di122/backend-project-lvl2

import _ from 'lodash';

const indentSize = (depth) => ' '.repeat(depth * 2);

const stringify = (value, depth) => {
  if (!(value instanceof Object)) {
    return value;
  }
  const result = _.keys(value).map(
    (key) => `${indentSize(depth + 2)}${key}: ${value[key]}`
  );
  return ['{', ...result, `${indentSize(depth)}}`].join('\n');
};

const propertyActions = {
  added: (depth, key, oldValue, newValue) =>
    `${indentSize(depth + 1)}+ ${key}: ${stringify(newValue, depth + 2)}`,

  unchanged: (depth, key, oldValue) =>
    `${indentSize(depth + 1)}  ${key}: ${stringify(oldValue, depth + 2)}`,

  deleted: (depth, key, oldValue) =>
    `${indentSize(depth + 1)}- ${key}: ${stringify(oldValue, depth + 2)}`,

  changed: (depth, key, oldValue, newValue) => `${indentSize(
    depth + 1
  )}- ${key}: ${stringify(oldValue, depth + 2)}
${indentSize(depth + 1)}+ ${key}: ${stringify(newValue, depth + 2)}`,

  nested: (depth, key, oldValue, newValue, children, render) =>
    `${indentSize(depth + 1)}${key}: {\n${render(
      children,
      depth + 1
    )}\n${indentSize(depth + 1)}}`,
};

const render = (ast, depth = 0) => {
  const result = ast.map((obj) => {
    const { key, type, oldValue, newValue, children } = obj;

    return propertyActions[type](
      depth,
      key,
      oldValue,
      newValue,
      children,
      render
    );
  });
  const output = _.flatten(result).join('\n');
  return output;
};

export default (ast) => `{\n${render(ast, 0)}\n}`;