/*  Title:      Pure/PIDE/markup_tree.scala

     Module:     PIDE

     Author:     Fabian Immler, TU Munich

     Author:     Makarius

 Markup trees over nested / non-overlapping text ranges.

 */

 package isabelle

 import java.lang.System

 import javax.swing.tree.DefaultMutableTreeNode

 import scala.collection.immutable.SortedMap

 object Markup_Tree

 {

   sealed case class Cumulate[A](

     info: A, result: PartialFunction[(A, Text.Markup), A], elements: Option[Set[String]])

   sealed case class Select[A](

     result: PartialFunction[Text.Markup, A], elements: Option[Set[String]])

   val empty: Markup_Tree = new Markup_Tree(Branches.empty)

   object Entry

   {

     def apply(markup: Text.Markup, subtree: Markup_Tree): Entry =

       Entry(markup.range, List(markup.info), Set(markup.info.markup.name), subtree)

   }

   sealed case class Entry(

     range: Text.Range,

     rev_markup: List[XML.Elem],

     elements: Set[String],

     subtree: Markup_Tree)

   {

     def + (info: XML.Elem): Entry =

       if (elements(info.markup.name)) copy(rev_markup = info :: rev_markup)

       else copy(rev_markup = info :: rev_markup, elements = elements + info.markup.name)

     def markup: List[XML.Elem] = rev_markup.reverse

   }

   object Branches

   {

     type T = SortedMap[Text.Range, Entry]

     val empty: T = SortedMap.empty(Text.Range.Ordering)

   }

 }

 class Markup_Tree private(branches: Markup_Tree.Branches.T)

 {

   private def this(branches: Markup_Tree.Branches.T, entry: Markup_Tree.Entry) =

     this(branches + (entry.range -> entry))

   import Markup_Tree._

   override def toString =

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

       case Nil => "Empty"

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

     }

   private def overlapping(range: Text.Range): Branches.T =

   {

     val start = Text.Range(range.start)

     val stop = Text.Range(range.stop)

     val bs = branches.range(start, stop)

     // FIXME check after Scala 2.8.x

     branches.get(stop) match {

       case Some(end) if range overlaps end.range => bs + (end.range -> end)

       case _ => bs

     }

   }

   def + (new_markup: Text.Markup): Markup_Tree =

   {

     val new_range = new_markup.range

     branches.get(new_range) match {

       case None => new Markup_Tree(branches, Entry(new_markup, empty))

       case Some(entry) =>

         if (entry.range == new_range)

           new Markup_Tree(branches, entry + new_markup.info)

         else if (entry.range.contains(new_range))

           new Markup_Tree(branches, entry.copy(subtree = entry.subtree + new_markup))

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

           new Markup_Tree(Branches.empty, Entry(new_markup, this))

         else {

           val body = overlapping(new_range)

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

             val rest = // branches -- body, modulo workarounds for Redblack in Scala 2.8.0 FIXME

               if (body.size > 1)

                 (Branches.empty /: branches)((rest, entry) =>

                   if (body.isDefinedAt(entry._1)) rest else rest + entry)

               else branches

             new Markup_Tree(rest, Entry(new_markup, new Markup_Tree(body)))

           }

           else { // FIXME split markup!?

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

             this

           }

         }

     }

   }

   def cumulate[A](root_range: Text.Range)(body: Cumulate[A]): Stream[Text.Info[A]] =

   {

     val root_info = body.info

     def result(x: A, entry: Entry): Option[A] =

       if (body.elements match { case Some(es) => es.exists(entry.elements) case None => true }) {

         val (y, changed) =

           (entry.markup :\ (x, false))((info, res) =>

             {

               val (y, changed) = res

               val arg = (y, Text.Info(entry.range, info))

               if (body.result.isDefinedAt(arg)) (body.result(arg), true)

               else res

             })

         if (changed) Some(y) else None

       }

       else None

     def stream(

       last: Text.Offset,

       stack: List[(Text.Info[A], Stream[(Text.Range, Entry)])]): Stream[Text.Info[A]] =

     {

       stack match {

         case (parent, (range, entry) #:: more) :: rest =>

           val subrange = range.restrict(root_range)

           val subtree = entry.subtree.overlapping(subrange).toStream

           val start = subrange.start

           result(parent.info, entry) match {

             case Some(res) =>

               val next = Text.Info(subrange, res)

               val nexts = stream(start, (next, subtree) :: (parent, more) :: rest)

               if (last < start) parent.restrict(Text.Range(last, start)) #:: nexts

               else nexts

             case None => stream(last, (parent, subtree #::: more) :: rest)

           }

         case (parent, Stream.Empty) :: rest =>

           val stop = parent.range.stop

           val nexts = stream(stop, rest)

           if (last < stop) parent.restrict(Text.Range(last, stop)) #:: nexts

           else nexts

         case Nil =>

           val stop = root_range.stop

           if (last < stop) Stream(Text.Info(Text.Range(last, stop), root_info))

           else Stream.empty

       }

     }

     stream(root_range.start,

       List((Text.Info(root_range, root_info), overlapping(root_range).toStream)))

   }

   def swing_tree(parent: DefaultMutableTreeNode)

     (swing_node: Text.Markup => DefaultMutableTreeNode)

   {

     for ((_, entry) <- branches) {

       var current = parent

       for (info <- entry.markup) {

         val node = swing_node(Text.Info(entry.range, info))

         current.add(node)

         current = node

       }

       entry.subtree.swing_tree(current)(swing_node)

     }

   }

 }