<?php

/**
 * Form.inc.php
 *
 * Copyright (c) 2000-2007 John Willinsky
 * Distributed under the GNU GPL v2. For full terms see the file docs/COPYING.
 *
 * @package core
 *
 * Class defining basic operations for handling HTML forms.
 *
 * $Id: Form.inc.php,v 1.6 2007/05/11 03:20:45 mj Exp $
 */

import('form.FormError');
import('form.validation.FormValidator');

class Form {

	/** The template file containing the HTML form */
	var $_template;
	
	/** Associative array containing form data */
	var $_data;
	
	/** Validation checks for this form */
	var $_checks;
	
	/** Errors occurring in form validation */
	var $_errors;
	
	/** Array of field names where an error occurred and the associated error message */
	var $errorsArray;
	
	/** Array of field names where an error occurred */
	var $errorFields;
	
	/**
	 * Constructor.
	 * @param $template string the path to the form template file
	 */
	function Form($template, $callHooks = true) {
		if ($callHooks === true && checkPhpVersion('4.3.0')) {
			$trace = debug_backtrace();
			// Call hooks based on the calling entity, assuming
			// this method is only called by a subclass. Results
			// in hook calls named e.g. "articlegalleyform::Constructor"
			// Note that class names are always lower case.
			HookRegistry::call(strtolower($trace[1]['class']) . '::Constructor', array(&$this, &$template));
		}

		$this->_template = $template;
		$this->_data = array();
		$this->_checks = array();
		$this->_errors = array();
		$this->errorsArray = array();
		$this->errorFields = array();
	}
	
	/**
	 * Display the form.
	 */
	function display() {
		$templateMgr = &TemplateManager::getManager();
		$templateMgr->register_function('fieldLabel', array(&$this, 'smartyFieldLabel'));
		
		$templateMgr->assign($this->_data);
		$templateMgr->assign('isError', !$this->isValid());
		$templateMgr->assign('errors', $this->getErrorsArray());
		
		$templateMgr->display($this->_template);
	}
	
	/**
	 * Get the value of a form field.
	 * @param $key string
	 * @return mixed
	 */
	function getData($key) {
		return isset($this->_data[$key]) ? $this->_data[$key] : null;
	}
	
	/**
	 * Set the value of a form field.
	 * @param $key
	 * @param $value
	 */
	function setData($key, $value) {

		if (is_string($value)) {

			// check for Windows-1252 encoding, and transliterate if necessary	
			if ($value === utf8_decode($value) && $value !== utf8_encode($value)) {
				// string is cp1252
				// transliterate cp1252->utf8 to work in utf-8 
				// utf8_decode to work in latin-1 (information may be lost)
				import('core.Transcoder');
				$trans =& new Transcoder('CP1252', 'UTF-8');
				$value = $trans->trans($value);

			} elseif ($value !== utf8_decode($value) && $value !== utf8_encode($value)) {
				// string is not within utf-8(?)
				// normalize to ASCII (lowest common encoding) - information will be lost
				import('core.Transcoder');
				$trans =& new Transcoder('UTF-8', 'ASCII');
				$value = $trans->trans($value);
			}
		}
		$this->_data[$key] = $value;
	}
	
	/**
	 * Initialize form data for a new form.
	 */
	function initData() {
	}
	
	/**
	 * Assign form data to user-submitted data.
	 */
	function readInputData() {
	}
	
	/**
	 * Validate form data.
	 */
	function validate($callHooks = true) {
		if (!isset($this->errorsArray)) {
			$this->getErrorsArray();
		}
		
		foreach ($this->_checks as $check) {
			if (!isset($this->errorsArray[$check->getField()]) && !$check->isValid()) {
				$this->addError($check->getField(), $check->getMessage());
				$this->errorFields[$check->getField()] = 1;
				
				if (method_exists($check, 'getErrorFields')) {
					$errorFields = call_user_func(array(&$check, 'getErrorFields'));
					for ($i=0, $count=count($errorFields); $i < $count; $i++) {
						$this->errorFields[$errorFields[$i]] = 1;
					}
				}
			}
		}

		if ($callHooks === true && checkPhpVersion('4.3.0')) {
			$trace = debug_backtrace();
			// Call hooks based on the calling entity, assuming
			// this method is only called by a subclass. Results
			// in hook calls named e.g. "articlegalleyform::validate"
			// Note that class and function names are always lower
			// case.
			$value = null;
			if (HookRegistry::call(strtolower($trace[0]['class'] . '::' . $trace[0]['function']), array(&$this, &$value))) {
				return $value;
			}
		}

		return $this->isValid();
	}
	
	/**
	 * Execute the form's action.
	 * (Note that it is assumed that the form has already been validated.)
	 */
	function execute() {
	}
	
	/**
	 * Adds specified user variables to input data. 
	 * @param $vars array the names of the variables to read
	 */
	function readUserVars($vars) {
		foreach ($vars as $k) {
			$this->setData($k, Request::getUserVar($k));
		}
	}
	
	/**
	 * Adds specified user date variables to input data. 
	 * @param $vars array the names of the date variables to read
	 */
	function readUserDateVars($vars) {
		foreach ($vars as $k) {
			$this->setData($k, Request::getUserDateVar($k));
		}
	}
	
	/**
	 * Add a validation check to the form.
	 * @param $formValidator FormValidator
	 */
	function addCheck($formValidator) {
		$this->_checks[] = &$formValidator;
	}
	
	/**
	 * Add an error to the form.
	 * Errors are typically assigned as the form is validated.
	 * @param $field string the name of the field where the error occurred
	 * @param $message string the error message (i18n key)
	 */
	function addError($field, $message) {
		$this->_errors[] = &new FormError($field, $message);
	}

	/**
	 * Add an error field for highlighting on form
	 * @param $field string the name of the field where the error occurred
	 */
	function addErrorField($field) {
		$this->errorFields[$field] = 1;
	}
	
	/**
	 * Check if form passes all validation checks.
	 * @return boolean
	 */
	function isValid() {
		return empty($this->_errors);
	}
	
	/**
	 * Return set of errors that occurred in form validation.
	 * If multiple errors occurred processing a single field, only the first error is included.
	 * @return array erroneous fields and associated error messages
	 */
	function getErrorsArray() {
		$this->errorsArray = array();
		foreach ($this->_errors as $error) {
			if (!isset($this->errorsArray[$error->getField()])) {
				$this->errorsArray[$error->getField()] = $error->getMessage();
			}
		}
		return $this->errorsArray;
	}
	
	/**
	 * Custom Smarty function for labelling/highlighting of form fields.
	 * @param $params array can contain 'name' (field name/ID), 'required' (required field), 'key' (localization key), 'label' (non-localized label string), 'suppressId' (boolean)
	 * @param $smarty Smarty
	 */
	function smartyFieldLabel($params, &$smarty) {
		if (isset($params) && !empty($params)) {
			if (isset($params['key'])) {
				$params['label'] = Locale::translate($params['key']);
			}
			
			if (isset($this->errorFields[$params['name']])) {
				$class = ' class="error"';
			} else {
				$class = '';	
			}
			echo '<label' . (isset($params['suppressId']) ? '' : ' for="' . $params['name'] . '"'), $class, '>', $params['label'], (isset($params['required']) && !empty($params['required']) ? '*' : ''), '</label>';
		}
	}
}

?>