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                 $html .= html_writer::start_tag('a', array('class' => 'comment-link', 'id' => 'comment-link-'.$this->cid, 'href' => '#'));
 426                 $html .= html_writer::empty_tag('img', array('id' => 'comment-img-'.$this->cid, 'src' => $OUTPUT->pix_url('t/collapsed'), 'alt' => $this->linktext, 'title' => $this->linktext));
 427                 $html .= html_writer::tag('span', $this->linktext.' '.$countstring, array('id' => 'comment-link-text-'.$this->cid));
 428                 $html .= html_writer::end_tag('a');
 429             }
 430
 431             $html .= html_writer::start_tag('div', array('id' => 'comment-ctrl-'.$this->cid, 'class' => 'comment-ctrl'));
 432
 433             if ($this->autostart) {
 434                 // If autostart has been enabled print the comments list immediatly
 435                 $html .= html_writer::start_tag('ul', array('id' => 'comment-list-'.$this->cid, 'class' => 'comment-list comments-loaded'));
 436                 $html .= html_writer::tag('li', '', array('class' => 'first'));
 437                 $html .= $this->print_comments(0, true, false);
 438                 $html .= html_writer::end_tag('ul'); // .comment-list
 439                 $html .= $this->get_pagination(0);
 440             } else {
 441                 $html .= html_writer::start_tag('ul', array('id' => 'comment-list-'.$this->cid, 'class' => 'comment-list'));
 442                 $html .= html_writer::tag('li', '', array('class' => 'first'));
 443                 $html .= html_writer::end_tag('ul'); // .comment-list
 444                 $html .= html_writer::tag('div', '', array('id' => 'comment-pagination-'.$this->cid, 'class' => 'comment-pagination'));
 445             }
 446
 447             if ($this->can_post()) {
 448                 // print posting textarea
 449                 $html .= html_writer::start_tag('div', array('class' => 'comment-area'));
 450                 $html .= html_writer::start_tag('div', array('class' => 'db'));
 451                 $html .= html_writer::tag('textarea', '', array('name' => 'content', 'rows' => 2, 'cols' => 20, 'id' => 'dlg-content-'.$this->cid));
 452                 $html .= html_writer::end_tag('div'); // .db
 453
 454                 $html .= html_writer::start_tag('div', array('class' => 'fd', 'id' => 'comment-action-'.$this->cid));
 455                 $html .= html_writer::link('#', get_string('savecomment'), array('id' => 'comment-action-post-'.$this->cid));
 456
 457                 if ($this->displaycancel) {
 458                     $html .= html_writer::tag('span', ' | ');
 459                     $html .= html_writer::link('#', get_string('cancel'), array('id' => 'comment-action-cancel-'.$this->cid));
 460                 }
 461
 462                 $html .= html_writer::end_tag('div'); // .fd
 463                 $html .= html_writer::end_tag('div'); // .comment-area
 464                 $html .= html_writer::tag('div', '', array('class' => 'clearer'));
 465             }
 466
 467             $html .= html_writer::end_tag('div'); // .comment-ctrl
 468             $html .= html_writer::end_tag('div'); // .mdl-left
 469         } else {
 470             $html = '';
 471         }
 472
 473         if ($return) {
 474             return $html;
 475         } else {
 476             echo $html;
 477         }
 478     }
 479
 480     /**
 481      * Return matched comments
 482      *
 483      * @param  int $page
 484      * @return array
 485      */
 486     public function get_comments($page = '') {
 487         global $DB, $CFG, $USER, $OUTPUT;
 488         if (!$this->can_view()) {
 489             return false;
 490         }
 491         if (!is_numeric($page)) {
 492             $page = 0;
 493         }
 494         $params = array();
 495         $perpage = (!empty($CFG->commentsperpage))?$CFG->commentsperpage:15;
 496         $start = $page * $perpage;
 497         $ufields = user_picture::fields('u');
 498         $sql = "SELECT $ufields, c.id AS cid, c.content AS ccontent, c.format AS cformat, c.timecreated AS ctimecreated
 499                   FROM {comments} c
 500                   JOIN {user} u ON u.id = c.userid
 501                  WHERE c.contextid = :contextid AND c.commentarea = :commentarea AND c.itemid = :itemid
 502               ORDER BY c.timecreated DESC";
 503         $params['contextid'] = $this->contextid;
 504         $params['commentarea'] = $this->commentarea;
 505         $params['itemid'] = $this->itemid;
 506
 507         $comments = array();
 508         $formatoptions = array('overflowdiv' => true);
 509         $rs = $DB->get_recordset_sql($sql, $params, $start, $perpage);
 510         foreach ($rs as $u) {
 511             $c = new stdClass();
 512             $c->id          = $u->cid;
 513             $c->content     = $u->ccontent;
 514             $c->format      = $u->cformat;
 515             $c->timecreated = $u->ctimecreated;
 516             $url = new moodle_url('/user/view.php', array('id'=>$u->id, 'course'=>$this->courseid));
 517             $c->profileurl = $url->out(false);
 518             $c->fullname = fullname($u);
 519             $c->time = userdate($c->timecreated, get_string('strftimerecent', 'langconfig'));
 520             $c->content = format_text($c->content, $c->format, $formatoptions);
 521             $c->avatar = $OUTPUT->user_picture($u, array('size'=>18));
 522
 523             $candelete = $this->can_delete($c->id);
 524             if (($USER->id == $u->id) || !empty($candelete)) {
 525                 $c->delete = true;
 526             }
 527             $comments[] = $c;
 528         }
 529         $rs->close();
 530
 531         if (!empty($this->plugintype)) {
 532             // moodle module will filter comments
 533             $comments = plugin_callback($this->plugintype, $this->pluginname, 'comment', 'display', array($comments, $this->comment_param), $comments);
 534         }
 535
 536         return $comments;
 537     }
 538
 539     /**
 540      * Returns the number of comments associated with the details of this object
 541      *
 542      * @global moodle_database $DB
 543      * @return int
 544      */
 545     public function count() {
 546         global $DB;
 547         if ($this->totalcommentcount === null) {
 548             $this->totalcommentcount = $DB->count_records('comments', array('itemid' => $this->itemid, 'commentarea' => $this->commentarea, 'contextid' => $this->context->id));
 549         }
 550         return $this->totalcommentcount;
 551     }
 552
 553     /**
 554      * Returns HTML to display a pagination bar
 555      *
 556      * @global stdClass $CFG
 557      * @global core_renderer $OUTPUT
 558      * @param int $page
 559      * @return string
 560      */
 561     public function get_pagination($page = 0) {
 562         global $CFG, $OUTPUT;
 563         $count = $this->count();
 564         $perpage = (!empty($CFG->commentsperpage))?$CFG->commentsperpage:15;
 565         $pages = (int)ceil($count/$perpage);
 566         if ($pages == 1 || $pages == 0) {
 567             return html_writer::tag('div', '', array('id' => 'comment-pagination-'.$this->cid, 'class' => 'comment-pagination'));
 568         }
 569         if (!empty(self::$nonjs)) {
 570             // used in non-js interface
 571             return $OUTPUT->paging_bar($count, $page, $perpage, $this->get_nojslink(), 'comment_page');
 572         } else {
 573             // return ajax paging bar
 574             $str = '';
 575             $str .= '<div class="comment-paging" id="comment-pagination-'.$this->cid.'">';
 576             for ($p=0; $p<$pages; $p++) {
 577                 if ($p == $page) {
 578                     $class = 'curpage';
 579                 } else {
 580                     $class = 'pageno';
 581                 }
 582                 $str .= '<a href="#" class="'.$class.'" id="comment-page-'.$this->cid.'-'.$p.'">'.($p+1).'</a> ';
 583             }
 584             $str .= '</div>';
 585         }
 586         return $str;
 587     }
 588
 589     /**
 590      * Add a new comment
 591      *
 592      * @global moodle_database $DB
 593      * @param string $content
 594      * @param int $format
 595      * @return stdClass
 596      */
 597     public function add($content, $format = FORMAT_MOODLE) {
 598         global $CFG, $DB, $USER, $OUTPUT;
 599         if (!$this->can_post()) {
 600             throw new comment_exception('nopermissiontocomment');
 601         }
 602         $now = time();
 603         $newcmt = new stdClass;
 604         $newcmt->contextid    = $this->contextid;
 605         $newcmt->commentarea  = $this->commentarea;
 606         $newcmt->itemid       = $this->itemid;
 607         $newcmt->content      = $content;
 608         $newcmt->format       = $format;
 609         $newcmt->userid       = $USER->id;
 610         $newcmt->timecreated  = $now;
 611
 612         // This callback allow module to modify the content of comment, such as filter or replacement
 613         plugin_callback($this->plugintype, $this->pluginname, 'comment', 'add', array(&$newcmt, $this->comment_param));
 614
 615         $cmt_id = $DB->insert_record('comments', $newcmt);
 616         if (!empty($cmt_id)) {
 617             $newcmt->id = $cmt_id;
 618             $newcmt->time = userdate($now, get_string('strftimerecent', 'langconfig'));
 619             $newcmt->fullname = fullname($USER);
 620             $url = new moodle_url('/user/view.php', array('id' => $USER->id, 'course' => $this->courseid));
 621             $newcmt->profileurl = $url->out();
 622             $newcmt->content = format_text($newcmt->content, $format, array('overflowdiv'=>true));
 623             $newcmt->avatar = $OUTPUT->user_picture($USER, array('size'=>16));
 624             return $newcmt;
 625         } else {
 626             throw new comment_exception('dbupdatefailed');
 627         }
 628     }
 629
 630     /**
 631      * delete by context, commentarea and itemid
 632      * @param stdClass|array $param {
 633      *            contextid => int the context in which the comments exist [required]
 634      *            commentarea => string the comment area [optional]
 635      *            itemid => int comment itemid [optional]
 636      * }
 637      * @return boolean
 638      */
 639     public static function delete_comments($param) {
 640         global $DB;
 641         $param = (array)$param;
 642         if (empty($param['contextid'])) {
 643             return false;
 644         }
 645         $DB->delete_records('comments', $param);
 646         return true;
 647     }
 648
 649     /**
 650      * Delete page_comments in whole course, used by course reset
 651      *
 652      * @param stdClass $context course context
 653      */
 654     public static function reset_course_page_comments($context) {
 655         global $DB;
 656         $contexts = array();
 657         $contexts[] = $context->id;
 658         $children = get_child_contexts($context);
 659         foreach ($children as $c) {
 660             $contexts[] = $c->id;
 661         }
 662         list($ids, $params) = $DB->get_in_or_equal($contexts);
 663         $DB->delete_records_select('comments', "commentarea='page_comments' AND contextid $ids", $params);
 664     }
 665
 666     /**
 667      * Delete a comment
 668      *
 669      * @param  int $commentid
 670      * @return bool
 671      */
 672     public function delete($commentid) {
 673         global $DB, $USER;
 674         $candelete = has_capability('moodle/comment:delete', $this->context);
 675         if (!$comment = $DB->get_record('comments', array('id'=>$commentid))) {
 676             throw new comment_exception('dbupdatefailed');
 677         }
 678         if (!($USER->id == $comment->userid || !empty($candelete))) {
 679             throw new comment_exception('nopermissiontocomment');
 680         }
 681         $DB->delete_records('comments', array('id'=>$commentid));
 682         return true;
 683     }
 684
 685     /**
 686      * Print comments
 687      *
 688      * @param int $page
 689      * @param bool $return return comments list string or print it out
 690      * @param bool $nonjs print nonjs comments list or not?
 691      * @return string|void
 692      */
 693     public function print_comments($page = 0, $return = true, $nonjs = true) {
 694         global $DB, $CFG, $PAGE;
 695
 696         if (!$this->can_view()) {
 697             return '';
 698         }
 699
 700         $html = '';
 701         if (!(self::$comment_itemid == $this->itemid &&
 702             self::$comment_context == $this->context->id &&
 703             self::$comment_area == $this->commentarea)) {
 704             $page = 0;
 705         }
 706         $comments = $this->get_comments($page);
 707
 708         $html = '';
 709         if ($nonjs) {
 710             $html .= html_writer::tag('h3', get_string('comments'));
 711             $html .= html_writer::start_tag('ul', array('id' => 'comment-list-'.$this->cid, 'class' => 'comment-list'));
 712         }
 713         // Reverse the comments array to display them in the correct direction
 714         foreach (array_reverse($comments) as $cmt) {
 715             $html .= html_writer::tag('li', $this->print_comment($cmt, $nonjs), array('id' => 'comment-'.$cmt->id.'-'.$this->cid));
 716         }
 717         if ($nonjs) {
 718             $html .= html_writer::end_tag('ul');
 719             $html .= $this->get_pagination($page);
 720         }
 721         if ($nonjs && $this->can_post()) {
 722             // Form to add comments
 723             $html .= html_writer::start_tag('form', array('method' => 'post', 'action' => new moodle_url('/comment/comment_post.php')));
 724             // Comment parameters
 725             $html .= html_writer::empty_tag('input', array('type' => 'hidden', 'name' => 'contextid', 'value' => $this->contextid));
 726             $html .= html_writer::empty_tag('input', array('type' => 'hidden', 'name' => 'action',    'value' => 'add'));
 727             $html .= html_writer::empty_tag('input', array('type' => 'hidden', 'name' => 'area',      'value' => $this->commentarea));
 728             $html .= html_writer::empty_tag('input', array('type' => 'hidden', 'name' => 'component', 'value' => $this->component));
 729             $html .= html_writer::empty_tag('input', array('type' => 'hidden', 'name' => 'itemid',    'value' => $this->itemid));
 730             $html .= html_writer::empty_tag('input', array('type' => 'hidden', 'name' => 'courseid',  'value' => $this->courseid));
 731             $html .= html_writer::empty_tag('input', array('type' => 'hidden', 'name' => 'sesskey',   'value' => sesskey()));
 732             $html .= html_writer::empty_tag('input', array('type' => 'hidden', 'name' => 'returnurl', 'value' => $PAGE->url));
 733             // Textarea for the actual comment
 734             $html .= html_writer::tag('textarea', '', array('name' => 'content', 'rows' => 2));
 735             // Submit button to add the comment
 736             $html .= html_writer::empty_tag('input', array('type' => 'submit', 'value' => get_string('submit')));
 737             $html .= html_writer::end_tag('form');
 738         }
 739         if ($return) {
 740             return $html;
 741         } else {
 742             echo $html;
 743         }
 744     }
 745
 746     /**
 747      * Returns an array containing comments in HTML format.
 748      *
 749      * @global core_renderer $OUTPUT
 750      * @param stdClass $cmt {
 751      *          id => int comment id
 752      *          content => string comment content
 753      *          format  => int comment text format
 754      *          timecreated => int comment's timecreated
 755      *          profileurl  => string link to user profile
 756      *          fullname    => comment author's full name
 757      *          avatar      => string user's avatar
 758      *          delete      => boolean does user have permission to delete comment?
 759      * }
 760      * @param bool $nonjs
 761      * @return array
 762      */
 763     public function print_comment($cmt, $nonjs = true) {
 764         global $OUTPUT;
 765         $patterns = array();
 766         $replacements = array();
 767
 768         if (!empty($cmt->delete) && empty($nonjs)) {
 769             $deletelink  = html_writer::start_tag('div', array('class'=>'comment-delete'));
 770             $deletelink .= html_writer::start_tag('a', array('href' => '#', 'id' => 'comment-delete-'.$this->cid.'-'.$cmt->id));
 771             $deletelink .= $OUTPUT->pix_icon('t/delete', get_string('delete'));
 772             $deletelink .= html_writer::end_tag('a');
 773             $deletelink .= html_writer::end_tag('div');
 774             $cmt->content = $deletelink . $cmt->content;
 775         }
 776         $patterns[] = '___picture___';
 777         $patterns[] = '___name___';
 778         $patterns[] = '___content___';
 779         $patterns[] = '___time___';
 780         $replacements[] = $cmt->avatar;
 781         $replacements[] = html_writer::link($cmt->profileurl, $cmt->fullname);
 782         $replacements[] = $cmt->content;
 783         $replacements[] = userdate($cmt->timecreated, get_string('strftimerecent', 'langconfig'));
 784
 785         // use html template to format a single comment.
 786         return str_replace($patterns, $replacements, $this->template);
 787     }
 788
 789     /**
 790      * Revoke validate callbacks
 791      *
 792      * @param stdClass $params addtionall parameters need to add to callbacks
 793      */
 794     protected function validate($params=array()) {
 795         foreach ($params as $key=>$value) {
 796             $this->comment_param->$key = $value;
 797         }
 798         $validation = plugin_callback($this->plugintype, $this->pluginname, 'comment', 'validate', array($this->comment_param), false);
 799         if (!$validation) {
 800             throw new comment_exception('invalidcommentparam');
 801         }
 802     }
 803
 804     /**
 805      * Returns true if the user is able to view comments
 806      * @return bool
 807      */
 808     public function can_view() {
 809         $this->validate();
 810         return !empty($this->viewcap);
 811     }
 812
 813     /**
 814      * Returns true if the user can add comments against this comment description
 815      * @return bool
 816      */
 817     public function can_post() {
 818         $this->validate();
 819         return isloggedin() && !empty($this->postcap);
 820     }
 821
 822     /**
 823      * Returns true if the user can delete this comment
 824      * @param int $commentid
 825      * @return bool
 826      */
 827     public function can_delete($commentid) {
 828         $this->validate(array('commentid'=>$commentid));
 829         return has_capability('moodle/comment:delete', $this->context);
 830     }
 831
 832     /**
 833      * Returns the component associated with the comment
 834      * @return string
 835      */
 836     public function get_compontent() {
 837         return $this->component;
 838     }
 839
 840     /**
 841      * Returns the context associated with the comment
 842      * @return stdClass
 843      */
 844     public function get_context() {
 845         return $this->context;
 846     }
 847
 848     /**
 849      * Returns the course id associated with the comment
 850      * @return int
 851      */
 852     public function get_courseid() {
 853         return $this->courseid;
 854     }
 855
 856     /**
 857      * Returns the course module associated with the comment
 858      *
 859      * @return stdClass
 860      */
 861     public function get_cm() {
 862         return $this->cm;
 863     }
 864
 865     /**
 866      * Returns the item id associated with the comment
 867      *
 868      * @return int
 869      */
 870     public function get_itemid() {
 871         return $this->itemid;
 872     }
 873
 874     /**
 875      * Returns the comment area associated with the commentarea
 876      *
 877      * @return stdClass
 878      */
 879     public function get_commentarea() {
 880         return $this->commentarea;
 881     }
 882 }
 883
 884 /**
 885  * Comment exception class
 886  *
 887  * @package   core
 888  * @copyright 2010 Dongsheng Cai {@link http://dongsheng.org}
 889  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 890  */
 891 class comment_exception extends moodle_exception {
 892 }