import yaml from 'js-yaml';
import { type KeyValueMap } from '../types';

const getPredicate = (type: string) => (data) =>
  typeof data === 'string' && data.startsWith(`${type} `);
const getRepresent = (type: string) => (data) =>
  typeof data === 'string' ? data.replace(`${type} `, '') : JSON.stringify(data);
const getConstruct = (type: string) => (data) =>
  typeof data === 'string' ? `${type} ${data}` : `${type} ${typeof data}`;

const growYamlConstructors = [
  '!g.csv',
  '!g.doc',
  '!g.json',
  '!g.static',
  '!g.string',
  '!g.url',
  '!g.yaml',
];

const growYamlTypes = growYamlConstructors.map(
  (type: string) =>
    new yaml.Type(type, {
      kind: 'scalar',
      predicate: getPredicate(type),
      represent: getRepresent(type),
      construct: getConstruct(type),
    }),
);

/**
 * Convert object to yaml
 * @param {Object} obj Source object
 * @returns {String} Yaml representation of source object
 */
export const stringify = <T = KeyValueMap>(obj: T): string => {
  const GROW_SCHEMA = yaml.DEFAULT_SCHEMA.extend(growYamlTypes);
  return yaml.dump(obj, { schema: GROW_SCHEMA });
};

/**
 * Parse yaml to object
 * @param {String} string yaml string
 * @returns {Object} parsed object
 */
export const parse = <T = KeyValueMap>(obj: string): T => {
  const GROW_SCHEMA = yaml.DEFAULT_SCHEMA.extend(growYamlTypes);
  return yaml.load(obj, { schema: GROW_SCHEMA }) as T;
};