src/Pure/Thy/thy_syntax.scala

clarified boundary cases of Document.Node.Name;

/*  Title:      Pure/Thy/thy_syntax.scala
    Author:     Makarius

Superficial theory syntax: tokens and spans.
*/

package isabelle


import scala.collection.mutable
import scala.annotation.tailrec


object Thy_Syntax
{
  /** nested structure **/

  object Structure
  {
    sealed abstract class Entry { def length: Int }
    case class Block(val name: String, val body: List[Entry]) extends Entry
    {
      val length: Int = (0 /: body)(_ + _.length)
    }
    case class Atom(val command: Command) extends Entry
    {
      def length: Int = command.length
    }

    def parse(syntax: Outer_Syntax, node_name: Document.Node.Name, text: CharSequence): Entry =
    {
      /* stack operations */

      def buffer(): mutable.ListBuffer[Entry] = new mutable.ListBuffer[Entry]
      var stack: List[(Int, String, mutable.ListBuffer[Entry])] =
        List((0, node_name.toString, buffer()))

      @tailrec def close(level: Int => Boolean)
      {
        stack match {
          case (lev, name, body) :: (_, _, body2) :: rest if level(lev) =>
            body2 += Block(name, body.toList)
            stack = stack.tail
            close(level)
          case _ =>
        }
      }

      def result(): Entry =
      {
        close(_ => true)
        val (_, name, body) = stack.head
        Block(name, body.toList)
      }

      def add(command: Command)
      {
        syntax.heading_level(command) match {
          case Some(i) =>
            close(_ > i)
            stack = (i + 1, command.source, buffer()) :: stack
          case None =>
        }
        stack.head._3 += Atom(command)
      }


      /* result structure */

      val spans = parse_spans(syntax.scan(text))
      spans.foreach(span => add(Command(Document_ID.none, node_name, span, Nil)))
      result()
    }
  }



  /** parse spans **/

  def parse_spans(toks: List[Token]): List[List[Token]] =
  {
    val result = new mutable.ListBuffer[List[Token]]
    val span = new mutable.ListBuffer[Token]
    val improper = new mutable.ListBuffer[Token]

    def flush()
    {
      if (!span.isEmpty) { result += span.toList; span.clear }
      if (!improper.isEmpty) { result += improper.toList; improper.clear }
    }
    for (tok <- toks) {
      if (tok.is_command) { flush(); span += tok }
      else if (tok.is_improper) improper += tok
      else { span ++= improper; improper.clear; span += tok }
    }
    flush()

    result.toList
  }



  /** perspective **/

  def command_perspective(
      node: Document.Node,
      perspective: Text.Perspective,
      overlays: Document.Node.Overlays): (Command.Perspective, Command.Perspective) =
  {
    if (perspective.is_empty && overlays.is_empty)
      (Command.Perspective.empty, Command.Perspective.empty)
    else {
      val has_overlay = overlays.commands
      val visible = new mutable.ListBuffer[Command]
      val visible_overlay = new mutable.ListBuffer[Command]
      @tailrec
      def check_ranges(ranges: List[Text.Range], commands: Stream[(Command, Text.Offset)])
      {
        (ranges, commands) match {
          case (range :: more_ranges, (command, offset) #:: more_commands) =>
            val command_range = command.range + offset
            range compare command_range match {
              case 0 =>
                visible += command
                visible_overlay += command
                check_ranges(ranges, more_commands)
              case c =>
                if (has_overlay(command)) visible_overlay += command

                if (c < 0) check_ranges(more_ranges, commands)
                else check_ranges(ranges, more_commands)
            }

          case (Nil, (command, _) #:: more_commands) =>
            if (has_overlay(command)) visible_overlay += command

            check_ranges(Nil, more_commands)

          case _ =>
        }
      }

      val commands =
        if (overlays.is_empty) node.command_range(perspective.range)
        else node.command_range()
      check_ranges(perspective.ranges, commands.toStream)
      (Command.Perspective(visible.toList), Command.Perspective(visible_overlay.toList))
    }
  }



  /** header edits: structure and outer syntax **/

  private def header_edits(
    base_syntax: Outer_Syntax,
    previous: Document.Version,
    edits: List[Document.Edit_Text])
    : (Outer_Syntax, List[Document.Node.Name], Document.Nodes, List[Document.Edit_Command]) =
  {
    var updated_imports = false
    var updated_keywords = false
    var nodes = previous.nodes
    val doc_edits = new mutable.ListBuffer[Document.Edit_Command]

    edits foreach {
      case (name, Document.Node.Deps(header)) =>
        val node = nodes(name)
        val update_header =
          !node.header.errors.isEmpty || !header.errors.isEmpty || node.header != header
        if (update_header) {
          val node1 = node.update_header(header)
          updated_imports = updated_imports || (node.header.imports != node1.header.imports)
          updated_keywords = updated_keywords || (node.header.keywords != node1.header.keywords)
          nodes += (name -> node1)
          doc_edits += (name -> Document.Node.Deps(header))
        }
      case _ =>
    }

    val syntax =
      if (previous.is_init || updated_keywords)
        (base_syntax /: nodes.entries) {
          case (syn, (_, node)) => syn.add_keywords(node.header.keywords)
        }
      else previous.syntax

    val reparse =
      if (updated_imports || updated_keywords)
        nodes.descendants(doc_edits.iterator.map(_._1).toList)
      else Nil

    (syntax, reparse, nodes, doc_edits.toList)
  }



  /** text edits **/

  /* edit individual command source */

  @tailrec def edit_text(eds: List[Text.Edit], commands: Linear_Set[Command]): Linear_Set[Command] =
  {
    eds match {
      case e :: es =>
        Document.Node.Commands.starts(commands.iterator).find {
          case (cmd, cmd_start) =>
            e.can_edit(cmd.source, cmd_start) ||
              e.is_insert && e.start == cmd_start + cmd.length
        } match {
          case Some((cmd, cmd_start)) if e.can_edit(cmd.source, cmd_start) =>
            val (rest, text) = e.edit(cmd.source, cmd_start)
            val new_commands = commands.insert_after(Some(cmd), Command.unparsed(text)) - cmd
            edit_text(rest.toList ::: es, new_commands)

          case Some((cmd, cmd_start)) =>
            edit_text(es, commands.insert_after(Some(cmd), Command.unparsed(e.text)))

          case None =>
            require(e.is_insert && e.start == 0)
            edit_text(es, commands.insert_after(None, Command.unparsed(e.text)))
        }
      case Nil => commands
    }
  }


  /* inlined files */

  private def find_file(tokens: List[Token]): Option[String] =
  {
    def clean(toks: List[Token]): List[Token] =
      toks match {
        case t :: _ :: ts if t.is_keyword && (t.source == "%" || t.source == "--") => clean(ts)
        case t :: ts => t :: clean(ts)
        case Nil => Nil
      }
    val clean_tokens = clean(tokens.filter(_.is_proper))
    clean_tokens.reverse.find(_.is_name).map(_.content)
  }

  def span_files(syntax: Outer_Syntax, span: List[Token]): List[String] =
    syntax.thy_load(span) match {
      case Some(exts) =>
        find_file(span) match {
          case Some(file) =>
            if (exts.isEmpty) List(file)
            else exts.map(ext => file + "." + ext)
          case None => Nil
        }
      case None => Nil
    }

  def resolve_files(
      syntax: Outer_Syntax,
      all_blobs: Map[Document.Node.Name, Bytes],
      name: Document.Node.Name,
      span: List[Token]): Command.Blobs =
  {
    val files = span_files(syntax, span)
    files.map(file => {
      // FIXME proper thy_load append
      val file_name = Document.Node.Name(name.master_dir + file)
      (file_name, all_blobs.get(file_name).map(_.sha1_digest))
    })
  }


  /* reparse range of command spans */

  @tailrec private def chop_common(
      cmds: List[Command], spans: List[(List[Token], Command.Blobs)])
      : (List[Command], List[(List[Token], Command.Blobs)]) =
    (cmds, spans) match {
      case (c :: cs, (span, blobs) :: ps) if c.span == span && c.blobs == blobs =>
        chop_common(cs, ps)
      case _ => (cmds, spans)
    }

  private def reparse_spans(
    syntax: Outer_Syntax,
    all_blobs: Map[Document.Node.Name, Bytes],
    name: Document.Node.Name,
    commands: Linear_Set[Command],
    first: Command, last: Command): Linear_Set[Command] =
  {
    val cmds0 = commands.iterator(first, last).toList
    val spans0 =
      parse_spans(syntax.scan(cmds0.iterator.map(_.source).mkString)).
        map(span => (span, resolve_files(syntax, all_blobs, name, span)))

    val (cmds1, spans1) = chop_common(cmds0, spans0)

    val (rev_cmds2, rev_spans2) = chop_common(cmds1.reverse, spans1.reverse)
    val cmds2 = rev_cmds2.reverse
    val spans2 = rev_spans2.reverse

    cmds2 match {
      case Nil =>
        assert(spans2.isEmpty)
        commands
      case cmd :: _ =>
        val hook = commands.prev(cmd)
        val inserted =
          spans2.map({ case (span, blobs) => Command(Document_ID.make(), name, span, blobs) })
        (commands /: cmds2)(_ - _).append_after(hook, inserted)
    }
  }


  /* recover command spans after edits */

  // FIXME somewhat slow
  private def recover_spans(
    syntax: Outer_Syntax,
    all_blobs: Map[Document.Node.Name, Bytes],
    name: Document.Node.Name,
    perspective: Command.Perspective,
    commands: Linear_Set[Command]): Linear_Set[Command] =
  {
    val visible = perspective.commands.toSet

    def next_invisible_command(cmds: Linear_Set[Command], from: Command): Command =
      cmds.iterator(from).dropWhile(cmd => !cmd.is_command || visible(cmd))
        .find(_.is_command) getOrElse cmds.last

    @tailrec def recover(cmds: Linear_Set[Command]): Linear_Set[Command] =
      cmds.find(_.is_unparsed) match {
        case Some(first_unparsed) =>
          val first = next_invisible_command(cmds.reverse, first_unparsed)
          val last = next_invisible_command(cmds, first_unparsed)
          recover(reparse_spans(syntax, all_blobs, name, cmds, first, last))
        case None => cmds
      }
    recover(commands)
  }


  /* consolidate unfinished spans */

  private def consolidate_spans(
    syntax: Outer_Syntax,
    all_blobs: Map[Document.Node.Name, Bytes],
    reparse_limit: Int,
    name: Document.Node.Name,
    perspective: Command.Perspective,
    commands: Linear_Set[Command]): Linear_Set[Command] =
  {
    if (perspective.commands.isEmpty) commands
    else {
      commands.find(_.is_unfinished) match {
        case Some(first_unfinished) =>
          val visible = perspective.commands.toSet
          commands.reverse.find(visible) match {
            case Some(last_visible) =>
              val it = commands.iterator(last_visible)
              var last = last_visible
              var i = 0
              while (i < reparse_limit && it.hasNext) {
                last = it.next
                i += last.length
              }
              reparse_spans(syntax, all_blobs, name, commands, first_unfinished, last)
            case None => commands
          }
        case None => commands
      }
    }
  }


  /* main */

  def diff_commands(old_cmds: Linear_Set[Command], new_cmds: Linear_Set[Command])
    : List[Command.Edit] =
  {
    val removed = old_cmds.iterator.filter(!new_cmds.contains(_)).toList
    val inserted = new_cmds.iterator.filter(!old_cmds.contains(_)).toList

    removed.reverse.map(cmd => (old_cmds.prev(cmd), None)) :::
    inserted.map(cmd => (new_cmds.prev(cmd), Some(cmd)))
  }

  private def text_edit(
    syntax: Outer_Syntax,
    all_blobs: Map[Document.Node.Name, Bytes],
    reparse_limit: Int,
    node: Document.Node, edit: Document.Edit_Text): Document.Node =
  {
    edit match {
      case (_, Document.Node.Clear()) => node.clear

      case (name, Document.Node.Edits(text_edits)) =>
        val commands0 = node.commands
        val commands1 = edit_text(text_edits, commands0)
        val commands2 = recover_spans(syntax, all_blobs, name, node.perspective.visible, commands1)
        node.update_commands(commands2)

      case (_, Document.Node.Deps(_)) => node

      case (name, Document.Node.Perspective(required, text_perspective, overlays)) =>
        val (visible, visible_overlay) = command_perspective(node, text_perspective, overlays)
        val perspective: Document.Node.Perspective_Command =
          Document.Node.Perspective(required, visible_overlay, overlays)
        if (node.same_perspective(perspective)) node
        else
          node.update_perspective(perspective).update_commands(
            consolidate_spans(syntax, all_blobs, reparse_limit, name, visible, node.commands))

      case (_, Document.Node.Blob(_)) => node
    }
  }

  def text_edits(
      base_syntax: Outer_Syntax,
      reparse_limit: Int,
      previous: Document.Version,
      edits: List[Document.Edit_Text])
    : (List[Document.Edit_Command], Document.Version) =
  {
    val (syntax, reparse, nodes0, doc_edits0) = header_edits(base_syntax, previous, edits)
    val reparse_set = reparse.toSet

    var nodes = nodes0
    val doc_edits = new mutable.ListBuffer[Document.Edit_Command]; doc_edits ++= doc_edits0

    val node_edits =
      (edits ::: reparse.map((_, Document.Node.Edits(Nil)))).groupBy(_._1)
        .asInstanceOf[Map[Document.Node.Name, List[Document.Edit_Text]]]  // FIXME ???

    val all_blobs: Map[Document.Node.Name, Bytes] =
      (Map.empty[Document.Node.Name, Bytes] /: node_edits) {
        case (bs1, (_, es)) => (bs1 /: es) {
          case (bs, (name, Document.Node.Blob(blob))) => bs + (name -> blob)
          case (bs, _) => bs
        }
      }

    node_edits foreach {
      case (name, edits) =>
        val node = nodes(name)
        val commands = node.commands

        val node1 =
          if (reparse_set(name) && !commands.isEmpty)
            node.update_commands(
              reparse_spans(syntax, all_blobs, name, commands, commands.head, commands.last))
          else node
        val node2 = (node1 /: edits)(text_edit(syntax, all_blobs, reparse_limit, _, _))

        if (!(node.same_perspective(node2.perspective)))
          doc_edits += (name -> node2.perspective)

        doc_edits += (name -> Document.Node.Edits(diff_commands(commands, node2.commands)))

        nodes += (name -> node2)
    }

    (doc_edits.toList, Document.Version.make(syntax, nodes))
  }
}