Runnable mergeTokens()

in hybrid/src/main/java/jetbrains/jetpad/hybrid/TokenOperations.java [162:230]
65 lines of code
8 McCabe index (conditional complexity)

  Runnable mergeTokens(Cell contextCell, boolean backward) {
    abstract class TokenHandler {
      abstract void handle(Token token);
    }

    final int index = tokenViews().indexOf(contextCell);
    Token token = tokens().get(index);

    final TokenHandler tokenHandler;
    Function<Token, Runnable> completer;
    final String newTokenText;
    final int pos;
    if (backward) {
      Token prevToken = tokens().get(index - 1);
      String prevText = prevToken.text();
      if (prevToken.noSpaceToRight() || token.noSpaceToLeft()) {
        prevText = prevText.substring(0, prevText.length() - 1);
      }
      pos = prevText.length();
      newTokenText = prevText + token.text();
      tokenHandler = new TokenHandler() {
        @Override
        public void handle(Token item) {
          tokens().remove(index);
          tokens().set(index - 1, item);
        }
      };
      completer = new Function<Token, Runnable>() {
        @Override
        public Runnable apply(Token token) {
          tokenHandler.handle(token);
          return select(index - 1, 0);
        }
      };
    } else {
      String currentText = token.text();
      pos = currentText.length();
      Token nextToken = tokens().get(index + 1);
      String nextText = nextToken.text();
      if (token.noSpaceToRight() || nextToken.noSpaceToLeft()) {
        nextText = nextText.substring(1);
      }
      newTokenText = currentText + nextText;
      tokenHandler = new TokenHandler() {
        @Override
        public void handle(Token item) {
          tokens().remove(index + 1);
          tokens().set(index, item);
        }
      };
      completer = new Function<Token, Runnable>() {
        @Override
        public Runnable apply(Token token) {
          tokenHandler.handle(token);
          return select(index, 0);
        }
      };
    }

    CompletionItems completion = mySync.tokenCompletion().completion(completer);
    List<CompletionItem> matches = completion.matches(newTokenText);
    if (matches.size() == 1) {
      matches.get(0).complete(newTokenText);
    } else {
      tokenHandler.handle(new ErrorToken(newTokenText));
    }

    return select(backward ? index - 1 : index, pos);
  }