is $options an associative array? (default=true). Specify false if $options is intended to be
	 *   a regular PHP array, where the array keys/indexes should be ignored, and option value will also be the label.
	 * @return $this
	 *
	 */
	public function setOptions(array $options, $assoc = true) {
		$this->options = array();
		return $this->addOptions($options, $assoc);
	}

	/**
	 * Get or set label for given option value/key (default language)
	 * 
	 * @param string|int $key Option value to get or set label for
	 * @param string|null $label If setting label, specify label to set. If getting, then omit. 
	 * @return string|bool Returns boolean false if option not found, otherwise returns option label (string).
	 * @since 3.0.134
	 * @see InputfieldSelect::optionLanguageLabel()
	 * 
	 */
	public function optionLabel($key, $label = null) {
		if(!isset($this->options[$key])) return false;
		if($label !== null) $this->options[$key] = $label;
		return isset($this->options[$key]) ? $this->options[$key] : null;
	}

	/**
	 * Get or set alternative language label(s) 
	 * 
	 * @param Language|int|string $language Language object, id or name (required). 
	 * @param string|null|bool $key Option key/value to get/set label for, 
	 *  OR omit to return all currently set option language labels for language,
	 *  OR boolean false to remove all language labels for this option value/key.
	 *  OR array of [ optionValue => optionLabel ] to add multiple option values for language.
	 * @param $label|string|bool Translated label text to set,
	 *  OR omit to GET language label.
	 *  OR boolean false to remove.
	 * @return string|array|Inputfield Return value depends on given arguments
	 * 
	 */
	public function optionLanguageLabel($language, $key = null, $label = null) {
		if(is_string($language) && !ctype_digit("$language")) {
			$language = $this->wire('languages')->get($language);
		}
		$languageID = (int) "$language"; // converts Page or string to id
		if(!isset($this->optionLanguageLabels[$languageID])) {
			$this->optionLanguageLabels[$languageID] = array();
		}
		if($key === null) {
			return $this->optionLanguageLabels[$languageID];
		} else if($key === false) {
			unset($this->optionLanguageLabels[$languageID]);
		} else if(is_array($key)) {
			foreach($key as $k => $v) $this->optionLanguageLabels[$languageID][$k] = $v;
		} else if($label === null) {
			return isset($this->optionLanguageLabels[$languageID][$key]) ? $this->optionLanguageLabels[$languageID][$key] : '';
		} else if($label === false) {
			unset($this->optionLanguageLabels[$languageID][$key]);
		} else {
			$this->optionLanguageLabels[$languageID][$key] = $label;
		}
		return $this;	
	}
	
	/**
	 * Given a multi-line string, convert it to options, one per line
	 *
	 * Lines preceded with a plus "+" are assumed selected, i.e. +option
	 * Lines with an equals sign are split into separate value and label, i.e. value=label
	 *
	 * @param string $value 
	 * @return $this
	 *
	 */
	public function addOptionsString($value) {

		$value = (string) $value; 
		$options = explode("\n", $value);
		$lastOption = '';
		$optgroup = array();
		$optgroupLabel = '';

		foreach($options as $option) {

			// in an optgroup when line starts with 3 or more spaces
			if(strpos($option, '   ') === 0 && !empty($lastOption)) {
				// if no optgroupLabel, we're starting a new option group
				if(empty($optgroupLabel)) $optgroupLabel = $lastOption; 
				$option = trim($option);
			} else {
				if($optgroupLabel) $this->addOption($optgroupLabel, $optgroup); 
				$optgroup = array();
				$optgroupLabel = '';
			}

			$option = trim($option); 
			$attrs = array(); 
			$label = null;

			if(strpos($option, '++') === 0) {
				// double plus should convert to single plus and not make it selected
				$option = substr($option, 1);
			} else if(substr($option, 0, 1) === '+') {
				// if option starts with a plus then make it selected
				$attrs['selected'] = 'selected';
				$option = ltrim($option, '+');
			} else if(strpos($option, 'disabled:') === 0) {
				// if option starts with "disabled:" then make it disabled
				$attrs['disabled'] = 'disabled';
				$option = preg_replace('/^disabled:\s*/', '', $option);
			}

			if(strpos($option, '=') !== false && strpos($option, '==') === false) {
				// option has an equals "=", but not "==", then assume it's a: value=label
				list($option, $label) = explode('=', $option);
			}

			if(strpos($option, '==') !== false) {
				// convert double equals "==" to single equals "=", as a means of allowing escaped equals sign
				$option = str_replace('==', '=', $option);
			}

			$option = trim($option, '+ '); 
		
			if($optgroupLabel) {
				// add option to optgroup
				$optgroup[$option] = is_null($label) ? $option : $label;
				if(count($attrs)) $this->optionAttributes[$option] = $attrs; 
			} else {	
				// add the option
				$this->addOption($option, $label, $attrs);
			}

			$lastOption = $option;
		}

		if($optgroupLabel && count($optgroup)) {
			$this->addOption($optgroupLabel, $optgroup);
		}

		return $this; 
	}

	/**
	 * Add/modify existing option labels from a line separated key=value string, primarily for multi-language support
	 * 
	 * @param string $str String of optionValue=optionLabel with each on its own line
	 * @param int $languageID Language ID to set for, or omit for default language
	 * 
	 */
	protected function addOptionLabelsString($str, $languageID = 0) {
		foreach(explode("\n", $str) as $line) {
			$line = trim($line);
			$line = ltrim($line, '+');
			if(strpos($line, 'disabled:') === 0) list(,$line) = explode('disabled:', $line, 2);
			if(!strpos($line, '=')) continue; // 0 or false OK
			list($key, $label) = explode('=', $line, 2);
			if($languageID) {
				$this->optionLanguageLabel($languageID, $key, $label); 
			} else {
				$this->addOption($key, $label);
			}
		}
	}

	/**
	 * Remove the option with the given value
	 * 
	 * @param string|int $value
	 * @return $this
	 *
	 */
	public function removeOption($value) {
		unset($this->options[$value]); 
		return $this; 
	}

	/**
	 * Replace an option already present with the new value (and optionally new label and attributes)
	 * 
	 * @param string|int|float $oldValue
	 * @param string|int|float $newValue
	 * @param string|null $newLabel Specify string to replace or omit (null) to leave existing label
	 * @param array|null $newAttributes Specify array to replace, or omit (null) to leave existing attributes
	 * @return bool True if option was replaced, false if oldValue was not found to replace, 
	 * @since 3.0.134
	 * 
	 */
	public function replaceOption($oldValue, $newValue, $newLabel = null, $newAttributes = null) {
		$options = array();
		$found = false;
		
		foreach($this->options as $value => $label) {
			if($value === $oldValue) {
				$found = true;
				$options[$newValue] = ($newLabel === null ? $label : $newLabel);
				$attributes = is_array($newAttributes) ? $newAttributes : $this->getOptionAttributes($oldValue);
				unset($this->optionAttributes[$oldValue], $this->optionAttributes[$newValue]);
				if(!empty($attributes)) $this->setOptionAttributes($newValue, $attributes);
			} else {
				$options[$value] = $label;
			}
		}
		
		if($found) $this->options = $options;
		
		return $found;
	}

	/**
	 * Insert options before or after existing option
	 * 
	 * @param array $options New options to insert [ value => label ]
	 * @param string|int|null $existingValue Insert before or after option having this value
	 * @param bool $insertAfter Insert after rather than before? (default=false)
	 * @return self
	 * @since 3.0.134
	 * 
	 */
	protected function insertOptions(array $options, $existingValue = null, $insertAfter = false) {
		$a = array(); 
		
		if($existingValue === null || !isset($this->options[$existingValue])) {
			// existing value isn’t present, so we will prepend or append instead
			if($insertAfter) {
				// append new options to end and return
				$this->addOptions($options);
				return $this;
			} else {
				// prepend to beginning
				$a = $options;
			}
		}

		foreach($this->options as $value => $label) {
			
			if($value !== $existingValue) {
				if(!isset($a[$value])) $a[$value] = $label;
				continue;
			}

			// if inserting after, new options will be inserted after this existing option
			if($insertAfter) $a[$value] = $label;
		
			// add the new options
			foreach($options as $k => $v) {
				if(isset($a[$k])) unset($a[$k]);
				$a[$k] = $v;
			}

			// add existing option back, after the new ones
			if(!$insertAfter && !isset($a[$value])) $a[$value] = $label; 
		}
		
		$this->options = $a;
		
		return $this;
	}

	/**
	 * Insert new options before an existing option (or prepend options to beginning)
	 * 
	 * @param array $options Associative array of `[ 'value' => 'label' ]` containing new options to add.
	 * @param string|int|null $existingValue Existing option value to add options before, or omit to add at beginning.
	 * @return self
	 * @since 3.0.134
	 * 
	 */
	public function insertOptionsBefore(array $options, $existingValue = null) {
		return $this->insertOptions($options, $existingValue, false);
	}

	/**
	 * Insert new options after an existing option
	 *
	 * @param array $options Associative array of `[ 'value' => 'label' ]` containing new options to add.
	 * @param string|int|null $existingValue Existing option value to add options after, or omit to append at end.
	 * @return self
	 * @since 3.0.134
	 *
	 */
	public function insertOptionsAfter(array $options, $existingValue = null) {
		return $this->insertOptions($options, $existingValue, true);
	}
		
	/**
	 * Get all options for this Select
	 *
	 * @return array
	 *
	 */
	public function getOptions() {
		return $this->options; 
	}

	/**
	 * Returns whether the provided value is one of the available options
	 *
	 * @param string|int $value
	 * @param array $options Array of options to check, or omit if using this classes options. 
	 * @return bool
	 *
	 */
	public function isOption($value, array $options = null) {

		if(is_null($options)) $options = $this->options; 
		$is = false;
		
		foreach($options as $key => $option) {
			if(is_array($option)) {
				// fieldgroup
				if($this->isOption($value, $option)) {
					$is = true;
					break;
				}
			} else {
				if("$value" === "$key") {
					$is = true;
					break;
				}
			}
		}
		
		return $is; 
	}

	/**
	 * Returns whether the provided value is selected
	 * 
	 * @param string|int $value
	 * @return bool
	 *
	 */
	public function isOptionSelected($value) {

		$valueAttr = $this->attr('value'); 
		if($this->isEmpty()) {
			// no value set yet, check if it's set in any of the option attributes
			$selected = false;
			if(isset($this->optionAttributes[$value])) {
				$attrs = $this->optionAttributes[$value]; 
				if(!empty($attrs['selected']) || !empty($attrs['checked'])) $selected = true; 
				
			}
			if($selected) return true; 
		}

		if($this instanceof InputfieldHasArrayValue) { 
			// multiple selection
			$selected = false;
			foreach($valueAttr as $v) {
				$selected = "$v" === "$value";
				if($selected) break;
			}
			return $selected; 
		}

		return "$value" == (string) $this->value; 
	}

	/**
	 * Is the given option value disabled?
	 * 
	 * @param $value
	 * @return bool
	 * 
	 */
	public function isOptionDisabled($value) {
		$disabled = false;
		if(isset($this->optionAttributes[$value])) {
			$attrs = $this->optionAttributes[$value];
			if(!empty($attrs['disabled'])) $disabled = true; 
		}
		return $disabled;
	}

	/**
	 * Get or set option attributes
	 * 
	 * This method is a combined getOptionAttributes() and setOptionAttributes(). Use the dedicated get/set
	 * methods when you need more options. 
	 * 
	 * @param string|int $key Option value to get or set attributes for, or omit to get all option attributes.
	 * @param array|null|bool $attributes Specify array to set attributes, omit to get attributes
	 * @param bool $append Specify true to append to existing attributes rather than replacing
	 * @return array Associative array of attributes
	 * @since 3.0.134
	 * 
	 */
	public function optionAttributes($key = null, $attributes = null, $append = false) {
		if($key === null) return $this->optionAttributes;
		if(is_array($attributes)) {
			if($append) {
				$this->addOptionAttributes($key, $attributes);
			} else {
				$this->setOptionAttributes($key, $attributes);
			}
		}
		return $this->getOptionAttributes($key);
	}
	
	/**
	 * Get an attributes array intended for an item (or for all items)
	 *
	 * @param string|int|null $key Option value, or omit to return ALL option attributes indexed by option value
	 * @return array Array of attributes
	 *
	 */
	public function getOptionAttributes($key = null) {
		if($key === null) return $this->optionAttributes;
		if(!isset($this->optionAttributes[$key])) return array();
		return $this->optionAttributes[$key];
	}

	/**
	 * Set/replace entire attributes array for an item
	 *
	 * @param string|int|array $key Option value, or specify associative array (indexed by option value) to set ALL option attributes
	 * @param array $attrs Array of attributes to set, or omit if you specified array for first argument.
	 * @return $this
	 *
	 */
	public function setOptionAttributes($key, array $attrs = array()) {
		if(is_array($key)) {
			$this->optionAttributes = $key;
		} else {
			$this->optionAttributes[$key] = $attrs;
		}
		return $this;
	}

	/**
	 * Add attributes for an item (without removing existing attributes), or for multiple items
	 *
	 * @param string|int|array $key Option value, or array of option attributes indexed by option value.
	 * @param array $attrs Array of attributes to set, or omit if you specified array for first argument.
	 * @return $this
	 *
	 */
	public function addOptionAttributes($key, array $attrs = array()) {
		if(is_array($key)) {
			foreach($key as $k => $v) {
				$this->addOptionAttributes($k, $v); 
			}
		} else {
			$value = isset($this->optionAttributes[$key]) ? $this->optionAttributes[$key] : array();
			$this->optionAttributes[$key] = array_merge($value, $attrs);
		}
		return $this;
	}

	/**
	 * Get an attributes string intended for the <option> element
	 *
	 * @param string|array $key If given an array, it will be assumed to the attributes you want rendered. 
	 *   If given a value for an existing option, then the attributes for that option will be rendered.
	 * @return string
	 *
	 */
	public function getOptionAttributesString($key) {
		if(is_array($key)) {
			$attrs = $key;
		} else if(!isset($this->optionAttributes[$key])) {
			return '';
		} else {
			$attrs = $this->optionAttributes[$key];
		}
		return $this->getAttributesString($attrs);
	}

	/**
	 * Render the given options
	 * 
	 * Note: method was protected prior to 3.0.116
	 * 
	 * @param array|null $options Options array or omit (null) to use already specified options
	 * @param bool $allowBlank Allow first item to be blank when supported? (default=true)
	 * @return string
	 * 
	 */
	public function renderOptions($options = null, $allowBlank = true) {

		if($options === null) $options = $this->options;
		$out = '';
		reset($options); 
		$key = key($options); 
		$hasBlankOption = empty($key); 
		if($allowBlank && !$hasBlankOption && !$this->attr('multiple')) { 
			if($this->getSetting('required') && $this->attr('value')) {
				// if required and a value is already selected, do not add a blank option
			} else {
				$out .= "<option value=''>&nbsp;</option>";
			}
		}

		foreach($options as $value => $label) {

			if(is_array($label)) {
				$out .= 
					"<optgroup label='" . htmlspecialchars($value, ENT_QUOTES, 'UTF-8') . "'>" . 
					$this->renderOptions($label, false) . 
					"</optgroup>";
				continue; 
			}

			$selected = $this->isOptionSelected($value) ? " selected='selected'" : '';
			$attrs = $this->getOptionAttributes($value);
			unset($attrs['selected'], $attrs['checked'], $attrs['value']);
			$attrs = $this->getOptionAttributesString($attrs);
			$out .= 
				"<option$selected $attrs value='" . htmlspecialchars($value, ENT_QUOTES, "UTF-8") . "'>" . 
				$this->entityEncode($label) . 
				"</option>";
		}

		return $out; 
	}

	/**
	 * Check for default value and populate when appropriate
	 *
	 * This should be called at the beginning of render() and at the end of processInput()
	 *
	 */
	protected function checkDefaultValue() {

		if(!$this->required || !$this->defaultValue || !$this->isEmpty()) return;

		// when a value is required and the value is empty and a default value is specified, we use it.
		if($this instanceof InputfieldHasArrayValue) {
			/** @var InputfieldSelect $this */
			$value = explode("\n", $this->defaultValue); 
			foreach($value as $k => $v) {
				$value[$k] = trim($v); // remove possible extra LF
			}
		} else {
			$value = $this->defaultValue; 
			$pos = strpos($value, "\n"); 
			if($pos) $value = substr($value, 0, $pos); 
			$value = trim($value); 
		}
		$this->attr('value', $value); 
	}

	/**
	 * Render ready
	 * 
	 * @param Inputfield|null $parent
	 * @param bool $renderValueMode
	 * @return bool
	 * 
	 */
	public function renderReady(Inputfield $parent = null, $renderValueMode = false) {
		if(!empty($this->optionLanguageLabels) && $this->wire('languages') && $this->hasFieldtype === false) {
			// make option labels use use language where available
			$language = $this->wire('user')->language;
			$defaultLanguage = $this->wire('languages')->getDefault();
			if(!empty($this->optionLanguageLabels[$language->id])) {
				$labels = $this->optionLanguageLabels[$language->id];
				foreach($this->options as $key => $defaultLabel) {
					if(empty($labels[$key])) continue;
					$this->options[$key] = $labels[$key];
					if($language->id != $defaultLanguage->id) {
						$this->optionLanguageLabel($defaultLanguage, $key, $defaultLabel);
					}
				}
			}
		}
		return parent::renderReady($parent, $renderValueMode);
	}

	/**
	 * Render and return the output for this Select
	 * 
	 * @return string
	 *
	 */
	public function ___render() {
		$this->checkDefaultValue();
		$attrs = $this->getAttributes();
		unset($attrs['value']); 

		$out =	
			"<select " . $this->getAttributesString($attrs) . ">" . 
			$this->renderOptions($this->options) . 
			"</select>";

		return $out; 
	}

	/**
	 * Render non-editable value
	 * 
	 * @return string
	 * 
	 */
	public function ___renderValue() {
		
		$out = '';
		
		foreach($this->options as $value => $label) {
			
			$o = '';
			
			if(is_array($label)) {
				foreach($label as $k => $v) {
					if($this->isOptionSelected($k)) {
						$o = trim($value, ' :') . ": $v";
					}
				}
			} else {
				if($this->isOptionSelected($value)) $o = $label;
			}
			
			if(strlen($o)) {
				$out .= "<li>" . $this->wire('sanitizer')->entities($o) . "</li>";
			}
		}
	
		if(strlen($out)) $out = "<ul class='pw-bullets'>$out</ul>";
		
		return $out; 
	}

	/**
	 * Process input from the provided array
	 *
	 * In this case we're having the Inputfield base process the input and we're going back and validating the value.
	 * If the value(s) that were set aren't in our specific list of options, we remove them. This is a security measure.
	 *
	 * @param WireInputData $input
	 * @return $this
	 *
	 */
	public function ___processInput(WireInputData $input) {

		parent::___processInput($input); 	

		$name = $this->attr('name');
		if(!isset($input[$name])) {
			$value = $this instanceof InputfieldHasArrayValue ? array() : null;
			$this->setAttribute('value', $value); 
			return $this;
		}

		// validate that the selected posted option(s) are those from our options list 
		// removing any that aren't

		$value = $this->attr('value'); 

		if($this instanceof InputfieldHasArrayValue) {
			/** @var InputfieldSelect $this */
			foreach($value as $k => $v) {
				if(!$this->isOption($v)) {
					// $this->message("Removing invalid option: " . wire('sanitizer')->entities($value[$k]), Notice::debug); 
					unset($value[$k]); 
				}
			}

		} else if($value && !$this->isOption($value)) {
			$value = null;
		}

		$this->setAttribute('value', $value); 
		$this->checkDefaultValue();

		return $this; 
	}

	/**
	 * Get property
	 * 
	 * @param string $key
	 * @return array|mixed|null
	 * 
	 */
	public function get($key) {
		if($key == 'options') return $this->options; 
		if($key == 'optionAttributes') return $this->optionAttributes;
		return parent::get($key); 
	}

	/**
	 * Set property
	 * 
	 * @param string $key
	 * @param mixed $value
	 * @return Inputfield|InputfieldSelect
	 * 
	 */
	public function set($key, $value) {

		if($key == 'options') {
			if(is_string($value)) {
				return $this->addOptionsString($value);
			} else if(is_array($value)) {
				$this->options = $value;
			}
			return $this;
		} else if(strpos($key, 'options') === 0 && $this->hasFieldtype === false) {
			list(,$languageID) = explode('options', $key);
			if(ctype_digit($languageID)) {
				$this->addOptionLabelsString($value, (int) $languageID); 
				return $this;
			}
		} else if($key == 'optionAttributes') {
			if(is_array($value)) {
				$this->optionAttributes = $value; 
			}
			return $this;
		}

		return parent::set($key, $value); 
	}

	/**
	 * Set attribute
	 * 
	 * @param array|string $key
	 * @param array|int|string $value
	 * @return Inputfield|InputfieldSelect
	 * 
	 */
	public function setAttribute($key, $value) {
		if($key == 'value') {
			if(is_object($value) || (is_string($value) && strpos($value, '|'))) {
				$value = (string) $value;
				if($this instanceof InputfieldHasArrayValue) {
					$value = explode('|', $value);
				}
			} else if(is_array($value)) {
				if($this instanceof InputfieldHasArrayValue) {
					// ok
				} else {
					$value = reset($value); 
				}
			}
		}
		return parent::setAttribute($key, $value);
	}

	/**
	 * Is the value empty?
	 * 
	 * @return bool
	 * 
	 */
	public function isEmpty() {
		$value = $this->attr('value');

		if(is_array($value)) {
			$cnt = count($value);
			if(!$cnt) return true; 
			if($cnt === 1) return strlen(reset($value)) === 0; 
			return false; // $cnt > 1

		} else if($value === null || $value === false) {
			return true; 

		} else if($value == "0") {
			if(!array_key_exists("$value", $this->options)) return true; 

		} else {
			return strlen($value) === 0; 
		}
		
		return false;
	}

	/**
	 * Field configuration
	 * 
	 * @return InputfieldWrapper
	 * 
	 */
	public function ___getConfigInputfields() {

		$inputfields = parent::___getConfigInputfields();

		if($this instanceof InputfieldHasArrayValue) {
			$f = $this->wire('modules')->get('InputfieldTextarea');
			$f->description = $this->_('To have pre-selected default value(s), enter the option values (one per line) below.'); 
		} else {
			$f = $this->wire('modules')->get('InputfieldText');
			$f->description = $this->_('To have a pre-selected default value, enter the option value below.'); 
		}
		$f->attr('name', 'defaultValue'); 
		$f->label = $this->_('Default value'); 
		$f->attr('value', $this->defaultValue);
		$f->description .= ' ' . $this->_('For default page selection, the value would be the page ID number.'); 
		$f->notes = $this->_('IMPORTANT: The default value is not used unless the field is required (see the “required” checkbox on this screen).'); 
		$f->collapsed = $this->hasFieldtype === false ? Inputfield::collapsedBlank : Inputfield::collapsedNo;
		
		$inputfields->add($f); 

		// if dealing with an inputfield that has an associated fieldtype, 
		// we don't need to perform the remaining configuration
		if($this->hasFieldtype !== false) return $inputfields;

		// the following configuration specific to non-Fieldtype use of single/multi-selects
		$isInputfieldSelect = $this->className() == 'InputfieldSelect';
		/** @var Languages|null $languages */
		$languages = $this->wire('languages');

		$f = $this->wire('modules')->get('InputfieldTextarea'); 
		$f->attr('name', 'options');
		$f->label = $this->_('Options');
		$value = '';
		foreach($this->options as $key => $option) {
			if(is_array($option)) {
				$value .= "$key\n";
				foreach($option as $o) {
					$value .= "   $o\n";
				}
			} else {
				$value .= "$option\n";
			}
		}
		$value = trim($value);
		if(empty($value)) {
			$optionLabel = $f->label;
			if($optionLabel === 'Options') $optionLabel = 'Option';
			$value = "=\n$optionLabel 1\n$optionLabel 2\n$optionLabel 3";
			if(!$isInputfieldSelect) $value = ltrim($value, '='); 
		}
		$f->attr('value', $value); 
		$f->attr('rows', 10); 
		$f->description = $this->_('Enter the options that may be selected, one per line.');
		if($languages) $f->description .= ' ' . $this->_('To use multi-language option labels, please see the instructions below this field.'); 
		$f->notes = 
			($languages ? '**' . $this->_('Instructions:') . "**\n" : '') .
			'• ' . $this->_('Specify one option per line.') . "\n" . 
			'• ' . $this->_('To keep a separate value and label, separate them with an equals sign. Example: value=My Option') . " \n"  . 
			($isInputfieldSelect ? '• ' . $this->_('To precede your list with a blank option, enter just a equals sign "=" as the first option.') . "\n" : '') .
			'• ' . $this->_('To make an option selected, precede it with a plus sign. Example: +My Option') . 
			($isInputfieldSelect ? "\n• " . $this->_('To create an optgroup (option group) indent the options in the group with 3 or more spaces.') : ''); 
		if($languages) $f->notes .= " \n\n**" . $this->_('Multi-language instructions:') . "**\n" .
			'• ' . $this->_('We recommend using using `value=label`, where `value` is the same across languages and `label` is translated.') . " \n" . 
			'• ' . $this->_('First define your default language options, and then copy/paste into the other languages and translate labels.') . " \n" . 
			'• ' . $this->_('Selected options and optgroups are defined on the default language; the other inputs are only for label translation.') . "\n" . 
			'• ' . $this->_('Labels that are not translated inherit the default language label.'); 
		
		if($languages) {
			$f->useLanguages = true;
		}
			
		$inputfields->add($f); 

		return $inputfields; 
	}

	
}