vbwdev/project-lvl2-s269

import _ from 'lodash';

const getSpaces = depth => '    '.repeat(depth);

const renderObjectInner = (values, depth) => `{\n${values.join('')}${getSpaces(depth)}}`;

const renderString = (sign, key, value, depth) => {
  if (!_.isPlainObject(value)) {
    return `${getSpaces(depth)}  ${sign} ${key}: ${value}\n`;
  }

  const objectDepth = depth + 1;
  const renderedItems = _.keys(value).map(objectKey => renderString(' ', objectKey, value[objectKey], objectDepth));
  return renderString(sign, key, renderObjectInner(renderedItems, objectDepth), depth);
};

const renderers = {
  nested: ({ key, children }, depth, process) => renderString(' ', key, process(children, depth + 1), depth),

  changed: ({ key, oldValue, newValue }, depth) => [
    renderString('+', key, newValue, depth),
    renderString('-', key, oldValue, depth),
  ],

  added: ({ key, value }, depth) => renderString('+', key, value, depth),

  deleted: ({ key, value }, depth) => renderString('-', key, value, depth),

  unchanged: ({ key, value }, depth) => renderString(' ', key, value, depth),
};

const renderDiffIter = (diff, depth = 0) => {
  const strings = diff.reduce((acc, item) => {
    const render = renderers[item.type];
    if (!render) {
      return acc;
    }
    return [...acc, render(item, depth, renderDiffIter)];
  }, []);
  const flattenedStrings = _.flatten(strings);
  return renderObjectInner(flattenedStrings, depth);
};

const renderDiff = diff => renderDiffIter(diff, 0);

export default renderDiff;