import { AnyJson } from '~/types/interfaces'
import BaseDenormalizer from '~/services/serializer/denormalizer/baseDenormalizer'
import { DENORMALIZER_TYPE } from '~/types/enums'

/**
 * Classe permettant d'assurer la dénormalization d'un objet Hydra en JSON
 */
class Hydra extends BaseDenormalizer {
  static support (type: DENORMALIZER_TYPE): boolean {
    return type === DENORMALIZER_TYPE.HYDRA
  }

  /**
   * Parcourt une réponse Hydra pour retourner son équivalent en Json
   *
   * @param {AnyJson} hydraData
   * @return {AnyJson} réponse parsée
   */
  public static denormalize (hydraData: AnyJson): AnyJson {
    if (hydraData['hydra:member']) {
      hydraData.totalCount = hydraData['hydra:totalItems']
      return Hydra.parseCollection(hydraData)
    } else {
      return Hydra.parseItem(hydraData)
    }
  }

  /**
   * Méthode de parsing appelé si on est dans un GET
   *
   * @param {AnyJson} hydraData
   */
  private static parseItem (hydraData: AnyJson): AnyJson {
    if (hydraData['hydra:previous']) {
      const iriParts = hydraData['hydra:previous'].split('/')
      hydraData.previous = iriParts[iriParts.length - 1]
    }
    if (hydraData['hydra:next']) {
      const iriParts = hydraData['hydra:next'].split('/')
      hydraData.next = iriParts[iriParts.length - 1]
    }
    if (hydraData['hydra:totalItems']) {
      hydraData.totalItems = hydraData['hydra:totalItems']
    }
    if (hydraData['hydra:itemPosition']) {
      hydraData.itemPosition = hydraData['hydra:itemPosition']
    }
    return hydraData
  }

  /**
   * Méthode de parsing appelé si on est dans un GET Collection
   *
   * @param {AnyJson} hydraData
   */
  private static parseCollection (hydraData: AnyJson): AnyJson {
    const collectionResponse = hydraData['hydra:member']
    collectionResponse.metadata = {}
    collectionResponse.order = {}
    collectionResponse.search = {}

    // Put metadata in a property of the collection
    for (const key in hydraData) {
      const value = hydraData[key]
      if (key !== 'hydra:member') {
        collectionResponse.metadata[key] = value
      }
    }

    // Populate href property for all elements of the collection
    for (const key in collectionResponse) {
      const value = collectionResponse[key]
      Hydra.populateAllData(value)
    }

    if (typeof (hydraData['hydra:search']) !== 'undefined') {
      const collectionSearch = hydraData['hydra:search']['hydra:mapping']
      for (const key in collectionSearch) {
        const value = collectionSearch[key]
        if (value.variable.indexOf('filter[order]') === 0) {
          collectionResponse.order[value.property] = value
        } else if (value.variable.indexOf('filter[where]') === 0) {
          collectionResponse.search[value.property] = value
        }
      }
    }
    return collectionResponse
  }

  /**
   * Hydrate l'objet JSON de façon récursive (afin de gérer les objet nested)
   *
   * @param {AnyJson} data
   */
  private static populateAllData (data: AnyJson): void {
    for (const key in data) {
      const value = data[key]
      if (value instanceof Object) {
        Hydra.populateAllData(value)
      }
    }
  }
}

export default Hydra