/*  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)

    }

  }

}