/*  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

import scala.collection.mutable

import scala.annotation.tailrec

object Markup_Tree

{

  /* construct trees */

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

  def merge_disjoint(trees: List[Markup_Tree]): Markup_Tree =

    trees match {

      case Nil => empty

      case head :: tail =>

        new Markup_Tree(

          (head.branches /: tail) {

            case (branches, tree) =>

              (branches /: tree.branches) {

                case (bs, (r, entry)) =>

                  require(!bs.isDefinedAt(r))

                  bs + (r -> entry)

              }

          })

    }

  /* tree building blocks */

  object Elements

  {

    val empty = new Elements(Set.empty)

  }

  final class Elements private(private val rep: Set[String])

  {

    def contains(name: String): Boolean = rep.contains(name)

    def + (name: String): Elements =

      if (contains(name)) this

      else new Elements(rep + name)

    def + (elem: XML.Elem): Elements = this + elem.markup.name

    def ++ (elems: Iterable[XML.Elem]): Elements = (this /: elems.iterator)(_ + _)

    def ++ (other: Elements): Elements =

      if (this eq other) this

      else if (rep.isEmpty) other

      else (this /: other.rep)(_ + _)

  }

  object Entry

  {

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

      Entry(markup.range, List(markup.info), Elements.empty + markup.info,

        subtree, subtree.make_elements)

    def apply(range: Text.Range, rev_markups: List[XML.Elem], subtree: Markup_Tree): Entry =

      Entry(range, rev_markups, Elements.empty ++ rev_markups,

        subtree, subtree.make_elements)

  }

  sealed case class Entry(

    range: Text.Range,

    rev_markup: List[XML.Elem],

    elements: Elements,

    subtree: Markup_Tree,

    subtree_elements: Elements)

  {

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

    def + (markup: Text.Markup): Entry =

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

    def \ (markup: Text.Markup): Entry =

      copy(subtree = subtree + markup, subtree_elements = subtree_elements + markup.info)

  }

  object Branches

  {

    type T = SortedMap[Text.Range, Entry]

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

  }

  /* XML representation */

  @tailrec private def strip_elems(

      elems: List[XML.Elem], body: XML.Body): (List[XML.Elem], XML.Body) =

    body match {

      case List(XML.Wrapped_Elem(markup1, body1, body2)) =>

        strip_elems(XML.Elem(markup1, body1) :: elems, body2)

      case List(XML.Elem(markup1, body1)) =>

        strip_elems(XML.Elem(markup1, Nil) :: elems, body1)

      case _ => (elems, body)

    }

  private def make_trees(acc: (Int, List[Markup_Tree]), tree: XML.Tree): (Int, List[Markup_Tree]) =

    {

      val (offset, markup_trees) = acc

      strip_elems(Nil, List(tree)) match {

        case (Nil, body) =>

          (offset + XML.text_length(body), markup_trees)

        case (elems, body) =>

          val (end_offset, subtrees) = ((offset, Nil: List[Markup_Tree]) /: body)(make_trees)

          val range = Text.Range(offset, end_offset)

          val entry = Entry(range, elems, merge_disjoint(subtrees))

          (end_offset, new Markup_Tree(Branches.empty, entry) :: markup_trees)

      }

    }

  def from_XML(body: XML.Body): Markup_Tree =

    merge_disjoint(((0, Nil: List[Markup_Tree]) /: body)(make_trees)._2)

}

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

{

  import Markup_Tree._

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

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

  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)

    branches.get(stop) match {

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

      case _ => bs

    }

  }

  def make_elements: Elements =

    (Elements.empty /: branches)(

      { case (elements, (_, entry)) => elements ++ entry.subtree_elements ++ entry.elements })

  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)

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

          new Markup_Tree(branches, entry \ 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)))

            new Markup_Tree(branches -- body.keys, Entry(new_markup, new Markup_Tree(body)))

          else {

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

              body.filter(e => !new_range.contains(e._1)).mkString("\n"))

            this

          }

        }

    }

  }

  def to_XML(root_range: Text.Range, text: CharSequence, filter: XML.Elem => Boolean): XML.Body =

  {

    def make_text(start: Text.Offset, stop: Text.Offset): XML.Body =

      if (start == stop) Nil

      else List(XML.Text(text.subSequence(start, stop).toString))

    def make_elems(rev_markups: List[XML.Elem], body: XML.Body): XML.Body =

      (body /: rev_markups) {

        case (b, elem) =>

          if (!filter(elem)) b

          else if (elem.body.isEmpty) List(XML.Elem(elem.markup, b))

          else List(XML.Wrapped_Elem(elem.markup, elem.body, b))

      }

    def make_body(elem_range: Text.Range, elem_markup: List[XML.Elem], entries: Branches.T)

      : XML.Body =

    {

      val body = new mutable.ListBuffer[XML.Tree]

      var last = elem_range.start

      for ((range, entry) <- entries) {

        val subrange = range.restrict(elem_range)

        body ++= make_text(last, subrange.start)

        body ++= make_body(subrange, entry.rev_markup, entry.subtree.overlapping(subrange))

        last = subrange.stop

      }

      body ++= make_text(last, elem_range.stop)

      make_elems(elem_markup, body.toList)

    }

   make_body(root_range, Nil, overlapping(root_range))

  }

  def to_XML(text: CharSequence): XML.Body =

    to_XML(Text.Range(0, text.length), text, (_: XML.Elem) => true)

  def cumulate[A](root_range: Text.Range, root_info: A, result_elements: Option[Set[String]],

    result: PartialFunction[(A, Text.Markup), A]): Stream[Text.Info[A]] =

  {

    val notable: Elements => Boolean =

      result_elements match {

        case Some(res) => (elements: Elements) => res.exists(elements.contains)

        case None => (elements: Elements) => true

      }

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

    {

      val (y, changed) =

        // FIXME proper cumulation order (including status markup) (!?)

        ((x, false) /: entry.rev_markup)((res, info) =>

          {

            val (y, changed) = res

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

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

            else res

          })

      if (changed) Some(y) 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 =

            if (notable(entry.subtree_elements))

              entry.subtree.overlapping(subrange).toStream

            else Stream.empty

          val start = subrange.start

          (if (notable(entry.elements)) results(parent.info, entry) else None) 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.Info[List[XML.Elem]] => DefaultMutableTreeNode)

  {

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

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

      entry.subtree.swing_tree(node, swing_node)

      parent.add(node)

    }

  }

}