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