moodle/mod/forum/lib.php

<?PHP  // $Id$

include_once("$CFG->dirroot/files/mimetypes.php");

/// CONSTANTS ///////////////////////////////////////////////////////////

$FORUM_DEFAULT_DISPLAY_MODE = 3; 

$FORUM_LAYOUT_MODES = array ( "1"  => get_string("modeflatoldestfirst", "forum"),
                              "-1" => get_string("modeflatnewestfirst", "forum"),
                              "2"  => get_string("modethreaded", "forum"),
                              "3"  => get_string("modenested", "forum") );

// These are course content forums that can be added to the course manually
$FORUM_TYPES   = array ("general"    => get_string("generalforum", "forum"),
                        "eachuser"   => get_string("eachuserforum", "forum"),
                        "single"     => get_string("singleforum", "forum") );

$FORUM_POST_RATINGS = array ("3" => get_string("postrating3", "forum"),
                             "2" => get_string("postrating2", "forum"),
                             "1" => get_string("postrating1", "forum") );

$FORUM_SHORT_POST = 300;  // Less than this is "short"

$FORUM_LONG_POST  = 600;  // More than this is "long"

$FORUM_MANY_DISCUSSIONS = 10;


/// FUNCTIONS ///////////////////////////////////////////////////////////


function forum_get_course_forum($courseid, $type) {
// How to set up special 1-per-course forums
    if ($forum = get_record_sql("SELECT * from forum WHERE course = '$courseid' AND type = '$type'")) {
        return $forum;

    } else {
        // Doesn't exist, so create one now.
        $forum->course = $courseid;
        $forum->type = "$type";
        switch ($forum->type) {
            case "news":
                $forum->name  = get_string("namenews", "forum");
                $forum->intro = get_string("intronews", "forum");
                $forum->open  = 0;
                $forum->assessed = 0;
                $forum->forcesubscribe = 1;
                break;
            case "social":
                $forum->name  = get_string("namesocial", "forum");
                $forum->intro = get_string("introsocial", "forum");
                $forum->open  = 1;
                $forum->assessed = 0;
                $forum->forcesubscribe = 0;
                break;
            case "teacher":
                $forum->name  = get_string("nameteacher", "forum");
                $forum->intro = get_string("introteacher", "forum");
                $forum->open  = 0;
                $forum->assessed = 0;
                $forum->forcesubscribe = 0;
                break;
            default:
                notify("That forum type doesn't exist!");
                return false;
                break;

        }
        $forum->timemodified = time();
        $forum->id = insert_record("forum", $forum);
        return get_record_sql("SELECT * from forum WHERE id = '$forum->id'");
    }
}


function forum_make_mail_post(&$post, $user, $touser, $course, 
                              $ownpost=false, $reply=false, $link=false, $rate=false, $footer="") {
// Given the data about a posting, builds up the HTML to display it and 
// returns the HTML in a string.  This is designed for sending via HTML email.

    global $THEME, $CFG;

    $output = "";

    if ($post->parent) {
        $output .= "<TABLE BORDER=0 CELLPADDING=1 CELLSPACING=1><TR><TD BGCOLOR=#888888>";
        $output .= "<TABLE BORDER=0 CELLPADDING=3 CELLSPACING=0>";
    } else {
        $output .= "<TABLE BORDER=0 CELLPADDING=1 CELLSPACING=1 WIDTH=100%><TR><TD BGCOLOR=#888888>";
        $output .= "<TABLE BORDER=0 CELLPADDING=3 CELLSPACING=0 WIDTH=100%>";
    }

    $output .= "<TR><TD BGCOLOR=\"$THEME->body\" WIDTH=35 VALIGN=TOP>";
    $output .= print_user_picture($user->id, $course->id, $user->picture, false, true);
    $output .= "</TD>";

    if ($post->parent) {
        $output .= "<TD NOWRAP BGCOLOR=\"$THEME->cellheading\">";
    } else {
        $output .= "<TD NOWRAP BGCOLOR=\"$THEME->cellheading2\">";
    }
    $output .= "<P>";
    $output .= "<FONT SIZE=3><B>$post->subject</B></FONT><BR>";
    $output .= "<FONT SIZE=2>";
    $by->name = "<A HREF=\"$CFG->wwwroot/user/view.php?id=$user->id&course=$course->id\">$user->firstname $user->lastname</A>";
    $by->date = userdate($post->created, "", $touser->timezone);
    $output .= get_string("bynameondate", "forum", $by);
    $output .= "</FONT></P></TD></TR>";
    $output .= "<TR><TD BGCOLOR=\"$THEME->body\" WIDTH=10>";
    $output .= "&nbsp;";
    $output .= "</TD><TD BGCOLOR=\"$THEME->cellcontent\">\n";

    if ($post->attachment) {
        $post->course = $course->id;
        $post->forum = get_field("forum_discussions", "forum", "id", $post->discussion);
        $output .= "<DIV ALIGN=right>";
        $output .= forum_print_attachments($post, "html");
        $output .= "</DIV>";
    }

    $output .= text_to_html($post->message);

    $output .= "<P ALIGN=right><FONT SIZE=-1>";

    $age = time() - $post->created;
    if ($ownpost) {
        $output .= "<A HREF=\"$CFG->wwwroot/mod/forum/post.php?delete=$post->id\">".get_string("delete", "forum")."</A>";
        if ($reply) {
            $output .= " | <A HREF=\"$CFG->wwwroot/mod/forum/post.php?reply=$post->id\">".get_string("reply", "forum")."</A>";
        }
        $output .= "&nbsp;&nbsp;";
    } else {
        if ($reply) {
            $output .= "<A HREF=\"$CFG->wwwroot/mod/forum/post.php?reply=$post->id\">".get_string("reply", "forum")."</A>&nbsp;&nbsp;";
        }
    }

    $output .= "<DIV ALIGN=right><P ALIGN=right>";
    
    if ($link) {
        if ($post->replies == 1) {
            $replystring = get_string("repliesone", "forum", $post->replies);
        } else {
            $replystring = get_string("repliesmany", "forum", $post->replies);
        }
        $output .= "<A HREF=\"$CFG->wwwroot/mod/forum/discuss.php?d=$post->discussion\"><B>".get_string("discussthistopic", "forum")."</B></A> ($replystring)&nbsp;&nbsp;";
    }
    $output .= "</P></DIV>";
    if ($footer) {
        $output .= "<P>$footer</P>";
    }
    $output .= "</TD></TR></TABLE>\n";
    $output .= "</TD></TR></TABLE>\n\n";

    return $output;
}


function forum_print_post(&$post, $courseid, $ownpost=false, $reply=false, $link=false, $rate=false, $footer="") {
    global $THEME, $USER, $CFG, $FORUM_LONG_POST;

    if ($post->parent) {
        echo "<TABLE BORDER=0 CELLPADDING=1 CELLSPACING=1><TR><TD BGCOLOR=#888888>";
        echo "<TABLE BORDER=0 CELLPADDING=3 CELLSPACING=0>";
    } else {
        echo "<TABLE BORDER=0 CELLPADDING=1 CELLSPACING=1 WIDTH=100%><TR><TD BGCOLOR=#888888>";
        echo "<TABLE BORDER=0 CELLPADDING=3 CELLSPACING=0 WIDTH=100%>";
    }

    echo "<TR><TD BGCOLOR=\"$THEME->body\" WIDTH=35 VALIGN=TOP>";
    print_user_picture($post->userid, $courseid, $post->picture);
    echo "</TD>";

    if ($post->parent) {
        echo "<TD NOWRAP BGCOLOR=\"$THEME->cellheading\" WIDTH=\"100%\">";
    } else {
        echo "<TD NOWRAP BGCOLOR=\"$THEME->cellheading2\" WIDTH=\"100%*\">";
    }
    echo "<P>";
    echo "<FONT SIZE=3><B>$post->subject</B></FONT><BR>";
    echo "<FONT SIZE=2>";
    $by->name = "<A HREF=\"$CFG->wwwroot/user/view.php?id=$post->userid&course=$courseid\">$post->firstname $post->lastname</A>";
    $by->date = userdate($post->created);
    print_string("bynameondate", "forum", $by);
    echo "</FONT></P></TD></TR>";
    echo "<TR><TD BGCOLOR=\"$THEME->body\" WIDTH=10>";
    echo "&nbsp;";
    echo "</TD><TD BGCOLOR=\"$THEME->cellcontent\">\n";

    if ($post->attachment) {
        $post->course = $courseid;
        $post->forum = get_field("forum_discussions", "forum", "id", $post->discussion);
        echo "<DIV ALIGN=right>";
        forum_print_attachments($post);
        echo "</DIV>";
    }

    if ($link && (strlen($post->message) > $FORUM_LONG_POST)) {
        // Print shortened version
        echo text_to_html(forum_shorten_post($post->message));
        $numwords = count_words($post->message);
        echo "<A HREF=\"$CFG->wwwroot/mod/forum/discuss.php?d=$post->discussion\">";
        echo get_string("readtherest", "forum");
        echo "</A> (".get_string("numwords", "", $numwords).")...";
    } else {
        // Print whole message
        echo text_to_html($post->message);
    }

    echo "<P ALIGN=right><FONT SIZE=-1>";

    $age = time() - $post->created;
    if ($ownpost) {
        if ($age < $CFG->maxeditingtime) {
            echo "<A HREF=\"$CFG->wwwroot/mod/forum/post.php?edit=$post->id\">".get_string("edit", "forum")."</A> | ";
        }
    }
    if ($ownpost or isteacher($courseid)) {
        echo "<A HREF=\"$CFG->wwwroot/mod/forum/post.php?delete=$post->id\">".get_string("delete", "forum")."</A>";
        if ($reply) {
            echo "| ";
        } else {
            echo "&nbsp;&nbsp;";
        }
    }
    if ($reply) {
        echo "<A HREF=\"$CFG->wwwroot/mod/forum/post.php?reply=$post->id\">".get_string("reply", "forum")."</A>";
        echo "&nbsp;&nbsp;";
    }


    echo "<DIV ALIGN=right><P ALIGN=right>";
    if ($rate && $USER->id) {
        if ($USER->id == $post->userid) {
            forum_print_ratings($post->id);
        } else {
            forum_print_rating($post->id, $USER->id);
        }
    }
    
    if ($link) {
        if ($post->replies == 1) {
            $replystring = get_string("repliesone", "forum", $post->replies);
        } else {
            $replystring = get_string("repliesmany", "forum", $post->replies);
        }
        echo "<A HREF=\"$CFG->wwwroot/mod/forum/discuss.php?d=$post->discussion\"><B>".get_string("discussthistopic", "forum")."</B></A> ($replystring)&nbsp;&nbsp;";
    }
    echo "</P>";
    if ($footer) {
        echo "<P>$footer</P>";
    }
    echo "</DIV>";
    echo "</TD></TR></TABLE>";
    echo "</TD></TR>\n</TABLE>\n\n";
}


function forum_print_post_header(&$post, $courseid, $ownpost=false, $reply=false, $link=false, $rate=false, $footer="") {
    global $THEME, $USER, $CFG, $FORUM_LONG_POST;

    if ($post->parent) {
        echo "<TABLE BORDER=0 CELLPADDING=1 CELLSPACING=1><TR><TD BGCOLOR=#888888>";
        echo "<TABLE BORDER=0 CELLPADDING=3 CELLSPACING=0>";
    } else {
        echo "<TABLE BORDER=0 CELLPADDING=1 CELLSPACING=1 WIDTH=100%><TR><TD BGCOLOR=#888888>";
        echo "<TABLE BORDER=0 CELLPADDING=3 CELLSPACING=0 WIDTH=100%>";
    }

    echo "<TR><TD BGCOLOR=\"$THEME->body\" WIDTH=35 VALIGN=TOP>";
    print_user_picture($post->userid, $courseid, $post->picture);
    echo "</TD>";

    if ($post->parent) {
        echo "<TD NOWRAP BGCOLOR=\"$THEME->cellheading\">";
    } else {
        echo "<TD NOWRAP BGCOLOR=\"$THEME->cellheading2\">";
    }
    echo "<P>";
    echo "<FONT SIZE=3><B>$post->subject</B></FONT><BR>";
    echo "<FONT SIZE=2>";
    $by->name = "<A HREF=\"$CFG->wwwroot/user/view.php?id=$post->userid&course=$courseid\">$post->firstname $post->lastname</A>";
    $by->date = userdate($post->created);
    print_string("bynameondate", "forum", $by);
    echo "</FONT></P></TD>";

    if ($post->parent) {
        echo "<TD VALIGN=BOTTOM BGCOLOR=\"$THEME->cellheading\">";
    } else {
        echo "<TD VALIGN=BOTTOM BGCOLOR=\"$THEME->cellheading2\">";
    }
    echo "<P ALIGN=right><FONT SIZE=-1>";

    if ($link) {
        if ($post->replies == 1) {
            $replystring = get_string("repliesone", "forum", $post->replies);
        } else {
            $replystring = get_string("repliesmany", "forum", $post->replies);
        }
        echo "<A HREF=\"$CFG->wwwroot/mod/forum/discuss.php?d=$post->discussion\"><B>".get_string("discussthistopic", "forum")."</B></A> ($replystring)&nbsp;&nbsp;";
    }
    echo "</P>";
    echo "</TD></TR></TABLE>";
    echo "</TD></TR>\n</TABLE>\n\n";
}


function forum_shorten_post($message) {
    global $FORUM_LONG_POST, $FORUM_SHORT_POST;

    if (strlen($message) > $FORUM_LONG_POST) {
        // Look for the first return between $FORUM_SHORT_POST and $FORUM_LONG_POST
        $shortmessage = substr($message, $FORUM_SHORT_POST, $FORUM_LONG_POST);
        if ($pos = strpos($shortmessage, "\n")) {
            return substr($message, 0, $FORUM_SHORT_POST + $pos);
        } else {
            return substr($message, 0, $FORUM_LONG_POST)."...";
        }
    } else {
        return $message;
    }
}


function forum_print_ratings($post) {
    if ($ratings = get_records_sql("SELECT * from forum_ratings WHERE post='$post'")) {
        $sumrating[1] = 0;
        $sumrating[2] = 0;
        $sumrating[3] = 0;
        foreach ($ratings as $rating) {
            $sumrating[$rating->rating]++;
        }
        $summary = $sumrating[1]."s/".$sumrating[2]."/".$sumrating[3]."c";

        echo get_string("ratings", "forum").": ";
        link_to_popup_window ("/mod/forum/report.php?id=$post", "ratings", $summary, 400, 550);
    }
}

function forum_print_rating($post, $user) {
    global $FORUM_POST_RATINGS;

    if ($rs = get_record_sql("SELECT rating from forum_ratings WHERE user='$user' AND post='$post'")) {
        if ($FORUM_POST_RATINGS[$rs->rating]) {
            echo "<FONT SIZE=-1>".get_string("youratedthis", "forum").": <FONT COLOR=green>";
            echo $FORUM_POST_RATINGS[$rs->rating];
            echo "</FONT></FONT>";
            return;
        }
    }
    choose_from_menu($FORUM_POST_RATINGS, $post, "", get_string("rate", "forum")."...");
}

function forum_print_mode_form($discussion, $mode) {
    GLOBAL $FORUM_LAYOUT_MODES;

    echo "<CENTER><P>";
    popup_form("discuss.php?d=$discussion&mode=", $FORUM_LAYOUT_MODES, "mode", $mode, "");
    echo "</P></CENTER>\n";
}

function forum_print_search_form($course, $search="") {
    global $CFG;

    echo "<TABLE BORDER=0 CELLPADDING=10 CELLSPACING=0><TR><TD ALIGN=CENTER>";
    echo "<FORM NAME=search ACTION=\"$CFG->wwwroot/mod/forum/search.php\">";
    echo "<INPUT NAME=search TYPE=text SIZE=15 VALUE=\"$search\"><BR>";
    echo "<INPUT VALUE=\"".get_string("searchforums", "forum")."\" TYPE=submit>";
    echo "<INPUT NAME=id TYPE=hidden VALUE=\"$course->id\">";
    echo "</FORM>";
    echo "</TD></TR></TABLE>";
}


function forum_count_discussion_replies($forum="0") {
// Returns an array of counts of replies to each discussion (optionally in one forum)
    if ($forum) {
        $forumselect = " AND d.forum = '$forum'";
    }
    return get_records_sql("SELECT p.discussion, (count(*)) as replies
                            FROM forum_posts p, forum_discussions d
                            WHERE p.parent > 0 AND p.discussion = d.id 
                            GROUP BY p.discussion");
}

function forum_count_unrated_posts($discussionid, $userid) {
// How many unrated posts are in the given discussion for a given user?
    if ($posts = get_record_sql("SELECT count(*) as num
                                 FROM forum_posts
                                 WHERE parent > 0 AND 
                                       discussion = '$discussionid' AND 
                                       user <> '$userid' ")) {

        if ($rated = get_record_sql("SELECT count(*) as num 
                                     FROM forum_posts p, forum_ratings r
                                     WHERE p.discussion = '$discussionid'
                                       AND p.id = r.post 
                                       AND r.user = '$userid'")) {
            $difference = $posts->num - $rated->num;
            if ($difference > 0) {
                return $difference;
            } else {
                return 0;    // Just in case there was a counting error
            }
        } else {
            return $posts->num;
        }
    } else {
        return 0;
    }
}


function forum_set_return() {
    global $CFG, $SESSION, $HTTP_REFERER;

    if (! isset($SESSION->fromdiscussion)) {
        // If the referer is NOT a login screen then save it.
        if (! strncasecmp("$CFG->wwwroot/login", $HTTP_REFERER, 300)) {
            $SESSION->fromdiscussion = $HTTP_REFERER;
            save_session("SESSION");
        }
    }
}


function forum_go_back_to($default) {
    global $SESSION;

    if ($SESSION->fromdiscussion) {
        $returnto = $SESSION->fromdiscussion;
        unset($SESSION->fromdiscussion);
        save_session("SESSION");
        return $returnto;
    } else {
        return $default;
    }
}

function forum_get_post_full($postid) {
    return get_record_sql("SELECT p.*, u.firstname, u.lastname, 
                                  u.email, u.picture, u.id as userid
                           FROM forum_posts p, user u 
                           WHERE p.id = '$postid' AND p.user = u.id");
}

function forum_file_area_name($post) {
//  Creates a directory file name, suitable for make_upload_directory()
    global $CFG;

    return "$post->course/$CFG->moddata/forum/$post->forum/$post->id";
}

function forum_file_area($post) {
    return make_upload_directory( forum_file_area_name($post) );
}

function forum_delete_old_attachments($post, $exception="") {
// Deletes all the user files in the attachments area for a post
// EXCEPT for any file named $exception

    if ($basedir = forum_file_area($post)) {
        if ($files = get_directory_list($basedir)) {
            foreach ($files as $file) {
                if ($file != $exception) {
                    unlink("$basedir/$file");
                    notify("Existing file '$file' has been deleted!");
                }
            }
        }
        if (!$exception) {  // Delete directory as well, if empty
            rmdir("$basedir");
        }
    }
}

function forum_print_attachments($post, $return=NULL) {
// if return=html, then return a html string.
// if return=text, then return a text-only string.
// otherwise, print HTML

    global $CFG;

    $filearea = forum_file_area_name($post);

    if ($basedir = forum_file_area($post)) {
        if ($files = get_directory_list($basedir)) {
            $strattachment = get_string("attachment", "forum");
            foreach ($files as $file) {
                $icon = mimeinfo("icon", $file);
                if ($CFG->slasharguments) {
                    $ffurl = "file.php/$filearea/$file";
                } else {
                    $ffurl = "file.php?file=/$filearea/$file";
                }
                $image = "<IMG BORDER=0 SRC=\"$CFG->wwwroot/files/pix/$icon\" HEIGHT=16 WIDTH=16 ALT=\"File\">";

                if ($return == "html") {
                    $output .= "<A HREF=\"$CFG->wwwroot/$ffurl\">$image</A> ";
                    $output .= "<A HREF=\"$CFG->wwwroot/$ffurl\">$file</A><BR>";

                } else if ($return == "text") {
                    $output .= "$strattachment $file:\n$CFG->wwwroot/$ffurl\n";

                } else {
                    link_to_popup_window("/$ffurl", "attachment", $image, 500, 500, $strattachment);
                    echo "<A HREF=\"$CFG->wwwroot/$ffurl\">$file</A>";
                    echo "<BR>";
                }
            }
        }
    }
    if ($return) {
        return $output;
    }
}

function forum_add_attachment($post, $newfile) {
// $post is a full post record, including course and forum
// $newfile is a full upload array from HTTP_POST_FILES
// If successful, this function returns the name of the file

    if (!isset($newfile['name'])) {
        return "";
    }

    $newfile_name = clean_filename($newfile['name']);

    if (valid_uploaded_file($newfile)) {
        if (! $newfile_name) {
            notify("This file had a wierd filename and couldn't be uploaded");

        } else if (! $dir = forum_file_area($post)) {
            notify("Attachment could not be stored");
            $newfile_name = "";

        } else {
            if (move_uploaded_file($newfile['tmp_name'], "$dir/$newfile_name")) {
                forum_delete_old_attachments($post, $newfile_name);
            } else {
                notify("An error happened while saving the file on the server");
                $newfile_name = "";
            }
        }
    } else {
        $newfile_name = "";
    }

    return $newfile_name;
}

function forum_add_new_post($post) {

    $post->created = $post->modified = time();
    $post->mailed = "0";

    $newfile = $post->attachment;
    $post->attachment = "";

    if (! $post->id = insert_record("forum_posts", $post)) { 
        return false;
    }

    if ($post->attachment = forum_add_attachment($post, $newfile)) {
        set_field("forum_posts", "attachment", $post->attachment, "id", $post->id);
    }
    
    return $post->id;
}

function forum_update_post($post) {

    $post->modified = time();

    if (!$post->parent) {   // Post is a discussion starter - update discussion title too
        set_field("forum_discussions", "name", $post->subject, "id", $post->discussion);
    }
    if ($newfilename = forum_add_attachment($post, $post->attachment)) {
        $post->attachment = $newfilename;
    } else {
        unset($post->attachment);
    }
    return update_record("forum_posts", $post);
}

function forum_add_discussion($discussion) {
// Given an object containing all the necessary data, 
// create a new discussion and return the id

    GLOBAL $USER;

    $timenow = time();

    // The first post is stored as a real post, and linked 
    // to from the discuss entry.

    $post->discussion  = 0;
    $post->parent      = 0;
    $post->user        = $USER->id;
    $post->created     = $timenow;
    $post->modified    = $timenow;
    $post->mailed      = 0;
    $post->subject     = $discussion->name;
    $post->message     = $discussion->intro;
    $post->attachment  = "";
    $post->forum       = $discussion->forum;
    $post->course      = $discussion->course;

    if (! $post->id = insert_record("forum_posts", $post) ) {
        return 0;
    }

    if ($post->attachment = forum_add_attachment($post, $discussion->attachment)) {
        set_field("forum_posts", "attachment", $post->attachment, "id", $post->id); //ignore errors
    }

    // Now do the real module entry

    $discussion->firstpost    = $post->id;
    $discussion->timemodified = $timenow;

    if (! $discussion->id = insert_record("forum_discussions", $discussion) ) {
        delete_records("forum_posts", "id", $post->id);
        return 0;
    }

    // Finally, set the pointer on the post.
    if (! set_field("forum_posts", "discussion", $discussion->id, "id", $post->id)) {
        delete_records("forum_posts", "id", $post->id);
        delete_records("forum_discussions", "id", $discussion->id);
        return 0;
    }

    return $discussion->id;
}


function forum_delete_discussion($discussion) {
// $discussion is a discussion record object

    $result = true;

    if ($posts = get_records("forum_posts", "discussion", $discussion->id)) {
        foreach ($posts as $post) {
            $post->course = $discussion->course;
            $post->forum  = $discussion->forum;
            if (! delete_records("forum_ratings", "post", "$post->id")) {
                $result = false;
            }
            if (! forum_delete_post($post)) {
                $result = false;
            }
        }
    }

    if (! delete_records("forum_discussions", "id", "$discussion->id")) {
        $result = false;
    }

    return $result;
}


function forum_delete_post($post) {
   if (delete_records("forum_posts", "id", $post->id)) {
       delete_records("forum_ratings", "post", $post->id);  // Just in case
       if ($post->attachment) {
           $discussion = get_record("forum_discussions", "id", $post->discussion);
           $post->course = $discussion->course;
           $post->forum  = $discussion->forum;
           forum_delete_old_attachments($post);
       }
       return true;
   }
   return false;
}


function forum_print_user_discussions($courseid, $userid) {
    global $CFG, $USER;

    $discussions = get_records_sql("SELECT p.*, u.firstname, u.lastname, u.email, u.picture, 
                                           u.id as userid, f.type as forumtype, f.name as forumname, f.id as forumid
                                    FROM forum_discussions d, forum_posts p, user u, forum f
                                    WHERE d.course = '$courseid' AND p.discussion = d.id AND 
                                          p.parent = 0 AND p.user = u.id AND u.id = '$userid' AND
                                          d.forum = f.id
                                    ORDER BY p.created ASC");
    
    if ($discussions) {
        $user = get_record("user", "id", $userid);
        echo "<HR>";
        print_heading( get_string("discussionsstartedby", "forum", "$user->firstname $user->lastname") );
        $replies = forum_count_discussion_replies();
        foreach ($discussions as $discussion) {
            if (($discussion->forumtype == "teacher") and !isteacher($courseid)) {
                continue;
            }
            if ($replies[$discussion->discussion]) {
                $discussion->replies = $replies[$discussion->discussion]->replies;
            } else {
                $discussion->replies = 0;
            }
            $inforum = get_string("inforum", "forum", "<A HREF=\"$CFG->wwwroot/mod/forum/view.php?f=$discussion->forumid\">$discussion->forumname</A>");
            $discussion->subject .= " ($inforum)";
            $ownpost = ($discussion->userid == $USER->id);
            forum_print_post($discussion, $courseid, $ownpost, $reply=0, $link=1, $assessed=false);
            echo "<BR>\n";
        }
    }
}


function forum_user_outline($course, $user, $mod, $forum) {

    if ($posts = get_records_sql("SELECT p.*, u.id as userid, u.firstname, u.lastname, u.email, u.picture
                                  FROM forum f, forum_discussions d, forum_posts p, user u 
                                  WHERE f.id = '$forum->id' AND d.forum = f.id AND p.discussion = d.id
                                  AND p.user = '$user->id' AND p.user = u.id
                                  ORDER BY p.modified ASC")) {

        $result->info = get_string("numposts", "forum", count($posts));

        $lastpost = array_pop($posts);
        $result->time = $lastpost->modified;
        return $result;
    }
    return NULL;
}


function forum_user_complete($course, $user, $mod, $forum) {
    global $CFG;

    if ($posts = get_records_sql("SELECT p.*, u.id as userid, u.firstname, u.lastname, u.email, u.picture
                                  FROM forum f, forum_discussions d, forum_posts p, user u 
                                  WHERE f.id = '$forum->id' AND d.forum = f.id AND p.discussion = d.id
                                  AND p.user = '$user->id' AND p.user = u.id
                                  ORDER BY p.modified ASC")) {

        foreach ($posts as $post) {
            if ($post->parent) {
                $footer = "<A HREF=\"$CFG->wwwroot/mod/forum/discuss.php?d=$post->discussion&parent=$post->parent\">".
                           get_string("parentofthispost", "forum")."</A>";
            } else {
                $footer = "";
            }

            forum_print_post($post, $course->id, $ownpost=false, $reply=false, $link=false, $rate=false, $footer);
        }

    } else {
        echo "<P>".get_string("noposts", "forum")."</P>";
    }

}


function forum_add_instance($forum) {
// Given an object containing all the necessary data, 
// (defined by the form in mod.html) this function 
// will create a new instance and return the id number 
// of the new instance.

    global $CFG;

    $forum->timemodified = time();

    if (! $forum->id = insert_record("forum", $forum)) {
        return false;
    }

    if ($forum->type == "single") {  // Create related discussion.

        $discussion->course   = $forum->course;
        $discussion->forum    = $forum->id;
        $discussion->name     = $forum->name;
        $discussion->intro    = $forum->intro;
        $discussion->assessed = $forum->assessed;

        if (! forum_add_discussion($discussion)) {
            error("Could not add the discussion for this forum");
        }
    }
    add_to_log($forum->course, "forum", "add", "index.php?f=$forum->id", "$forum->id");

    return $forum->id;
}


function forum_update_instance($forum) {
// Given an object containing all the necessary data, 
// (defined by the form in mod.html) this function 
// will update an existing instance with new data.

    $forum->timemodified = time();
    $forum->id = $forum->instance;

    if ($forum->type == "single") {  // Update related discussion and post.
        if (! $discussion = get_record("forum_discussions", "forum", $forum->id)) {
            if ($discussions = get_records("forum_discussions", "forum", $forum->id, "timemodified ASC")) {
                notify("Warning! There is more than one discussion in this forum - using the most recent");
                $discussion = array_pop($discussions);
            } else {
                error("Could not find the discussion in this forum");
            }
        }
        if (! $post = get_record("forum_posts", "id", $discussion->firstpost)) {
            error("Could not find the first post in this forum discussion");
        }

        $post->subject  = $forum->name;
        $post->message  = $forum->intro;
        $post->modified = $forum->timemodified;

        if (! update_record("forum_posts", $post)) {
            error("Could not update the first post");
        }

        $discussion->name = $forum->name;

        if (! update_record("forum_discussions", $discussion)) {
            error("Could not update the discussion");
        }
    }

    if (update_record("forum", $forum)) {
        add_to_log($forum->course, "forum", "update", "index.php?f=$forum->id", "$forum->id");
        return true;
    } else {
        return false;
    }
}


function forum_delete_instance($id) {
// Given an ID of an instance of this module, 
// this function will permanently delete the instance 
// and any data that depends on it.  

    if (! $forum = get_record("forum", "id", "$id")) {
        return false;
    }

    $result = true;

    if ($discussions = get_records("forum_discussions", "forum", $forum->id)) {
        foreach ($discussions as $discussion) {
            if (! forum_delete_discussion($discussion)) {
                $result = false;
            }
        }
    }

    if (! delete_records("forum_subscriptions", "forum", "$forum->id")) {
        $result = false;
    }

    if (! delete_records("forum", "id", "$forum->id")) {
        $result = false;
    }

    return $result;
}


function forum_cron () {
// Function to be run periodically according to the moodle cron
// Finds all posts that have yet to be mailed out, and mails them

    global $CFG, $USER;

    $cutofftime = time() - $CFG->maxeditingtime;

    if ($posts = get_records_sql("SELECT p.*, d.course FROM forum_posts p, forum_discussions d
                                  WHERE p.mailed = '0' AND p.created < '$cutofftime' AND p.discussion = d.id")) {

        $timenow = time();

        foreach ($posts as $post) {

            print_string("processingpost", "forum", $post->id);
            echo " ... ";

            if (! $userfrom = get_record("user", "id", "$post->user")) {
                echo "Could not find user $post->user\n";
                continue;
            }

            if (! $discussion = get_record("forum_discussions", "id", "$post->discussion")) {
                echo "Could not find discussion $post->discussion\n";
                continue;
            }

            if (! $forum = get_record("forum", "id", "$discussion->forum")) {
                echo "Could not find forum $discussion->forum\n";
                continue;
            }

            if (! $course = get_record("course", "id", "$forum->course")) {
                echo "Could not find course $forum->course\n";
                continue;
            }

            if ($users = forum_subscribed_users($course, $forum)) {
                $canunsubscribe = ! forum_is_forcesubscribed($forum->id);

                $mailcount=0;
                foreach ($users as $userto) {
                    $USER->lang = $userto->lang;  // Affects the language of get_string


                    $by->name = "$userfrom->firstname $userfrom->lastname";
                    $by->date = userdate($post->created, "", $userto->timezone);
                    $strbynameondate = get_string("bynameondate", "forum", $by);

                    $strforums = get_string("forums", "forum");

                    $postsubject = "$course->shortname: $post->subject";
                    $posttext  = "$course->shortname -> $strforums -> $forum->name";

                    if ($discussion->name == $forum->name) {
                        $posttext  .= "\n";
                    } else {
                        $posttext  .= " -> $discussion->name\n";
                    }
                    $posttext .= "---------------------------------------------------------------------\n";
                    $posttext .= "$post->subject\n";
                    $posttext .= $strbynameondate."\n";
                    $posttext .= "---------------------------------------------------------------------\n";
                    $posttext .= strip_tags($post->message);
                    $posttext .= "\n\n";
                    if ($post->attachment) {
                        $post->course = $course->id;
                        $post->forum = $forum->id;
                        $posttext .= forum_print_attachments($post, "text");
                    }
                    $posttext .= "---------------------------------------------------------------------\n";
                    $posttext .= get_string("postmailinfo", "forum", $course->shortname)."\n";
                    $posttext .= "$CFG->wwwroot/mod/forum/post.php?reply=$post->id\n";
                    if ($canunsubscribe) {
                        $posttext .= "\n---------------------------------------------------------------------\n";
                        $posttext .= get_string("unsubscribe", "forum");
                        $posttext .= ": $CFG->wwwroot/mod/forum/subscribe.php?id=$forum->id\n";
                    }
  
                    if ($userto->mailformat == 1) {  // HTML
                        $posthtml = "<P><FONT FACE=sans-serif>".
                        "<A HREF=\"$CFG->wwwroot/course/view.php?id=$course->id\">$course->shortname</A> -> ".
                        "<A HREF=\"$CFG->wwwroot/mod/forum/index.php?id=$course->id\">$strforums</A> -> ".
                        "<A HREF=\"$CFG->wwwroot/mod/forum/view.php?f=$forum->id\">$forum->name</A>";
                        if ($discussion->name == $forum->name) {
                            $posthtml .= "</FONT></P>";
                        } else {
                            $posthtml .= " -> <A HREF=\"$CFG->wwwroot/mod/forum/discuss.php?d=$discussion->id\">$discussion->name</A></FONT></P>";
                        }
                        $posthtml .= forum_make_mail_post($post, $userfrom, $userto, $course, false, true, false, false);

                        if ($canunsubscribe) {
                            $posthtml .= "\n<BR><HR SIZE=1 NOSHADE><P ALIGN=RIGHT><FONT SIZE=1><A HREF=\"$CFG->wwwroot/mod/forum/subscribe.php?id=$forum->id\">".get_string("unsubscribe", "forum")."</A></FONT></P>";
                        }

                    } else {
                      $posthtml = "";
                    }
   
                    if (! email_to_user($userto, $userfrom, $postsubject, $posttext, $posthtml)) {
                        echo "Error: mod/forum/cron.php: Could not send out mail for id $post->id to user $userto->id ($userto->email)\n";
                    } else {
                        $mailcount++;
                    }
                }
                echo "mailed to $mailcount users ...";
            }

            if (! set_field("forum_posts", "mailed", "1", "id", "$post->id")) {
                echo "Could not update the mailed field for id $post->id\n";
            }
            echo "\n";
        }
    }

    return true;
}


function forum_forcesubscribe($forumid, $value=1) {
    return set_field("forum", "forcesubscribe", $value, "id", $forumid);
}

function forum_is_forcesubscribed($forumid) {
    return get_field("forum", "forcesubscribe", "id", $forumid);
}

function forum_is_subscribed($userid, $forumid) {
    if (forum_is_forcesubscribed($forumid)) {
        return true;
    }
    return record_exists_sql("SELECT * FROM forum_subscriptions WHERE user='$userid' AND forum='$forumid'");
}

function forum_subscribed_users($course, $forum) {
// Returns list of user objects that are subscribed to this forum

    if ($course->category) {   // normal course
        if ($forum->forcesubscribe) {
            return get_course_users($course->id);
        }
    }
    return get_records_sql("SELECT u.* FROM user u, forum_subscriptions s
                            WHERE s.forum = '$forum->id'
                              AND s.user = u.id AND u.deleted <> '1'");
}

function forum_subscribe($userid, $forumid) {
    global $db;

    return $db->Execute("INSERT INTO forum_subscriptions SET user = '$userid', forum = '$forumid'");
}

function forum_unsubscribe($userid, $forumid) {
    global $db;

    return $db->Execute("DELETE FROM forum_subscriptions WHERE user = '$userid' AND forum = '$forumid'");
}


function forum_user_has_posted_discussion($forumid, $userid) {
    if ($discussions = forum_get_discussions($forumid, "DESC", $userid)) {
        return true;
    } else {
        return false;
    }
}

function forum_user_can_post_discussion($forum) {
// $forum is an object
    global $USER;

    if ($forum->type == "eachuser") {
        return (! forum_user_has_posted_discussion($forum->id, $USER->id));
    } else if ($forum->type == "teacher") {
        return isteacher($forum->course);
    } else if (isteacher($forum->course)) {
        return true;
    } else {
        return $forum->open;
    }
}


function forum_get_discussions($forum="0", $forum_sort="DESC", $user=0) {
    if ($user) {
        $userselect = " AND u.id = '$user' ";
    } else {
        $userselect = "";
    }
    return get_records_sql("SELECT p.*, u.firstname, u.lastname, u.email, u.picture, u.id as userid
                            FROM forum_discussions d, forum_posts p, user u 
                            WHERE d.forum = '$forum' AND p.discussion = d.id AND 
                                  p.parent= 0 AND p.user = u.id $userselect
                            ORDER BY p.created $forum_sort");
}



function forum_print_latest_discussions($forum_id=0, $forum_numdiscussions=5, $forum_style="plain", $forum_sort="DESC") {
    global $CFG, $USER, $FORUM_MANY_DISCUSSIONS;
    
    if ($forum_id) {
        if (! $forum = get_record("forum", "id", $forum_id)) {
            error("Forum ID was incorrect");
        }
        if (! $course = get_record("course", "id", $forum->course)) {
            error("Could not find the course this forum belongs to!");
        }

        if ($course->category) {
            require_login($course->id);
        }

    } else {
        if (! $course = get_record("course", "category", 0)) {
            error("Could not find a top-level course!");
        }
        if (! $forum = forum_get_course_news_forum($course->id)) {
            error("Could not find or create a main forum in this course (id $course->id)");
        }
    }

    if (forum_user_can_post_discussion($forum)) {
        echo "<P ALIGN=CENTER>";
        echo "<A HREF=\"$CFG->wwwroot/mod/forum/post.php?forum=$forum->id\">";
        echo get_string("addanewdiscussion", "forum")."</A>...";
        echo "</P>\n";
    }

    if (! $discussions = forum_get_discussions($forum->id, $forum_sort) ) {
        echo "<P ALIGN=CENTER><B>(".get_string("nodiscussions", "forum").")</B></P>";
        return;

    }
    
    if ((!$forum_numdiscussions) && ($forum_style == "plain") && (count($discussions) > $FORUM_MANY_DISCUSSIONS) ) { 
        $forum_style = "header";  // Abbreviate display if it's going to be long.
    }

    $replies = forum_count_discussion_replies($forum->id);

    $discussioncount = 0;

    foreach ($discussions as $discussion) {
        $discussioncount++;

        if ($forum_numdiscussions && ($discussioncount > $forum_numdiscussions)) {
            echo "<P ALIGN=right><A HREF=\"$CFG->wwwroot/mod/forum/view.php?f=$forum->id\">";
            echo get_string("olderdiscussions", "forum")."</A> ...</P>";
            break;
        }
        if ($replies[$discussion->discussion]) {
            $discussion->replies = $replies[$discussion->discussion]->replies;
        } else {
            $discussion->replies = 0;
        }
        $ownpost = ($discussion->userid == $USER->id);
        switch ($forum_style) {
            case "minimal":
                echo "<P><FONT COLOR=#555555>".userdate($discussion->modified, "%e %b, %H:%M")." - $discussion->firstname</FONT>";
                echo "<BR>$discussion->subject ";
                echo "<A HREF=\"$CFG->wwwroot/mod/forum/discuss.php?d=$discussion->discussion\">";
                echo get_string("more", "forum")."...</A>";
                echo "</P>\n";
            break;
            case "header":
                forum_print_post_header($discussion, $forum->course, $ownpost, $reply=0, $link=1, $assessed=false);
            break;
            default:
                forum_print_post($discussion, $forum->course, $ownpost, $reply=0, $link=1, $assessed=false);
                echo "<BR>\n";
            break;
        }
    }
}

function forum_print_discussion($course, $forum, $discussion, $post, $mode) {

    global $USER;

    $ownpost = ($USER->id == $post->user);

    forum_print_post($post, $course->id, $ownpost, $reply=true, $link=false, $rate=false);

    forum_print_mode_form($discussion->id, $mode);

    $ratingform = false;
    if ($forum->assessed && $USER->id) {
        $unrated = forum_count_unrated_posts($discussion->id, $USER->id);
        if ($unrated > 0) {
            $ratingform = true;
        }
    }

    if ($ratingform) {
        echo "<FORM NAME=form METHOD=POST ACTION=rate.php>";
        echo "<INPUT TYPE=hidden NAME=id VALUE=\"$course->id\">";
    }

    switch ($mode) {
        case 1 :   // Flat ascending
        case -1 :  // Flat descending
        default:   
            echo "<UL>";
            forum_print_posts_flat($post->discussion, $course->id, $mode, $forum->assessed);
            echo "</UL>";
            break;

        case 2 :   // Threaded 
            forum_print_posts_threaded($post->id, $course->id, 0, $forum->assessed);
            break;

        case 3 :   // Nested
            forum_print_posts_nested($post->id, $course->id, $forum->assessed);
            break;
    }

    if ($ratingform) {
        echo "<CENTER><P ALIGN=center><INPUT TYPE=submit VALUE=\"".get_string("sendinratings", "forum")."\">";
        helpbutton("ratings", get_string("separateandconnected"), "forum");
        echo "</P></CENTER>";
        echo "</FORM>";
    }
}

function forum_print_posts_flat($discussion, $course, $direction, $assessed) { 
    global $USER;

    $reply = true;
    $link  = false;

    if ($direction < 0) {
        $sort = "ORDER BY created DESC";
    } else {
        $sort = "ORDER BY created ASC";
    }

    if ($posts = get_records_sql("SELECT p.*, u.id as userid, u.firstname, u.lastname, u.email, u.picture
                                  FROM forum_posts p, user u
                                  WHERE p.discussion = $discussion AND p.parent > 0 AND p.user = u.id $sort")) {

        foreach ($posts as $post) {
            $ownpost = ($USER->id == $post->user);
            forum_print_post($post, $course, $ownpost, $reply, $link, $assessed);
        }
    } else {
        return;
    }
}

function forum_print_posts_threaded($parent, $course, $depth, $assessed) { 
    global $USER;

    $reply = true;
    $link  = false;

    if ($posts = get_records_sql("SELECT p.*, u.id as userid, u.firstname, u.lastname, u.email, u.picture
                                  FROM forum_posts p, user u
                                  WHERE p.parent = '$parent' AND p.user = u.id")) {

        foreach ($posts as $post) {

            echo "<UL>";
            if ($depth > 0) {
                $ownpost = ($USER->id == $post->user);
                forum_print_post($post, $course, $ownpost, $reply, $link, $assessed);  // link=true?
                echo "<BR>";
            } else {
                $by->name = "$post->firstname $post->lastname";
                $by->date = userdate($post->created);
                echo "<LI><P><FONT SIZE=-1><B><A HREF=\"discuss.php?d=$post->discussion&parent=$post->id\">$post->subject</A></B> ";
                print_string("bynameondate", "forum", $by);
                echo "</FONT></P></LI>";
            }

            forum_print_posts_threaded($post->id, $course, $depth-1, $assessed);
            echo "</UL>\n";
        }
    } else {
        return;
    }
}

function forum_print_posts_nested($parent, $course, $assessed) { 
    global $USER;

    $reply = true;
    $link  = false;

    if ($posts = get_records_sql("SELECT p.*, u.id as userid, u.firstname, u.lastname, u.email, u.picture
                                  FROM forum_posts p, user u
                                  WHERE p.parent = $parent AND p.user = u.id
                                  ORDER BY p.created ASC ")) {

        foreach ($posts as $post) {

            $ownpost = ($USER->id == $post->user);

            echo "<UL>";
            forum_print_post($post, $course, $ownpost, $reply, $link, $assessed);
            echo "<BR>";
            forum_print_posts_nested($post->id, $course, $assessed);
            echo "</UL>\n";
        }
    } else {
        return;
    }
}

function forum_set_display_mode($mode=0) {
    global $USER, $FORUM_DEFAULT_DISPLAY_MODE;

    if ($mode) {
        $USER->mode = $mode;
        save_session("USER");
    } else if (!$USER->mode) {
        $USER->mode = $FORUM_DEFAULT_DISPLAY_MODE;
        save_session("USER");
    }
}

function forum_print_recent_activity(&$logs, $isteacher=false) {
    global $CFG, $COURSE_TEACHER_COLOR;

    $heading = false;
    $content = false;

    foreach ($logs as $log) {
        if ($log->module == "forum") {
            $post = NULL;

            if ($log->action == "add post") {
                $post = get_record_sql("SELECT p.*, d.forum, u.firstname, u.lastname, 
                                               u.email, u.picture, u.id as userid
                                        FROM forum_discussions d, forum_posts p, user u 
                                        WHERE p.id = '$log->info' AND d.id = p.discussion 
                                        AND p.user = u.id and u.deleted <> '1'");

            } else if ($log->action == "add discussion") {
                $post = get_record_sql("SELECT p.*, d.forum, u.firstname, u.lastname, 
                                               u.email, u.picture, u.id as userid
                                        FROM forum_discussions d, forum_posts p, user u 
                                        WHERE d.id = '$log->info' AND d.firstpost = p.id 
                                        AND p.user = u.id and u.deleted <> '1'");
            }

            if ($post) {
                $teacherpost = "";
                if ($forum = get_record("forum", "id", $post->forum) ) {
                    if ($forum->type == "teacher") {
                        if ($isteacher) {
                            $teacherpost = "COLOR=$COURSE_TEACHER_COLOR";
                        } else {
                            continue;
                        }
                    }
                }
                if (! $heading) {
                    print_headline(get_string("newforumposts", "forum").":");
                    $heading = true;
                    $content = true;
                }
                $date = userdate($post->modified, "%e %b, %H:%M");
                echo "<P><FONT SIZE=1 $teacherpost>$date - $post->firstname $post->lastname<BR>";
                echo "\"<A HREF=\"$CFG->wwwroot/mod/forum/$log->url\">";
                if ($log->action == "add") {
                    echo "<B>$post->subject</B>";
                } else {
                    echo "$post->subject";
                }
                echo "</A>\"</FONT></P>";
            }
        }
    }
    return $content;
}

?>