comment/lib.php

   1 <?php
   2 // This file is part of Moodle - http://moodle.org/
   3 //
   4 // Moodle is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // Moodle is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 /**
  18  * Comment is helper class to add/delete comments anywhere in moodle
  19  *
  20  * @package   comment
  21  * @copyright 2010 Dongsheng Cai <dongsheng@moodle.com>
  22  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23  */
  24
  25 defined('MOODLE_INTERNAL') || die();
  26
  27 class comment {
  28     /**
  29      * there may be several comment box in one page
  30      * so we need a client_id to recognize them
  31      * @var integer
  32      */
  33     private $cid;
  34     /**
  35      * commentarea is used to specify different
  36      * parts shared the same itemid
  37      * @var string
  38      */
  39     private $commentarea;
  40     /**
  41      * itemid is used to associate with commenting content
  42      * @var integer
  43      */
  44     private $itemid;
  45     /**
  46      * this html snippet will be used as a template
  47      * to build comment content
  48      * @var string
  49      */
  50     private $template;
  51     /**
  52      * The context id for comments
  53      * @var int
  54      */
  55     private $contextid;
  56     /**
  57      * The context itself
  58      * @var stdClass
  59      */
  60     private $context;
  61     /**
  62      * The course id for comments
  63      * @var int
  64      */
  65     private $courseid;
  66     /**
  67      * course module object, only be used to help find pluginname automatically
  68      * if pluginname is specified, it won't be used at all
  69      * @var stdClass
  70      */
  71     private $cm;
  72     /**
  73      * The component that this comment is for. It is STRONGLY recommended to set this.
  74      * @var string
  75      */
  76     private $component;
  77     /**
  78      * This is calculated by normalising the component
  79      * @var string
  80      */
  81     private $pluginname;
  82     /**
  83      * This is calculated by normalising the component
  84      * @var string
  85      */
  86     private $plugintype;
  87     /**
  88      * Whether the user has the required capabilities/permissions to view comments.
  89      * @var bool
  90      */
  91     private $viewcap = false;
  92     /**
  93      * Whether the user has the required capabilities/permissions to post comments.
  94      * @var bool
  95      */
  96     private $postcap = false;
  97     /**
  98      * to costomize link text
  99      * @var string
 100      */
 101     private $linktext;
 102     /**
 103      * If set to true then comment sections won't be able to be opened and closed
 104      * instead they will always be visible.
 105      * @var bool
 106      */
 107     protected $notoggle = false;
 108     /**
 109      * If set to true comments are automatically loaded as soon as the page loads.
 110      * Normally this happens when the user expands the comment section.
 111      * @var bool
 112      */
 113     protected $autostart = false;
 114     /**
 115      * If set to true the total count of comments is displayed when displaying comments.
 116      * @var bool
 117      */
 118     protected $displaytotalcount = false;
 119     /**
 120      * If set to true a cancel button will be shown on the form used to submit comments.
 121      * @var bool
 122      */
 123     protected $displaycancel = false;
 124     /**
 125      * The number of comments associated with this comments params
 126      * @var int
 127      */
 128     protected $totalcommentcount = null;
 129     /**
 130      * When set to true any user to the system is able to view comments.
 131      *
 132      * This can be set to true by a plugin by implementing a allow_anonymous_access callback.
 133      * By default it is false except on the front page.
 134      *
 135      * @var bool
 136      */
 137     protected $allowanonymousaccess = false;
 138
 139     /**#@+
 140      * static variable will be used by non-js comments UI
 141      */
 142     private static $nonjs = false;
 143     private static $comment_itemid = null;
 144     private static $comment_context = null;
 145     private static $comment_area = null;
 146     private static $comment_page = null;
 147     private static $comment_component = null;
 148     /**#@-*/
 149
 150     /**
 151      * Construct function of comment class, initialise
 152      * class members
 153      * @param stdClass $options
 154      * @param object $options {
 155      *            context => context context to use for the comment [required]
 156      *            component => string which plugin will comment being added to [required]
 157      *            itemid  => int the id of the associated item (forum post, glossary item etc) [required]
 158      *            area    => string comment area
 159      *            cm      => stdClass course module
 160      *            course  => course course object
 161      *            client_id => string an unique id to identify comment area
 162      *            autostart => boolean automatically expend comments
 163      *            showcount => boolean display the number of comments
 164      *            displaycancel => boolean display cancel button
 165      *            notoggle => boolean don't show/hide button
 166      *            linktext => string title of show/hide button
 167      * }
 168      */
 169     public function __construct(stdClass $options) {
 170         $this->viewcap = false;
 171         $this->postcap = false;
 172
 173         // setup client_id
 174         if (!empty($options->client_id)) {
 175             $this->cid = $options->client_id;
 176         } else {
 177             $this->cid = uniqid();
 178         }
 179
 180         // setup context
 181         if (!empty($options->context)) {
 182             $this->context = $options->context;
 183             $this->contextid = $this->context->id;
 184         } else if(!empty($options->contextid)) {
 185             $this->contextid = $options->contextid;
 186             $this->context = get_context_instance_by_id($this->contextid);
 187         } else {
 188             print_error('invalidcontext');
 189         }
 190
 191         if (!empty($options->component)) {
 192             // set and validate component
 193             $this->set_component($options->component);
 194         } else {
 195             // component cannot be empty
 196             throw new comment_exception('invalidcomponent');
 197         }
 198
 199         // setup course
 200         // course will be used to generate user profile link
 201         if (!empty($options->course)) {
 202             $this->courseid = $options->course->id;
 203         } else if (!empty($options->courseid)) {
 204             $this->courseid = $options->courseid;
 205         } else {
 206             $this->courseid = SITEID;
 207         }
 208
 209         // setup coursemodule
 210         if (!empty($options->cm)) {
 211             $this->cm = $options->cm;
 212         } else {
 213             $this->cm = null;
 214         }
 215
 216         // setup commentarea
 217         if (!empty($options->area)) {
 218             $this->commentarea = $options->area;
 219         }
 220
 221         // setup itemid
 222         if (!empty($options->itemid)) {
 223             $this->itemid = $options->itemid;
 224         } else {
 225             $this->itemid = 0;
 226         }
 227
 228         // setup customized linktext
 229         if (!empty($options->linktext)) {
 230             $this->linktext = $options->linktext;
 231         } else {
 232             $this->linktext = get_string('comments');
 233         }
 234
 235         // setup options for callback functions
 236         $this->comment_param = new stdClass();
 237         $this->comment_param->context     = $this->context;
 238         $this->comment_param->courseid    = $this->courseid;
 239         $this->comment_param->cm          = $this->cm;
 240         $this->comment_param->commentarea = $this->commentarea;
 241         $this->comment_param->itemid      = $this->itemid;
 242
 243         $this->allowanonymousaccess = false;
 244         // By default everyone can view comments on the front page
 245         if ($this->context->contextlevel == CONTEXT_COURSE && $this->context->instanceid == SITEID) {
 246             $this->allowanonymousaccess = true;
 247         } else if ($this->context->contextlevel == CONTEXT_MODULE && $this->courseid == SITEID) {
 248             $this->allowanonymousaccess = true;
 249         }
 250         if (!empty($this->plugintype) && !empty($this->pluginname)) {
 251             // Plugins can override this if they wish.
 252             $this->allowanonymousaccess = plugin_callback($this->plugintype, $this->pluginname, 'comment', 'allow_anonymous_access', array($this), $this->allowanonymousaccess);
 253         }
 254
 255         // setup notoggle
 256         if (!empty($options->notoggle)) {
 257             $this->set_notoggle($options->notoggle);
 258         }
 259
 260         // setup notoggle
 261         if (!empty($options->autostart)) {
 262             $this->set_autostart($options->autostart);
 263         }
 264
 265         // setup displaycancel
 266         if (!empty($options->displaycancel)) {
 267             $this->set_displaycancel($options->displaycancel);
 268         }
 269
 270         // setup displaytotalcount
 271         if (!empty($options->showcount)) {
 272             $this->set_displaytotalcount($options->showcount);
 273         }
 274
 275         // setting post and view permissions
 276         $this->check_permissions();
 277
 278         // load template
 279         $this->template  = html_writer::tag('div', '___picture___', array('class' => 'comment-userpicture'));
 280         $this->template .= html_writer::start_tag('div', array('class' => 'comment-content'));
 281         $this->template .= '___name___ - ';
 282         $this->template .= html_writer::tag('span', '___time___');
 283         $this->template .= html_writer::tag('div', '___content___');
 284         $this->template .= html_writer::end_tag('div'); // .comment-content
 285         if (!empty($this->plugintype)) {
 286             $this->template = plugin_callback($this->plugintype, $this->pluginname, 'comment', 'template', array($this->comment_param), $this->template);
 287         }
 288
 289         unset($options);
 290     }
 291
 292     /**
 293      * Receive nonjs comment parameters
 294      *
 295      * @param moodle_page $page The page object to initialise comments within
 296      *                          If not provided the global $PAGE is used
 297      */
 298     public static function init(moodle_page $page = null) {
 299         global $PAGE;
 300
 301         if (empty($page)) {
 302             $page = $PAGE;
 303         }
 304         // setup variables for non-js interface
 305         self::$nonjs = optional_param('nonjscomment', '', PARAM_ALPHANUM);
 306         self::$comment_itemid  = optional_param('comment_itemid',  '', PARAM_INT);
 307         self::$comment_context = optional_param('comment_context', '', PARAM_INT);
 308         self::$comment_page    = optional_param('comment_page',    '', PARAM_INT);
 309         self::$comment_area    = optional_param('comment_area',    '', PARAM_ALPHAEXT);
 310
 311         $page->requires->string_for_js('addcomment', 'moodle');
 312         $page->requires->string_for_js('deletecomment', 'moodle');
 313         $page->requires->string_for_js('comments', 'moodle');
 314         $page->requires->string_for_js('commentsrequirelogin', 'moodle');
 315     }
 316
 317     /**
 318      * Sets the component.
 319      *
 320      * This method shouldn't be public, changing the component once it has been set potentially
 321      * invalidates permission checks.
 322      * A coding_error is now thrown if code attempts to change the component.
 323      *
 324      * @param string $component
 325      * @return void
 326      */
 327     public function set_component($component) {
 328         if (!empty($this->component) && $this->component !== $component) {
 329             throw new coding_exception('You cannot change the component of a comment once it has been set');
 330         }
 331         $this->component = $component;
 332         list($this->plugintype, $this->pluginname) = normalize_component($component);
 333     }
 334
 335     /**
 336      * Determines if the user can view the comment.
 337      *
 338      * @param bool $value
 339      */
 340     public function set_view_permission($value) {
 341         $this->viewcap = (bool)$value;
 342     }
 343
 344     /**
 345      * Determines if the user can post a comment
 346      *
 347      * @param bool $value
 348      */
 349     public function set_post_permission($value) {
 350         $this->postcap = (bool)$value;
 351     }
 352
 353     /**
 354      * check posting comments permission
 355      * It will check based on user roles and ask modules
 356      * If you need to check permission by modules, a
 357      * function named $pluginname_check_comment_post must be implemented
 358      */
 359     private function check_permissions() {
 360         $this->postcap = has_capability('moodle/comment:post', $this->context);
 361         $this->viewcap = has_capability('moodle/comment:view', $this->context);
 362         if (!empty($this->plugintype)) {
 363             $permissions = plugin_callback($this->plugintype, $this->pluginname, 'comment', 'permissions', array($this->comment_param), array('post'=>false, 'view'=>false));
 364             if ($this->allowanonymousaccess) {
 365                 $this->postcap = $permissions['post'];
 366                 $this->viewcap = $permissions['view'];
 367             } else {
 368                 $this->postcap = $this->postcap && $permissions['post'];
 369                 $this->viewcap = $this->viewcap && $permissions['view'];
 370             }
 371         }
 372     }
 373
 374     /**
 375      * Gets a link for this page that will work with JS disabled.
 376      *
 377      * @global moodle_page $PAGE
 378      * @param moodle_page $page
 379      * @return moodle_url
 380      */
 381     public function get_nojslink(moodle_page $page = null) {
 382         if ($page === null) {
 383             global $PAGE;
 384             $page = $PAGE;
 385         }
 386
 387         $link = new moodle_url($page->url, array(
 388             'nonjscomment'    => true,
 389             'comment_itemid'  => $this->itemid,
 390             'comment_context' => $this->context->id,
 391             'comment_area'    => $this->commentarea,
 392         ));
 393         $link->remove_params(array('comment_page'));
 394         return $link;
 395     }
 396
 397     /**
 398      * Sets the value of the notoggle option.
 399      *
 400      * If set to true then the user will not be able to expand and collase
 401      * the comment section.
 402      *
 403      * @param bool $newvalue
 404      */
 405     public function set_notoggle($newvalue = true) {
 406         $this->notoggle = (bool)$newvalue;
 407     }
 408
 409     /**
 410      * Sets the value of the autostart option.
 411      *
 412      * If set to true then the comments will be loaded during page load.
 413      * Normally this happens only once the user expands the comment section.
 414      *
 415      * @param bool $newvalue
 416      */
 417     public function set_autostart($newvalue = true) {
 418         $this->autostart = (bool)$newvalue;
 419     }
 420
 421     /**
 422      * Sets the displaycancel option
 423      *
 424      * If set to true then a cancel button will be shown when using the form
 425      * to post comments.
 426      *
 427      * @param bool $newvalue
 428      */
 429     public function set_displaycancel($newvalue = true) {
 430         $this->displaycancel = (bool)$newvalue;
 431     }
 432
 433     /**
 434      * Sets the displaytotalcount option
 435      *
 436      * If set to true then the total number of comments will be displayed
 437      * when printing comments.
 438      *
 439      * @param bool $newvalue
 440      */
 441     public function set_displaytotalcount($newvalue = true) {
 442         $this->displaytotalcount = (bool)$newvalue;
 443     }
 444
 445     /**
 446      * Initialises the JavaScript that enchances the comment API.
 447      *
 448      * @param moodle_page $page The moodle page object that the JavaScript should be
 449      *                          initialised for.
 450      */
 451     public function initialise_javascript(moodle_page $page) {
 452
 453         $options = new stdClass;
 454         $options->client_id   = $this->cid;
 455         $options->commentarea = $this->commentarea;
 456         $options->itemid      = $this->itemid;
 457         $options->page        = 0;
 458         $options->courseid    = $this->courseid;
 459         $options->contextid   = $this->contextid;
 460         $options->component   = $this->component;
 461         $options->notoggle    = $this->notoggle;
 462         $options->autostart   = $this->autostart;
 463
 464         $page->requires->js_init_call('M.core_comment.init', array($options), true);
 465
 466         return true;
 467     }
 468
 469     /**
 470      * Prepare comment code in html
 471      * @param  boolean $return
 472      * @return mixed
 473      */
 474     public function output($return = true) {
 475         global $PAGE, $OUTPUT;
 476         static $template_printed;
 477
 478         $this->initialise_javascript($PAGE);
 479
 480         if (!empty(self::$nonjs)) {
 481             // return non js comments interface
 482             return $this->print_comments(self::$comment_page, $return, true);
 483         }
 484
 485         $html = '';
 486
 487         // print html template
 488         // Javascript will use the template to render new comments
 489         if (empty($template_printed) && $this->can_view()) {
 490             $html .= html_writer::tag('div', $this->template, array('style' => 'display:none', 'id' => 'cmt-tmpl'));
 491             $template_printed = true;
 492         }
 493
 494         if ($this->can_view()) {
 495             // print commenting icon and tooltip
 496             $html .= html_writer::start_tag('div', array('class' => 'mdl-left'));
 497             $html .= html_writer::link($this->get_nojslink($PAGE), get_string('showcommentsnonjs'), array('class' => 'showcommentsnonjs'));
 498
 499             if (!$this->notoggle) {
 500                 // If toggling is enabled (notoggle=false) then print the controls to toggle
 501                 // comments open and closed
 502                 $countstring = '';
 503                 if ($this->displaytotalcount) {
 504                     $countstring = '('.$this->count().')';
 505                 }
 506                 $html .= html_writer::start_tag('a', array('class' => 'comment-link', 'id' => 'comment-link-'.$this->cid, 'href' => '#'));
 507                 $html .= html_writer::empty_tag('img', array('id' => 'comment-img-'.$this->cid, 'src' => $OUTPUT->pix_url('t/collapsed'), 'alt' => $this->linktext, 'title' => $this->linktext));
 508                 $html .= html_writer::tag('span', $this->linktext.' '.$countstring, array('id' => 'comment-link-text-'.$this->cid));
 509                 $html .= html_writer::end_tag('a');
 510             }
 511
 512             $html .= html_writer::start_tag('div', array('id' => 'comment-ctrl-'.$this->cid, 'class' => 'comment-ctrl'));
 513
 514             if ($this->autostart) {
 515                 // If autostart has been enabled print the comments list immediatly
 516                 $html .= html_writer::start_tag('ul', array('id' => 'comment-list-'.$this->cid, 'class' => 'comment-list comments-loaded'));
 517                 $html .= html_writer::tag('li', '', array('class' => 'first'));
 518                 $html .= $this->print_comments(0, true, false);
 519                 $html .= html_writer::end_tag('ul'); // .comment-list
 520                 $html .= $this->get_pagination(0);
 521             } else {
 522                 $html .= html_writer::start_tag('ul', array('id' => 'comment-list-'.$this->cid, 'class' => 'comment-list'));
 523                 $html .= html_writer::tag('li', '', array('class' => 'first'));
 524                 $html .= html_writer::end_tag('ul'); // .comment-list
 525                 $html .= html_writer::tag('div', '', array('id' => 'comment-pagination-'.$this->cid, 'class' => 'comment-pagination'));
 526             }
 527
 528             if ($this->can_post()) {
 529                 // print posting textarea
 530                 $html .= html_writer::start_tag('div', array('class' => 'comment-area'));
 531                 $html .= html_writer::start_tag('div', array('class' => 'db'));
 532                 $html .= html_writer::tag('textarea', '', array('name' => 'content', 'rows' => 2, 'cols' => 20, 'id' => 'dlg-content-'.$this->cid));
 533                 $html .= html_writer::end_tag('div'); // .db
 534
 535                 $html .= html_writer::start_tag('div', array('class' => 'fd', 'id' => 'comment-action-'.$this->cid));
 536                 $html .= html_writer::link('#', get_string('savecomment'), array('id' => 'comment-action-post-'.$this->cid));
 537
 538                 if ($this->displaycancel) {
 539                     $html .= html_writer::tag('span', ' | ');
 540                     $html .= html_writer::link('#', get_string('cancel'), array('id' => 'comment-action-cancel-'.$this->cid));
 541                 }
 542
 543                 $html .= html_writer::end_tag('div'); // .fd
 544                 $html .= html_writer::end_tag('div'); // .comment-area
 545                 $html .= html_writer::tag('div', '', array('class' => 'clearer'));
 546             }
 547
 548             $html .= html_writer::end_tag('div'); // .comment-ctrl
 549             $html .= html_writer::end_tag('div'); // .mdl-left
 550         } else {
 551             $html = '';
 552         }
 553
 554         if ($return) {
 555             return $html;
 556         } else {
 557             echo $html;
 558         }
 559     }
 560
 561     /**
 562      * Return matched comments
 563      *
 564      * @param  int $page
 565      * @return mixed
 566      */
 567     public function get_comments($page = '') {
 568         global $DB, $CFG, $USER, $OUTPUT;
 569         if (!$this->can_view()) {
 570             return false;
 571         }
 572         if (!is_numeric($page)) {
 573             $page = 0;
 574         }
 575         $params = array();
 576         $perpage = (!empty($CFG->commentsperpage))?$CFG->commentsperpage:15;
 577         $start = $page * $perpage;
 578         $ufields = user_picture::fields('u');
 579         $sql = "SELECT $ufields, c.id AS cid, c.content AS ccontent, c.format AS cformat, c.timecreated AS ctimecreated
 580                   FROM {comments} c
 581                   JOIN {user} u ON u.id = c.userid
 582                  WHERE c.contextid = :contextid AND c.commentarea = :commentarea AND c.itemid = :itemid
 583               ORDER BY c.timecreated DESC";
 584         $params['contextid'] = $this->contextid;
 585         $params['commentarea'] = $this->commentarea;
 586         $params['itemid'] = $this->itemid;
 587
 588         $comments = array();
 589         $formatoptions = array('overflowdiv' => true);
 590         $rs = $DB->get_recordset_sql($sql, $params, $start, $perpage);
 591         foreach ($rs as $u) {
 592             $c = new stdClass();
 593             $c->id          = $u->cid;
 594             $c->content     = $u->ccontent;
 595             $c->format      = $u->cformat;
 596             $c->timecreated = $u->ctimecreated;
 597             $url = new moodle_url('/user/view.php', array('id'=>$u->id, 'course'=>$this->courseid));
 598             $c->profileurl = $url->out();
 599             $c->fullname = fullname($u);
 600             $c->time = userdate($c->timecreated, get_string('strftimerecent', 'langconfig'));
 601             $c->content = format_text($c->content, $c->format, $formatoptions);
 602             $c->avatar = $OUTPUT->user_picture($u, array('size'=>18));
 603
 604             $candelete = $this->can_delete($c->id);
 605             if (($USER->id == $u->id) || !empty($candelete)) {
 606                 $c->delete = true;
 607             }
 608             $comments[] = $c;
 609         }
 610         $rs->close();
 611
 612         if (!empty($this->plugintype)) {
 613             // moodle module will filter comments
 614             $comments = plugin_callback($this->plugintype, $this->pluginname, 'comment', 'display', array($comments, $this->comment_param), $comments);
 615         }
 616
 617         return $comments;
 618     }
 619
 620     /**
 621      * Returns the number of comments associated with the details of this object
 622      *
 623      * @global moodle_database $DB
 624      * @return int
 625      */
 626     public function count() {
 627         global $DB;
 628         if ($this->totalcommentcount === null) {
 629             $this->totalcommentcount = $DB->count_records('comments', array('itemid' => $this->itemid, 'commentarea' => $this->commentarea, 'contextid' => $this->context->id));
 630         }
 631         return $this->totalcommentcount;
 632     }
 633
 634     /**
 635      * Returns HTML to display a pagination bar
 636      *
 637      * @global stdClass $CFG
 638      * @global core_renderer $OUTPUT
 639      * @param int $page
 640      * @return string
 641      */
 642     public function get_pagination($page = 0) {
 643         global $CFG, $OUTPUT;
 644         $count = $this->count();
 645         $perpage = (!empty($CFG->commentsperpage))?$CFG->commentsperpage:15;
 646         $pages = (int)ceil($count/$perpage);
 647         if ($pages == 1 || $pages == 0) {
 648             return html_writer::tag('div', '', array('id' => 'comment-pagination-'.$this->cid, 'class' => 'comment-pagination'));
 649         }
 650         if (!empty(self::$nonjs)) {
 651             // used in non-js interface
 652             return $OUTPUT->paging_bar($count, $page, $perpage, $this->get_nojslink(), 'comment_page');
 653         } else {
 654             // return ajax paging bar
 655             $str = '';
 656             $str .= '<div class="comment-paging" id="comment-pagination-'.$this->cid.'">';
 657             for ($p=0; $p<$pages; $p++) {
 658                 if ($p == $page) {
 659                     $class = 'curpage';
 660                 } else {
 661                     $class = 'pageno';
 662                 }
 663                 $str .= '<a href="#" class="'.$class.'" id="comment-page-'.$this->cid.'-'.$p.'">'.($p+1).'</a> ';
 664             }
 665             $str .= '</div>';
 666         }
 667         return $str;
 668     }
 669
 670     /**
 671      * Add a new comment
 672      *
 673      * @global moodle_database $DB
 674      * @param string $content
 675      * @return mixed
 676      */
 677     public function add($content, $format = FORMAT_MOODLE) {
 678         global $CFG, $DB, $USER, $OUTPUT;
 679         if (!$this->can_post()) {
 680             throw new comment_exception('nopermissiontocomment');
 681         }
 682         $now = time();
 683         $newcmt = new stdClass;
 684         $newcmt->contextid    = $this->contextid;
 685         $newcmt->commentarea  = $this->commentarea;
 686         $newcmt->itemid       = $this->itemid;
 687         $newcmt->content      = $content;
 688         $newcmt->format       = $format;
 689         $newcmt->userid       = $USER->id;
 690         $newcmt->timecreated  = $now;
 691
 692         // This callback allow module to modify the content of comment, such as filter or replacement
 693         plugin_callback($this->plugintype, $this->pluginname, 'comment', 'add', array(&$newcmt, $this->comment_param));
 694
 695         $cmt_id = $DB->insert_record('comments', $newcmt);
 696         if (!empty($cmt_id)) {
 697             $newcmt->id = $cmt_id;
 698             $newcmt->time = userdate($now, get_string('strftimerecent', 'langconfig'));
 699             $newcmt->fullname = fullname($USER);
 700             $url = new moodle_url('/user/view.php', array('id' => $USER->id, 'course' => $this->courseid));
 701             $newcmt->profileurl = $url->out();
 702             $newcmt->content = format_text($newcmt->content, $format, array('overflowdiv'=>true));
 703             $newcmt->avatar = $OUTPUT->user_picture($USER, array('size'=>16));
 704             return $newcmt;
 705         } else {
 706             throw new comment_exception('dbupdatefailed');
 707         }
 708     }
 709
 710     /**
 711      * delete by context, commentarea and itemid
 712      * @param stdClass|array $param {
 713      *            contextid => int the context in which the comments exist [required]
 714      *            commentarea => string the comment area [optional]
 715      *            itemid => int comment itemid [optional]
 716      * }
 717      * @return boolean
 718      */
 719     public function delete_comments($param) {
 720         global $DB;
 721         $param = (array)$param;
 722         if (empty($param['contextid'])) {
 723             return false;
 724         }
 725         $DB->delete_records('comments', $param);
 726         return true;
 727     }
 728
 729     /**
 730      * Delete page_comments in whole course, used by course reset
 731      *
 732      * @param stdClass $context course context
 733      */
 734     public function reset_course_page_comments($context) {
 735         global $DB;
 736         $contexts = array();
 737         $contexts[] = $context->id;
 738         $children = get_child_contexts($context);
 739         foreach ($children as $c) {
 740             $contexts[] = $c->id;
 741         }
 742         list($ids, $params) = $DB->get_in_or_equal($contexts);
 743         $DB->delete_records_select('comments', "commentarea='page_comments' AND contextid $ids", $params);
 744     }
 745
 746     /**
 747      * Delete a comment
 748      *
 749      * @param  int $commentid
 750      * @return mixed
 751      */
 752     public function delete($commentid) {
 753         global $DB, $USER;
 754         $candelete = has_capability('moodle/comment:delete', $this->context);
 755         if (!$comment = $DB->get_record('comments', array('id'=>$commentid))) {
 756             throw new comment_exception('dbupdatefailed');
 757         }
 758         if (!($USER->id == $comment->userid || !empty($candelete))) {
 759             throw new comment_exception('nopermissiontocomment');
 760         }
 761         $DB->delete_records('comments', array('id'=>$commentid));
 762         return true;
 763     }
 764
 765     /**
 766      * Print comments
 767      *
 768      * @param int $page
 769      * @param boolean $return return comments list string or print it out
 770      * @param boolean $nonjs print nonjs comments list or not?
 771      * @return mixed
 772      */
 773     public function print_comments($page = 0, $return = true, $nonjs = true) {
 774         global $DB, $CFG, $PAGE;
 775
 776         if (!$this->can_view()) {
 777             return '';
 778         }
 779
 780         $html = '';
 781         if (!(self::$comment_itemid == $this->itemid &&
 782             self::$comment_context == $this->context->id &&
 783             self::$comment_area == $this->commentarea)) {
 784             $page = 0;
 785         }
 786         $comments = $this->get_comments($page);
 787
 788         $html = '';
 789         if ($nonjs) {
 790             $html .= html_writer::tag('h3', get_string('comments'));
 791             $html .= html_writer::start_tag('ul', array('id' => 'comment-list-'.$this->cid, 'class' => 'comment-list'));
 792         }
 793         // Reverse the comments array to display them in the correct direction
 794         foreach (array_reverse($comments) as $cmt) {
 795             $html .= html_writer::tag('li', $this->print_comment($cmt, $nonjs), array('id' => 'comment-'.$cmt->id.'-'.$this->cid));
 796         }
 797         if ($nonjs) {
 798             $html .= html_writer::end_tag('ul');
 799             $html .= $this->get_pagination($page);
 800         }
 801         if ($nonjs && $this->can_post()) {
 802             // Form to add comments
 803             $html .= html_writer::start_tag('form', array('method' => 'post', 'action' => new moodle_url('/comment/comment_post.php')));
 804             // Comment parameters
 805             $html .= html_writer::empty_tag('input', array('type' => 'hidden', 'name' => 'contextid', 'value' => $this->contextid));
 806             $html .= html_writer::empty_tag('input', array('type' => 'hidden', 'name' => 'action',    'value' => 'add'));
 807             $html .= html_writer::empty_tag('input', array('type' => 'hidden', 'name' => 'area',      'value' => $this->commentarea));
 808             $html .= html_writer::empty_tag('input', array('type' => 'hidden', 'name' => 'component', 'value' => $this->component));
 809             $html .= html_writer::empty_tag('input', array('type' => 'hidden', 'name' => 'itemid',    'value' => $this->itemid));
 810             $html .= html_writer::empty_tag('input', array('type' => 'hidden', 'name' => 'courseid',  'value' => $this->courseid));
 811             $html .= html_writer::empty_tag('input', array('type' => 'hidden', 'name' => 'sesskey',   'value' => sesskey()));
 812             $html .= html_writer::empty_tag('input', array('type' => 'hidden', 'name' => 'returnurl', 'value' => $PAGE->url));
 813             // Textarea for the actual comment
 814             $html .= html_writer::tag('textarea', '', array('name' => 'content', 'rows' => 2));
 815             // Submit button to add the comment
 816             $html .= html_writer::empty_tag('input', array('type' => 'submit', 'value' => get_string('submit')));
 817             $html .= html_writer::end_tag('form');
 818         }
 819         if ($return) {
 820             return $html;
 821         } else {
 822             echo $html;
 823         }
 824     }
 825
 826     /**
 827      * Returns an array containing comments in HTML format.
 828      *
 829      * @global core_renderer $OUTPUT
 830      * @param stdClass $cmt {
 831      *          id => int comment id
 832      *          content => string comment content
 833      *          format  => int comment text format
 834      *          timecreated => int comment's timecreated
 835      *          profileurl  => string link to user profile
 836      *          fullname    => comment author's full name
 837      *          avatar      => string user's avatar
 838      *          delete      => boolean does user have permission to delete comment?
 839      * }
 840      * @param bool $nonjs
 841      * @return array
 842      */
 843     public function print_comment($cmt, $nonjs = true) {
 844         global $OUTPUT;
 845         $patterns = array();
 846         $replacements = array();
 847
 848         if (!empty($cmt->delete) && empty($nonjs)) {
 849             $deletelink  = html_writer::start_tag('div', array('class'=>'comment-delete'));
 850             $deletelink .= html_writer::start_tag('a', array('href' => '#', 'id' => 'comment-delete-'.$this->cid.'-'.$cmt->id));
 851             $deletelink .= $OUTPUT->pix_icon('t/delete', get_string('delete'));
 852             $deletelink .= html_writer::end_tag('a');
 853             $deletelink .= html_writer::end_tag('div');
 854             $cmt->content = $deletelink . $cmt->content;
 855         }
 856         $patterns[] = '___picture___';
 857         $patterns[] = '___name___';
 858         $patterns[] = '___content___';
 859         $patterns[] = '___time___';
 860         $replacements[] = $cmt->avatar;
 861         $replacements[] = html_writer::link($cmt->profileurl, $cmt->fullname);
 862         $replacements[] = $cmt->content;
 863         $replacements[] = userdate($cmt->timecreated, get_string('strftimerecent', 'langconfig'));
 864
 865         // use html template to format a single comment.
 866         return str_replace($patterns, $replacements, $this->template);
 867     }
 868
 869     /**
 870      * Revoke validate callbacks
 871      *
 872      * @param stdClass $params addtionall parameters need to add to callbacks
 873      */
 874     protected function validate($params=array()) {
 875         foreach ($params as $key=>$value) {
 876             $this->comment_param->$key = $value;
 877         }
 878         $validation = plugin_callback($this->plugintype, $this->pluginname, 'comment', 'validate', array($this->comment_param), false);
 879         if (!$validation) {
 880             throw new comment_exception('invalidcommentparam');
 881         }
 882     }
 883
 884     /**
 885      * Returns true if the user is able to view comments
 886      * @return bool
 887      */
 888     public function can_view() {
 889         $this->validate();
 890         return !empty($this->viewcap);
 891     }
 892
 893     /**
 894      * Returns true if the user can add comments against this comment description
 895      * @return bool
 896      */
 897     public function can_post() {
 898         $this->validate();
 899         return isloggedin() && !empty($this->postcap);
 900     }
 901
 902     /**
 903      * Returns true if the user can delete this comment
 904      * @param int $commentid
 905      * @return bool
 906      */
 907     public function can_delete($commentid) {
 908         $this->validate(array('commentid'=>$commentid));
 909         return has_capability('moodle/comment:delete', $this->context);
 910     }
 911
 912     /**
 913      * Returns the component associated with the comment
 914      * @return string
 915      */
 916     public function get_compontent() {
 917         return $this->component;
 918     }
 919
 920     /**
 921      * Returns the context associated with the comment
 922      * @return stdClass
 923      */
 924     public function get_context() {
 925         return $this->context;
 926     }
 927
 928     /**
 929      * Returns the course id associated with the comment
 930      * @return int
 931      */
 932     public function get_courseid() {
 933         return $this->courseid;
 934     }
 935
 936     /**
 937      * Returns the course module associated with the comment
 938      *
 939      * @return stdClass
 940      */
 941     public function get_cm() {
 942         return $this->cm;
 943     }
 944
 945     /**
 946      * Returns the item id associated with the comment
 947      *
 948      * @return int
 949      */
 950     public function get_itemid() {
 951         return $this->itemid;
 952     }
 953
 954     /**
 955      * Returns the comment area associated with the commentarea
 956      *
 957      * @return stdClass
 958      */
 959     public function get_commentarea() {
 960         return $this->commentarea;
 961     }
 962 }
 963
 964 class comment_exception extends moodle_exception {
 965 }