mod/lesson/action/moveit.php

   1 <?php // $Id$
   2 /**
   3  * Action for actually moving the page (database changes)
   4  *
   5  * @version $Id$
   6  * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
   7  * @package lesson
   8  **/
   9     confirm_sesskey();
  10
  11     $pageid = required_param('pageid', PARAM_INT); //  page to move
  12     if (!$page = get_record("lesson_pages", "id", $pageid)) {
  13         error("Moveit: page not found");
  14     }
  15     $after = required_param('after', PARAM_INT); // target page
  16
  17     // first step. determine the new first page
  18     // (this is done first as the current first page will be lost in the next step)
  19     if (!$after) {
  20         // the moved page is the new first page
  21         $newfirstpageid = $pageid;
  22         // reset $after so that is points to the last page
  23         // (when the pages are in a ring this will in effect be the first page)
  24         if ($page->nextpageid) {
  25             if (!$after = get_field("lesson_pages", "id", "lessonid", $lesson->id, "nextpageid", 0)) {
  26                 error("Moveit: last page id not found");
  27             }
  28         } else {
  29             // the page being moved is the last page, so the new last page will be
  30             $after = $page->prevpageid;
  31         }
  32     } elseif (!$page->prevpageid) {
  33         // the page to be moved was the first page, so the following page must be the new first page
  34         $newfirstpageid = $page->nextpageid;
  35     } else {
  36         // the current first page remains the first page
  37         if (!$newfirstpageid = get_field("lesson_pages", "id", "lessonid", $lesson->id, "prevpageid", 0)) {
  38             error("Moveit: current first page id not found");
  39         }
  40     }
  41     // the rest is all unconditional...
  42
  43     // second step. join pages into a ring
  44     if (!$firstpageid = get_field("lesson_pages", "id", "lessonid", $lesson->id, "prevpageid", 0)) {
  45         error("Moveit: firstpageid not found");
  46     }
  47     if (!$lastpageid = get_field("lesson_pages", "id", "lessonid", $lesson->id, "nextpageid", 0)) {
  48         error("Moveit: lastpage not found");
  49     }
  50     if (!set_field("lesson_pages", "prevpageid", $lastpageid, "id", $firstpageid)) {
  51         error("Moveit: unable to update link");
  52     }
  53     if (!set_field("lesson_pages", "nextpageid", $firstpageid, "id", $lastpageid)) {
  54         error("Moveit: unable to update link");
  55     }
  56
  57     // third step. remove the page to be moved
  58     if (!$prevpageid = get_field("lesson_pages", "prevpageid", "id", $pageid)) {
  59         error("Moveit: prevpageid not found");
  60     }
  61     if (!$nextpageid = get_field("lesson_pages", "nextpageid", "id", $pageid)) {
  62         error("Moveit: nextpageid not found");
  63     }
  64     if (!set_field("lesson_pages", "nextpageid", $nextpageid, "id", $prevpageid)) {
  65         error("Moveit: unable to update link");
  66     }
  67     if (!set_field("lesson_pages", "prevpageid", $prevpageid, "id", $nextpageid)) {
  68         error("Moveit: unable to update link");
  69     }
  70
  71     // fourth step. insert page to be moved in new place...
  72     if (!$nextpageid = get_field("lesson_pages", "nextpageid", "id", $after)) {
  73         error("Movit: nextpageid not found");
  74     }
  75     if (!set_field("lesson_pages", "nextpageid", $pageid, "id", $after)) {
  76         error("Moveit: unable to update link");
  77     }
  78     if (!set_field("lesson_pages", "prevpageid", $pageid, "id", $nextpageid)) {
  79         error("Moveit: unable to update link");
  80     }
  81     // ...and set the links in the moved page
  82     if (!set_field("lesson_pages", "prevpageid", $after, "id", $pageid)) {
  83         error("Moveit: unable to update link");
  84     }
  85     if (!set_field("lesson_pages", "nextpageid", $nextpageid, "id", $pageid)) {
  86         error("Moveit: unable to update link");
  87     }
  88
  89     // fifth step. break the ring
  90     if (!$newlastpageid = get_field("lesson_pages", "prevpageid", "id", $newfirstpageid)) {
  91         error("Moveit: newlastpageid not found");
  92     }
  93     if (!set_field("lesson_pages", "prevpageid", 0, "id", $newfirstpageid)) {
  94         error("Moveit: unable to update link");
  95     }
  96     if (!set_field("lesson_pages", "nextpageid", 0, "id", $newlastpageid)) {
  97             error("Moveit: unable to update link");
  98     }
  99     lesson_set_message(get_string('movedpage', 'lesson'), 'notifysuccess');
 100     redirect("$CFG->wwwroot/mod/lesson/edit.php?id=$cm->id");
 101 ?>