import * as util from '../util.js';

export { addTextLabel };

/*
 * Attaches a text label to the specified root. Handles escape sequences.
 */
function addTextLabel(root, node) {
  var domNode = root.append('text');

  var lines = processEscapeSequences(node.label).split('\n');
  for (var i = 0; i < lines.length; i++) {
    domNode
      .append('tspan')
      .attr('xml:space', 'preserve')
      .attr('dy', '1em')
      .attr('x', '1')
      .text(lines[i]);
  }

  util.applyStyle(domNode, node.labelStyle);

  return domNode;
}

function processEscapeSequences(text) {
  var newText = '';
  var escaped = false;
  var ch;
  for (var i = 0; i < text.length; ++i) {
    ch = text[i];
    if (escaped) {
      switch (ch) {
        case 'n':
          newText += '\n';
          break;
        default:
          newText += ch;
      }
      escaped = false;
    } else if (ch === '\\') {
      escaped = true;
    } else {
      newText += ch;
    }
  }
  return newText;
}