Index: lib/db/install.xml
===================================================================
RCS file: /cvsroot/moodle/moodle/lib/db/install.xml,v
retrieving revision 1.135.2.16
diff -u -r1.135.2.16 install.xml
--- lib/db/install.xml	8 Sep 2009 09:06:15 -0000	1.135.2.16
+++ lib/db/install.xml	14 Dec 2009 12:09:37 -0000
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" ?>
-<XMLDB PATH="lib/db" VERSION="20090904" COMMENT="XMLDB file for core Moodle tables"
+<XMLDB PATH="lib/db" VERSION="20091212" COMMENT="XMLDB file for core Moodle tables"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:noNamespaceSchemaLocation="../../lib/xmldb/xmldb.xsd"
 >
@@ -1652,7 +1652,7 @@
         <INDEX NAME="courseid-name" UNIQUE="true" FIELDS="courseid, name"/>
       </INDEXES>
     </TABLE>
-    <TABLE NAME="webdav_locks" COMMENT="Resource locks for WebDAV users" PREVIOUS="grade_settings">
+    <TABLE NAME="webdav_locks" COMMENT="Resource locks for WebDAV users" PREVIOUS="grade_settings" NEXT="friend">
       <FIELDS>
         <FIELD NAME="id" TYPE="int" LENGTH="10" NOTNULL="true" UNSIGNED="true" SEQUENCE="true" ENUM="false" NEXT="token"/>
         <FIELD NAME="token" TYPE="char" LENGTH="255" NOTNULL="true" SEQUENCE="false" ENUM="false" PREVIOUS="id" NEXT="path"/>
@@ -1674,6 +1674,25 @@
         <INDEX NAME="expiry" UNIQUE="false" FIELDS="expiry" PREVIOUS="path"/>
       </INDEXES>
     </TABLE>
+    <TABLE NAME="friend" COMMENT="Main friends table" PREVIOUS="webdav_locks">
+      <FIELDS>
+        <FIELD NAME="id" TYPE="int" LENGTH="10" NOTNULL="true" UNSIGNED="true" SEQUENCE="true" ENUM="false" NEXT="userid1"/>
+        <FIELD NAME="userid1" TYPE="int" LENGTH="10" NOTNULL="true" UNSIGNED="true" SEQUENCE="false" ENUM="false" PREVIOUS="id" NEXT="userid2"/>
+        <FIELD NAME="userid2" TYPE="int" LENGTH="10" NOTNULL="true" UNSIGNED="true" SEQUENCE="false" ENUM="false" PREVIOUS="userid1" NEXT="status"/>
+        <FIELD NAME="status" TYPE="int" LENGTH="1" NOTNULL="true" UNSIGNED="true" DEFAULT="0" SEQUENCE="false" ENUM="false" PREVIOUS="userid2" NEXT="created"/>
+        <FIELD NAME="created" TYPE="int" LENGTH="10" NOTNULL="true" UNSIGNED="true" DEFAULT="0" SEQUENCE="false" ENUM="false" PREVIOUS="status" NEXT="message"/>
+        <FIELD NAME="message" TYPE="char" LENGTH="255" NOTNULL="false" SEQUENCE="false" ENUM="false" PREVIOUS="created"/>
+      </FIELDS>
+      <KEYS>
+        <KEY NAME="primary" TYPE="primary" FIELDS="id" NEXT="userid1"/>
+        <KEY NAME="userid1" TYPE="foreign" FIELDS="userid1" REFTABLE="user" REFFIELDS="id" PREVIOUS="primary" NEXT="userid2"/>
+        <KEY NAME="userid2" TYPE="foreign" FIELDS="userid2" REFTABLE="user" REFFIELDS="id" PREVIOUS="userid1"/>
+      </KEYS>
+      <INDEXES>
+        <INDEX NAME="created" UNIQUE="false" FIELDS="created" NEXT="status"/>
+        <INDEX NAME="status" UNIQUE="false" FIELDS="status" PREVIOUS="created"/>
+      </INDEXES>
+    </TABLE>
   </TABLES>
   <STATEMENTS>
     <STATEMENT NAME="insert mnet_application" TYPE="insert" TABLE="mnet_application" COMMENT="Initial insert of records on table mnet_application" NEXT="insert log_display">
Index: lib/db/upgrade.php
===================================================================
RCS file: /cvsroot/moodle/moodle/lib/db/upgrade.php,v
retrieving revision 1.154.2.67
diff -u -r1.154.2.67 upgrade.php
--- lib/db/upgrade.php	26 Nov 2009 06:48:43 -0000	1.154.2.67
+++ lib/db/upgrade.php	14 Dec 2009 12:06:04 -0000
@@ -3291,6 +3291,34 @@
         upgrade_main_savepoint($result, 2007101563.03);
     }
 
+    if ($result && $oldversion < 2007101563.04) {
+    // add the new "friends" table
+
+    /// Define table friend to be created
+        $table = new XMLDBTable('friend');
+
+    /// Adding fields to table friend
+        $table->addFieldInfo('id', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, XMLDB_SEQUENCE, null, null, null);
+        $table->addFieldInfo('userid1', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, null, null, null, null);
+        $table->addFieldInfo('userid2', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, null, null, null, null);
+        $table->addFieldInfo('status', XMLDB_TYPE_INTEGER, '1', XMLDB_UNSIGNED, XMLDB_NOTNULL, null, null, null, '0');
+        $table->addFieldInfo('created', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, null, null, null, '0');
+        $table->addFieldInfo('message', XMLDB_TYPE_CHAR, '255', null, null, null, null, null, null);
+
+    /// Adding keys to table friend
+        $table->addKeyInfo('primary', XMLDB_KEY_PRIMARY, array('id'));
+        $table->addKeyInfo('userid1', XMLDB_KEY_FOREIGN, array('userid1'), 'user', array('id'));
+        $table->addKeyInfo('userid2', XMLDB_KEY_FOREIGN, array('userid2'), 'user', array('id'));
+
+    /// Adding indexes to table friend
+        $table->addIndexInfo('created', XMLDB_INDEX_NOTUNIQUE, array('created'));
+        $table->addIndexInfo('status', XMLDB_INDEX_NOTUNIQUE, array('status'));
+
+    /// Launch create table for friend
+        $result = $result && create_table($table);
+
+        upgrade_main_savepoint($result, 2007101563.04);
+    }    
     return $result;
 }
 
Index: user/tabs.php
===================================================================
RCS file: /cvsroot/moodle/moodle/user/tabs.php,v
retrieving revision 1.43.2.8
diff -u -r1.43.2.8 tabs.php
--- user/tabs.php	19 Dec 2008 01:44:48 -0000	1.43.2.8
+++ user/tabs.php	14 Dec 2009 11:53:36 -0000
@@ -268,6 +268,12 @@
             }
         }
     }
+	
+// Friends tab
+    if (!empty($user)) { // and (!empty($CFG->enablefriends))
+        $toprow[] = new tabobject('friends', $CFG->wwwroot.'/friends/view.php?userid='.$user->id.'&amp;courseid='.$course->id, get_string('friends', 'friends'));
+    }	
+	
 /// Add second row to display if there is one
 
     if (!empty($secondrow)) {
Index: user/view.php
===================================================================
RCS file: /cvsroot/moodle/moodle/user/view.php,v
retrieving revision 1.168.2.28
diff -u -r1.168.2.28 view.php
--- user/view.php	2 Oct 2009 06:28:06 -0000	1.168.2.28
+++ user/view.php	14 Dec 2009 11:54:42 -0000
@@ -532,6 +532,18 @@
         echo "</div>";
         echo "</form>";
     }
+
+	// Add as friend button
+	if (!empty($USER->id) and ($USER->id != $user->id)) {
+		echo "<form action=\"../friends/add.php\" method=\"get\">";
+		echo "<div>";
+        echo "<input type=\"hidden\" name=\"courseid\" value=\"$course->id\" />";
+        echo "<input type=\"hidden\" name=\"userid\" value=\"$user->id\" />";
+        echo "<input type=\"submit\" value=\"".get_string("addfriend", "friends")."\" />";
+		echo "</div>";
+		echo "</form>";
+	}
+
     echo "</div>\n";
 
     if ($CFG->debugdisplay && debugging('', DEBUG_DEVELOPER) && $USER->id == $user->id) {  // Show user object
--- friends/add.php
+++ friends/add.php
@@ -0,0 +1,126 @@
+<?php
+
+/**
+ * Friends - add.php - confirm (asking for message) and add a user
+ *
+ * @copyright 2009 Ariel Martini
+ * @licence http://www.gnu.org/copyleft/gpl.html GNU Public License
+ *
+ */
+
+
+require_once('../config.php');
+require_once('lib.php');
+require_once('locallib.php');
+require_once('add_form.php');
+
+require_login();
+
+// if (empty($CFG->enablefriends)) { print_error('friendsaredisabled', 'friends'); }
+
+$userid = optional_param('userid', 0, PARAM_INT);
+$courseid = optional_param('courseid', SITEID, PARAM_INT); // needed for user tabs and course tracking
+
+$friendsstring = get_string('addfriend', 'friends');
+$navlinks = array();
+
+if (!empty($userid)) {
+    $user = get_record('user', 'id', $userid);
+    $course = get_record('course', 'id', $courseid);
+
+    $a = fullname($user);
+    $title = get_string('requestfriendship', 'friends', $a);
+
+    $navlinks[] = array('name' => fullname($user),
+                        'link' => "$CFG->wwwroot/user/view.php?id=$userid&amp;course=$courseid",
+                        'type' => 'misc');
+    $navlinks[] = array('name' => $title, 'link' => null, 'type' => 'misc');
+    $navigation = build_navigation($navlinks);
+    print_header("$course->shortname: $friendsstring", $course->fullname,
+                 $navigation, "", "", true, "&nbsp;", navmenu($course));
+
+    $currenttab = 'friends';
+    $showroles = 1;
+    include('../user/tabs.php');
+}
+else {
+    $title = get_string('friends', 'friends');
+    $navlinks[] = array('name' => $title, 'link' => null, 'type' => 'misc');
+    $navigation = build_navigation($navlinks);
+    print_header_simple(get_string('friends', 'friends'), '', $navigation);
+}
+
+$friendform = new friends_add_form();
+
+// If new data has been sent, add friend request
+if ($newfriend = $friendform->get_data()) {
+
+    friends_add($newfriend);
+
+    friends_print_message(get_string('friendshiprequested', 'friends'), 
+        $CFG->wwwroot.'/user/view.php?id='.$newfriend->userid2.'&course='.$newfriend->courseid,
+        get_string('return', 'friends'));
+    
+    print_footer();
+    return;
+}
+else {
+    $friends = friends_get_friends($USER->id, $user->id);
+    
+    if (!empty($friends)) {
+    
+        if (friends_exist_friend_status($friends, FRIENDS_STATUS_FRIEND)) {
+        
+            // Friendship already exist
+        
+            friends_print_message(get_string('alreadyfriends', 'friends'));
+            print_footer();
+            return;
+            
+        }
+        else {
+        
+            $friend = friends_get_friend_by_status($friends, FRIENDS_STATUS_NEW);
+        
+            if (!empty($friend)) {
+        
+            // Friendship request already exist
+        
+                if ($friend->userid1 == $user->id) { 
+                
+                    // The other user requested -> Confirm friendship
+
+                    $friend->status = FRIENDS_STATUS_FRIEND;
+                    friends_update($friend);
+                    
+                    friends_print_message(get_string('alreadyrequested', 'friends') . '<br />' . get_string('friendshipconfirmed', 'friends'));
+                
+                } else {
+
+                    // I requested -> Warn
+                    
+                    friends_print_message(get_string('alreadyrequested', 'friends') . ' ' . get_string('pleasewaitconfirmation', 'friends'));
+                }
+            
+                print_footer();
+                return;
+            }
+        }
+    }
+    
+    $newfriend = friends_create($USER->id, $user->id);
+    $newfriend->courseid = $courseid;
+
+    $friendform->set_data($newfriend);
+
+    print_heading($title, '', 2);
+
+    $friendform->display();
+
+    print_footer($course);
+}
+
+
+
+
+?>

--- friends/add_form.php
+++ friends/add_form.php
@@ -0,0 +1,44 @@
+<?php
+
+/**
+ * Friends - add_form.php - add.php form
+ *
+ * @copyright 2009 Ariel Martini
+ * @licence http://www.gnu.org/copyleft/gpl.html GNU Public License
+ *
+ */
+
+
+require_once($CFG->dirroot.'/lib/formslib.php');
+
+class friends_add_form extends moodleform {
+
+    function definition () {
+
+        $mform =& $this->_form;
+
+        $mform->addElement('header', 'friends', get_string('addfriend','friends'));
+        
+        $mform->addElement('hidden', 'userid1');
+        $mform->setType('userid1', PARAM_INT);
+
+        $mform->addElement('hidden', 'userid2');
+        $mform->setType('userid2', PARAM_INT);
+
+        $mform->addElement('hidden', 'courseid');
+        $mform->setType('courseid', PARAM_INT);
+
+        $mform->addElement('hidden', 'created');
+        $mform->setType('created', PARAM_INT);
+        
+        $systemcontext = get_context_instance(CONTEXT_SYSTEM);
+
+        $mform->addElement('textarea', 'message', get_string('introductionmessage', 'friends'), array('rows'=>5, 'cols'=>50));
+
+        $this->add_action_buttons(false, get_string('addfriend', 'friends'));
+
+    }
+
+}
+
+?>

--- friends/confirm.php
+++ friends/confirm.php
@@ -0,0 +1,58 @@
+<?php
+
+/**
+ * Friends confirm.php - update a friendship request to friendship link, 
+ * or delete a friendship request
+ *
+ * @copyright 2009 Ariel Martini
+ * @licence http://www.gnu.org/copyleft/gpl.html GNU Public License
+ *
+ */
+
+
+require_once('../config.php');
+require_once('lib.php');
+require_once('locallib.php');
+
+require_login();
+
+// if (empty($CFG->enablefriends)) { print_error('friendsaredisabled', 'friends'); }
+
+$userid = optional_param('userid', 0, PARAM_INT);
+$courseid = optional_param('courseid', SITEID, PARAM_INT); // needed for user tabs and course tracking
+
+$confirm = optional_param('confirm', 99, PARAM_INT);
+
+if (empty($userid) || empty($courseid) || $confirm == 99) {
+    print_error('Wrong parameters');
+}
+
+$friends = friends_get_friends($USER->id, $userid);
+$friend = friends_get_friend_by_status($friends, FRIENDS_STATUS_NEW);
+        
+if (empty($friend)) {
+    print_error('Friend record not found');
+}
+else {
+    if ($friend->userid1 != $userid) {
+        print_error('Wrong friendship status');
+    }
+    else {
+        // The other user requested -> Confirm or deny friendship
+
+        if ($confirm == 1) {
+            // Confirm
+            $friend->status = FRIENDS_STATUS_FRIEND;
+            friends_update($friend);
+        }
+        else {
+            // Deny (delete record)
+            friends_delete($friend);
+        }
+    }
+    
+    redirect($CFG->wwwroot.'/friends/view.php?courseid='.$courseid.'&userid='.$USER->id);
+}
+
+
+?>

--- friends/delete.php
+++ friends/delete.php
@@ -0,0 +1,106 @@
+<?php
+
+/**
+ * Friends delete.php - asks for confirmation and delete a friendship link, or a message
+ *
+ * @copyright 2009 Ariel Martini
+ * @licence http://www.gnu.org/copyleft/gpl.html GNU Public License
+ *
+ */
+
+
+require_once('../config.php');
+require_once('lib.php');
+require_once('locallib.php');
+
+require_login();
+
+// if (empty($CFG->enablefriends)) { print_error('friendsaredisabled', 'friends'); }
+
+$userid = optional_param('userid', 0, PARAM_INT);
+$messageid = optional_param('messageid', 0, PARAM_INT);
+$courseid = optional_param('courseid', SITEID, PARAM_INT); // needed for user tabs and course tracking
+
+$confirm = optional_param('confirm', 0, PARAM_INT); // if == 1 delete, else ask
+
+if (!empty($userid)) {
+    $friends = friends_get_friends($USER->id, $userid);
+    $friend = friends_get_friend_by_status($friends, FRIENDS_STATUS_FRIEND);
+    $deletingfriend = true;
+}
+else if (!empty($messageid)) {
+    $friend = get_record('friend', 'id', $messageid);
+    $deletingfriend = false;
+}
+
+if (empty($friend)) {
+    print_error('Friend record not found');
+}
+
+if ($deletingfriend) {
+    $whereiam = $USER->id; // home profile
+}
+else {
+    $whereiam = $friend->userid2; // recipient profile
+}
+
+if ($confirm == 1) {
+
+    // confirmed -> really delete
+
+    friends_delete($friend);
+    redirect($CFG->wwwroot.'/friends/view.php?courseid='.$courseid.'&userid='.$whereiam);
+    
+}
+else {
+
+    // not confirmed -> ask first
+
+    $targetuserid = $userid;
+    $userid = $whereiam;
+    $user = get_record('user', 'id', $userid);
+    $course = get_record('course', 'id', $courseid);
+
+    if ($deletingfriend) {
+        $title = get_string('delete', 'friends');
+    }
+    else { // deleting message
+        $title = get_string('deletemsg', 'friends');
+    }
+    $friendsstring = get_string('friends', 'friends');
+    $navlinks[] = array('name' => fullname($user),
+                        'link' => "$CFG->wwwroot/user/view.php?id=$USER->id&amp;course=$courseid",
+                        'type' => 'misc');
+    $navlinks[] = array('name' => $title, 'link' => null, 'type' => 'misc');
+    $navigation = build_navigation($navlinks);
+    print_header("$course->shortname: $friendsstring", $course->fullname,
+                 $navigation, "", "", true, "&nbsp;", navmenu($course));
+
+    $currenttab = 'friends';
+    $showroles = 1;
+    include('../user/tabs.php');
+
+    if ($deletingfriend) {
+        $targetuser = get_record('user', 'id', $targetuserid);
+        $a = fullname($targetuser);
+        $stringareyousure = get_string('deleteareyousure', 'friends', $a);
+        $deletelink = 'userid='.$targetuserid;
+        $deleteconfirm = get_string('deleteconfirm', 'friends');
+    }
+    else { // deleting message
+        $targetuser = get_record('user', 'id', $targetuserid);
+        $a = fullname($targetuser);
+        $stringareyousure = get_string('deletemsgareyousure', 'friends', $a);
+        $deletelink = 'messageid='.$messageid;
+        $deleteconfirm = get_string('deletemsgconfirm', 'friends');
+    }
+
+    friends_print_message($stringareyousure, 
+        'delete.php?'.$deletelink.'&courseid='.$courseid.'&confirm=1',
+        $deleteconfirm);
+    
+    print_footer();
+    return;
+}
+
+?>

--- friends/lib.php
+++ friends/lib.php
@@ -0,0 +1,165 @@
+<?php
+
+/**
+ * Library of interface functions and constants for module friends
+ *
+ * @copyright 2009 Ariel Martini
+ * @licence http://www.gnu.org/copyleft/gpl.html GNU Public License
+*/
+
+define('FRIENDS_STATUS_NEW', 0);
+define('FRIENDS_STATUS_FRIEND', 1);
+define('FRIENDS_STATUS_MESSAGE', 2);
+
+/**
+ * get all friends of the user in an array
+ *
+ * @param int $userid User we want to find the friends
+ * @param int $status Status of friendship
+ * @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set).
+ * @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
+ * @return array array of friends, or empty
+ */
+function friends_get_user_friends($userid, $status, $limitfrom='', $limitnum='') {
+    global $CFG;
+
+    $query = "SELECT fr.id friendid, usr.id userid, usr.picture, ".
+            "usr.firstname, usr.lastname, fr.message, fr.userid1, fr.userid2 ".
+            "FROM {$CFG->prefix}friend fr INNER JOIN {$CFG->prefix}user usr ".
+            "ON ((usr.id = fr.userid1 AND fr.userid2 = {$userid}) ".
+            "OR (usr.id = fr.userid2 AND fr.userid1 = {$userid})) ".
+            "WHERE fr.status = ".$status;
+
+    return get_records_sql($query, $limitfrom , $limitnum);
+}
+
+/**
+ * get all messages of the user in an array (only userid1 will be matched)
+ *
+ * @param int $userid User we want to find the friends
+ * @param int $status Status of friendship
+ * @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set).
+ * @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
+ * @return array array of friends, or empty
+ */
+function friends_get_user_messages($userid, $limitfrom='', $limitnum='') {
+    global $CFG;
+
+    $query = "SELECT fr.id friendid, usr.id userid, usr.picture, ".
+            "usr.firstname, usr.lastname, fr.message, fr.userid1, fr.userid2, fr.created ".
+            "FROM {$CFG->prefix}friend fr INNER JOIN {$CFG->prefix}user usr ".
+            "ON (fr.userid1=usr.id) WHERE ((fr.userid2={$userid}) AND ".
+            "(fr.status = ".FRIENDS_STATUS_MESSAGE.")) ".
+            "ORDER BY fr.created DESC";
+
+    return get_records_sql($query, $limitfrom, $limitnum);
+}
+
+/**
+ * get all friend records between two users, return an array
+ *
+ * @param int $userid1
+ * @param int $userid2
+ * @return array array of friends, or empty
+ */
+function friends_get_friends($userid1, $userid2) {
+    global $CFG;
+
+    $query = "SELECT fr.id, fr.* ".
+            "FROM {$CFG->prefix}friend fr ".
+			"WHERE (fr.userid1 = {$userid1} AND fr.userid2 = {$userid2}) ".
+			"OR (fr.userid1 = {$userid2} AND fr.userid2 = {$userid1})";
+
+	return get_records_sql($query);
+}
+
+/**
+ * scan an array of friends trying to find the status
+ *
+ * @param array $friends array of friends being searched
+ * @param int $status status to be searched
+ * @return bool true if exist
+ */
+function friends_exist_friend_status($friends, $status) {
+    $friend = friends_get_friend_by_status($friends, $status);
+    return (!empty($friend));
+}
+
+/**
+ * scan an array of friends trying to find the status
+ *
+ * @param array $friends array of friends being searched
+ * @param int $status status to be searched
+ * @return object friend found or empty
+ */
+function friends_get_friend_by_status($friends, $status) {
+	if (!empty($friends)) {
+		foreach ($friends as $friend) {
+			if ($friend->status == $status) {
+                return $friend;
+            }
+		}
+    }
+
+	return null;
+}
+
+/**
+ * create a friend relationship between userid1 and userid2
+ *
+ * @param int $userid1 User requesting friendship (logged user)
+ * @param int $userid2 User with friendship being requested
+ * @param int $status Record type (0 = new, 1 = friend, 2 = message)
+ * @return object Created object
+ */
+function friends_create($userid1, $userid2, $status=0, $message='') {
+    $friend_object = new StdClass;
+    $friend_object->userid1 = $userid1;
+    $friend_object->userid2 = $userid2;
+    $friend_object->status = $status;
+    $friend_object->message = $message;
+    $friend_object->created = time();
+
+	return $friend_object;
+}
+
+/**
+ * create a message between userid1 and userid2
+ *
+ * @param int $userid1 User requesting friendship (logged user)
+ * @param int $userid2 User with friendship being requested
+ * @return object Created object
+ */
+function friends_create_message($userid1, $userid2) {
+    return friends_create($userid1, $userid2, FRIENDS_STATUS_MESSAGE);
+}
+
+/**
+ * add a friend_object to database table friend
+ *
+ * @param object $friend_object Object being inserted
+ * @return int id of created record
+ */
+function friends_add($friend_object) {
+    return insert_record('friend', $friend_object);
+}
+
+/**
+ * update friend_object on database
+ *
+ * @param object $friend_object Object being updated
+ * @return int id of record
+ */
+function friends_update($friend_object) {
+    return update_record('friend', $friend_object);
+}
+
+/**
+ * delete friend_object on database
+ *
+ * @param object $friend_object Object being deleted
+ * @return bool true if deleted
+ */
+function friends_delete($friend_object) {
+    return delete_records('friend', 'id', $friend_object->id);
+}

--- friends/locallib.php
+++ friends/locallib.php
@@ -0,0 +1,389 @@
+<?php
+
+/**
+ * Friends local library - output functions
+ *
+ * @copyright 2009 Ariel Martini
+ * @licence http://www.gnu.org/copyleft/gpl.html GNU Public License
+ *
+ */
+
+/**
+ * Return the link to a profile page (/user/view.php)
+ *
+ * @param int $userid
+ * @param int $courseid
+ * @param $return if true return html string
+ */
+function friends_get_profile_link($userid, $courseid, $return=false) {
+    global $CFG, $USER;
+
+    $usercontext = get_context_instance(CONTEXT_USER, $userid);
+    if (!empty($courseid)) {
+        $courselink = "&course=".$courseid;
+    }
+    else {
+        $courselink = '';
+    }
+
+    if ( has_capability('moodle/user:viewdetails', $usercontext) || isteacherinanycourse($userid) || $userid == $USER->id) {
+        return $CFG->wwwroot .'/user/view.php?id='.$userid.$courselink;
+    }
+    else {
+        return '';
+    }
+}
+
+ /**
+ * Prints an user picture
+ *
+ * @param object $user user object (contains the following fields: userid, picture, firstname, lastname)
+ * @param int $courseid to assemble links correctly
+ * @param $return if true return html string
+ */
+function friends_print_user_picture($user, $courseid, $return=false) {
+    global $CFG, $USER;
+
+    $usercontext = get_context_instance(CONTEXT_USER, $user->userid);
+    $profilelink = friends_get_profile_link($user->userid, null);
+    $output = '';
+    $fullname = fullname($user);
+    $alt = '';
+
+    if (!empty($profilelink)) {
+        $output .= '<a href="'. $profilelink .'">';
+        $alt = $fullname;
+    }
+
+    //print user image - if image is only content of link it needs ALT text!
+    if ($user->picture) {
+        $output .= '<img alt="'. $alt .'" class="user-image" src="'. $CFG->wwwroot .'/user/pix.php/'. $user->userid .'/f1.jpg" />';
+    } else {
+        $output .= '<img alt="'. $alt .'" class="user-image" src="'. $CFG->wwwroot .'/pix/u/f1.png" />';
+    }
+    
+    $output .= '<br />';
+
+    if (!empty($profilelink)) {
+        $output .= '</a>';
+    }
+    
+    if ($return) {
+        return $output;
+    }
+    else {
+        echo $output;
+    }
+}
+
+/**
+ * Prints an individual user box
+ *
+ * @param $user user object (contains the following fields: userid, picture, firstname, lastname)
+ * @param int $courseid to assemble links correctly
+ * @param bool $looking_at_my_profile
+ * @param $return if true return html string
+ */
+function friends_print_user_box($user, $courseid, $looking_at_my_profile, $return=false) {
+
+    $output = print_box_start('user-box', 'user'. $user->userid, true);
+
+    $output .= friends_print_user_picture($user, $courseid, true);
+
+    $textlib = textlib_get_instance();
+
+    $fullname = fullname($user);
+    
+    //truncate name if it's too big
+    if ($textlib->strlen($fullname) > 26) {
+        $fullname = $textlib->substr($fullname, 0, 26) .'...';
+    }
+
+    $output .= '<strong>'. $fullname .'</strong>';
+    
+    if ($looking_at_my_profile) {
+        $output .= '<br />';
+        $output .= friends_print_image_link("/friends/delete.php?userid=".$user->userid."&courseid=".$courseid, 
+            "/pix/t/delete.gif", get_string("deletefriendtitle", "friends"));
+        $output .= friends_print_image_link("/friends/view.php?userid=".$user->userid."&courseid=".$courseid, 
+            "/pix/t/email.gif", get_string("sendmessagetitle", "friends"));
+    }
+    
+    $output .= print_box_end(true);
+    
+    if ($return) {
+        return $output;
+    }
+    else {
+        echo $output;
+    }
+}
+
+/**
+ * Returns an image link
+ *
+ * @param string $link
+ * @param string $image
+ * @param string $description for alt and title
+ */
+function friends_print_image_link($link, $image, $description) {
+    global $CFG;
+    
+    return ' <a href="'.$CFG->wwwroot.$link.'">'.
+        '<img src="'.$CFG->wwwroot.$image.'" alt="'.$description.'" title="'.$description.'"></a>';
+}
+
+/**
+ * Prints a list of users
+ *
+ * @param array $userlist an array of user objects
+ * @param int $courseid to assemble links correctly
+ * @param bool $looking_at_my_profile
+ * @param $return if true return html string
+ */
+function friends_print_user_list($userlist, $courseid, $looking_at_my_profile, $return=false) {
+    $output = null;
+
+	if (!empty($userlist)) {
+		$output = '<ul class="inline-list">';
+
+		foreach ($userlist as $user){
+			$output .= '<li>'. friends_print_user_box($user, $courseid, $looking_at_my_profile, true) ."</li>\n";
+		}
+		$output .= "</ul>\n";
+	}
+
+    if ($return) {
+        return $output;
+    }
+    else {
+        echo $output;
+    }
+}
+
+/**
+ * Prints a friends table
+ *
+ * @param int $userid
+ * @param int $courseid to assemble links correctly
+ * @param bool $looking_at_my_profile
+ * @param int $limitfrom prints users starting at this point (optional, required if $limitnum is set).
+ * @param int $limitnum prints this many users (optional, required if $limitfrom is set).
+ * @param $return if true return html string
+ */
+function friends_print_friends_table($userid, $courseid, $looking_at_my_profile, $limitfrom='' , $limitnum='', $return=false) {
+
+    //List of friends of this user
+    $userlist = friends_get_user_friends($userid, FRIENDS_STATUS_FRIEND, $limitfrom, $limitnum);
+
+    $output = friends_print_user_list($userlist, $courseid, $looking_at_my_profile, true);
+
+    if ($return) {
+        return $output;
+    }
+    else {
+        echo $output;
+    }
+}
+
+/**
+ * Prints a list of requests to be friend of userid
+ *
+ * @param int $userid
+ * @param int $courseid necessary to assemble the links
+ * @param $return if true return html string
+ */
+function friends_print_friends_requests($userid, $courseid, $return=false) {
+    global $CFG;
+
+    //List of friends of this user
+    $requestlist = friends_get_user_friends($userid, FRIENDS_STATUS_NEW);
+
+    $count = 0;
+	$output = '<table>';
+
+	if (!empty($requestlist)) {
+
+		foreach ($requestlist as $user){
+            if ($user->userid2 == $userid) {
+            
+                // Only cases that $userid have been requested (=userid2), not requested (=userid1)
+                
+                $output .= '<tr><td class="side" style="padding:10px">'. friends_print_user_picture($user, $courseid, true) ."</td>\n";
+                
+                $a = fullname($user);
+                
+                $output .= '<td>'.get_string('wantstobefriend', 'friends', $a).'<br /><br />';
+                $output .= '<i>'.stripslashes($user->message).'</i><br /><br />';
+                $output .= get_string('addfriendqm', 'friends');
+                
+                $output .= " <form action='".$CFG->wwwroot ."/friends/confirm.php' method='get' style='display:inline'>";
+                $output .= "<input type='hidden' name='courseid' value='".$courseid."' />";
+                $output .= "<input type='hidden' name='userid' value='".$user->userid."' />";
+                $output .= "<input type='hidden' name='confirm' value='1' />";
+                $output .= "<input type='submit' value='".get_string("addyes", "friends")."' />";
+                $output .= "</form>";
+
+                $output .= " <form action='".$CFG->wwwroot ."/friends/confirm.php' method='get' style='display:inline'>";
+                $output .= "<input type='hidden' name='courseid' value='".$courseid."' />";
+                $output .= "<input type='hidden' name='userid' value='".$user->userid."' />";
+                $output .= "<input type='hidden' name='confirm' value='0' />";
+                $output .= "<input type='submit' value='".get_string("addno", "friends")."' />";
+                $output .= "</form>";
+                
+                $output .= '</td></tr>';
+
+                $count++;
+            }
+		}
+	}
+
+	$output .= "</table>\n";
+    
+    if ($count == 0) {
+        $output = null;
+    }
+
+    if ($return) {
+        return $output;
+    }
+    else {
+        echo $output;
+    }
+}
+
+/**
+ * Prints a list of messages sent to the user
+ *
+ * @param int $userid
+ * @param int $courseid necessary to assemble the links
+ * @param bool $looking_at_my_profile
+ * @param int $limitfrom prints users starting at this point (optional, required if $limitnum is set).
+ * @param int $limitnum prints this many users (optional, required if $limitfrom is set).
+ * @param $return if true return html string
+ */
+function friends_print_friend_messages($userid, $courseid, $looking_at_my_profile, $limitfrom='', $limitnum='', $return=false) {
+    global $CFG, $USER;
+
+    $messagelist = friends_get_user_messages($userid, $limitfrom, $limitnum);
+
+    $count = 0;
+	$output = '<table>';
+
+	if (!empty($messagelist)) {
+
+		foreach ($messagelist as $message){
+            $output .= '<tr><td class="side" style="padding:10px">'. friends_print_user_picture($message, $courseid, true) ."</td>\n";
+            
+            // Print sender name
+
+            $a = fullname($message);
+
+            $profilelink = friends_get_profile_link($message->userid, null);
+            if (!empty($profilelink)) {
+                $a = '<a href="'. $profilelink .'">'.$a.'</a>';
+            }
+
+            $output .= '<td>'.get_string('userwrote', 'friends', $a);
+            
+            // Print message time
+
+            $datestring = null;
+            $datestring->year = 'y'; $datestring->years = 'y';
+            $datestring->day  = 'd'; $datestring->days  = 'd';
+            $datestring->hour = 'h'; $datestring->hours = 'h';
+            $datestring->min  = 'm'; $datestring->mins  = 'm';
+            $datestring->sec  = 's'; $datestring->secs  = 's';
+    
+            $a = str_replace(' ', '', format_time(time() - $message->created, $datestring));
+            $output .= ' ('.get_string('timeago', 'friends', $a).' / ';
+            $output .= userdate($message->created, get_string("strftimerecent")).') ';
+
+            if ($looking_at_my_profile or ($message->userid == $USER->id)) {
+            
+                // Show message delete link if im looking at my profile or if this message was written by me
+            
+                $output .= friends_print_image_link("/friends/delete.php?messageid=".$message->friendid."&courseid=".$courseid, 
+                    "/pix/t/delete.gif", get_string("deletemessagetitle", "friends"));
+            }
+                    
+            $output .= '<br /><br />';
+
+
+            $output .= '<i>'.stripslashes($message->message).'</i>';
+            
+            $output .= '</td></tr>';
+
+            $count++;
+		}
+	}
+
+	$output .= "</table>\n";
+    
+    if ($count == 0) {
+        $output = null;
+    }
+
+    if ($return) {
+        return $output;
+    }
+    else {
+        echo $output;
+    }
+}
+
+/**
+ * Prints a warning message centralized, with an optional link below.
+ *
+ * @param string $message
+ * @param string $linkurl
+ * @param string $linktext
+ * @param $return if true return html string
+ */
+function friends_print_message($message, $linkurl=null, $linktext=null, $return=false) {
+    $output = '<br /><div style="text-align:center">'.$message;
+    if (!empty($linktext) && !empty($linkurl)) {
+        $output .= '<br /><a href="'.$linkurl.'">'.$linktext.'</a>';
+    }
+    $output .= '</div><br />';
+
+    if ($return) {
+        return $output;
+    }
+    else {
+        echo $output;
+    }
+}
+
+/**
+ * Prints the beginning of a box, with a title
+ *
+ * @param string $title 
+ * @param $return if true return html string
+ */
+function friends_begin_box($title, $return=false) {
+    $output = '<fieldset class="clearfix"><legend class="ftoggler">'.$title.'</legend>';
+
+    if ($return) {
+        return $output;
+    }
+    else {
+        echo $output;
+    }
+}
+
+/**
+ * Prints the end of a box
+ *
+ * @param $return if true return html string
+ */
+function friends_end_box($return=false) {
+    $output = '</fieldset>';
+
+    if ($return) {
+        return $output;
+    }
+    else {
+        echo $output;
+    }
+}

--- friends/message_form.php
+++ friends/message_form.php
@@ -0,0 +1,46 @@
+<?php
+
+/**
+ * Friends - message_form.php - form used by view.php, to send a message
+ *
+ * @copyright 2009 Ariel Martini
+ * @licence http://www.gnu.org/copyleft/gpl.html GNU Public License
+ *
+ */
+
+
+require_once($CFG->dirroot.'/lib/formslib.php');
+
+class friends_message_form extends moodleform {
+
+    function definition () {
+
+        $mform =& $this->_form;
+
+        $mform->addElement('hidden', 'userid1');
+        $mform->setType('userid1', PARAM_INT);
+
+        $mform->addElement('hidden', 'userid2');
+        $mform->setType('userid2', PARAM_INT);
+
+        $mform->addElement('hidden', 'courseid');
+        $mform->setType('courseid', PARAM_INT);
+
+        $mform->addElement('hidden', 'created');
+        $mform->setType('created', PARAM_INT);
+        
+        $mform->addElement('hidden', 'status');
+        $mform->setType('status', PARAM_INT);
+
+        $systemcontext = get_context_instance(CONTEXT_SYSTEM);
+
+        $mform->addElement('textarea', 'message', get_string('messagedescription', 'friends'), array('rows'=>3, 'cols'=>50));
+        $mform->addRule('message', null, 'required', null, 'client');
+        
+        $this->add_action_buttons(false, get_string('sendmessagebutton', 'friends'));
+
+    }
+
+}
+
+?>

--- friends/view.php
+++ friends/view.php
@@ -0,0 +1,182 @@
+<?php
+
+/**
+ * Friends - view.php - main friend page, if you are looking at your own 
+ * profile it shows: friend list (with option to delete and send message) and 
+ * message list (with option to delete). if you are looking someone else 
+ * profile it shows: send message box and button, friend list, message 
+ * list (with option to delete messages sent by you).
+ *
+ * @copyright 2009 Ariel Martini
+ * @licence http://www.gnu.org/copyleft/gpl.html GNU Public License
+ *
+ */
+
+
+require_once('../config.php');
+require_once('lib.php');
+require_once('locallib.php');
+require_once('message_form.php');
+
+require_login();
+
+// if (empty($CFG->enablefriends)) { print_error('friendsaredisabled', 'friends'); }
+
+$userid = optional_param('userid', 0, PARAM_INT);
+$courseid = optional_param('courseid', 0, PARAM_INT); // needed for user tabs and course tracking
+$message = optional_param('message', 0, PARAM_INT); // if == 1 warn that the message have been sent
+
+$messageform = new friends_message_form();
+
+// If new data has been sent, add the message record
+if ($messagetosend = $messageform->get_data()) {
+    friends_add($messagetosend);
+    redirect($CFG->wwwroot.'/friends/view.php?courseid='.$messagetosend->courseid.'&userid='.$messagetosend->userid2.'&message=1');
+}
+
+if (empty($userid) || empty($courseid)) {
+    redirect($CFG->wwwroot.'/');
+}
+    
+$user = get_record('user', 'id', $userid);
+$course = get_record('course', 'id', $courseid);
+
+$a = fullname($user);
+$title = get_string('friendsof', 'friends', $a);
+$friendsstring = get_string('friends', 'friends');
+$navlinks = array();
+$navlinks[] = array('name' => fullname($user),
+					'link' => "$CFG->wwwroot/user/view.php?id=$userid&amp;course=$courseid",
+					'type' => 'misc');
+$navlinks[] = array('name' => $title, 'link' => null, 'type' => 'misc');
+
+$navigation = build_navigation($navlinks);
+
+print_header("$course->shortname: $friendsstring", $course->fullname,
+			 $navigation, "", "", true, "&nbsp;", navmenu($course));
+
+$currenttab = 'friends';
+$showroles = 1;
+include('../user/tabs.php');
+
+//echo '<style>div {display:inline}</style>';
+
+echo '<div class="mform">';
+
+$looking_at_my_profile = ($USER->id == $userid);
+
+if ($looking_at_my_profile) {
+
+    // Show friend requests
+
+    $result = friends_print_friends_requests($userid, $courseid, true);
+
+    if (!empty($result)) {
+        friends_begin_box(get_string('friendrequests', 'friends'));
+        echo $result;
+        friends_end_box();
+    }
+
+}
+else {
+
+    $friends = friends_get_friends($USER->id, $userid);
+    if (empty($friends)) {
+
+        // No relationship yet: offer to add
+        
+        friends_begin_box(get_string('addfriend', 'friends'));
+        friends_print_message(get_string('notyetfriend', 'friends'), 
+            'add.php?userid='.$userid.'&courseid='.$courseid,
+            get_string('clicktoadd', 'friends'));
+        friends_end_box();
+    }
+    else {
+        
+        $friend = friends_get_friend_by_status($friends, FRIENDS_STATUS_NEW);
+        if (!empty($friend)) {
+
+            // Friendship request pending
+            
+            friends_begin_box(get_string('addfriend', 'friends'));
+            friends_print_message(get_string('pendingrequest', 'friends'));
+            friends_end_box();
+        }
+
+        $friend = friends_get_friend_by_status($friends, FRIENDS_STATUS_FRIEND);
+        if (!empty($friend)) {
+
+            // User is viewing a friend's page. Show message form
+
+            friends_begin_box(get_string('sendmessage', 'friends'));
+            
+            if ($message == 1) {
+                friends_print_message('<b style="color:red">'.get_string('messagesent', 'friends').'</b>');
+            }
+            
+            $newmessage = friends_create_message($USER->id, $userid);
+            $newmessage->courseid = $courseid;
+
+            $messageform->set_data($newmessage);
+            
+            // Prevent rendering the fieldset tag to make it more compact
+            $GLOBALS['_HTML_QuickForm_default_renderer']->setOpenHiddenFieldsetTemplate('');
+            $GLOBALS['_HTML_QuickForm_default_renderer']->setCloseFieldsetTemplate('');
+            
+            // Dont show required information
+            $GLOBALS['_HTML_QuickForm_default_renderer']->setRequiredNoteTemplate('');
+            $messageform->_form->_reqHTML = '';
+            
+            $messageform->display();
+            
+            friends_end_box();
+        }
+    }
+}
+
+// List of friends
+
+friends_begin_box(get_string('listoffriends', 'friends'));
+    
+$result = friends_print_friends_table($userid, $courseid, $looking_at_my_profile, '', '', true); // TODO: pagination
+
+    
+if (!empty($result)) {
+    echo $result;
+}
+else { 
+
+    // No friends found
+    
+    if ($looking_at_my_profile) {
+        friends_print_message(get_string('ihavenofriends', 'friends'));
+    } 
+    else {
+        friends_print_message(get_string('hehavenofriends', 'friends'));
+    }
+}
+
+friends_end_box();
+
+// List of messages
+
+friends_begin_box(get_string('messages', 'friends'));
+    
+$result = friends_print_friend_messages($userid, $courseid, $looking_at_my_profile, '', '', true); // TODO: pagination
+
+if (!empty($result)) {
+    echo $result;
+}
+else { 
+    // No messages found
+    friends_print_message(get_string('nomessages', 'friends'));
+}
+
+friends_end_box();
+
+echo '</div>';
+
+print_footer($course);
+
+
+?>

--- lang/en_utf8/friends.php
+++ lang/en_utf8/friends.php
@@ -0,0 +1,45 @@
+<?PHP 
+
+
+$string['addfriend'] = 'Add as friend';
+$string['addfriendqm'] = 'Add friend?';
+$string['addno'] = 'No';
+$string['addyes'] = 'Yes, add friend';
+$string['alreadyfriends'] = 'You and this user are already friends.';
+$string['alreadyrequested'] = 'This friendship have already been requested.';
+$string['clicktoadd'] = 'Add as a friend.';
+$string['delete'] = 'Remove friend';
+$string['deleteareyousure'] = 'Are you sure you want to remove <b>$a</b> from your list of friends?';
+$string['deleteconfirm'] = 'Yes, remove the user';
+$string['deletefriendtitle'] = 'Remove this user from your list of friends';
+$string['deletemessagetitle'] = 'Remove this message';
+$string['deletemsg'] = 'Remove message';
+$string['deletemsgareyousure'] = 'Are you sure you want to remove this message?';
+$string['deletemsgconfirm'] = 'Yes, delete the message';
+$string['friendrequests'] = 'Friend requests';
+$string['friends'] = 'Friends';
+$string['friendsaredisabled'] = 'Friends are disabled';
+$string['friendshipconfirmed'] = 'Friendship successfully confirmed.';
+$string['friendshiprequested'] = 'Friendship successfully requested.';
+$string['friendsof'] = 'Friends of $a';
+$string['hehavenofriends'] = 'This user have no friends yet.';
+$string['ihavenofriends'] = 'No friends found. Use the button <i>Add as friend</i> on another user profile to add a friend.';
+$string['introductionmessage'] = 'Introduction message';
+$string['listoffriends'] = 'List of friends';
+$string['messagedescription'] = 'Send a message to your friend. This message will be visible by anyone on the site.';
+$string['messages'] = 'Messages';
+$string['messagesent'] = 'Message sent successfully';
+$string['nomessages'] = 'No messages found';
+$string['notyetfriend'] = 'This user is not your friend yet';
+$string['pendingrequest'] = 'You have sent a friendship request to this user. Please wait until it is confirmed.';
+$string['pleasewaitconfirmation'] = 'Please wait until the user confirms it.';
+$string['requestfriendship'] = 'Request friendship from $a';
+$string['return'] = 'Return to the user\'s profile';
+$string['sendmessage'] = 'Send a message';
+$string['sendmessagebutton'] = 'Send the message';
+$string['sendmessagetitle'] = 'Send a message to this friend';
+$string['timeago'] = '$a ago';
+$string['userwrote'] = '$a wrote:';
+$string['wantstobefriend'] = '<b>$a</b> wants to be part of your friend list.';
+
+?>