javiercejudo/modelico

import {objToArr, reviverOrAsIs, isFunction} from '../U'
import AbstractMap, {set, of, metadata} from './AbstractMap'

const stringifyReducer = (acc, pair) => {
  acc[pair[0]] = pair[1]

  return acc
}

const parseReducer = (valueReviver, obj, path) => (acc, key) => [
  ...acc,
  [key, valueReviver('', obj[key], path.concat(key))]
]

const reviverFactory = valueMetadata => (k, v, path = []) => {
  if (k !== '') {
    return v
  }

  const valueReviver = reviverOrAsIs(
    isFunction(valueMetadata) ? valueMetadata(v, path) : valueMetadata
  )

  const innerMap =
    v === null
      ? null
      : new Map(Object.keys(v).reduce(parseReducer(valueReviver, v, path), []))

  return StringMap.fromMap(innerMap)
}

let EMPTY_STRING_MAP

class StringMap extends AbstractMap {
  constructor(innerMap) {
    super(StringMap, innerMap, EMPTY_STRING_MAP)

    if (!EMPTY_STRING_MAP && this.size === 0) {
      EMPTY_STRING_MAP = this
    }

    Object.freeze(this)
  }

  get [Symbol.toStringTag]() {
    return 'ModelicoStringMap'
  }

  set(key, value) {
    return set(this, StringMap, key, value)
  }

  toJSON() {
    return [...this].reduce(stringifyReducer, {})
  }

  static fromMap(map) {
    return new StringMap(map)
  }

  static fromArray(pairs) {
    return StringMap.fromMap(new Map(pairs))
  }

  static of(...args) {
    return of(StringMap, args)
  }

  static fromObject(obj) {
    return StringMap.fromArray(objToArr(obj))
  }

  static metadata(valueMetadata) {
    return metadata(StringMap)(reviverFactory)(valueMetadata)()
  }

  static EMPTY() {
    return EMPTY_STRING_MAP || StringMap.of()
  }
}

StringMap.displayName = 'StringMap'

export default Object.freeze(StringMap)