<?php
// $Id: acl.module,v 1.1.2.1 2006-11-21 21:28:36 merlinofchaos Exp $

/** 
 * @file acl.module
 * 
 * This module handls ACLs on behalf of other modules. The two main reasons
 * to do this are so that modules using ACLs can share them with each
 * other without having to actually know much about them, and so that
 * ACLs can easily co-exist with the existing node_access system.
 */

/**
 * Implementation of hook_help
 */
function acl_help($section) {
  switch($section) {
    case 'admin/modules#description':
      return t('acls module provides an API for other modules to use Access Control List. It contains no user-serviceable parts.');
  }
}

/**
 * Create a new ACL.
 */
function acl_create_new_acl($module, $name) {
  $acl_id = db_next_id('acl_id');
  db_query("INSERT INTO {acl} (acl_id, module, name) VALUES (%d, '%s', '%s')", $acl_id, $module, $name);
  return $acl_id;
}

/**
 * Delete an existing ACL.
 */
function acl_delete_acl($acl_id) {
  db_query("DELETE FROM {acl} WHERE acl_id = %d", $acl_id);
  db_query("DELETE FROM {acl_user} WHERE acl_id = %d", $acl_id);
  db_query("DELETE FROM {acl_node} WHERE acl_id = %d", $acl_id);
}

/**
 * Add the specified UID to an ACL.
 */
function acl_add_user($acl_id, $uid) {
  $test_uid = db_result(db_query("SELECT uid FROM {acl_user} WHERE acl_id = $d AND uid = %d ", $acl_id, $uid));
  if (!$test_uid) {
    db_query("INSERT INTO {acl_user} (acl_id, uid) VALUES (%d, %d)", $acl_id, $uid);
  }
}

/**
 * Remove the specified UID from an ACL.
 */
function acl_remove_user($acl_id, $uid) {
  db_query("DELETE FROM {acl_user} WHERE acl_id = $d AND uid = %d ", $acl_id, $uid);
}

/**
 * Provide a special button type that doesn't get its #name blasted.
 */
function acl_elements() {
  $type['acl_button'] = array('#input' => TRUE, '#button_type' => 'submit', '#executes_submit_callback' => FALSE);
  return $type;
}

function theme_acl_button($element) {
  $element['#value'] = $element['#label'];
  return theme('button', $element);
}

/**
 * Provide a form to edit the ACL that can be embedded in other
 * forms.
 */
function acl_edit_form($acl_id, $label = NULL) {
  // Ensure the ACL in question even exists.
  if (!$acl_name = db_result(db_query("SELECT name FROM {acl} WHERE acl_id = %d", $acl_id))) {
    return $form;
  }
  if (!$label) {
    $label = $acl_name;
  }

  $form = array(
    '#type' => 'fieldset', 
    '#collapsible' => true, 
    '#title' => $label,
    '#tree' => true);


  $result = db_query("SELECT u.uid, u.name FROM {users} u LEFT JOIN {acl_user} aclu ON aclu.uid = u.uid WHERE acl_id = %d", $acl_id);
  $users = array();
  while ($user = db_fetch_object($result)) {
    $users[$user->uid] = $user->name;
  }

  $form['acl_id'] = array('#type' => 'value', '#value' => $acl_id);

  $form['deletions'] = array('#type' => 'hidden'); // placeholder
  $form['delete_button'] = array(
    '#type' => 'acl_button',
    '#label' => t('Remove Checked')
  );

  $form['add'] = array(
    '#type' => 'textfield', 
    '#title' => t('Add user'), 
    '#maxlength' => 60, 
    '#size' => 40,
    '#autocomplete_path' => 'user/autocomplete', 
  );
  $form['add_button'] = array(
    '#type' => 'acl_button',
    '#label' => t('Add User'),
  );

  $form['user_list'] = array(
    '#type' => 'hidden',
    '#default_value' => serialize($users),
  );

  $form['#after_build'] = array('acl_edit_form_after_build');
  
  return $form;
}

/**
 * Write the results of a form.
 */
function acl_save_form($form) {
  $users = unserialize($form['user_list']);
  db_query('DELETE FROM {acl_user} WHERE acl_id = %d', $form['acl_id']);
  foreach ($users as $uid => $name) {
    db_query('INSERT INTO {acl_user} (acl_id, uid) VALUES (%d, %d)', $form['acl_id'], $uid);
  }
}

/**
 * Process a form that had our buttons on it.
 */
function acl_edit_form_after_build($form, $form_values) {
  // We can't use form_values because it's the entire structure
  // and we have no clue where our values actually are. That's
  // ok tho cause #value still works for us.
  $user_list = unserialize($form['user_list']['#value']);
  if ($form['delete_button']['#value'] && is_array($form['deletions']['#value'])) {
    foreach($form['deletions']['#value'] as $uid) {
      unset($user_list[$uid]);
    }
  }
  else if ($form['add_button']['#value']) {
    $name = $form['add']['#value'];
    $u = db_fetch_object(db_query("SELECT uid, name FROM {users} WHERE name = '%s'", $name));
    if (!$u->uid) {
      form_error($form['add'], "Invalid user.");
    }
    else {
      $user_list[$u->uid] = $u->name;
      $form['add']['#value'] = NULL;
    }
  }

  if (count($user_list) != 0) {
    $form['deletions']['#type'] = 'checkboxes';
    $form['deletions']['#title'] = t("Current users");
    $form['deletions']['#options'] = $user_list;
    $form['deletions']['#value'] = array(); // don't carry value through.
    // need $form_id and have no way to get it but from $_POST that
    // I can find; and if we got here that variable's already been
    // checked.
    $form['deletions'] = form_builder($_POST['form_id'], $form['deletions']);
  }
  else {
    $form['delete_button']['#type'] = 'value';
  }
  $form['user_list']['#value'] = serialize($user_list);
  return $form;
}


/**
 * Provide access control to a node based upon an ACL id. 
 */
function acl_node_add_acl($nid, $acl_id, $view, $update, $delete) {
  db_query("DELETE FROM {acl_node} WHERE acl_id = %d AND nid = %d", $acl_id, $nid);
  db_query("INSERT INTO {acl_node} (acl_id, nid, grant_view, grant_update, grant_delete) VALUES (%d, %d, %d, %d, %d)", $acl_id, $nid, $view, $update, $delete);
}

/**
 * Remove an ACL completely from a node.
 */
function acl_node_remove_acl($nid, $acl_id) {
  db_query("DELETE FROM {acl_node} WHERE acl_id = %d AND nid = %d", $acl_id, $nid);
}

/**
 * Clear all of a module's ACL's from a node.
 */
function acl_node_clear_acls($nid, $module) {
  $result = db_query("SELECT acl_id FROM {acl} WHERE module = '%s'", $module);
  while ($o = db_fetch_object($result)) {
    $acls[] = $o->acl_id;
  }
  if ($acls) {
    db_query("DELETE FROM {acl_node} WHERE nid = %d AND acl_id in (%s)", $nid,
      implode(',', $acls));
  }
}

/**
 * Implementation of hook_node_access_grants (from node_access)
 */
function acl_node_access_records($node) {
  if (!$node->nid) {
    return;
  }
  $result = db_query("SELECT *, 'acl' AS realm, acl_id AS gid FROM {acl_node} WHERE nid = %d", $node->nid);
  while ($grant = db_fetch_array($result)) {
    $grants[] = $grant;
  }
  return $grants;
}