CodeMirror.registerHelper("fold", "brace", function(cm, start) {
  var line = start.line, lineText = cm.getLine(line);
  var startCh, tokenType;

  function findOpening(openCh) {
    for (var at = start.ch, pass = 0;;) {
      var found = lineText.lastIndexOf(openCh, at - 1);
      if (found == -1) {
        if (pass == 1) break;
        pass = 1;
        at = lineText.length;
        continue;
      }
      if (pass == 1 && found < start.ch) break;
      tokenType = cm.getTokenAt(CodeMirror.Pos(line, found + 1)).type;
      if (!/^(comment|string)/.test(tokenType)) return found + 1;
      at = found - 1;
    }
  }

  var startToken = "{", endToken = "}", startCh = findOpening("{");
  if (startCh == null) {
    startToken = "[", endToken = "]";
    startCh = findOpening("[");
  }

  if (startCh == null) return;
  var count = 1, lastLine = cm.lastLine(), end, endCh;
  outer: for (var i = line; i <= lastLine; ++i) {
    var text = cm.getLine(i), pos = i == line ? startCh : 0;
    for (;;) {
      var nextOpen = text.indexOf(startToken, pos), nextClose = text.indexOf(endToken, pos);
      if (nextOpen < 0) nextOpen = text.length;
      if (nextClose < 0) nextClose = text.length;
      pos = Math.min(nextOpen, nextClose);
      if (pos == text.length) break;
      if (cm.getTokenAt(CodeMirror.Pos(i, pos + 1)).type == tokenType) {
        if (pos == nextOpen) ++count;
        else if (!--count) { end = i; endCh = pos; break outer; }
      }
      ++pos;
    }
  }
  if (end == null || line == end && endCh == startCh) return;
  return {from: CodeMirror.Pos(line, startCh),
          to: CodeMirror.Pos(end, endCh)};
});
CodeMirror.braceRangeFinder = CodeMirror.fold.brace; // deprecated

CodeMirror.registerHelper("fold", "import", function(cm, start) {
  function hasImport(line) {
    if (line < cm.firstLine() || line > cm.lastLine()) return null;
    var start = cm.getTokenAt(CodeMirror.Pos(line, 1));
    if (!/\S/.test(start.string)) start = cm.getTokenAt(CodeMirror.Pos(line, start.end + 1));
    if (start.type != "keyword" || start.string != "import") return null;
    // Now find closing semicolon, return its position
    for (var i = line, e = Math.min(cm.lastLine(), line + 10); i <= e; ++i) {
      var text = cm.getLine(i), semi = text.indexOf(";");
      if (semi != -1) return {startCh: start.end, end: CodeMirror.Pos(i, semi)};
    }
  }

  var start = start.line, has = hasImport(start), prev;
  if (!has || hasImport(start - 1) || ((prev = hasImport(start - 2)) && prev.end.line == start - 1))
    return null;
  for (var end = has.end;;) {
    var next = hasImport(end.line + 1);
    if (next == null) break;
    end = next.end;
  }
  return {from: cm.clipPos(CodeMirror.Pos(start, has.startCh + 1)), to: end};
});
CodeMirror.importRangeFinder = CodeMirror.fold["import"]; // deprecated

CodeMirror.registerHelper("fold", "include", function(cm, start) {
  function hasInclude(line) {
    if (line < cm.firstLine() || line > cm.lastLine()) return null;
    var start = cm.getTokenAt(CodeMirror.Pos(line, 1));
    if (!/\S/.test(start.string)) start = cm.getTokenAt(CodeMirror.Pos(line, start.end + 1));
    if (start.type == "meta" && start.string.slice(0, 8) == "#include") return start.start + 8;
  }

  var start = start.line, has = hasInclude(start);
  if (has == null || hasInclude(start - 1) != null) return null;
  for (var end = start;;) {
    var next = hasInclude(end + 1);
    if (next == null) break;
    ++end;
  }
  return {from: CodeMirror.Pos(start, has + 1),
          to: cm.clipPos(CodeMirror.Pos(end))};
});
CodeMirror.includeRangeFinder = CodeMirror.fold.include; // deprecated
