import Attribute from '../conditions/Attribute';
import {forIn, isPlainObject, isNull, reduceRight, reduce} from 'lodash';

export default function getAttributesForPluckParams(topLevelOrNestedAttributes: (string|Object)[]): Attribute[] {
  let pluckAttributes: Attribute[] = [];
  topLevelOrNestedAttributes.forEach(attr => {
    switch(typeof attr) {
      case 'string':
        pluckAttributes.push(new Attribute(attr));
        break;
      case 'object':
        const attributes = getAttributesFromNestedObject(attr);
        // TODO: Allow for shorthand syntax {topLevel: { nested: ['nested1', 'nested2']}}
        attributes.forEach(nestedAttribute => {
          pluckAttributes.push(new Attribute(nestedAttribute));
        });
        break;
    }
  });
  return pluckAttributes;
}

export function getAttributesFromNestedObject(nestedObject: Object) {
  const nestedObjects: Object[] = [];
  recurse(nestedObject, []);
  return nestedObjects;

  function recurse(nestedObject: Object, path: string[]) {
    forIn(nestedObject, (value, key) => {
      const isObject = isPlainObject(value);
      const isArray = Array.isArray(value);
      if (isObject) {
        recurse(value, path.concat(key));
      } else if (isArray) {
        let pathToArray = path.concat(key);
        value.forEach(key => {
          nestedObjects.push(nestedAttributeFromPath(pathToArray.concat(key)));
        });
      }
      else if (value === true) {
        nestedObjects.push(nestedAttributeFromPath(path.concat(key)));
      } else {
        throw new Error()
      }
    });
  }
}

function nestedAttributeFromPath(path: string[]) {
  return reduceRight(path, (nested, key) => {
    let parent = {};
    parent[key] = nested;
    return parent;
  }, true);
}