<?php
/*
 * Copyright 2008 Marc Mongenet
 *
 * This program 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.
 *
 * This program 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.
 *
 */

function process_access_attributes($econf, $in_elm) {
	$ac = get_w2ml_attribute_value($in_elm, 'ac');
	if ($ac !== NULL) {
		$condition = process_ac_condition($econf, $in_elm);
		if ($condition !== NULL) {
			process_ac_attribute($econf, $ac, $condition);
		}
	}
}


# Return TRUE, FALSE, or NULL in case of error.
function process_ac_condition($econf, $in_elm) {
	$group    = get_w2ml_attribute_value($in_elm, 'group');
	$user     = get_w2ml_attribute_value($in_elm, 'user');
	$req      = get_w2ml_attribute_value($in_elm, 'req');
	$internal = get_w2ml_attribute_value($in_elm, 'internal');

	$nb_ac_conditions = 0;
	$nb_ac_conditions +=    $group !== NULL;
	$nb_ac_conditions +=     $user !== NULL;
	$nb_ac_conditions +=      $req !== NULL;
	$nb_ac_conditions += $internal !== NULL;

	if ($nb_ac_conditions === 0) {
		log_error('Missing condition attribute with ac W2ML attribute',
		          $econf->log);
		return NULL;
	}
	elseif ($nb_ac_conditions > 1) {
		log_error('Several condition attributes with ac W2ML attribute',
		          $econf->log);
		return NULL;
	}

	if ($group !== NULL) {
		return process_ac_group($econf, $in_elm, $group);
	} elseif ($user !== NULL) {
		return process_ac_user($econf, $in_elm, $user);
	} else {
		return process_ac_req_or_internal($econf, $in_elm, $req, $internal);
	}
}


function process_ac_group($econf, $in_elm, $ac_group) {
	$user = $econf->user();
	return $user->is_in_group($ac_group);
}


function process_ac_user($econf, $in_elm, $ac_user) {
	$user = $econf->user();
	return $user->name === $ac_user;
}


function process_ac_req_or_internal($econf, $in_elm, $req, $internal) {
	$match  = get_w2ml_attribute_value($in_elm, 'match');
	$nmatch = get_w2ml_attribute_value($in_elm, 'nmatch');
	if ($match !== NULL && $nmatch !== NULL) {
		log_error('W2ML match and nmatch attributes on same element',
		          $econf->log);
		return NULL;
	}

	if ($req !== NULL) {
		$var_val = get_http_parameter($req, TRUE);
	} else {
		$var_val = get_internal_var($econf, $internal);
	}

	if ($match === NULL && $nmatch === NULL) {
		return $var_val !== NULL;
	}
	elseif ($match !== NULL) {
		if (is_string($var_val)) {
			return @preg_match('/'.$match.'/u', $var_val) === 1;
		}
		elseif (is_array($var_val)) {
			foreach ($var_val as $one_val) {
				if (@preg_match('/'.$match.'/u', $one_val) === 1) {
					return TRUE;
				}
			}
			return FALSE;
		}
		return FALSE; # for undefined variable
	}
	else {
		if (is_string($var_val)) {
			# Note: preg_match returns FALSE on error, 0 for no match.
			return !@preg_match('/'.$nmatch.'/u', $var_val);
		}
		elseif (is_array($var_val)) {
			foreach ($var_val as $one_val) {
				# Note: preg_match returns FALSE on error, 0 for no match.
				if (!@preg_match('/'.$nmatch.'/u', $one_val)) {
					return FALSE;
				}
			}
			return TRUE;
		}
		return TRUE; # for undefined variable
	}
}


define('AC_SET', 1);
define('AC_PLUS', 2);
define('AC_MINUS', 3);


function process_ac_attribute($econf, $ac, $condition) {
	if (preg_match('/^([+-]?[xdne])*$/', $ac) !== 1) {
		log_error('Bad format in ac="'.$ac.'"', $econf->log);
		return;
	}
	$ac_len = strlen($ac);
	$set_plus_minus = AC_SET;
	for ($i = 0; $i < $ac_len; ++$i) {
		switch ($ac{$i}) {
		case '+':
			$set_plus_minus = AC_PLUS;
			break;
		case '-':
			$set_plus_minus = AC_MINUS;
			break;
		case 'x':
			$econf->x_access = eval_ac($econf->x_access, $condition,
			                           $set_plus_minus);
			$set_plus_minus = AC_SET;
			break;
		case 'd':
			$econf->d_access = eval_ac($econf->d_access, $condition,
			                           $set_plus_minus);
			$set_plus_minus = AC_SET;
			break;
		case 'n':
			$econf->n_access = eval_ac($econf->n_access, $condition,
			                           $set_plus_minus);
			$set_plus_minus = AC_SET;
			break;
		case 'e':
			$econf->e_access = eval_ac($econf->e_access, $condition,
			                           $set_plus_minus);
			$set_plus_minus = AC_SET;
			break;
		}
	}
}


function eval_ac($current_access, $condition, $set_plus_minus) {
	switch ($set_plus_minus) {
	case AC_SET:
		return $condition;
	case AC_PLUS:
		return $current_access || $condition;
	case AC_MINUS:
		return $condition ? FALSE : $current_access;
	}
}

?>