import { ById, CollectionById } from '@app/models/state'
import _ from 'lodash'

export function reduceById<T extends { id: string }>(collection: T[]): ById<T> {
  return collection.reduce((acc, value) => {
    acc[value.id] = value
    return acc
  }, {} as ById<T>)
}

export function mergeById<T extends { [id: string]: unknown }>(object: T, source: T): void {
  _.merge(object, source)
}

export function mapById<T>(object: ById<T>, ids: string[]): T[] {
  return ids.map(id => object[id]).filter(a => a !== undefined)
}

export function mapId(entities: { id: string }[]): string[] {
  return entities.map(e => e.id)
}

export function mapCollectionById<T, U extends { id: string }>(
  collection: T[],
  map: (item: T) => U,
): CollectionById<U> {
  const mapped = collection.map(map)
  return {
    byId: reduceById(mapped),
    allIds: mapId(mapped),
  }
}