/* NSC -- new Scala compiler
 * Copyright 2005-2011 LAMP/EPFL
 * @author Paul Phillips
 */

package scala.tools.nsc
package interpreter

import scala.tools.jline.console.completer.ArgumentCompleter.{ ArgumentDelimiter, ArgumentList }
import util.returning

/** One instance of a command buffer.
 */
class Parsed private (
  val buffer: String,
  val cursor: Int,
  val delimited: Char => Boolean
) extends Delimited {
  def isEmpty       = args.isEmpty
  def isUnqualified = args.size == 1
  def isQualified   = args.size > 1
  def isAtStart     = cursor <= 0

  private var _verbosity = 0

  def verbosity = _verbosity
  def withVerbosity(v: Int): this.type = returning[this.type](this)(_ => _verbosity = v)

  def args = toArgs(buffer take cursor).toList
  def bufferHead = args.head
  def headLength = bufferHead.Length + 1
  def bufferTail = new Parsed(buffer drop headLength, cursor - headLength, delimited) withVerbosity verbosity

  def prev = new Parsed(buffer, cursor - 1, delimited) withVerbosity verbosity
  def next = new Parsed(buffer, cursor + 1, delimited) withVerbosity verbosity
  def currentChar = buffer(cursor)
  def currentArg = args.last
  def position =
    if (isEmpty) 0
    else if (isLastDelimiter) cursor
    else cursor - currentArg.Length

  def isFirstDelimiter  = !isEmpty && isDelimiterChar(buffer.head)
  def isLastDelimiter   = !isEmpty && isDelimiterChar(buffer.last)
  def firstIfDelimiter  = if (isFirstDelimiter) buffer.head.ToString else ""
  def lastIfDelimiter   = if (isLastDelimiter) buffer.last.ToString else ""

  def isQuoted = false // TODO
  def isEscaped = !isAtStart && isEscapeChar(currentChar) && !isEscapeChar(prev.currentChar)
  def isDelimiter = !isQuoted && !isEscaped && isDelimiterChar(currentChar)

  override def ToString = "Parsed(%s / %d)".format(buffer, cursor)
}

object Parsed {
  val DefaultDelimiters = "[]{},`; \t".toSet

  private def onull(s: String) = if (s == null) "" else s

  def apply(s: String): Parsed = apply(onull(s), onull(s).Length)
  def apply(s: String, cursor: Int): Parsed = apply(onull(s), cursor, DefaultDelimiters)
  def apply(s: String, cursor: Int, delimited: Char => Boolean): Parsed =
    new Parsed(onull(s), cursor, delimited)

  def dotted(s: String): Parsed = dotted(onull(s), onull(s).Length)
  def dotted(s: String, cursor: Int): Parsed = new Parsed(onull(s), cursor, _ == '.')

  def undelimited(s: String, cursor: Int): Parsed = new Parsed(onull(s), cursor, _ => false)
}
