<?php //$Id$

    /**
     * Library of functions and constants for blog
     */
    require_once($CFG->libdir .'/blocklib.php');
    require_once($CFG->libdir .'/pagelib.php');
    require_once('rsslib.php');
    require_once($CFG->dirroot .'/blog/blogpage.php');


    /**
     * Blog access level constant declaration
     */
    define ('BLOG_USER_LEVEL', 1);
    define ('BLOG_GROUP_LEVEL', 2);
    define ('BLOG_COURSE_LEVEL', 3);
    define ('BLOG_SITE_LEVEL', 4);
    define ('BLOG_GLOBAL_LEVEL', 5);


    /**
     * Definition of blogcourse page type (blog page with course id present).
     */
    //not used at the moment, and may not need to be
    define('PAGE_BLOG_COURSE_VIEW', 'blog_course-view');

    $BLOG_YES_NO_MODES = array ( '0'  => get_string('no'),
                                 '1' => get_string('yes') );

    // Set default setting for $CFG->blog_* vars used by blog's blocks.
    // If they are not already. Otherwise errors are thrown when an attempt
    // is made to use an empty var.
    if (empty($SESSION->blog_editing_enabled)) {
        $SESSION->blog_editing_enabled = false;
    }


    /** 
     * Checks to see if user has visited blogpages before, if not, install 2
     * default blocks (blog_menu and blog_tags).
     */
    function blog_check_and_install_blocks() {
        global $USER;
        if (isloggedin() && !isguest()) {
            // if this user has not visited this page before
            if (!get_user_preferences('blogpagesize')) {
                // find the correct ids for blog_menu and blog_from blocks
                $menublock = get_record('block','name','blog_menu');
                $tagsblock = get_record('block','name','blog_tags');
                // add those 2 into block_instance page

                // add blog_menu block
                $newblock = new object;
                $newblock -> blockid = $menublock->id;
                $newblock -> pageid = $USER->id;
                $newblock -> pagetype = 'blog-view';
                $newblock -> position = 'r';
                $newblock -> weight = 0;
                $newblock -> visible = 1;
                insert_record('block_instance', $newblock);

                // add blog_tags menu
                $newblock -> blockid = $tagsblock->id;
                $newblock -> weight = 1;
                insert_record('block_instance', $newblock);

                // finally we set the page size pref
                set_user_preference('blogpagesize',8);
            }
        }
    }


    /**
     * Adaptation of isediting in moodlelib.php for blog module
     * @return bool
     */
    function blog_isediting() {
        global $SESSION;
        if (! isset($SESSION->blog_editing_enabled)) {
            $SESSION->blog_editing_enabled = false;
        }
        return ($SESSION->blog_editing_enabled);
    }


    /**
     *  This function is in lib and not in BlogInfo because entries being searched
     *   might be found in any number of blogs rather than just one.
     *
     *   $@param ...
     */
    function blog_print_html_formatted_entries($userid, $postid, $limit, $start, $filtertype, $filterselect, $tagid, $tag, $filtertype, $filterselect) {

        global $CFG, $USER;

        $blogpage = optional_param('blogpage', 0, PARAM_INT);
        $bloglimit = get_user_preferences('blogpagesize',10);

        // First let's see if the batchpublish form has submitted data
        $post = data_submitted();

        $morelink = '<br />&nbsp;&nbsp;';

        $blogEntries = fetch_entries($userid, $postid, $limit, $start, $filtertype, $filterselect, $tagid, $tag, $sort='lastmodified DESC', $limit=true);

        print_paging_bar(get_viewable_entry_count($userid, $postid, $limit, $start,$filtertype, $filterselect, $tagid, $tag, $sort='lastmodified DESC'), $blogpage, $bloglimit, get_baseurl($filtertype, $filterselect), 'blogpage');

        if ($CFG->enablerssfeeds) {
            blog_rss_print_link($filtertype, $filterselect, $tag);
        }

        if (isloggedin() && !isguest()) {
            //the user's blog is enabled and they are viewing their own blog
            $addlink = '<div align="center">';
            $addlink .= '<a href="'.$CFG->wwwroot .'/blog/edit.php'.'">'. get_string('addnewentry', 'blog').'</a>';
            $addlink .='</div>';
            echo $addlink;
        }

        if ($blogEntries) {

            $count = 0;
            foreach ($blogEntries as $blogEntry) {
                blog_print_entry($blogEntry, 'list', $filtertype, $filterselect); //print this entry.
                $count++;
            }
            if (!$count) {
                print '<br /><center>'. get_string('noentriesyet', 'blog') .'</center><br />';

            }

            print $morelink.'<br />'."\n";
            return;
        }

        $output = '<br /><center>'. get_string('noentriesyet', 'blog') .'</center><br />';
        print $output;
    }


    /**
     * This function is in lib and not in BlogInfo because entries being searched
     * might be found in any number of blogs rather than just one.
     *
     * This function builds an array which can be used by the included
     * template file, making predefined and nicely formatted variables available
     * to the template. Template creators will not need to become intimate
     * with the internal objects and vars of moodle blog nor will they need to worry
     * about properly formatting their data
     *
     *   @param BlogEntry blogEntry - a hopefully fully populated BlogEntry object
     *   @param string viewtype Default is 'full'. If 'full' then display this blog entry
     *     in its complete form (eg. archive page). If anything other than 'full'
     *     display the entry in its abbreviated format (eg. index page)
     */
    function blog_print_entry($blogEntry, $viewtype='full', $filtertype='', $filterselect='', $mode='loud') {

        global $USER, $CFG, $course, $ME;

        $template['body'] = get_formatted_entry_body(stripslashes_safe($blogEntry->summary), $blogEntry->format);
        $template['title'] = '<a name="'. $blogEntry->subject .'"></a>';
        //enclose the title in nolink tags so that moodle formatting doesn't autolink the text
        $template['title'] .= '<span class="nolink">'. stripslashes_safe($blogEntry->subject);
        $template['title'] .= '</span>';
        $template['userid'] = $blogEntry->userid;
        $template['author'] = fullname(get_record('user','id',$blogEntry->userid));
        $template['lastmod'] = userdate($blogEntry->lastmodified);
        $template['created'] = userdate($blogEntry->created);
        $template['publishstate'] = $blogEntry->publishstate;

        /// preventing user to browse blogs that they aren't supposed to see
        /// This might not be too good since there are multiple calls per page

        /*
        if (!blog_user_can_view_user_post($template['userid'])) {
            error ('you can not view this post');
        }*/

        $stredit = get_string('edit');
        $strdelete = get_string('delete');

        $user = get_record('user','id',$template['userid']);

        /// Start printing of the blog

        echo '<table cellspacing="0" class="forumpost blogpost blog'.$template['publishstate'].'" width="100%">';

        echo '<tr class="header"><td class="picture left">';
        print_user_picture($template['userid'], SITEID, $user->picture);
        echo '</td>';

        echo '<td class="topic starter"><div class="subject">'.$template['title'].'</div><div class="author">';
        $fullname = fullname($user, $template['userid']);
        $by->name =  '<a href="'.$CFG->wwwroot.'/user/view.php?id='.
                    $user->id.'&amp;course='.$course->id.'">'.$fullname.'</a>';
        $by->date = $template['lastmod'];
        print_string('bynameondate', 'forum', $by);
        echo '</div></td></tr>';

        echo '<tr><td class="left side">';

    /// Actual content

        echo '</td><td class="content">'."\n";

        switch ($template['publishstate']) {
            case 'draft':
                $blogtype = get_string('publishtonoone', 'blog');
            break;
            case 'site':
                $blogtype = get_string('publishtosite', 'blog');
            break;
            case 'public':
                $blogtype = get_string('publishtoworld', 'blog');
            break;
            default:
                $blogtype = '';
            break;

        } 

        echo '<div class="audience">'.$blogtype.'</div>'; 

        // Print whole message
        echo format_text($template['body']);

    /// Links to tags

        if ($blogtags = get_records_sql('SELECT t.* FROM '.$CFG->prefix.'tags t, '.$CFG->prefix.'blog_tag_instance ti
                                     WHERE t.id = ti.tagid
                                     AND ti.entryid = '.$blogEntry->id)) {
            echo '<div class="tags">';
            if ($blogtags) {
                print_string('tags');
                echo ': ';
                foreach ($blogtags as $key => $blogtag) {
                    $taglist[] = '<a href="index.php?filtertype='.$filtertype.'&amp;filterselect='.$filterselect.'&amp;tagid='.$blogtag->id.'">'.$blogtag->text.'</a>';
                }
                echo implode(', ', $taglist);
            }
            echo '</div>';
        }

    /// Commands

        echo '<div class="commands">';

        if (!empty($USER->id)) {
            $context = get_context_instance(CONTEXT_SYSTEM, SITEID);
            $canmanage = has_capability('moodle/blog:manageentries', $context->id);
            
            if (($template['userid'] == $USER->id) or $canmanage) {
                    echo '<a href="'.$CFG->wwwroot.'/blog/edit.php?editid='.$blogEntry->id.'&amp;sesskey='.sesskey().'">'.$stredit.'</a>';
            }

            if (($template['userid'] == $USER->id) or $canmanage) {
                echo '| <a href="'.$CFG->wwwroot.'/blog/edit.php?act=del&amp;editid='.$blogEntry->id.'&amp;sesskey='.sesskey().'">'.$strdelete.'</a>';
            }
        }

        echo '</div>';

        echo '</td></tr></table>'."\n\n";

    }


    /**
     * Use this function to retrieve a list of publish states available for
     * the currently logged in user.
     *
     * @return array This function returns an array ideal for sending to moodles'
     *                choose_from_menu function.
     */
    function blog_applicable_publish_states($courseid='') {

        global $CFG;

        // everyone gets draft access
        $options = array ( 'draft' => get_string('publishtonoone', 'blog') );
        $options['site'] = get_string('publishtosite', 'blog');
        $options['public'] = get_string('publishtoworld', 'blog');

        return $options;
    }


    /**
     * User can edit a blog entry if this is their own blog post and they have
     * the capability moodle/blog:writeentry, or if they have the capability
     * moodle/blog:manageentries.
     */
    function blog_user_can_edit_post($blogEntry, $context) {
        
        global $CFG, $USER;
        
        return ((has_capability('moodle/blog:writeentries', $context) &&
                    $blogEntry->userid == $USER->id) ||
                    has_capability('moodle/blog:manageentries', $context));
    }


    /**
     * Checks to see if a user can view the blogs of another user.
     * He can do so, if he has the moodle/blog:readentry capability. In the
     * case of spg group course, the user also needs to be in the same group.
     */
    function blog_user_can_view_user_post($targetuserid, $blogEntry=null) {
        
        global $CFG, $USER;
        $canview = 0;    //bad start
        
        $context = get_context_instance(CONTEXT_SYSTEM, SITEID);
        
        if (!has_capability('moodle/blog:readentry', $context)) {
            return false;
        }
        
        if ($USER->id && ($USER->id == $targetuserid)) {
            return true;
        }

        if ($blogEntry and $blogEntry->publishstate == 'draft') {  // can not view draft
            return false;
        }
        
        $usercourses = get_my_courses($targetuserid);
        foreach ($usercourses as $usercourse) {
            // If the viewer and user are sharing same non-spg course, then
            // grant permission.
            if (groupmode($usercourse) != SEPARATEGROUPS) {
                $canview = 1;
                return $canview;
            } else {
                // Now we need every group the user is in, and check to see
                // if view is a member.
                if ($usergroups = user_group($usercourse->id, $targetuserid)) {
                    foreach ($usergroups as $usergroup) {
                        if (ismember($usergroup->id)) {
                            $canview = 1;
                            return $canview;
                        }
                    }
                }
            }
        }

        if (!$canview && $CFG->bloglevel < BLOG_SITE_LEVEL) {
            error ('You can not view this user\'s blogs');
        }

        return $canview;
    }


    /**
     * Moved from BlogEntry class.
     */
    function get_formatted_entry_body($body, $format) {
        global $CFG;
        include_once($CFG->libdir .'/weblib.php');
        if ($format) {
            return format_text($body, $format);
        }
        return stripslashes_safe($body);
    }


    /**
     * Main filter function.
     */
    function fetch_entries($userid, $postid='', $fetchlimit=10, $fetchstart='', $filtertype='', $filterselect='', $tagid='', $tag ='', $sort='lastmodified DESC', $limit=true) {

        global $CFG, $USER;

        if (!isset($USER->id)) {
            $USER->id = 0;    //hack, for guests
        }

        /// set the tag id for searching
        if ($tagid) {
            $tag = $tagid;
        } else if ($tag) {
            if ($tagrec = get_record_sql('SELECT * FROM '.$CFG->prefix.'tags WHERE text LIKE "'.$tag.'"')) {
                $tag = $tagrec->id;
            } else {
                $tag = -1;    //no records found
            }
        }

        // If we have specified an ID
        // Just return 1 entry

        if ($postid) {

            if ($post = get_record('post', 'id', $postid)) {

                if (blog_user_can_view_user_post($post->userid)) {

                    if ($user = get_record('user', 'id', $post->userid)) {
                        $post->email = $user->email;
                        $post->firstname = $user->firstname;
                        $post->lastname = $user->lastname;
                    }
                    $retarray[] = $post;
                    return $retarray;
                } else {
                    return null;
                }
                
            } else { // bad postid
                return null;
            }
        }

        if ($tag) {
            $tagtablesql = $CFG->prefix.'blog_tag_instance bt, ';
            $tagquerysql = ' AND bt.entryid = p.id AND bt.tagid = '.$tag.' ';
        } else {
            $tagtablesql = '';
            $tagquerysql = '';
        }


        /****************************************
         * depending on the type, there are 4   *
         * different possible sqls              *
         ****************************************/

        $requiredfields = 'p.*, u.firstname,u.lastname,u.email';

        switch ($filtertype) {

            case 'site':

                if (isloggedin()) {
					
                    $SQL = 'SELECT '.$requiredfields.' FROM '.$CFG->prefix.'post p, '.$tagtablesql
                            .$CFG->prefix.'user u
                            WHERE p.userid = u.id '.$tagquerysql.'
                            AND (p.publishstate = \'site\' OR p.publishstate = \'public\' OR p.userid = '.$USER->id.')
                            AND u.deleted = 0';

                } else {

                    $SQL = 'SELECT '.$requiredfields.' FROM '.$CFG->prefix.'post p, '.$tagtablesql
                            .$CFG->prefix.'user u
                            WHERE p.userid = u.id '.$tagquerysql.'
                            AND p.publishstate = \'public\'
                            AND u.deleted = 0';
                }

            break;

            case 'course':
                if ($filterselect != SITEID) {
                    $SQL = '(SELECT '.$requiredfields.' FROM '.$CFG->prefix.'post p, '.$tagtablesql
                            .$CFG->prefix.'user_students s, '.$CFG->prefix.'user u
                            WHERE p.userid = s.userid '.$tagquerysql.'
                            AND s.course = '.$filterselect.'
                            AND u.id = p.userid
                            AND (p.publishstate = \'site\' OR p.publishstate = \'public\' OR p.userid = '.$USER->id.'))

                            UNION

                            (SELECT '.$requiredfields.' FROM '.$CFG->prefix.'post p, '.$tagtablesql
                            .$CFG->prefix.'user_teachers t, '.$CFG->prefix.'user u
                            WHERE p.userid = t.userid '.$tagquerysql.'
                            AND t.course = '.$filterselect.'
                            AND u.id = p.userid
                            AND (p.publishstate = \'site\' OR p.publishstate = \'public\' OR p.userid = '.$USER->id.'))';    //this will break for postgres, i think
                } else {

                    if (isloggedin()) {

                        $SQL = 'SELECT '.$requiredfields.' FROM '.$CFG->prefix.'post p, '.$tagtablesql
                                .$CFG->prefix.'user u
                                WHERE p.userid = u.id '.$tagquerysql.'
                                AND (p.publishstate = \'site\' OR p.publishstate = \'public\' OR p.userid = '.$USER->id.')
                                AND u.deleted = 0';

                    } else {

                        $SQL = 'SELECT '.$requiredfields.' FROM '.$CFG->prefix.'post p, '.$tagtablesql
                                .$CFG->prefix.'user u
                                WHERE p.userid = u.id '.$tagquerysql.'
                                AND p.publishstate = \'public\'
                                AND u.deleted = 0';
                    }

                }

            break;

            case 'group':

				$SQL = 'SELECT '.$requiredfields.' FROM '.$CFG->prefix.'post p, '.$tagtablesql
	                    .$CFG->prefix.'groups_members m, '.$CFG->prefix.'user u
	                    WHERE p.userid = m.userid '.$tagquerysql.'
	                    AND u.id = p.userid
	                    AND m.groupid = '.$filterselect.'
	                    AND (p.publishstate = \'site\' OR p.publishstate = \'public\' OR p.userid = '.$USER->id.')';

            break;

            case 'user':
				
				if (isloggedin()) {
				  
	                $SQL = 'SELECT '.$requiredfields.' FROM '.$CFG->prefix.'post p, '.$tagtablesql
	                        .$CFG->prefix.'user u
	                        WHERE p.userid = u.id '.$tagquerysql.'
	                        AND u.id = '.$filterselect.'
	                        AND (p.publishstate = \'site\' OR p.publishstate = \'public\' OR p.userid = '.$USER->id.')';
	            } else {
	                
					$SQL = 'SELECT '.$requiredfields.' FROM '.$CFG->prefix.'post p, '.$tagtablesql
	                        .$CFG->prefix.'user u
	                        WHERE p.userid = u.id '.$tagquerysql.'
	                        AND u.id = '.$filterselect.'
	                        AND p.publishstate = \'public\'';	              
	              
	            }

            break;


        }

        if ($fetchstart !== '' && $limit) {
            $limit = sql_paging_limit($fetchstart, $fetchlimit);
        } else {
            $limit = '';
        }

        $orderby = ' ORDER BY '. $sort .' ';

        //echo 'Debug: BlogFilter fetch_entries() sql="'. $SQL . $orderby . $limit .'"<br />'. $this->categoryid; //debug
        $records = get_records_sql($SQL . $orderby . $limit);

//        print_object($records); //debug

        if (empty($records)) {
            return array();
        }

        return $records;
    }


    /**
     * get the count of viewable entries, easiest way is to count fetch_entries
     * this is used for print_paging_bar
     * this is not ideal, but because of the UNION in the sql in fetch_entries,
     * it is hard to use count_records_sql
     */
    function get_viewable_entry_count($userid, $postid='', $fetchlimit=10,
                $fetchstart='', $filtertype='', $filterselect='', $tagid='',
                $tag ='', $sort='lastmodified DESC') {

        $blogEntries = fetch_entries($userid, $postid, $fetchlimit,
                $fetchstart, $filtertype, $filterselect, $tagid, $tag,
                $sort='lastmodified DESC', false);
        
        return count($blogEntries);
    }


    /// Find the base url from $_GET variables, for print_paging_bar
    function get_baseurl($filtertype, $filterselect) {

        $getcopy  = $_GET;

        unset($getcopy['blogpage']);

        $strippedurl = strip_querystring(qualified_me());
        if(!empty($getcopy)) {
            $first = false;
            $querystring = '';
            foreach($getcopy as $var => $val) {
                if(!$first) {
                    $first = true;
                    if ($var != 'filterselect' && $var != 'filtertype') {
                        $querystring .= '?'.$var.'='.$val;
                        $hasparam = true;
                    } else {
                        $querystring .= '?';
                    }
                } else {
                    if ($var != 'filterselect' && $var != 'filtertype') {
                    $querystring .= '&amp;'.$var.'='.$val;
                    $hasparam = true;
                    }
                }
            }
            if (isset($hasparam)) {
                $querystring .= '&amp;';
            } else {
                $querystring = '?';
            }
        } else {
            $querystring = '?';
        }

        return strip_querystring(qualified_me()) . $querystring. 'filtertype='.
                $filtertype.'&amp;filterselect='.$filterselect.'&amp;';

    }
?>