<?php
/**
 * TCheckBox class file
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.pradosoft.com/
 * @copyright Copyright &copy; 2005-2014 PradoSoft
 * @license http://www.pradosoft.com/license/
 * @package Prado\Web\UI\WebControls
 */

namespace Prado\Web\UI\WebControls;

/**
 * TCheckBox class
 *
 * TCheckBox displays a check box on the page.
 * You can specify the caption to display beside the check box by setting
 * the {@link setText Text} property.  The caption can appear either on the right
 * or left of the check box, which is determined by the {@link setTextAlign TextAlign}
 * property.
 *
 * To determine whether the TCheckBox component is checked, test the {@link getChecked Checked}
 * property. The {@link onCheckedChanged OnCheckedChanged} event is raised when
 * the {@link getChecked Checked} state of the TCheckBox component changes
 * between posts to the server. You can provide an event handler for
 * the {@link onCheckedChanged OnCheckedChanged} event to  to programmatically
 * control the actions performed when the state of the TCheckBox component changes
 * between posts to the server.
 *
 * If {@link setAutoPostBack AutoPostBack} is set true, changing the check box state
 * will cause postback action. And if {@link setCausesValidation CausesValidation}
 * is true, validation will also be processed, which can be further restricted within
 * a {@link setValidationGroup ValidationGroup}.
 *
 * Note, {@link setText Text} is rendered as is. Make sure it does not contain unwanted characters
 * that may bring security vulnerabilities.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package Prado\Web\UI\WebControls
 * @since 3.0
 */
class TCheckBox extends TWebControl implements IPostBackDataHandler, IValidatable, IDataRenderer, ISurroundable
{
	private $_dataChanged=false;
	private $_isValid=true;

	/**
	 * @return string tag name of the button
	 */
	protected function getTagName()
	{
		return 'input';
	}

	/**
	 * Loads user input data.
	 * This method is primarly used by framework developers.
	 * @param string the key that can be used to retrieve data from the input data collection
	 * @param array the input data collection
	 * @return boolean whether the data of the control has been changed
	 */
	public function loadPostData($key,$values)
	{
		$checked=$this->getChecked();
		if($newChecked=isset($values[$key]))
			$this->setValue($values[$key]);
		$this->setChecked($newChecked);
		return $this->_dataChanged=($newChecked!==$checked);
	}

	/**
	 * Raises postdata changed event.
	 * This method raises {@link onCheckedChanged OnCheckedChanged} event.
	 * This method is primarly used by framework developers.
	 */
	public function raisePostDataChangedEvent()
	{
		if($this->getAutoPostBack() && $this->getCausesValidation())
			$this->getPage()->validate($this->getValidationGroup());
		$this->onCheckedChanged(null);
	}

	/**
	 * Raises <b>OnCheckedChanged</b> event when {@link getChecked Checked} changes value during postback.
	 * If you override this method, be sure to call the parent implementation
	 * so that the event delegates can be invoked.
	 * @param TEventParameter event parameter to be passed to the event handlers
	 */
	public function onCheckedChanged($param)
	{
		$this->raiseEvent('OnCheckedChanged',$this,$param);
	}

	/**
	 * Registers the checkbox to receive postback data during postback.
	 * This is necessary because a checkbox if unchecked, when postback,
	 * does not have direct mapping between post data and the checkbox name.
	 *
	 * This method overrides the parent implementation and is invoked before render.
	 * @param mixed event parameter
	 */
	public function onPreRender($param)
	{
		parent::onPreRender($param);
		if($this->getEnabled(true))
			$this->getPage()->registerRequiresPostData($this);
	}

	/**
	 * Returns a value indicating whether postback has caused the control data change.
	 * This method is required by the IPostBackDataHandler interface.
	 * @return boolean whether postback has caused the control data change. False if the page is not in postback mode.
	 */
	public function getDataChanged()
	{
		return $this->_dataChanged;
	}

	/**
	 * Returns the value of the property that needs validation.
	 * @return mixed the property value to be validated
	 */
	public function getValidationPropertyValue()
	{
		return $this->getChecked();
	}

	/**
	 * Returns true if this control validated successfully.
	 * Defaults to true.
	 * @return bool wether this control validated successfully.
	 */
	public function getIsValid()
	{
	    return $this->_isValid;
	}
	/**
	 * @param bool wether this control is valid.
	 */
	public function setIsValid($value)
	{
	    $this->_isValid=TPropertyValue::ensureBoolean($value);
	}

	/**
	 * @return string the text caption of the checkbox
	 */
	public function getText()
	{
		return $this->getViewState('Text','');
	}

	/**
	 * Sets the text caption of the checkbox.
	 * @param string the text caption to be set
	 */
	public function setText($value)
	{
		$this->setViewState('Text',$value,'');
	}

	/**
	 * @return string the value of the checkbox. Defaults to empty.
	 */
	public function getValue()
	{
		return $this->getViewState('Value','');
	}

	/**
	 * @param string the value of the checkbox
	 */
	public function setValue($value)
	{
		$this->setViewState('Value',TPropertyValue::ensureString($value),'');
	}

	/**
	 * @return TTextAlign the alignment (Left or Right) of the text caption, defaults to TTextAlign::Right.
	 */
	public function getTextAlign()
	{
		return $this->getViewState('TextAlign',TTextAlign::Right);
	}

	/**
	 * @param TTextAlign the alignment of the text caption. Valid values include Left and Right.
	 */
	public function setTextAlign($value)
	{
		$this->setViewState('TextAlign',TPropertyValue::ensureEnum($value,'TTextAlign'),TTextAlign::Right);
	}

	/**
	 * @return boolean whether the checkbox is checked
	 */
	public function getChecked()
	{
		return $this->getViewState('Checked',false);
	}

	/**
	 * Sets a value indicating whether the checkbox is to be checked or not.
	 * @param boolean whether the checkbox is to be checked or not.
	 */
	public function setChecked($value)
	{
		$this->setViewState('Checked',TPropertyValue::ensureBoolean($value),false);
	}

	/**
	 * Returns the value indicating whether the checkbox is checked.
	 * This method is required by {@link IDataRenderer}.
	 * It is the same as {@link getChecked()}.
	 * @return boolean whether the checkbox is checked.
	 * @see getChecked
	 * @since 3.1.0
	 */
	public function getData()
	{
		return $this->getChecked();
	}

	/**
	 * Sets the value indicating whether the checkbox is to be checked or not.
	 * This method is required by {@link IDataRenderer}.
	 * It is the same as {@link setChecked()}.
	 * @param boolean whether the checkbox is to be checked
	 * @see setChecked
	 * @since 3.1.0
	 */
	public function setData($value)
	{
		$this->setChecked($value);
	}

	/**
	 * @return boolean whether clicking on the checkbox will post the page.
	 */
	public function getAutoPostBack()
	{
		return $this->getViewState('AutoPostBack',false);
	}

	/**
	 * Sets a value indicating whether clicking on the checkbox will post the page.
	 * @param boolean whether clicking on the checkbox will post the page.
	 */
	public function setAutoPostBack($value)
	{
		$this->setViewState('AutoPostBack',TPropertyValue::ensureBoolean($value),false);
	}

	/**
	 * @return boolean whether postback event triggered by this checkbox will cause input validation, default is true.
	 */
	public function getCausesValidation()
	{
		return $this->getViewState('CausesValidation',true);
	}

	/**
	 * Sets the value indicating whether postback event trigger by this checkbox will cause input validation.
	 * @param boolean whether postback event trigger by this checkbox will cause input validation.
	 */
	public function setCausesValidation($value)
	{
		$this->setViewState('CausesValidation',TPropertyValue::ensureBoolean($value),true);
	}

	/**
	 * @return string the group of validators which the checkbox causes validation upon postback
	 */
	public function getValidationGroup()
	{
		return $this->getViewState('ValidationGroup','');
	}

	/**
	 * @param string the group of validators which the checkbox causes validation upon postback
	 */
	public function setValidationGroup($value)
	{
		$this->setViewState('ValidationGroup',$value,'');
	}

	/**
	 * @return string the id of the surrounding tag or this clientID if no such tag needed
	 */
	public function getSurroundingTagID()
	{
        return $this->getSpanNeeded() ? $this->getClientID().'_parent' : $this->getClientID();
	}

	/**
	 * Renders the checkbox control.
	 * This method overrides the parent implementation by rendering a checkbox input element
	 * and a span element if needed.
	 * @param THtmlWriter the writer used for the rendering purpose
	 */
	public function render($writer)
	{
		$this->getPage()->ensureRenderInForm($this);
		if($this->getHasStyle())
			$this->getStyle()->addAttributesToRender($writer);
		if(($tooltip=$this->getToolTip())!=='')
			$writer->addAttribute('title',$tooltip);
		if($this->getHasAttributes())
		{
			$attributes=$this->getAttributes();
			$value=$attributes->remove('value');
			// onclick js should only be added to input tag
			if(($onclick=$attributes->remove('onclick'))===null)
				$onclick='';
			if($attributes->getCount())
				$writer->addAttributes($attributes);
			if($value!==null)
				$attributes->add('value',$value);
		}
		else
			$onclick='';
        if($needspan=$this->getSpanNeeded())
        {
            $writer->addAttribute('id',$this->getSurroundingTagID());
			$writer->renderBeginTag('span');
        }
		$clientID=$this->getClientID();
		if(($text=$this->getText())!=='')
		{
			if($this->getTextAlign()===TTextAlign::Left)
			{
				$this->renderLabel($writer,$clientID,$text);
				$this->renderInputTag($writer,$clientID,$onclick);
			}
			else
			{
				$this->renderInputTag($writer,$clientID,$onclick);
				$this->renderLabel($writer,$clientID,$text);
			}
		}
		else
			$this->renderInputTag($writer,$clientID,$onclick);
		if($needspan)
			$writer->renderEndTag();
	}

	/**
	 * @return TMap list of attributes to be rendered for label beside the checkbox
	 */
	public function getLabelAttributes()
	{
		if($attributes=$this->getViewState('LabelAttributes',null))
			return $attributes;
		else
		{
			$attributes=new TAttributeCollection;
			$this->setViewState('LabelAttributes',$attributes,null);
			return $attributes;
		}
	}

	/**
	 * @return TMap list of attributes to be rendered for the checkbox
	 */
	public function getInputAttributes()
	{
		if($attributes=$this->getViewState('InputAttributes',null))
			return $attributes;
		else
		{
			$attributes=new TAttributeCollection;
			$this->setViewState('InputAttributes',$attributes,null);
			return $attributes;
		}
	}

	/**
	 * @return string the value attribute to be rendered
	 */
	protected function getValueAttribute()
	{
		if(($value=$this->getValue())!=='')
			return $value;
		else
		{
			$attributes=$this->getViewState('InputAttributes',null);
			if($attributes && $attributes->contains('value'))
				return $attributes->itemAt('value');
			else if($this->hasAttribute('value'))
				return $this->getAttribute('value');
			else
				return '';
		}
	}

	/**
	 * @return boolean whether to render javascript.
	 */
	public function getEnableClientScript()
	{
		return $this->getViewState('EnableClientScript',true);
	}

	/**
	 * @param boolean whether to render javascript.
	 */
	public function setEnableClientScript($value)
	{
		$this->setViewState('EnableClientScript',TPropertyValue::ensureBoolean($value),true);
	}

    /**
     * Check if we need a span tag to surround this control. The span tag will be created if
     * the Text property is set for this control.
     *
     * @return bool wether this control needs a surrounding span tag
     */
    protected function getSpanNeeded() {
        return $this->getText()!=='';
    }

	/**
	 * Renders a label beside the checkbox.
	 * @param THtmlWriter the writer for the rendering purpose
	 * @param string checkbox id
	 * @param string label text
	 */
	protected function renderLabel($writer,$clientID,$text)
	{
		$writer->addAttribute('for',$clientID);
		if($attributes=$this->getViewState('LabelAttributes',null))
			$writer->addAttributes($attributes);
		$writer->renderBeginTag('label');
		$writer->write($text);
		$writer->renderEndTag();
	}

	/**
	 * Renders a checkbox input element.
	 * @param THtmlWriter the writer for the rendering purpose
	 * @param string checkbox id
	 * @param string onclick js
	 */
	protected function renderInputTag($writer,$clientID,$onclick)
	{
		if($clientID!=='')
			$writer->addAttribute('id',$clientID);
		$writer->addAttribute('type','checkbox');
		if(($value=$this->getValueAttribute())!=='')
			$writer->addAttribute('value',$value);
		if(!empty($onclick))
			$writer->addAttribute('onclick',$onclick);
		if(($uniqueID=$this->getUniqueID())!=='')
			$writer->addAttribute('name',$uniqueID);
		if($this->getChecked())
			$writer->addAttribute('checked','checked');
		if(!$this->getEnabled(true))
			$writer->addAttribute('disabled','disabled');

		$page=$this->getPage();
		if($this->getEnabled(true)
			&& $this->getEnableClientScript()
			&& $this->getAutoPostBack()
			&& $page->getClientSupportsJavaScript())
		{
			$this->renderClientControlScript($writer);
		}

		if(($accesskey=$this->getAccessKey())!=='')
			$writer->addAttribute('accesskey',$accesskey);
		if(($tabindex=$this->getTabIndex())>0)
			$writer->addAttribute('tabindex',"$tabindex");
		if($attributes=$this->getViewState('InputAttributes',null))
			$writer->addAttributes($attributes);
		$writer->renderBeginTag('input');
		$writer->renderEndTag();
	}

	/**
	 * Renders the client-script code.
	 */
	protected function renderClientControlScript($writer)
	{
		$cs = $this->getPage()->getClientScript();
		$cs->registerPostBackControl($this->getClientClassName(),$this->getPostBackOptions());
	}

	/**
	 * Gets the name of the javascript class responsible for performing postback for this control.
	 * This method overrides the parent implementation.
	 * @return string the javascript class name
	 */
	protected function getClientClassName()
	{
		return 'Prado.WebUI.TCheckBox';
	}

	/**
	 * Gets the post back options for this checkbox.
	 * @return array
	 */
	protected function getPostBackOptions()
	{
		$options['ID'] = $this->getClientID();
		$options['ValidationGroup'] = $this->getValidationGroup();
		$options['CausesValidation'] = $this->getCausesValidation();
		$options['EventTarget'] = $this->getUniqueID();
		return $options;
	}
}