<?php
/**
 * Copyright 2009, 2010 AEGEE-Europe
 *
 * This file is part of AEGEE-Europe Online Membership System.
 *
 * AEGEE-Europe Online Membership System is free software: you can
 * redistribute it and/or modify it under the terms of the GNU General
 * Public License as published by the Free Software Foundation, either
 * version 3 of the License, or (at your option) any later version.
 *
 * AEGEE-Europe Online Membership System is distributed in the hope
 * that it will be useful, but WITHOUT ANY WARRANTY; without even the
 * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 * PURPOSE.  See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with AEGEE-Europe Online Membership System.  If not, see
 * <http://www.gnu.org/licenses/>.
 */

/**
 * Form object to display a form
 */

require_once(ROOTPATH."include/form/CheckboxField.php");
require_once(ROOTPATH."include/form/DateSelectField.php");
require_once(ROOTPATH."include/form/HiddenField.php");
require_once(ROOTPATH."include/form/PasswordField.php");
require_once(ROOTPATH."include/form/RadioField.php");
require_once(ROOTPATH."include/form/SelectField.php");
require_once(ROOTPATH."include/form/TextField.php");

abstract class AbstractForm {
	private $model;
	private $fields;
	private $hiddenFields;
	private $submitText = "Save";
	private $resetText = NULL;
	private $headerText = NULL;

	/**
	 * Constructor
	 */
	public function __construct(array $model) {
		$this->model = $model;
		$this->fields = array();
		$this->hiddenFields = array();
	}

	/**
	 * Save the edited data
	 *
	 * @param Model to be saved
	 */
	protected abstract function save(array $model);

	/**
	 * Retrun the html of the form
	 * 
	 * @return String html statements to display the form
	 */
	public function display() {
		$ret = "";
		if( $_SERVER['REQUEST_METHOD']=="GET" ) {
			$this->setModelValuesOnFields();
			$ret .= $this->printForm();
		}else {
			$errors = $this->setFieldValuesOnModel();
			if( $errors == NULL && $this->isValid($this->model)) {
				$this->save($this->model);
			}else {
				$ret .= $errors;
				$ret .= $this->printForm();
			}
		}
		return $ret;
	}

	/**
	 * Add a field to the form
	 *
	 * @param IFormField field to be added
	 */
	public function addField(IFormField $field) {
		$this->fields[$field->getName()] = $field;
	}

	/**
	 * Add a hidden field to the form (shouldn't generate visible output)
	 *
	 * @param IFormField field that does not generate visible HTML output
	 */
	public function addHiddenField(IFormField $field) {
		$this->hiddenFields[$field->getName()] = $field;
	}
	
	/**
	 * Set the text for the submit button
	 *
	 * @param string text to be displayed on the submit button
	 */
	public function setSubmitText($submitText) {
		$this->submitText = $submitText;
	}

	/**
	 * Get the text for the submit button
	 *
	 * @return string the text to be displayed on the submit button
	 */
	public function getSubmitText() {
		return $this->submitText;
	}

	/**
	 * Set the text for the reset button, set to NULL to disable the button
	 *
	 * @param string text to be displayed on the reset button, or NULL to disable the button
	 */
	public function setResetText($resetText) {
		$this->resetText = $resetText;
	}

	/**
	 * Get the text for the reset button
	 *
	 * @return string the text to be displayed on the reset button
	 */
	public function getResetText() {
		return $this->resetText;
	}

	/**
	 * Set the text to be displayed above the form, set to NULL not show anything
	 *
	 * @param string text to be displayed above the form, or NULL to not show anything
	 */
	public function setHeaderText($headerText) {
		$this->headerText = $headerText;
	}

	/**
	 * Get the text to be displayed above the form
	 *
	 * @return string the text to be displayed above the form
	 */
	public function getHeaderText() {
		return $this->headerText;
	}

	/**
	 * Overridable validator for the submitted form
	 *
	 * @param array filled model
	 * @return boolean true in case model validates, false otherwise
	 */
	protected function isValid(array $model) {
		return true;
	}
	
	protected function getModel() {
		return $this->model;
	}
	
	protected function setModel(array $model) {
		$this->model = $model;
	}
	
	/**
	 * Overridable validator for validating separate fields
	 * 
	 * @param string $field the field on which the value will be set
	 * @param string $value the value which should be set on the field
	 * @return true in case of success, or an error string in case of failure
	 */
	protected function isValidField($field, $value) {
		return true;
	}

	protected function setModelValuesOnFields() {
		foreach( $this->fields as $fieldKey => $fieldObject ) {
			$this->setModelValueOnField($fieldKey, $fieldObject);
		}
	}

	private function setModelValueOnField($fieldKey, $fieldObject) {
		$fieldObject->setValue($this->model[$fieldKey]);
	}

	/**
	 * @return NULL in case of success, or string of html elements to display error
	 */
	protected function setFieldValuesOnModel() {
		$success = true;
		$errors = "";
		foreach( $this->fields as $fieldKey => $fieldObject ) {
			try {
				if( $fieldObject->isReadonly() ) {
					$this->setModelValueOnField($fieldKey, $fieldObject);
				}else {
					$fieldObject->setValue($fieldObject->getInputValue());
					$this->model[$fieldKey] = $fieldObject->getInputValue();
					$validator = $this->isValidField($fieldKey, $fieldObject->getInputValue());
					if( $validator!==true ) {
						$errors .= "<li>" . $validator . "</li>";
						$success = false;
					}elseif( $fieldObject->isCompulsory() &&
							((is_array($fieldObject->getInputValue()) && count($fieldObject->getInputValue())==0) ||
							(!is_array($fieldObject->getInputValue()) && trim($fieldObject->getInputValue())=="")) ) {
						$errors .= "<li>" . sprintf(_("The field '%s' is compulsory."), $fieldObject->getName()) . "</li>";
						$success = false;
					}
				}
			}catch( InvalidInputException $e ) {
				$errors .= "<li>" . $e->getMessage() . "</li>";
				$success = false;
			}
		}
		if( !$success ) {
			return "<ul class=\"error\">" . $errors . "</ul>";
		}else {
			return NULL;
		}
	}

	protected function printForm() {
		$ret = "";
		$ret .= "<form method=\"POST\" action=\"".$_SERVER['REQUEST_URI']."\">";
		$ret .= $this->printFormFields();
		$ret .= "<br /><input type=\"submit\" value=\"".$this->submitText."\">";
		if( $this->resetText!=NULL ) {
			$ret .= " &nbsp; <input type=\"reset\" value=\"".$this->resetText."\">";
		}
		$ret .= "</form>";
		return $ret;
	}
	
	protected function printFormFields() {
		$ret = "";
		foreach( $this->hiddenFields as $key => $field ) {
			$ret .= $field->getField();
		}
		if( $this->headerText!=NULL ) {
			$ret .= $this->headerText . "<p>";
		}
		$ret .= "<table class=\"form\">";
		$c = 0;
		foreach( $this->fields as $key => $field ) {
			$ret .= "<tr class=\"" . (($c++) % 2==1 ? "odd" : "even") . "\">";
			$ret .= "<th>" . $field->getTitle() . "</th>";
			$ret .= "<td id=\"input_".$field->getName()."\">";
			$ret .= $field->getField() . ($field->isCompulsory() ? "<span class=\"compulsory\">*</span>" : "");
			if( $field->getExplanation()!=NULL ) {
				$ret .= "<br><span class=\"explain\">" . $field->getExplanation() . "</span>";
			}
			$ret .= "</td>";
			$ret .= "</tr>";
		}
		$ret .= "</table>";
		return $ret;
	}
}
?>