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<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle 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.
//
// Moodle 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 Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
* Classes for displaying and editing a nested list of items.
*
* Handles functionality for :
*
* Construction of nested list from db records with some key pointing to a parent id.
* Display of list with or without editing icons with optional pagination.
* Reordering of items works across pages.
* Processing of editing actions on list.
*
* @package core
* @subpackage lib
* @copyright Jamie Pratt
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
defined('MOODLE_INTERNAL') || die();
/**
* Clues to reading this code:
*
* The functions that move things around the tree structure just update the
* database - they don't update the in-memory structure, instead they trigger a
* page reload so everything is rebuilt from scratch.
*
* @package moodlecore
* @copyright Jamie Pratt
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
abstract class moodle_list {
public $attributes;
public $listitemclassname = 'list_item';
/** @var array of $listitemclassname objects. */
public $items = array();
/** @var string 'ol' or 'ul'. */
public $type;
/** @var list_item or derived class. */
public $parentitem = null;
public $table;
public $fieldnamesparent = 'parent';
/** @var array Records from db, only used in top level list. */
public $records = array();
public $editable;
/** @var array keys are child ids, values are parents. */
public $childparent;
//------------------------------------------------------
//vars used for pagination.
public $page = 0; // 0 means no pagination
public $firstitem = 1;
public $lastitem = 999999;
public $pagecount;
public $paged = false;
public $offset = 0;
//------------------------------------------------------
public $pageurl;
public $pageparamname;
/**
* Constructor.
*
* @param string $type
* @param string $attributes
* @param boolean $editable
* @param moodle_url $pageurl url for this page
* @param integer $page if 0 no pagination. (These three params only used in top level list.)
* @param string $pageparamname name of url param that is used for passing page no
* @param integer $itemsperpage no of top level items.
*/
public function __construct($type='ul', $attributes='', $editable = false, $pageurl=null, $page = 0, $pageparamname = 'page', $itemsperpage = 20) {
global $PAGE;
$this->editable = $editable;
$this->attributes = $attributes;
$this->type = $type;
$this->page = $page;
$this->pageparamname = $pageparamname;
$this->itemsperpage = $itemsperpage;
if ($pageurl === null) {
$this->pageurl = new moodle_url($PAGE->url);
$this->pageurl->params(array($this->pageparamname => $this->page));
} else {
$this->pageurl = $pageurl;
}
}
/**
* Returns html string.
*
* @param integer $indent depth of indentation.
*/
public function to_html($indent=0, $extraargs=array()) {
if (count($this->items)) {
$tabs = str_repeat("\t", $indent);
$first = true;
$itemiter = 1;
$lastitem = '';
$html = '';
foreach ($this->items as $item) {
$last = (count($this->items) == $itemiter);
if ($this->editable) {
$item->set_icon_html($first, $last, $lastitem);
}
if ($itemhtml = $item->to_html($indent+1, $extraargs)) {
$html .= "$tabs\t<li".((!empty($item->attributes))?(' '.$item->attributes):'').">";
$html .= $itemhtml;
$html .= "</li>\n";
}
$first = false;
$lastitem = $item;
$itemiter++;
}
} else {
$html = '';
}
if ($html) { //if there are list items to display then wrap them in ul / ol tag.
$tabs = str_repeat("\t", $indent);
$html = $tabs.'<'.$this->type.((!empty($this->attributes))?(' '.$this->attributes):'').">\n".$html;
$html .= $tabs."</".$this->type.">\n";
} else {
$html ='';
}
return $html;
}
/**
* Recurse down the tree and find an item by it's id.
*
* @param integer $id
* @param boolean $suppresserror error if not item found?
* @return list_item *copy* or null if item is not found
*/
public function find_item($id, $suppresserror = false) {
if (isset($this->items)) {
foreach ($this->items as $key => $child) {
if ($child->id == $id) {
return $this->items[$key];
}
}
foreach (array_keys($this->items) as $key) {
$thischild = $this->items[$key];
$ref = $thischild->children->find_item($id, true);//error always reported at top level
if ($ref !== null) {
return $ref;
}
}
}
if (!$suppresserror) {
print_error('listnoitem');
}
return null;
}
public function add_item($item) {
$this->items[] = $item;
}
public function set_parent($parent) {
$this->parentitem = $parent;
}
/**
* Produces a hierarchical tree of list items from a flat array of records.
* 'parent' field is expected to point to a parent record.
* records are already sorted.
* If the parent field doesn't point to another record in the array then this is
* a top level list
*
* @param integer $offset how many list toplevel items are there in lists before this one
* @return array(boolean, integer) whether there is more than one page, $offset + how many toplevel items where there in this list.
*
*/
public function list_from_records($paged = false, $offset = 0) {
$this->paged = $paged;
$this->offset = $offset;
$this->get_records();
$records = $this->records;
$page = $this->page;
if (!empty($page)) {
$this->firstitem = ($page - 1) * $this->itemsperpage;
$this->lastitem = $this->firstitem + $this->itemsperpage - 1;
}
$itemiter = $offset;
//make a simple array which is easier to search
$this->childparent = array();
foreach ($records as $record) {
$this->childparent[$record->id] = $record->parent;
}
//create top level list items and they're responsible for creating their children
foreach ($records as $record) {
if (array_key_exists($record->parent, $this->childparent)) {
// This record is a child of another record, so it will be dealt
// with by a call to list_item::create_children, not here.
continue;
}
$inpage = $itemiter >= $this->firstitem && $itemiter <= $this->lastitem;
// Make list item for top level for all items
// we need the info about the top level items for reordering peers.
if ($this->parentitem !== null) {
$newattributes = $this->parentitem->attributes;
} else {
$newattributes = '';
}
$this->items[$itemiter] = new $this->listitemclassname($record, $this, $newattributes, $inpage);
if ($inpage) {
$this->items[$itemiter]->create_children($records, $this->childparent, $record->id);
} else {
// Don't recurse down the tree for items that are not on this page
$this->paged = true;
}
$itemiter++;
}
return array($this->paged, $itemiter);
}
/**
* Should be overriden to return an array of records of list items.
*/
public abstract function get_records();
/**
* display list of page numbers for navigation
*/
public function display_page_numbers() {
$html = '';
$topcount = count($this->items);
$this->pagecount = (integer) ceil(($topcount + $this->offset)/ QUESTION_PAGE_LENGTH );
if (!empty($this->page) && ($this->paged)) {
$html = "<div class=\"paging\">".get_string('page').":\n";
foreach (range(1,$this->pagecount) as $currentpage) {
if ($this->page == $currentpage) {
$html .= " $currentpage \n";
}
else {
$html .= "<a href=\"".$this->pageurl->out(true, array($this->pageparamname => $currentpage))."\">";
$html .= " $currentpage </a>\n";
}
}
$html .= "</div>";
}
return $html;
}
/**
* Returns an array of ids of peers of an item.
*
* @param int itemid - if given, restrict records to those with this parent id.
* @return array peer ids
*/
public function get_items_peers($itemid) {
$itemref = $this->find_item($itemid);
$peerids = $itemref->parentlist->get_child_ids();
return $peerids;
}
/**
* Returns an array of ids of child items.
*
* @return array peer ids
*/
public function get_child_ids() {
$childids = array();
foreach ($this->items as $child) {
$childids[] = $child->id;
}
return $childids;
}
/**
* Returns the value to be used as the parent for the $item when it goes to the top level.
* Override if needed.
*
* @param list_item $item The item which its top level parent is going to be returned.
* @return int
*/
public function get_top_level_parent_id($item) {
return 0; // Top level items have no parent.
}
/**
* Move a record up or down
*
* @param string $direction up / down
* @param integer $id
*/
public function move_item_up_down($direction, $id) {
$peers = $this->get_items_peers($id);
$itemkey = array_search($id, $peers);
switch ($direction) {
case 'down' :
if (isset($peers[$itemkey+1])) {
$olditem = $peers[$itemkey+1];
$peers[$itemkey+1] = $id;
$peers[$itemkey] = $olditem;
} else {
print_error('listcantmoveup');
}
break;
case 'up' :
if (isset($peers[$itemkey-1])) {
$olditem = $peers[$itemkey-1];
$peers[$itemkey-1] = $id;
$peers[$itemkey] = $olditem;
} else {
print_error('listcantmovedown');
}
break;
}
$this->reorder_peers($peers);
}
public function reorder_peers($peers) {
global $DB;
foreach ($peers as $key => $peer) {
$DB->set_field($this->table, "sortorder", $key, array("id"=>$peer));
}
}
/**
* Moves the item one step up in the tree.
*
* @param int $id an item index.
* @return list_item the item that used to be the parent of the item moved.
*/
public function move_item_left($id) {
global $DB;
$item = $this->find_item($id);
if (!isset($item->parentlist->parentitem->parentlist)) {
print_error('listcantmoveleft');
} else {
$newpeers = $this->get_items_peers($item->parentlist->parentitem->id);
if (isset($item->parentlist->parentitem->parentlist->parentitem)) {
$newparent = $item->parentlist->parentitem->parentlist->parentitem->id;
} else {
$newparent = $this->get_top_level_parent_id($item);
}
$DB->set_field($this->table, "parent", $newparent, array("id"=>$item->id));
$oldparentkey = array_search($item->parentlist->parentitem->id, $newpeers);
$neworder = array_merge(array_slice($newpeers, 0, $oldparentkey+1), array($item->id), array_slice($newpeers, $oldparentkey+1));
$this->reorder_peers($neworder);
}
return $item->parentlist->parentitem;
}
/**
* Make item with id $id the child of the peer that is just above it in the sort order.
*
* @param integer $id
*/
public function move_item_right($id) {
global $DB;
$peers = $this->get_items_peers($id);
$itemkey = array_search($id, $peers);
if (!isset($peers[$itemkey-1])) {
print_error('listcantmoveright');
} else {
$DB->set_field($this->table, "parent", $peers[$itemkey-1], array("id"=>$peers[$itemkey]));
$newparent = $this->find_item($peers[$itemkey-1]);
if (isset($newparent->children)) {
$newpeers = $newparent->children->get_child_ids();
}
if ($newpeers) {
$newpeers[] = $peers[$itemkey];
$this->reorder_peers($newpeers);
}
}
}
/**
* process any actions.
*
* @param integer $left id of item to move left
* @param integer $right id of item to move right
* @param integer $moveup id of item to move up
* @param integer $movedown id of item to move down
* @return unknown
*/
public function process_actions($left, $right, $moveup, $movedown) {
//should this action be processed by this list object?
if (!(array_key_exists($left, $this->records) || array_key_exists($right, $this->records) || array_key_exists($moveup, $this->records) || array_key_exists($movedown, $this->records))) {
return false;
}
if (!empty($left)) {
$oldparentitem = $this->move_item_left($left);
if ($this->item_is_last_on_page($oldparentitem->id)) {
// Item has jumped onto the next page, change page when we redirect.
$this->page ++;
$this->pageurl->params(array($this->pageparamname => $this->page));
}
} else if (!empty($right)) {
$this->move_item_right($right);
if ($this->item_is_first_on_page($right)) {
// Item has jumped onto the previous page, change page when we redirect.
$this->page --;
$this->pageurl->params(array($this->pageparamname => $this->page));
}
} else if (!empty($moveup)) {
$this->move_item_up_down('up', $moveup);
if ($this->item_is_first_on_page($moveup)) {
// Item has jumped onto the previous page, change page when we redirect.
$this->page --;
$this->pageurl->params(array($this->pageparamname => $this->page));
}
} else if (!empty($movedown)) {
$this->move_item_up_down('down', $movedown);
if ($this->item_is_last_on_page($movedown)) {
// Item has jumped onto the next page, change page when we redirect.
$this->page ++;
$this->pageurl->params(array($this->pageparamname => $this->page));
}
} else {
return false;
}
redirect($this->pageurl);
}
/**
* @param integer $itemid an item id.
* @return boolean Is the item with the given id the first top-level item on
* the current page?
*/
public function item_is_first_on_page($itemid) {
return $this->page && isset($this->items[$this->firstitem]) &&
$itemid == $this->items[$this->firstitem]->id;
}
/**
* @param integer $itemid an item id.
* @return boolean Is the item with the given id the last top-level item on
* the current page?
*/
public function item_is_last_on_page($itemid) {
return $this->page && isset($this->items[$this->lastitem]) &&
$itemid == $this->items[$this->lastitem]->id;
}
}
/**
* @package moodlecore
* @copyright Jamie Pratt
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
abstract class list_item {
/** @var integer id of record, used if list is editable. */
public $id;
/** @var string name of this item, used if list is editable. */
public $name;
/** @var mixed The object or string representing this item. */
public $item;
public $fieldnamesname = 'name';
public $attributes;
public $display;
public $icons = array();
/** @var moodle_list */
public $parentlist;
/** @var moodle_list Set if there are any children of this listitem. */
public $children;
/**
* Constructor
* @param mixed $item fragment of html for list item or record
* @param object $parent reference to parent of this item
* @param string $attributes attributes for li tag
* @param boolean $display whether this item is displayed. Some items may be loaded so we have a complete
* structure in memory to work with for actions but are not displayed.
* @return list_item
*/
public function __construct($item, $parent, $attributes = '', $display = true) {
$this->item = $item;
if (is_object($this->item)) {
$this->id = $this->item->id;
$this->name = $this->item->{$this->fieldnamesname};
}
$this->set_parent($parent);
$this->attributes = $attributes;
$parentlistclass = get_class($parent);
$this->children = new $parentlistclass($parent->type, $parent->attributes, $parent->editable, $parent->pageurl, 0);
$this->children->set_parent($this);
$this->display = $display;
}
/**
* Output the html just for this item. Called by to_html which adds html for children.
*
*/
public function item_html($extraargs = array()) {
if (is_string($this->item)) {
$html = $this->item;
} elseif (is_object($this->item)) {
//for debug purposes only. You should create a sub class to
//properly handle the record
$html = join(', ', (array)$this->item);
}
return $html;
}
/**
* Returns html
*
* @param integer $indent
* @param array $extraargs any extra data that is needed to print the list item
* may be used by sub class.
* @return string html
*/
public function to_html($indent = 0, $extraargs = array()) {
if (!$this->display) {
return '';
}
$tabs = str_repeat("\t", $indent);
if (isset($this->children)) {
$childrenhtml = $this->children->to_html($indent+1, $extraargs);
} else {
$childrenhtml = '';
}
return $this->item_html($extraargs).' '.(join('', $this->icons)).(($childrenhtml !='')?("\n".$childrenhtml):'');
}
public function set_icon_html($first, $last, $lastitem) {
global $CFG;
$strmoveup = get_string('moveup');
$strmovedown = get_string('movedown');
$strmoveleft = get_string('maketoplevelitem', 'question');
if (right_to_left()) { // Exchange arrows on RTL
$rightarrow = 'left';
$leftarrow = 'right';
} else {
$rightarrow = 'right';
$leftarrow = 'left';
}
if (isset($this->parentlist->parentitem)) {
$parentitem = $this->parentlist->parentitem;
if (isset($parentitem->parentlist->parentitem)) {
$action = get_string('makechildof', 'question', $parentitem->parentlist->parentitem->name);
} else {
$action = $strmoveleft;
}
$url = new moodle_url($this->parentlist->pageurl, (array('sesskey'=>sesskey(), 'left'=>$this->id)));
$this->icons['left'] = $this->image_icon($action, $url, $leftarrow);
} else {
$this->icons['left'] = $this->image_spacer();
}
if (!$first) {
$url = new moodle_url($this->parentlist->pageurl, (array('sesskey'=>sesskey(), 'moveup'=>$this->id)));
$this->icons['up'] = $this->image_icon($strmoveup, $url, 'up');
} else {
$this->icons['up'] = $this->image_spacer();
}
if (!$last) {
$url = new moodle_url($this->parentlist->pageurl, (array('sesskey'=>sesskey(), 'movedown'=>$this->id)));
$this->icons['down'] = $this->image_icon($strmovedown, $url, 'down');
} else {
$this->icons['down'] = $this->image_spacer();
}
if (!empty($lastitem)) {
$makechildof = get_string('makechildof', 'question', $lastitem->name);
$url = new moodle_url($this->parentlist->pageurl, (array('sesskey'=>sesskey(), 'right'=>$this->id)));
$this->icons['right'] = $this->image_icon($makechildof, $url, $rightarrow);
} else {
$this->icons['right'] = $this->image_spacer();
}
}
public function image_icon($action, $url, $icon) {
global $OUTPUT;
return '<a title="' . s($action) .'" href="'.$url.'">' .
$OUTPUT->pix_icon('t/' . $icon, $action) . '</a> ';
}
public function image_spacer() {
global $OUTPUT;
return $OUTPUT->spacer();
}
/**
* Recurse down tree creating list_items, called from moodle_list::list_from_records
*
* @param array $records
* @param array $children
* @param integer $thisrecordid
*/
public function create_children(&$records, &$children, $thisrecordid) {
//keys where value is $thisrecordid
$thischildren = array_keys($children, $thisrecordid);
foreach ($thischildren as $child) {
$thisclass = get_class($this);
$newlistitem = new $thisclass($records[$child], $this->children, $this->attributes);
$this->children->add_item($newlistitem);
$newlistitem->create_children($records, $children, $records[$child]->id);
}
}
public function set_parent($parent) {
$this->parentlist = $parent;
}
}