locallib.php

<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Library of extra functions for the dialogue module not part of the standard add-on module API set
 * but used by scripts in the mod/dialogue folder
 * 
 * @package dialogue
 * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
 */


define ('DIALOGUETYPE_TEACHERSTUDENT', 0);
define ('DIALOGUETYPE_STUDENTSTUDENT', 1);
define ('DIALOGUETYPE_EVERYONE', 2);
define ('DIALOGUEPANE_OPEN', 0);
define ('DIALOGUEPANE_CURRENT', 1);
define ('DIALOGUEPANE_CLOSED', 3);

/**
 * Count the number of closed conversations in a given dialogue for a given user
 *  
 * @param   object  $dialogue
 * @param   object  $user
 * @param   bool    $viewall if true count all open records, not just those where user is initator or receipient
 * @param   int     $groupid    filter conversations by recipients in the group specified
 * @return  int     count of the records found
 */
function dialogue_count_closed($dialogue, $user, $viewall=false, $groupid=0) {
    global $DB;   
    if ($viewall) {
        $userwhere = '';
    } else {
        $userwhere = "(userid = '$user->id' OR recipientid = '$user->id') AND ";

    }


    if($groupid) {
        $members = groups_get_members($groupid, 'u.id');
        if ($members) {
            $list = '( '.implode(', ', array_keys($members)).' )';

        } else {
            $list = '( 0 ) ';
        }
        $where = " ( userid IN $list AND recipientid IN $list ) AND $userwhere closed = 1";
    } else {
        $where = " $userwhere closed = 1";
    }
    return $DB->count_records_select("dialogue_conversations", "dialogueid = $dialogue->id AND $where ");
}


/**
 * Count the number of open conversations in a given dialogue for a given user
 *  
 * @param   object  $dialogue
 * @param   object  $user
 * @param   bool    $viewall if true count all closed records, not just those where user is initator or receipient
 * @param   int     $groupid    filter conversations by recipients in the group specified
 * @return  int     count of the records found
 */
function dialogue_count_open($dialogue, $user, $viewall=false,  $groupid=0) {
    global $DB;

    if ($viewall) {
        $userwhere = '';
    } else {
        $userwhere = ' (userid='.$user->id.' OR recipientid='.$user->id.') AND ';
    }
    if($groupid) {
        $members = groups_get_members($groupid, 'u.id');
        if($members) {
            $list = '( '.implode(', ', array_keys($members)).' )';
        } else {
            $list = '( 0 ) ';
        }
        $where = " ( userid IN $list OR recipientid IN $list ) AND $userwhere closed = 0";
    } else {
        $where = " $userwhere closed = 0";
    }
    return $DB->count_records_select('dialogue_conversations', "dialogueid = $dialogue->id AND $where ");
}


/**
 * Return a list of users that the current user is able to open a dialogue with
 * 
 * Makes calls to dialogue_get_available_students() and dialogue_get_available_teachers()
 * depending on the capability and type of dialogue
 * @param   object  $dialogue
 * @param   object  $context    for a user in this activity
 * @param   int     $editconversationid
 * @return  array   usernames and ids
 */
function dialogue_get_available_users($dialogue, $context, $editconversationid) {
    global $DB;

    if (! $course = $DB->get_record('course', array('id' => $dialogue->course))) {
        print_error('Course is misconfigured');
    }
    $hascapopen = has_capability('mod/dialogue:participate', $context);
    $hascapmanage = has_capability('mod/dialogue:manage', $context); 


    switch ($dialogue->dialoguetype) {
        case DIALOGUETYPE_TEACHERSTUDENT : // teacher to student
            if ($hascapmanage) {
                return dialogue_get_available_students($dialogue, $context, $editconversationid);
            }
            else {
                return dialogue_get_available_teachers($dialogue,  $context, $editconversationid);
            }
        case DIALOGUETYPE_STUDENTSTUDENT: // student to student
            if (! $hascapmanage && $hascapopen) {
                return dialogue_get_available_students($dialogue, $context, $editconversationid);
            }
            else {
                return; // dont return any students if this is a teacher, ie has manage capability
            }
        case DIALOGUETYPE_EVERYONE: // everyone
            if ($teachers = dialogue_get_available_teachers($dialogue, $context, $editconversationid)) {
                foreach ($teachers as $userid=>$name) {
                    $names[$userid] = $name;
                }
                $names[-1] = '-------------';
            }
            if ($students = dialogue_get_available_students($dialogue, $context, $editconversationid)) {
                foreach ($students as $userid=>$name) {
                    $names[$userid] = $name;
                }
            }
            if (isset($names)) {
                return $names;
            }
            return;
    }
}

                    
/**
 * Return a list of students that the current user is able to open a dialogue with
 * 
 * Called by dialogue_get_available_users(). The list is used to populate a drop-down
 * list in the UI. The returned array of usernames starts with a list of student-groups 
 * for a teacher, followed by an "All Participants" entry if a teacher, followed by a
 * list of students. The students list is refined to just the student's own group 
 * if the activity is in group-mode and also filters out the students own name
 * @param   object  $dialogue
 * @param   object  $context    for a user in this activity
 * @param   int     $editconversationid
 * @return  array   usernames and ids
 */
function dialogue_get_available_students($dialogue, $context, $editconversationid=0) {
    global $DB, $USER, $CFG;
    
    if (! $course = $DB->get_record('course', array('id' =>  $dialogue->course))) {
        print_error('Course is misconfigured');
    }
    if (! $cm = get_coursemodule_from_instance('dialogue', $dialogue->id, $course->id)) {
        print_error('Course Module ID was incorrect');
    }

    // get the list of teachers (actually, those who have dialogue:manage capability)
    $teachers = array();
    if ($users = get_users_by_capability($context, 'mod/dialogue:manage', '', 
                                         null, null, null, null, null, null,null,false)) {
        foreach ($users as $user) {
            $teachers[$user->id] = 1;
        }
    }

    $groupid = groups_get_activity_group($cm, true);
    // add current group before list of students if it's the teacher
    if (isset($teachers[$USER->id])) {
        // show teacher their current group
        if ($groupid) {
            if (! $group = $DB->get_record('groups', array('id' => $groupid))) {
                print_error('Dialogue get available students: group not found');
            }
            $gnames["g$groupid"] = $group->name;
        }
        $gnames['g0'] = get_string('allparticipants');
        $gnames['spacer'] = '------------';
    }


    // get the students on this course (default sort order)...
    if ($users = get_users_by_capability($context, 'mod/dialogue:participate', 
                                         null, null, null, null, null, null, null,null,false)) {

        if (! empty($CFG->enablegroupings) && ! empty($cm->groupingid) && ! empty($users)) {
            $groupingusers = groups_get_grouping_members($cm->groupingid, 'u.id', 'u.id');
            foreach($users as $key => $user) {
                if (! isset($groupingusers[$user->id])) {
                    unset($users[$key]);
                }
            }
        }
        foreach ($users as $otheruser) {
            // ...exclude self and...
            if ($USER->id != $otheruser->id) {

                // ...if not a student (eg co-teacher, teacher) then exclude from students list
                if (isset($teachers[$otheruser->id]) && $teachers[$otheruser->id] == 1) {
                    continue;
                }

                $groupmode = groupmode($course, $cm);
                // ...if teacher and groups then exclude students not in the current group
                if (isset($teachers[$USER->id]) and $groupmode and $groupid) {
                    if (! groups_is_member($groupid, $otheruser->id)) {
                        continue;
                    }
                }

                // ...if student and groupmode then exclude students not in student's group
                if (!isset($teachers[$USER->id]) && $groupmode && $groupid) {
                    if (!groups_is_member($groupid, $otheruser->id)) {
                        continue;
                    }
                }

                // ... and any already in any open conversations unless multiple conversations allowed

                $countparams = array('dialogueid' => $dialogue->id, 'editconversationid' => $editconversationid,
                                     'userid0' => $USER->id, 'userid1' => $USER->id, 'otheruserid0' => $otheruser->id,
                                     'otheruserid1' => $otheruser->id);

                $countsql = "dialogueid = :dialogueid AND id != :editconversationid AND
                            ((userid = :userid0 AND recipientid = :otheruserid0) OR
                            (userid = :otheruserid1 AND recipientid = :userid1)) AND closed = 0";

                if ($dialogue->multipleconversations or
                    $DB->count_records_select('dialogue_conversations',$countsql, $countparams) == 0) {
                    
                    $names[$otheruser->id] = fullname($otheruser);
                }
            }
        }
    }
    if (isset($gnames)) {   // group names
        $list = $gnames;
    }
    if (isset($names)) {
        natcasesort($names);
        if (isset($list)) {
            $list += $names;
        } else {
            $list = $names;
        }
    }
    if (isset($list)) {
        return $list;
    } else {
        return;
    }
}


/**
 * Return a list of teachers that the current user is able to open a dialogue with
 * 
 * Called by dialogue_get_available_users(). The list is used to populate a drop-down
 * list in the UI. The returned array of usernames is filtered to hide teacher names
 * if those teachers have a hidden role assignment, unless the list is being returned
 * for a teacher in which case those hidden teachers are listed
 * @param   object  $dialogue
 * @param   object  $context    for a user in this activity
 * @param   int     $editconversationid
 * @return  array   usernames and ids
 */
function dialogue_get_available_teachers($dialogue, $context, $editconversationid = 0) {
    global $DB, $USER, $CFG;
    //$canseehidden = has_capability('moodle/role:viewhiddenassigns', $context);
 
    if (! $course = $DB->get_record('course', array('id'=>$dialogue->course))) {
        print_error('Course is misconfigured');
        }
    if (! $cm = get_coursemodule_from_instance('dialogue', $dialogue->id, $course->id)) {
        print_error('Course Module ID was incorrect');
    }
    // get the list of teachers (actually, those who have dialogue:manage capability)
    $hiddenTeachers = array();
    if ($users = get_users_by_capability($context, 'mod/dialogue:manage', '', 
                                         null, null, null, null, null, null,true,null)) {
        /*foreach ($users as $user) {
            $userRoles = get_user_roles($context, $user->id, true);
            foreach ($userRoles as $role) {
                if ($role->hidden == 1) {
                    $hiddenTeachers[$user->id] = 1;
                    break;
                }
            }
        }
        $canSeeHidden = false;
        if (has_capability('moodle/role:viewhiddenassigns', $context)) {
            $canSeeHidden = true;
        }*/
        $groupid = get_current_group($course->id);
        foreach ($users as $otheruser) {
            // ...exclude self and ...
            if ($USER->id != $otheruser->id) {
                // ...if groupmode is SEPARATEGROUPS then exclude teachers not in student's group
                if ($groupid and (groupmode($course, $cm) == SEPARATEGROUPS)) {
                    if (! groups_is_member($groupid, $otheruser->id)) {
                        continue;
                    }
                }
                /*if (! $canSeeHidden && array_key_exists($otheruser->id, $hiddenTeachers)
                      && ($hiddenTeachers[$otheruser->id] == 1)) {
                    continue;
                }*/
                // ...any already in open conversations unless multiple conversations allowed 
                if ($dialogue->multipleconversations or $DB->count_records_select('dialogue_conversations',
                        "dialogueid = $dialogue->id AND id != $editconversationid AND ((userid = $USER->id AND 
                        recipientid = $otheruser->id) OR (userid = $otheruser->id AND 
                        recipientid = $USER->id)) AND closed = 0") == 0) {
                    $names[$otheruser->id] = fullname($otheruser);
                }
            }
        }
    }
    if (isset($names)) {
        natcasesort($names);
        return $names;
    }
    return;
}


/**
 * Print a conversation and allow a new entry
 * 
 * Render out entries for the specified conversation as HTML showing the
 * avatar for the user who initiated  the dialogue. Follow up with a text
 * box to allow user to add a new response entry
 *  
 * @param   object  $dialogue
 * @param   int     $conversation
 */
function dialogue_print_conversation($dialogue, $conversation) {

    global $CFG, $DB, $USER, $OUTPUT;

    if (! $course = $DB->get_record('course', array('id' => $dialogue->course))) {
        print_error('Course is misconfigured');
    }
    if (! $cm = get_coursemodule_from_instance('dialogue', $dialogue->id, $course->id)) {
        print_error('Course Module ID was incorrect');
    }
    $context = get_context_instance(CONTEXT_MODULE, $cm->id);

    $timenow = time();
    $showbutton = false;

    //$otheruser always recipient if admin or other viewing
    if ($USER->id == $conversation->userid) {
        if (! $otheruser = $DB->get_record('user', array('id' => $conversation->recipientid))) {
            print_error("User's record not found");
        }
    } else if ($USER->id == $conversation->recipientid) {
        if (! $otheruser = $DB->get_record('user', array('id' => $conversation->userid))) {
            print_error("User's record not found");
        }
    } else {
        if (! $otheruser = $DB->get_record('user', array('id' => $conversation->recipientid))) {
            print_error("User's record not found");
        }
    }
    
    // Prepare an array of commands
    $commands = array();    
    // conversation does not have a subject, create a subject link
    if (! $conversation->subject) {
        $nosubject = '';
        if ($conversation->userid == $USER->id) {
            $addsubjecturl = new moodle_url('dialogues.php', array('action'=>'getsubject',
                                                                   'id'=>$cm->id,
                                                                   'cid'=>$conversation->id,
                                                                   'pane'=>DIALOGUEPANE_CURRENT));

            $nosubject = html_writer::link($addsubjecturl, get_string('addsubject', 'dialogue')) . $OUTPUT->help_icon('addsubject', 'dialogue');;
        } else {
            $nosubject = get_string('nosubject', 'dialogue');
        }
    }
    // can close dialogue?
    if (! $conversation->closed && has_capability('mod/dialogue:close', $context)) {            
        $closeurl = new moodle_url('dialogues.php', array('id'=>$cm->id,
                                                          'cid'=>$conversation->id,
                                                          'action'=>'confirmclose',
                                                          'pane'=>DIALOGUEPANE_CURRENT));
        
        $commands['close'] = array('url'=>$closeurl, 'text'=>get_string('close', 'dialogue'));
    }
    

    if ($entries = $DB->get_records_select('dialogue_entries', "conversationid = ?", array($conversation->id), 'id')) {
        $firstentry = true;
        foreach ($entries as $entry) {
            $canedit = false; //default
            $output = ''; // reset output var
            $modified = '';
            $modifiedstamp = '';

            // Author of entry
            if (! $author = $DB->get_record('user', array('id'=>$entry->userid))) {
                print_error("User's record not found");
            }

            // Can edit?
            if (! $conversation->closed && $entry->userid == $USER->id 
                  && $timenow < $entry->timecreated + ($dialogue->edittime * 60)) {
            	 $canedit = true;
            }
    
            if ($entry->timecreated != $entry->timemodified) {
                $modified = get_string('updated', 'dialogue', userdate($entry->timemodified));            
            } else {
                $modified = '';
            }
            // Build edit command and modified stamp.
            if ($entry->userid == $USER->id) {
                if ($canedit) {
                    if ($firstentry) {
                        $editconversationurl = new moodle_url('dialogues.php', array('id'=>$cm->id,
                                                                                     'cid'=>$conversation->id,
                                                                                     'entryid'=>$entry->id,
                                                                                     'action'=>'editconversation',
                                                                                     'pane'=>DIALOGUEPANE_CURRENT));

                        $commands['edit'] = array('url'=>$editconversationurl, 'text'=>get_string('edit'));

                    } else {
                        $editreplyurl = new moodle_url('dialogues.php', array('id'=>$cm->id,
                                                                              'cid'=>$conversation->id,
                                                                              'entryid'=>$entry->id,
                                                                              'action'=>'editreply',
                                                                              'pane'=>DIALOGUEPANE_CURRENT));

                        $commands['edit'] = array('url'=>$editreplyurl, 'text'=>get_string('edit'));
                        
                    }
                }
                $a->timestamp = userdate($entry->timecreated);
                $a->picture = '';
                if ($author->picture) {
                    $a->picture = $OUTPUT->user_picture($author, array('courseid'=>$course->id, 'size'=>'12'));
                }
                $modifiedstamp = get_string('onyouwrote', 'dialogue', $a);
            } else {
                $a->timestamp = userdate($entry->timecreated);
                $a->author = fullname($author);
                $a->picture = '';
                if ($author->picture) {
                    $a->picture = $OUTPUT->user_picture($author, array('courseid'=>$course->id, 'size'=>'12'));
                }
                $modifiedstamp = get_string('onwrote', 'dialogue', $a);
            }
            
            $options = new stdClass;
            $options->para    = false;
            $options->trusted = $entry->trust;
            $options->context = $context;

            $commandshtml = array(); // command links

            $content = file_rewrite_pluginfile_urls($entry->text, 'pluginfile.php', $context->id, 'mod_dialogue', 'entry', $entry->id);
            $content = format_text($content, 1, $options, $course->id);

            $attachments = dialogue_print_attachments($entry, $cm, 'html');

            if ($firstentry) {
                
                $picture = $OUTPUT->user_picture($otheruser, array('courseid'=>$course->id));
                $conversant = get_string('dialoguewith', 'dialogue', fullname($otheruser));
                $conversationsubject = empty($conversation->subject) ?  $nosubject : format_string($conversation->subject);
                

                $output .= html_writer::start_tag('div', array('class'=>'dialogue-entry first'));
                $output .= html_writer::start_tag('div', array('class'=>'row header clearfix'));
                $output .= html_writer::start_tag('div', array('class'=>'left'));
                $output .= html_writer::tag('span', $picture, array('class'=>'picture')); // Picture
                $output .= html_writer::end_tag('div'); // end left column
                //$output .= html_writer::start_tag('div', array('class'=>'no-overflow'));
                $output .= html_writer::start_tag('div', array('class'=>'content'));
                $output .= html_writer::tag('h1', $conversationsubject, array('class'=>'subject')); // subject
                
                $output .= html_writer::tag('span', $conversant, array('class'=>'conversant')); // conversant
                //$output .= html_writer::end_tag('div'); // no-overflow
                $output .= html_writer::end_tag('div'); // end content
                $output .= html_writer::end_tag('div'); // end header row
                $output .= html_writer::start_tag('div', array('class'=>'row maincontent clearfix'));
                $output .= html_writer::tag('div', '&nbsp;', array('class'=>'left'));
                $output .= html_writer::start_tag('div', array('class'=>'no-overflow'));
                $output .= html_writer::start_tag('div', array('class'=>'content'));
                if (isset($commands['edit'])) {
                    $commandshtml[] = html_writer::link($commands['edit']['url'], $commands['edit']['text']);
                }
                if (isset($commands['close'])) {
                    $commandshtml[] = html_writer::link($commands['close']['url'], $commands['close']['text']);
                }
                $output .= html_writer::tag('div', implode(' | ', $commandshtml), array('class'=>'commands'));
                $output .= html_writer::tag('span', '<i>'.$modifiedstamp.'</i>', array('class'=>'modified')); // margin hack
                $output .= html_writer::tag('div', $content, array('class'=>'body'));
                if (!empty($attachments)) {
                    $output .= html_writer::tag('div', $attachments, array('class'=>'attachments'));
                }
                
                $output .= html_writer::end_tag('div'); // content   
                $output .= html_writer::end_tag('div'); // no-overflow
                $output .= html_writer::end_tag('div'); // row maincontent
                $output .= html_writer::end_tag('div'); // end
               
                $firstentry = false;
           } else {
               
                //$content = format_text($entry->text, 1, $options, $course->id);
                $output .= html_writer::start_tag('div', array('class'=>'dialogue-entry reply'));
                //$output .= html_writer::start_tag('div', array('class'=>'row header'));
                $output .= html_writer::tag('div', '&nbsp;', array('class'=>'left')); // left column
                //$output .= html_writer::end_tag('div');
                $output .= html_writer::start_tag('div', array('class'=>'row maincontent clearfix'));
                $output .= html_writer::start_tag('div', array('class'=>'no-overflow'));
                $output .= html_writer::start_tag('div', array('class'=>'content'));
                if (isset($commands['edit'])) {
                    $commandshtml[] = html_writer::link($commands['edit']['url'], $commands['edit']['text']);
                }
                
                $output .= html_writer::tag('div', implode(' | ', $commandshtml), array('class'=>'commands'));
                $output .= html_writer::tag('span', '<i>'.$modifiedstamp.'</i>', array('class'=>'modified')); // margin hack
                $output .= html_writer::tag('div', $content, array('class'=>'body'));
                if (!empty($attachments)) {
                    $output .= html_writer::tag('div', $attachments, array('class'=>'attachments'));
                }
                $output .= html_writer::end_tag('div'); // content
                $output .= html_writer::end_tag('div'); // no-overflow
                $output .= html_writer::end_tag('div'); // row maincontent
                $output .= html_writer::end_tag('div'); // end
                  
           }
           echo $output;           
        }
    }
    /// Finally add the reply form.
    if (! $conversation->closed && (has_capability('mod/dialogue:participateany', $context) 
          || $conversation->userid == $USER->id || $conversation->recipientid == $USER->id)) {

        require_once('dialogue_reply_form.php');
        $mform = new mod_dialogue_reply_form('dialogues.php', array('conversationid' => $conversation->id,
                                                                    'context' => $context ));
        $mform->set_data(array('id' => $cm->id,
                               'action' => 'insertentries',
                               'pane' => DIALOGUEPANE_CURRENT));
        $mform->display();
    }

    if (! $conversation->seenon && $conversation->lastrecipientid == $USER->id) {
        $DB->set_field('dialogue_conversations', 'seenon', time(), array('id' => $conversation->id));
    }
    dialogue_mark_conversation_read($conversation->id, $USER->id);
}


/**
 * List conversations of either open or closed type for the current user
 * 
 * Called when a user clicks the "Current Dialogues" or "Closed Dialogues" tabs
 * rendering those out directly as HTML inside a print_table() showing who the
 * conversation is with, what the subject is, how many entries there are, 
 * how many are un-read and what the most recent post date is 
 *  
 * @param   object  $dialogue
 * @param   int     $groupid    of the group to filter conversations by (default: 0)
 * @param   string  $type       'open' (default) or 'closed'
 * @todo    remove the embedded style for 'th', make it a class driven thing in the theme
 */
function dialogue_list_conversations($dialogue, $groupid=0, $type='open') {
    global $CFG, $DB, $USER, $OUTPUT;

    $condition = array(" closed=? ");
    $cond_params = ($type == 'closed') ? array(1) : array(0);
    $tabid = 1;
    
    if (! $course = $DB->get_record('course', array('id' => $dialogue->course))) {
        print_error('Course is misconfigured');
    }
    if (! $cm = get_coursemodule_from_instance('dialogue', $dialogue->id, $course->id)) {
        print_error('Course Module ID was incorrect');
    }
    
    $context = get_context_instance(CONTEXT_MODULE, $cm->id);
    
    $dialoguemanagers = array_keys(get_users_by_capability($context, 'mod/dialogue:manage'));

    echo '<style>th.header { text-align: left; }</style>';
    require_once($CFG->libdir.'/tablelib.php');
    $tablecolumns = array('picture', 'subject', 'fullname', 'total', 'unread', 'lastentry');
    $tableheaders = array('',
                            get_string('subject', 'dialogue'),  
                            get_string('fullname', ''),  
                            get_string('numberofentries', 'dialogue'), 
                            get_string('unread', 'dialogue'), 
                            get_string('lastentry', 'dialogue')
    );
    $table = new flexible_table('mod-dialogue-submissions');
    $table->define_columns($tablecolumns);
    $table->define_headers($tableheaders);
    $table->define_baseurl($CFG->wwwroot.'/mod/dialogue/view.php?id='.$cm->id.'&amp;pane='.$tabid);
    $table->sortable(true, 'subject');
    $table->collapsible(false);
    //$table->column_suppress('picture'); // supress multiple subsequent row entries
    //$table->column_suppress('fullname');
    $table->set_attribute('cellspacing', '0');
    $table->set_attribute('id', 'dialogue');
    $table->set_attribute('class', 'conversations');
    $table->set_attribute('width', '100%');
    $table->setup();

    $order = '';    // so we can filter the get_conversations() call later
    $namesort = ''; // if we want to sort by other calculated fields, e.g. first/last name
    if ($sort = $table->get_sql_sort('mod-dialogue-submissions')) {
        $sortparts = explode(',', $sort);
        $sqlsort = $sortparts[0];
        if (strpos($sqlsort,'subject') !== false) {
            $order = $sqlsort;
        }
        if (strpos($sqlsort,'total') !== false) {
            $order = $sqlsort;
        }
        if (strpos($sqlsort,'lastentry') !== false) {
            $order = $sqlsort;
            $order = str_replace('lastentry','c.timemodified',$order);
        }
        if (strpos($sqlsort,'firstname') !== false) {
            $namesort = $sqlsort;
        }
        if (strpos($sqlsort,'lastname') !== false) {
            $namesort = $sqlsort;
        }
        if (strpos($sqlsort,'unread') !== false) {
            $namesort = $sqlsort;
        }
    }
    // list the conversations requiring a resonse from this user in full
    if ($conversations = dialogue_get_conversations($dialogue, $USER, $condition, $cond_params, $order, $groupid)) {
        foreach ($conversations as $conversation) {
            if ($USER->id == $conversation->userid) {
                if (! $with = $DB->get_record('user', array('id' => $conversation->recipientid))) {
                    $with = $USER; // incomplete record need cleanup function
                }
            } else if ($USER->id == $conversation->recipientid) {
                if (! $with = $DB->get_record('user', array('id' => $conversation->userid))) {
                    $with = $USER; // incomplete record need cleanup function
                }
            } else {
                if (! $with = $DB->get_record('user', array('id' => $conversation->recipientid))) {
                    $with = $USER; // incomplete record need cleanup function
                }
            }

            // save sortable field values for each conversation so can sort by them later
            $names[$conversation->id] = fullname($with);
            $unread[$conversation->id] = $conversation->total-$conversation->readings;
            $names_firstlast[$conversation->id] = $with->firstname.' '.$with->lastname;
            $names_lastfirst[$conversation->id] = $with->lastname.' '.$with->firstname;
            $photos[$conversation->id] = $OUTPUT->user_picture($with, array('courseid' => $course->id));
            $ids[$conversation->id] = $with->id;
            
        }

        // sort an array of conversations based on which field user clicked to sort in the UI
        $sortedvalues = $names; // default is sort by fullname from above
        switch ($namesort) {
        	case 'firstname ASC':
                $sortedvalues = $names_firstlast;
                natcasesort($sortedvalues);
                break;
            case 'firstname DESC':
                $sortedvalues = $names_firstlast;
                natcasesort($sortedvalues);
                $sortedvalues = array_reverse($sortedvalues,true);
                break;
            case 'lastname ASC':
                $sortedvalues = $names_lastfirst;
                natcasesort($sortedvalues);
                break;
            case 'lastname DESC':
                $sortedvalues = $names_lastfirst;
                natcasesort($sortedvalues);
                $sortedvalues = array_reverse($sortedvalues,true);
                break;
            case 'unread ASC':
                $sortedvalues = $unread;
                asort($sortedvalues);
                break;
            case 'unread DESC':
                $sortedvalues = $unread;
                arsort($sortedvalues);
                break;
        }

        foreach ($sortedvalues as $cid=>$val) {
            $conversation = $conversations[$cid];
            if ($unread[$cid] > 0) {
                $unreadcount = '<span class="unread">'.($unread[$cid]).'</span>';
            } else {
                $unreadcount = 0;
            }
            $profileurl = "$CFG->wwwroot/user/view.php?id=".$ids[$conversation->id]."&amp;course=$dialogue->course";
            $entryurl = "$CFG->wwwroot/mod/dialogue/dialogues.php?id=".$cm->id."&amp;action=printdialogue&amp;cid=".$cid;
            $subject = empty($conversation->subject) ? get_string('nosubject', 'dialogue') : $conversation->subject;
            $row = array($photos[$conversation->id], 
                         "<a href='$entryurl'>".$subject.'</a>',
                         "<a href='$profileurl'>".$names[$conversation->id].'</a>',
                         $conversation->total,
                         $unreadcount,
                         userdate($conversation->timemodified)
                        );
            $table->add_data($row);

        }
        $table->print_html();  /// Print the whole table
    }
}

/**
 * Mark all entries in a conversation as read for a given user 
 * 
 * Called when a user views a conversation
 * @param   int  $conversationid
 * @param   int  $userid
 */
function dialogue_mark_conversation_read($conversationid, $userid) {
    global $CFG, $DB;

    $lastread = time();

    // Update any previously seen entries in this conversaion
    $DB->set_field('dialogue_read', 'lastread', $lastread, array('conversationid' => $conversationid, 'userid' => $userid));

    $sql = "SELECT e.id FROM {dialogue_entries} e
                LEFT JOIN {dialogue_read} r ON e.id = r.entryid AND r.userid = :userid
            WHERE e.conversationid = :conversationid AND r.id IS NULL ";
    $params = array('userid' => $userid, 'conversationid' => $conversationid);

    if ($unread = $DB->get_records_sql($sql, $params)) {
        foreach($unread as $entry) {
            $read = new stdClass;
            $read->conversationid = $conversationid;
            $read->entryid        = $entry->id;
            $read->userid         = $userid;
            $read->firstread      = $lastread;
            $read->lastread       = $lastread;

            $DB->insert_record('dialogue_read', $read);
        }
    }
}