/*  Title:      Pure/PIDE/markup_tree.scala

    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

{

  type Select[A] = PartialFunction[Text.Markup, A]

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

  object Branches

  {

    type Entry = (Text.Markup, Markup_Tree)

    type T = SortedMap[Text.Range, Entry]

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

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

    def single(entry: Entry): T = update(empty, entry)

    def overlapping(range: Text.Range, branches: T): T =  // FIXME special cases!?

    {

      val start = Text.Range(range.start)

      val stop = Text.Range(range.stop)

      val bs = branches.range(start, stop)

      branches.get(stop) match {

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

        case _ => bs

      }

    }

  }

}

class Markup_Tree private(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.Markup): Markup_Tree =

  {

    val new_range = new_info.range

    branches.get(new_range) match {

      case None =>

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

      case Some((info, subtree)) =>

        val range = info.range

        if (range.contains(new_range))

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

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

          new Markup_Tree(Branches.single(new_info -> this))

        else {

          val body = Branches.overlapping(new_range, branches)

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

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

              if (body.size > 1)

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

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

              else branches

            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

          }

        }

    }

  }

  private def overlapping(range: Text.Range): Stream[(Text.Range, Branches.Entry)] =

    Branches.overlapping(range, branches).toStream

  def select[A](root_range: Text.Range)(result: Markup_Tree.Select[A])

    : Stream[Text.Info[Option[A]]] =

  {

    def stream(

      last: Text.Offset,

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

        : Stream[Text.Info[Option[A]]] =

    {

      stack match {

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

          val subrange = range.restrict(root_range)

          val subtree = tree.overlapping(subrange)

          val start = subrange.start

          if (result.isDefinedAt(info)) {

            val next = Text.Info[Option[A]](subrange, Some(result(info)))

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

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

            else nexts

          }

          else 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), None))

          else Stream.empty

      }

    }

    stream(root_range.start, List((Text.Info(root_range, None), overlapping(root_range))))

  }

  def swing_tree(parent: DefaultMutableTreeNode)

    (swing_node: Text.Markup => DefaultMutableTreeNode)

  {

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

      val current = swing_node(info)

      subtree.swing_tree(current)(swing_node)

      parent.add(current)

    }

  }

}