--- rat/lonpageflip.pm	2000/10/17 10:36:17	1.8
+++ rat/lonpageflip.pm	2001/05/28 14:21:22	1.16
@@ -10,7 +10,9 @@
 # 08/30,08/31,09/06,09/14,09/15,09/16,09/19,09/20,09/21,09/23,
 # 10/02 Gerd Kortemeyer)
 #
-# 10/03,10/05,10/06,10/07,10/09,10/10,10/11,10/16,10/17 Gerd Kortemeyer
+# 10/03,10/05,10/06,10/07,10/09,10/10,10/11,10/16,10/17,
+# 11/14,11/16,
+# 10/01/01,05/01,05/28 Gerd Kortemeyer
 
 package Apache::lonpageflip;
 
@@ -37,6 +39,80 @@ sub addrid {
     return $current;
 }
 
+sub move {
+    my ($rid,$mapurl,$direction)=@_;
+
+    my $next='';
+
+              my $mincond=1;
+              my $posnext='';
+              if ($direction eq 'forward') {
+# --------------------------------------------------------------------- Forward
+                  if ($hash{'type_'.$rid} eq 'finish') {
+	             $rid=$hash{'ids_/res/'.$mapurl}; 
+                  }
+                  map {
+                      my $thiscond=
+      &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$_}});
+                      if ($thiscond>=$mincond) {
+		          if ($posnext) {
+		             $posnext.=','.$_.':'.$thiscond;
+                          } else {
+                             $posnext=$_.':'.$thiscond;
+		          }
+                          if ($thiscond>$mincond) { $mincond=$thiscond; }
+	              }
+                  } split(/\,/,$hash{'to_'.$rid});
+                  map {
+                      my ($linkid,$condval)=split(/\:/,$_);
+                      if ($condval>=$mincond) {
+		          $next=&addrid($next,$hash{'goesto_'.$linkid},
+                                $hash{'condid_'.$hash{'undercond_'.$linkid}});
+                      }
+                  } split(/\,/,$posnext);
+                  if ($hash{'is_map_'.$next}) {
+                      if (
+      $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'sequence') {
+			  $mapurl=$hash{'src_'.$next};
+			  $next=$hash{'map_start_'.$hash{'src_'.$next}};
+                     }
+                  }
+              } elsif ($direction eq 'back') {
+# ------------------------------------------------------------------- Backwards
+                  if ($hash{'type_'.$rid} eq 'start') {
+	             $rid=$hash{'ids_/res/'.$mapurl};
+                  }
+                  map {
+                      my $thiscond=
+      &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$_}});
+                      if ($thiscond>=$mincond) {
+		          if ($posnext) {
+		             $posnext.=','.$_.':'.$thiscond;
+                          } else {
+                             $posnext=$_.':'.$thiscond;
+		          }
+                          if ($thiscond>$mincond) { $mincond=$thiscond; }
+	              }
+                  } split(/\,/,$hash{'from_'.$rid});
+                  map {
+                      my ($linkid,$condval)=split(/\:/,$_);
+                      if ($condval>=$mincond) {
+		          $next=&addrid($next,$hash{'comesfrom_'.$linkid},
+                                $hash{'condid_'.$hash{'undercond_'.$linkid}});
+                      }
+                  } split(/\,/,$posnext);
+                  if ($hash{'is_map_'.$next}) {
+                      if (
+      $hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$next}}} eq 'sequence') {
+			  $mapurl=$hash{'src_'.$next};
+			  $next=$hash{'map_finish_'.$hash{'src_'.$next}};
+                     }
+                  }
+	      }
+
+              return ($next,$mapurl);
+}
+
 # ================================================================ Main Handler
 
 sub handler {
@@ -61,6 +137,26 @@ sub handler {
       $ENV{'form.postdata'}=~/(\w+)\:(.*)/;
       my $direction=$1;
       my $currenturl=$2;
+      if ($direction eq 'return') {
+# -------------------------------------------------------- Return to last known
+         my $last;
+         if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'_symb.db',
+                    &GDBM_READER,0640)) {
+	     $last=$hash{'last_known'};
+             untie(%hash);
+         }
+         my $newloc;
+         if ($last) {
+            $newloc='/res/'.(split(/\_\_\_/,$last))[1];
+         } else {
+	    $newloc='/adm/noidea.html';
+         }  
+	 $r->content_type('text/html');
+         $r->header_out(Location => 
+			'http://'.$ENV{'HTTP_HOST'}.$newloc);
+                               
+         return REDIRECT;
+      }
       $currenturl=~s/^http\:\/\///;
       $currenturl=~s/^[^\/]+//;
       unless ($currenturl=~/\/res\//) {
@@ -76,8 +172,8 @@ sub handler {
 	     $r->content_type('text/html');
              $r->header_out(Location => 
                                'http://'.$ENV{'HTTP_HOST'}.'/adm/noidea.html');
+             return REDIRECT;
          }
-         return REDIRECT;
       }
 # ------------------------------------------- Do we have any idea where we are?
       my $position;
@@ -89,55 +185,16 @@ sub handler {
           if (tie(%hash,'GDBM_File',$ENV{'request.course.fn'}.'.db',
                         &GDBM_READER,0640)) {
               my $rid=$hash{'map_pc_/res/'.$mapurl}.'.'.$mapnum;
-              my $next='';
-              my $mincond=1;
-              my $posnext='';
-              if ($direction eq 'forward') {
-# --------------------------------------------------------------------- Forward
-                  map {
-                      my $thiscond=
-      &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$_}});
-                      if ($thiscond>=$mincond) {
-		          if ($posnext) {
-		             $posnext.=','.$_.':'.$thiscond;
-                          } else {
-                             $posnext=$_.':'.$thiscond;
-		          }
-                          if ($thiscond>$mincond) { $mincond=$thiscond; }
-	              }
-                  } split(/\,/,$hash{'to_'.$rid});
-                  map {
-                      my ($linkid,$condval)=split(/\:/,$_);
-                      if ($condval>=$mincond) {
-		          $next=&addrid($next,$hash{'goesto_'.$linkid},
-                                $hash{'condid_'.$hash{'undercond_'.$linkid}});
-                      }
-                  } split(/\,/,$posnext);
-              } elsif ($direction eq 'back') {
-# ------------------------------------------------------------------- Backwards
-                  map {
-                      my $thiscond=
-      &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$_}});
-                      if ($thiscond>=$mincond) {
-		          if ($posnext) {
-		             $posnext.=','.$_.':'.$thiscond;
-                          } else {
-                             $posnext=$_.':'.$thiscond;
-		          }
-                          if ($thiscond>$mincond) { $mincond=$thiscond; }
-	              }
-                  } split(/\,/,$hash{'from_'.$rid});
-                  map {
-                      my ($linkid,$condval)=split(/\:/,$_);
-                      if ($condval>=$mincond) {
-		          $next=&addrid($next,$hash{'comesfrom_'.$linkid},
-                                $hash{'condid_'.$hash{'undercond_'.$linkid}});
-                      }
-                  } split(/\,/,$posnext);
- 	      } elsif ($direction eq 'up') {
-# -------------------------------------------------------------------------- Up
-              } elsif ($direction eq 'down') {
-# ------------------------------------------------------------------------ Down
+
+# ------------------------------------------------- Move forward, backward, etc
+
+              ($next,$mapurl)=&move($rid,$mapurl,$direction);
+# -------------------------------------- Do we have one and only one empty URL?
+              my $safecount=0;
+              while (($next) && ($next!~/\,/) && (!$hash{'src_'.$next})
+                     && ($safecount<25)) {
+                  ($next,$mapurl)=&move($next,$mapurl,$direction);
+                  $safecount++;
               }
 # ----------------------------------------------------- Check out possibilities
               if ($next) {