extension.driver.php

<?php
Class extension_author_roles extends Extension
{
	// About this extension:
	public function about()
	{
		return array(
			'name' => 'Author Roles',
			'version' => '1.2',
			'release-date' => '2012-10-04',
			'author' => array(
				'name' => 'Twisted Interactive',
				'website' => 'http://www.twisted.nl'),
			'description' => 'Author Roles for Symphony 2.2 and above'
		);
	}

	// Set the delegates:
	public function getSubscribedDelegates()
	{
		return array(
			array(
				'page' => '/backend/',
				'delegate' => 'NavigationPreRender',
				'callback' => 'extendNavigation'
			),
			array(
				'page' => '/system/authors/',
				'delegate' => 'AuthorPreDelete',
				'callback' => 'deleteAuthorRole'
			),
			array(
				'page' => '/system/authors/',
				'delegate' => 'AuthorPostCreate',
				'callback' => 'saveAuthorRole'
			),
			array(
				'page' => '/system/authors/',
				'delegate' => 'AuthorPostEdit',
				'callback' => 'saveAuthorRole'
			),
			array(
				'page' => '/system/authors/',
				'delegate' => 'AddElementstoAuthorForm',
				'callback' => 'addRolePicker'
			),
			array(
				'page' => '/backend/',
				'delegate' => 'AdminPagePreGenerate',
				'callback' => 'checkCallback'
			),
			array(
				'page' => '/backend/',
				'delegate' => 'InitaliseAdminPageHead',
				'callback' => 'makePreAdjustements'
			),
			array(
				'page' => '/system/authors/',
				'delegate' => 'AddDefaultAuthorAreas',
				'callback' => 'modifyAreas'
			)
		);
	}

	public function fetchNavigation() {
		return array(
			array(
				'name' => __('Author Roles'),
				'location' => 100,
				'limit' => 'developer'
			)
		);
	}

	/** Extend the navigation. Adds a 'Roles'-button to the system-tab, and hides hidden sections from the navigation
	 * @param	$context
	 *  The context object
	 */
	public function extendNavigation($context) {
		$data = $this->getCurrentAuthorRoleData();

		if($data == false || Administration::instance()->Author->isDeveloper()) {
			return;
		}

		$custom_elements = explode("\n", $data['custom_elements']);

		foreach($custom_elements as &$elem) {
			$elem = trim($elem);
		}

		// Disable non-visible sections:
		$visible = array();

		foreach($data['sections'] as $id => $rules) {
			if($rules['visible'] == 1) {
				array_push($visible, $id);
			}
		}

		foreach($context['navigation'] as &$group) {
			foreach($group['children'] as &$section) {
				if(isset($section['section'])) {
					if(!in_array($section['section']['id'], $visible)) {
						$section['visible'] = 'no';
					}
				}

				if(isset($section['link'])) {
					if(in_array($section['link'], $custom_elements)) {
						$section['visible'] = 'no';
					}
				}
			}
		}
	}

	/**
	 * Delete the links to this author
	 * @param	$context
	 *  Can be a Symphony Context object, an id of an author, or an array with author-id's
	 */
	public function deleteAuthorRole($context) {
		// When a new author is created $context is false:
		if($context == false) {
			return;
		}

		// When a bulk action delete is performed the ID's are stored in this manner:
		if(isset($context['author_ids'])) {
			$context = $context['author_ids'];
		}

		// When 'Delete' is clicked in the author-edit screen:
		if(isset($context['author_id'])) {
			$context = array($context['author_id']);
		}

		// When a single ID is provided:
		if(!is_array($context)) {
			$context = array($context);
		}

		// Delete the links:
		foreach($context as $id_author) {
			Symphony::Database()->query('DELETE FROM `tbl_author_roles_authors` WHERE `id_author` = '.$id_author.';');
		}
	}

	/**
	 * Add the role field to the author-form:
	 * @param	$context
	 *  The context, providing the form and the author object
	 */
	public function addRolePicker($context) {
		if(Administration::instance()->Author->isDeveloper()) {
			$group = new XMLElement('fieldset');
			$group->setAttribute('class', 'settings');
			$group->appendChild(new XMLElement('legend', __('Author Role')));

			$div = new XMLElement('div');

			$label = Widget::Label(__('This author belongs to'));

			$options = array(
				array(0, false, __('No role assigned'))
			);

			$roles = $this->getRoles();

			// See which role this user has:
			$id_role = $context['author']->get('id') != false ? Symphony::Database()->fetchVar('id_role', 0, 'SELECT `id_role` FROM `tbl_author_roles_authors` WHERE `id_author` = '.$context['author']->get('id').';') : 0;

			foreach($roles as $role) {
				$options[] = array($role['id'], $role['id'] == $id_role, $role['name']);
			}

			$label->appendChild(Widget::Select('fields[role]', $options));

			$div->appendChild($label);
			$div->appendChild(new XMLElement('p', __('<strong>Please note:</strong> According to the role you selected, some sections may not be visible to this author. If the <strong>Default Area</strong> of this author is set to one of these hidden sections, it will result in an authorization error message when he or she logs in. Be aware to set the Default Area to an area the author is allowed to see.')));
			$group->appendChild($div);

			$i = 0;

			foreach($context['form']->getChildren() as $formChild) {
				if($formChild->getName() != 'fieldset') {
					// Inject here:
					$context['form']->insertChildAt($i, $group);
				}

				$i++;
			}
		}
	}

	/**
	 * Perform certain actions according to the page callback
	 * @param	$context
	 *  The context object
	 */
	public function checkCallback($context) {
		$callback = Symphony::Engine()->getPageCallback();

		// Perform an action according to the callback:
		switch($callback['driver']) {
			case 'publish' :
				// The Publish Screen:
				switch($callback['context']['page']) {
					case 'index' :
						// The index:
						$this->adjustIndex($context, $callback);
						break;
					case 'new' :
					case 'edit' :
						// The Entry Editor:
						$this->adjustEntryEditor($context, $callback);
						break;
				}
				break;
		}
	}

	/**
	 * Adjust the publish index screen
	 * @param $context
	 *  The context
	 * @param $callback
	 *  The callback
	 * @return mixed
	 */
	private function adjustIndex($context, $callback) {
		$data = $this->getCurrentAuthorRoleData();

		if($data == false || Administration::instance()->Author->isDeveloper()) {
			return;
		}

		// Set the hidden fields:
		$hiddenFields = array();

		foreach($data['fields'] as $id_field => $rules) {
			if($rules['hidden'] == 1) {
				// This field is hidden.
				array_push($hiddenFields, $id_field);
			}
		}

		$section = $callback['context']['section_handle'];

		foreach($data['sections'] as $id_section => $rules) {
			if($rules['handle'] == $section) {
				// Check if there are rules:
				if($rules['create'] == 0) {
					// It is not allowed to create new items:
					$children = current($context['oPage']->Context->getChildrenByName('ul'))->getChildrenByName('li');

					foreach($children as $key => $child) {
						
						$xChild = $child->getValue();
						$value = $xChild->getValue();
						if(is_string($value) && strpos($value,__('Create New')) !== false) {
							$child->removeChildAt(0);
							$child->setValue('');
 						}
 						
					}
				}

				if($rules['own_entries'] == 1 || $rules['edit'] == 0 || $rules['delete'] == 0 || $rules['use_filter'] == 1) {
					// For only show entries created by this author:
					// Get a list of entry id's created by this author:
					$id_author = Administration::instance()->Author->get('id');

					if($rules['own_entries'] == 1) {
						// Only get the ID's of the current author to begin with:
						$results = Symphony::Database()->fetch('SELECT `id` FROM `tbl_entries` WHERE `author_id` = '.$id_author.';');
					}
					else {
						// Get all the ID's:
						$results = Symphony::Database()->fetch('SELECT `id` FROM `tbl_entries`;');
					}

					$ids = array();

					foreach($results as $result)
					{
						$ids[] = $result['id'];
					}

					// Add or remove ID's from the filter:
					if($rules['use_filter'] == 1) {
						$rule = explode(':', $rules['filter_rule']);

						if(count($rule) == 2) {
							// Valid filter, now get the ID's:
							$filteredIDs = array();
							$action = $rule[0];
							$idsArr = explode(',', $rule[1]);

							foreach($idsArr as $idExpr) {
								$a = explode('-', trim($idExpr));

								if(count($a)==1) {
									// Regular ID
									$filteredIDs[] = $a[0];
								}
								elseif(count($a)==2) {
									// Range
									$from = $a[0];
									$to   = $a[1];

									if($to >= $from) {
										for($i = $from; $i <= $to; $i++){
											$filteredIDs[] = $i;
										}
									}
								}
							}

							switch($action) {
								case 'show' :
									// Only show the given ids. Well that's easy:
									$ids = $filteredIDs;
									break;
								case 'hide' :
									// Remove the filtered ids from the ids-array:
									$ids = array_diff($ids, $filteredIDs);
									break;
							}
						}
					}

					// Now, check each table row:
					$newContents = new XMLElement('div', null, $context['oPage']->Contents->getAttributes());

					foreach($context['oPage']->Contents->getChildren() as $contentsChild) {
						if($contentsChild->getName() == 'form') {
							$newForm = new XMLElement('form', null, $contentsChild->getAttributes());

							foreach($contentsChild->getChildren() as $formChild) {
								// only show entries created by this author, or which are allowed by the filter:
								if($formChild->getName() == 'table' && ($rules['own_entries'] == 1 || $rules['use_filter'] == 1)) {
									$newTable = new XMLElement('table', null, $formChild->getAttributes());

									foreach($formChild->getChildren() as $tableChild) {
										if($tableChild->getName() == 'tbody') {
											$newTableBody = new XMLElement('tbody', null, $tableChild->getAttributes());

											foreach($tableChild->getChildren() as $tableRow) {
												// Check the ID:
												$id = explode('-', $tableRow->getAttribute('id'));

												if(in_array($id[1], $ids)) {
													$newTableBody->appendChild($tableRow);
												}
											}

											$newTable->appendChild($newTableBody);
										}
										else {
											$newTable->appendChild($tableChild);
										}
									}

									$newForm->appendChild($newTable);
								}
								elseif($formChild->getName() == 'div' && $formChild->getAttribute('class') == 'actions') {
									// Only proceed if you can either edit or delete. Otherwise it would have much sense to have an apply-button here...
									if($rules['delete'] == 1 || $rules['edit'] == 1) {
										$child = self::findChildren($formChild,'select');
										$child = $child[0];

										$newSelect = new XMLElement('select', null, $child->getAttributes());

										foreach($child->getChildren() as $selectChild) {
											// See if delete is allowed:
											if($selectChild->getAttribute('value') == 'delete' && $rules['delete'] == 1) {
												$newSelect->appendChild($selectChild);
											}
											elseif($selectChild->getName() == 'optgroup' && $rules['edit'] == 1) {
												// Check if the field that is edited is not a hidden field, because then editing is not allowed:
												$optGroupChildren = $selectChild->getChildren();

												if(!empty($optGroupChildren)) {
													$value = $optGroupChildren[0]->getAttribute('value');

													$a = explode('-', str_replace('toggle-', '', $value));

													if(!in_array($a[0], $hiddenFields)) {
														$newSelect->appendChild($selectChild);
													}
												}
											}
											elseif($selectChild->getName() == 'option' && $selectChild->getAttribute('value') != 'delete' && ($rules['edit'] == 1 || $rules['delete'] == 1)) {
												$newSelect->appendChild($selectChild);
											}
										}

										// if the new select has only one entry,
										// it is the dummy entry and we can discard it
										if($newSelect->getNumberOfChildren() > 1 ) {
											self::replaceChild($formChild, $newSelect);
											$newForm->appendChild($formChild);
										}
									}
								}
								else {
									$newForm->appendChild($formChild);
								}
							}

							$newContents->appendChild($newForm);
							$context['oPage']->Form = $newForm;
						}
						else {
							$newContents->appendChild($contentsChild);
						}
					}

					$context['oPage']->Contents = $newContents;
				}
			}
		}
	}

	/**
	 * See if there should be made some adjustments to the current page:
	 * @param	$context
	 *  The context
	 */
	public function makePreAdjustements($context) {
		$data = $this->getCurrentAuthorRoleData();

		if($data == false || Administration::instance()->Author->isDeveloper()) {
			return;
		}

		// Check if something needs to be done before anything is done:
		$callback = Symphony::Engine()->getPageCallback();

		// If the user is only allowed to see his or her own entries, then the configuration should be overwritten to a maximum.
		if($callback['driver'] == 'publish' && $callback['context']['page'] == 'index') {
			$section = $callback['context']['section_handle'];

			foreach($data['sections'] as $id_section => $rules) {
				if($rules['handle'] == $section && $rules['own_entries'] == 1) {
					Symphony::Configuration()->set('pagination_maximum_rows', PHP_INT_MAX, 'symphony');
				}
			}
		}
	}

	// return all ancestors of the given element with the given names
	// names can be a comma seperated list or an array of strings
	private static function findChildren(XMLElement $element, $names) {
		if(!is_array($names)) {
			$names = explode(',', $names);
		}

		$children = array();
		

		foreach($element->getChildren() as $child) {
			if(!($child instanceof XMLElement)) continue;
			
			$children = array_merge($children, self::findChildren($child,$names));

			if(in_array($child->getName(), $names )) {
				$children[] = $child;
			}
		}

		return $children;
	}

	// replaces the first ancestor of the first argument which
	// name matches the name of the second argument with
	// the second argument
	private static function replaceChild($parent, $child) {
        if (is_object($parent)) {
            foreach($parent->getChildren() as $position => $oldChild) {
                if(is_object($oldChild) && $oldChild->getName() == $child->getName()) {
                    $parent->replaceChildAt($position,$child);

                    return true;
                }

                if(self::replaceChild($oldChild, $child)) {
                    return true;
                }
            }
        }
        return false;
    }
	/** Adjust the entry editor on the publish page
	 * @param	$context
	 *  Provided with a page object
	 * @param	$callback
	 *  The current callback
	 */
	private function adjustEntryEditor($context, $callback) {
		$data = $this->getCurrentAuthorRoleData();

		if($data == false || Administration::instance()->Author->isDeveloper()) {
			return;
		}

		// Set the hidden fields:
		$hiddenFields = array();

		foreach($data['fields'] as $id_field => $rules) {
			if($rules['hidden'] == 1) {
				// This field is hidden.
				array_push($hiddenFields, $id_field);
			}
		}

		// Fields should be hidden with JavaScript, so the data still gets posted when saving an entry:
		$script = new XMLElement('script', 'var roles_hidden_fields = ['.implode(',', $hiddenFields).'];', array('type'=>'text/javascript'));
		$context['oPage']->addElementToHead($script);
		$context['oPage']->addScriptToHead(URL.'/extensions/author_roles/assets/author_roles.js');

		$section = $callback['context']['section_handle'];

		foreach($data['sections'] as $id_section => $rules) {
			if($rules['handle'] == $section) {
				if($rules['edit'] == 0 || $rules['delete'] == 0 || $rules['create'] == 0) {
					// Hide the delete button when the author is not allowed to delete:
					// Hide the submit-button when the author is not allowed to create or edit:
					$newContents = new XMLElement('div', null, $context['oPage']->Contents->getAttributes());

					foreach($context['oPage']->Contents->getChildren() as $contentsChild) {
						if($contentsChild->getName() == 'form') {
							$newForm = new XMLElement('form', null, $contentsChild->getAttributes());

							foreach($contentsChild->getChildren() as $formChild) {
								if($formChild->getName() == 'div' && $formChild->getAttribute('class') == 'actions') {
									$actionDiv = new XMLElement('div', null, $formChild->getAttributes());

									foreach($formChild->getChildren() as $actionChild) {
										if($actionChild->getAttribute('name') == 'action[save]') {
											// Check whether this is a create or an edit:
											if(
											   ($callback['context']['page'] == 'edit' && $rules['edit'] == 1) ||
											   ($callback['context']['page'] == 'new' && $rules['create'] == 1))
											{
												$actionDiv->appendChild($actionChild);
											}
										}
										elseif($actionChild->getAttribute('name') == 'action[delete]' && $rules['delete'] == 1) {
											$actionDiv->appendChild($actionChild);
										}
									}

									if($rules['edit'] == 1|| $rules['create'] == 1) {
										$newForm->appendChild($actionDiv);
									}
								}
								else {
									if($rules['edit'] == 0) {
										foreach(self::findChildren($formChild,'input,select,textarea') as $child) {
											$child->setAttribute('disabled','disabled');
										}
									}

									$newForm->appendChild($formChild);
								}
							}

							$newContents->appendChild($newForm);
							$context['oPage']->Form = $newForm;
						}
						else {
							$newContents->appendChild($contentsChild);
						}
					}

					$context['oPage']->Contents = $newContents;
				}
			}
		}
	}

	/**
	 * Get the role of the current logged in author
	 * @return array|boolean
	 *  An associated array with all the information you need, or false if no role is assigned
	 */
	private function getCurrentAuthorRoleData() {
		if(Administration::instance()->isLoggedIn()) {
			$id_author = Administration::instance()->Author->get('id');
			$id_role   = $this->getAuthorRole($id_author);

			if($id_role != false) {
				$data = $this->getData($id_role);
				return $data;
			}
			else {
				return false;
			}
		}
	}

	/**
	 * Change the dropdown with the default author areas
	 * @param	$context
	 *  The context
	 */
	public function modifyAreas($context) {
		$data = $this->getCurrentAuthorRoleData();

		if($data == false || Administration::instance()->Author->isDeveloper()) {
			return;
		}

		$newOptions = array();

		foreach($data['sections'] as $id_section => $rules) {
			if($rules['visible'] == 1) {
				$newOptions[] = array($id_section, $id_section == $context['default_area'], $rules['name']);
			}
		}

		$context['options'] = $newOptions;
	}

	/**
	 * Save the role to this author. This is send after the save-button is clicked on the author-screen.
	 * @param	$context
	 *  The context
	 */
	public function saveAuthorRole($context) {
		if(Administration::instance()->Author->isDeveloper()) {
			$id_role = intval($_POST['fields']['role']);
			$id_author = $context['author']->get('id');

			if($id_author == null) {
				// This author has just been created, get the ID of this newly created author:
				$id_author = Symphony::Database()->fetchVar('id', 0, 'SELECT `id` FROM `tbl_authors` WHERE `username` = \''.$context['author']->get('username').'\';');
			}

			// Delete previously set roles:
			$this->deleteAuthorRole($id_author);

			if($id_role != 0) {
				// Insert new role:
				Symphony::Database()->insert(array('id_role'=>$id_role, 'id_author'=>$id_author), 'tbl_author_roles_authors');
			}
		}
	}

	/**
	 * Get the roles
	 * @return	array
	 *  An array with the roles
	 */
	public function getRoles() {
		$roles = Symphony::Database()->fetch('SELECT * FROM `tbl_author_roles` ORDER BY `name` ASC');

		return $roles;
	}

	/**
	 * Get the authors from a specific role:
	 * @param	$id_role
	 *  The ID of the role
	 * @return	array
	 *  An array with the id, first_name and last_name of the authors
	 */
	public function getAuthors($id_role) {
		$authors = Symphony::Database()->fetch('
			SELECT
				A.`id`,
				A.`first_name`,
				A.`last_name`
			FROM
				`tbl_authors` A,
				`tbl_author_roles_authors` B
			WHERE
				B.`id_role` = '.$id_role.' AND
				B.`id_author` = A.`id`;');

		return $authors;
	}

	/**
	 * Get the role of this author
	 * @param	$id_author
	 *  The ID of the author
	 * @return  int
	 *  The role ID
	 */
	public function getAuthorRole($id_author) {
		$id_role = Symphony::Database()->fetchVar('id_role', 0, 'SELECT `id_role` FROM `tbl_author_roles_authors` WHERE `id_author` = '.$id_author.';');

		return $id_role;
	}

	/**
	 * Load the data
	 * @param	$id_role
	 *  int	The ID of the Role
	 * @return array|boolean
	 *  An associated array with all the information you need of this role, or false of no role is supplied
	 */
	public function getData($id_role) {
		if($id_role != false) {
			$data = array();
			// The name of the role:
			$roleResult = Symphony::Database()->fetch('SELECT * FROM `tbl_author_roles` WHERE `id` = '.$id_role.';');
			$data['name'] = $roleResult[0]['name'];
			$data['custom_elements'] = $roleResult[0]['custom_elements'];

			// Get sections from the section manager:
			$availableSections = SectionManager::fetch();
//			print_r($availableSections);

			// The associated sections:
			$sections = Symphony::Database()->fetch('
				SELECT
					A.`id_section`,
					A.`visible`,
					A.`create`,
					A.`edit`,
					A.`delete`,
					A.`own_entries`,
					A.`use_filter`,
					A.`filter_rule`
				FROM
					`tbl_author_roles_sections` A
				WHERE
					A.`id_role` = '.$id_role.'
				;');

			$data['sections'] = array();

			foreach($sections as $section) {
				$id_section = $section['id_section'];
				unset($section['id_section']);

				foreach($availableSections as $s) {
					/* @var $s Section */
					if($s->get('id') == $id_section) {
						$section['name'] = $s->get('name');
						$section['handle'] = $s->get('handle');
					}
				}

				$data['sections'][$id_section] = $section;
			}

			// The fields:
			$fields = Symphony::Database()->fetch('SELECT * FROM `tbl_author_roles_fields` WHERE `id_role` = '.$id_role.';');
			$data['fields'] = array();

			foreach($fields as $field) {
				$id_field = $field['id_field'];
				unset($field['id']);
				unset($field['id_field']);
				$data['fields'][$id_field] = $field;
			}

			// The entries:

			return $data;
		}
		else {
			return false;
		}
	}

	/**
	 * Delete a role
	 * @param	$id
	 *  The ID of the role
	 */
	public function deleteRole($id) {
		Symphony::Database()->query('DELETE FROM `tbl_author_roles` WHERE `id` = '.$id.';');
		Symphony::Database()->query('DELETE FROM `tbl_author_roles_authors` WHERE `id_role` = '.$id.';');
		Symphony::Database()->query('DELETE FROM `tbl_author_roles_sections` WHERE `id_role` = '.$id.';');
		Symphony::Database()->query('DELETE FROM `tbl_author_roles_fields` WHERE `id_role` = '.$id.';');
	}

	/**
	 * Save Role data
	 * @param	$values
	 *  An array with information about the role to be stored
	 * @return int|boolean
	 *  The ID of the role, or false on failure
	 */
	public function saveData($values) {
		// Get the main data:
		$name = isset($values['name']) ? Symphony::Database()->cleanValue($values['name']) : '';
		$custom_elements = isset($values['custom_elements']) ? $values['custom_elements'] : '';

		if(!empty($name) && isset($values['id_role'])) {
			// Create the role:
			if($values['id_role'] == 0) {
				Symphony::Database()->insert(array('name'=>$name, 'custom_elements'=>$custom_elements), 'tbl_author_roles');
				$id_role = Symphony::Database()->getInsertId();
			}
			else {
				$id_role = $values['id_role'];
				Symphony::Database()->update(array('name'=>$name, 'custom_elements'=>$custom_elements), 'tbl_author_roles', '`id` = '.$id_role);
			}

			// First delete all links in the database before new ones are created:
			Symphony::Database()->query('DELETE FROM `tbl_author_roles_sections` WHERE `id_role` = '.$id_role.';');
			Symphony::Database()->query('DELETE FROM `tbl_author_roles_fields` WHERE `id_role` = '.$id_role.';');

			foreach($values['section'] as $id_section => $info) {
				$insert 			= array('id_role'=>$id_role, 'id_section'=>$id_section);
				$insert['visible']	= isset($info['visible']) ? 1 : 0;
				$insert['create']	= isset($info['create']) ? 1 : 0;
				$insert['edit']		= isset($info['edit']) ? 1 : 0;
				$insert['delete']	= isset($info['delete']) ? 1 : 0;
				$insert['own_entries'] = isset($info['own_entries']) ? 1 : 0;
				$insert['use_filter']  = isset($info['use_filter']) ? 1 : 0;

				// Filter rule:
				if(isset($info['filter_rule']) && isset($info['filter_rule_type'])) {
					$insert['filter_rule'] = $info['filter_rule_type'].':'.$info['filter_rule'];
				}

				Symphony::Database()->insert($insert, 'tbl_author_roles_sections');

				// Fields:
				if(isset($info['fields'])) {
					foreach($info['fields'] as $id_field => $value) {
						Symphony::Database()->insert(array('id_role'=>$id_role, 'id_field'=>$id_field, 'hidden'=>1), 'tbl_author_roles_fields');
					}
				}
				// Entries:

			}

			return $id_role;
		}
		else {
			return false;
		}
	}

	/**
	 * Installation
	 */
	public function install() {
		// Roles table:
		Symphony::Database()->query("
			CREATE TABLE IF NOT EXISTS `tbl_author_roles` (
				`id` INT(11) unsigned NOT NULL auto_increment,
				`name` VARCHAR(255) NOT NULL,
				`custom_elements` TEXT NULL,
				PRIMARY KEY (`id`)
			);
		");

		// Roles <-> Authors
		Symphony::Database()->query("
			CREATE TABLE IF NOT EXISTS `tbl_author_roles_authors` (
				`id` INT(11) unsigned NOT NULL auto_increment,
				`id_role` INT(255) unsigned NOT NULL,
				`id_author` INT(255) unsigned NOT NULL,
				PRIMARY KEY (`id`),
				KEY `id_role` (`id_role`),
				KEY `id_author` (`id_author`)
			);
		");

		// Roles <-> Sections
		Symphony::Database()->query("
			CREATE TABLE IF NOT EXISTS `tbl_author_roles_sections` (
				`id` INT(11) unsigned NOT NULL auto_increment,
				`id_role` INT(255) unsigned NOT NULL,
				`id_section` INT(255) unsigned NOT NULL,
				`visible` TINYINT(1) unsigned NOT NULL,
				`create` TINYINT(1) unsigned NOT NULL,
				`edit` TINYINT(1) unsigned NOT NULL,
				`delete` TINYINT(1) unsigned NOT NULL,
				`own_entries` TINYINT(1) unsigned NOT NULL,
				`use_filter` TINYINT(1) unsigned NOT NULL,
				`filter_rule` TEXT NOT NULL,
				PRIMARY KEY (`id`),
				KEY `id_role` (`id_role`),
				KEY `id_section` (`id_section`)
			);
		");

		// Roles <-> Fields
		Symphony::Database()->query("
			CREATE TABLE IF NOT EXISTS `tbl_author_roles_fields` (
				`id` INT(11) unsigned NOT NULL auto_increment,
				`id_role` INT(255) unsigned NOT NULL,
				`id_field` INT(255) unsigned NOT NULL,
				`hidden` TINYINT(1) unsigned NOT NULL,
				PRIMARY KEY (`id`),
				KEY `id_role` (`id_role`),
				KEY `id_field` (`id_field`)
			);
		");
	}

	/**
	 * Uninstallation
	 */
	public function uninstall() {
		// Drop all the tables:
		Symphony::Database()->query("DROP TABLE `tbl_author_roles`");
		Symphony::Database()->query("DROP TABLE `tbl_author_roles_authors`");
		Symphony::Database()->query("DROP TABLE `tbl_author_roles_sections`");
		Symphony::Database()->query("DROP TABLE `tbl_author_roles_fields`");
	}

	/**
	 * Update instructions
	 * @param $previousVersion
	 *  The version that is currently installed in this Symphony installation
	 * @return boolean
	 */
	public function update($previousVersion) {
		if(version_compare($previousVersion, '1.2', '<')) {
			// Update from pre-1.1 to 1.2:
			return Symphony::Database()->query('ALTER TABLE  `tbl_author_roles` ADD  `custom_elements` TEXT NULL;');
		}
	}
}