/*  Title:      Pure/PIDE/markup_tree.scala

     Author:     Fabian Immler, TU Munich

     Author:     Makarius

 Markup trees over nested / non-overlapping text ranges.

 */

 package isabelle

 import javax.swing.tree.DefaultMutableTreeNode

 import scala.collection.immutable.SortedMap

 import scala.collection.mutable

 import scala.annotation.tailrec

 object Markup_Tree

 {

   /* branches sorted by quasi-order -- overlapping ranges appear as equivalent */

   object Branches

   {

     type Entry = (Text.Info[Any], Markup_Tree)

     type T = SortedMap[Text.Info[Any], Entry]

     val empty = SortedMap.empty[Text.Info[Any], Entry](new scala.math.Ordering[Text.Info[Any]]

       {

         def compare(x: Text.Info[Any], y: Text.Info[Any]): Int = x.range compare y.range

       })

     def update(branches: T, entry: Entry): T = branches + (entry._1 -> entry)

     def overlapping(range: Text.Range, branches: T): T =

     {

       val start = Text.Info[Any](Text.Range(range.start), Nil)

       val stop = Text.Info[Any](Text.Range(range.stop), Nil)

       branches.get(stop) match {

         case Some(end) if range overlaps end._1.range =>

           update(branches.range(start, stop), end)

         case _ => branches.range(start, stop)

       }

     }

   }

   val empty = new Markup_Tree(Branches.empty)

 }

 case class Markup_Tree(val branches: Markup_Tree.Branches.T)

 {

   import Markup_Tree._

   override def toString =

     branches.toList.map(_._2) match {

       case Nil => "Empty"

       case list => list.mkString("Tree(", ",", ")")

     }

   def + (new_info: Text.Info[Any]): Markup_Tree =

   {

     branches.get(new_info) match {

       case None =>

         new Markup_Tree(Branches.update(branches, new_info -> empty))

       case Some((info, subtree)) =>

         if (info.range != new_info.range && info.contains(new_info))

           new Markup_Tree(Branches.update(branches, info -> (subtree + new_info)))

         else if (new_info.contains(branches.head._1) && new_info.contains(branches.last._1))

           new Markup_Tree(Branches.update(Branches.empty, (new_info -> this)))

         else {

           val body = Branches.overlapping(new_info.range, branches)

           if (body.forall(e => new_info.contains(e._1))) {

             val rest = (branches /: body) { case (bs, (e, _)) => bs - e }

             new Markup_Tree(Branches.update(rest, new_info -> new Markup_Tree(body)))

           }

           else { // FIXME split markup!?

             System.err.println("Ignored overlapping markup information: " + new_info)

             this

           }

         }

     }

   }

   def select[A](root: Text.Info[A])(sel: PartialFunction[Text.Info[Any], A]): Stream[Text.Info[A]] =

   {

     def stream(parent: Text.Info[A], bs: Branches.T): Stream[Text.Info[A]] =

     {

       val substream =

         (for ((_, (info, subtree)) <- Branches.overlapping(parent.range, bs).toStream) yield {

           if (sel.isDefinedAt(info)) {

             val current = Text.Info(info.range.restrict(parent.range), sel(info))

             stream(current, subtree.branches)

           }

           else stream(parent.restrict(info.range), subtree.branches)

         }).flatten

       def padding(last: Text.Offset, s: Stream[Text.Info[A]]): Stream[Text.Info[A]] =

         s match {

           case info #:: rest =>

             val Text.Range(start, stop) = info.range

             if (last < start)

               parent.restrict(Text.Range(last, start)) #:: info #:: padding(stop, rest)

             else info #:: padding(stop, rest)

           case Stream.Empty =>

             if (last < parent.range.stop)

               Stream(parent.restrict(Text.Range(last, parent.range.stop)))

             else Stream.Empty

         }

       if (substream.isEmpty) Stream(parent)

       else padding(parent.range.start, substream)

     }

     stream(root, branches)

   }

   def swing_tree(parent: DefaultMutableTreeNode)

     (swing_node: Text.Info[Any] => DefaultMutableTreeNode)

   {

     for ((_, (info, subtree)) <- branches) {

       val current = swing_node(info)

       subtree.swing_tree(current)(swing_node)

       parent.add(current)

     }

   }

 }