import type {
  Query as PiniaOrmQuery,
  Repository,
  Collection as PiniaOrmCollection,
} from 'pinia-orm'
import { v4 as uuid4 } from 'uuid'
import * as _ from 'lodash-es'
import { computed, type ComputedRef } from 'vue'
import type ApiRequestService from './apiRequestService'
import UrlUtils from '~/services/utils/urlUtils'
import type ApiModel from '~/models/ApiModel'
import type ApiResource from '~/models/ApiResource'
import type { AnyJson, AssociativeArray, Collection } from '~/types/data.d'
import modelsIndex from '~/models/models'
import HydraNormalizer from '~/services/data/normalizer/hydraNormalizer'
import ObjectUtils from '~/services/utils/objectUtils'
import type Query from '~/services/data/Query'

/**
 * Entity manager: make operations on the models defined with the Pinia-Orm library
 *
 * TODO: améliorer le typage des méthodes sur le modèle de find()
 * @see https://pinia-orm.codedredd.de/
 */
class EntityManager {
  protected CLONE_PREFIX = '_clone_'

  /**
   * In instance of ApiRequestService
   * @protected
   */
  protected apiRequestService: ApiRequestService

  /**
   * A method to retrieve the repository of a given ApiResource
   * @protected
   */
  protected _getRepo: <T extends typeof ApiResource>(
    model: T,
  ) => Repository<InstanceType<T>>

  protected _getProfileMask: () => object

  public constructor(
    apiRequestService: ApiRequestService,
    getRepo: <T extends typeof ApiResource>(
      model: T,
    ) => Repository<InstanceType<T>>,
    getProfileMask: () => object,
  ) {
    this.apiRequestService = apiRequestService
    this._getRepo = getRepo
    this._getProfileMask = getProfileMask
  }

  /**
   * Return the repository for the model
   *
   * @param model
   */
  public getRepository<T extends typeof ApiResource>(
    model: T,
  ): Repository<InstanceType<T>> {
    return this._getRepo(model)
  }

  /**
   * Return a pinia-orm query for the model
   *
   * @param model
   */
  public getQuery<T extends typeof ApiResource>(
    model: T,
  ): PiniaOrmQuery<InstanceType<T>> {
    // TODO: quid des uuid?
    return this.getRepository(model).where((val) => Number.isInteger(val.id))
  }

  public getModel(instance: ApiResource): typeof ApiResource {
    return instance.constructor as typeof ApiModel
  }

  /**
   * Cast an object as an ApiResource
   * This in used internally to ensure the object is recognized as an ApiResource
   *
   * @param model
   * @param instance
   */
  // noinspection JSMethodCanBeStatic
  public cast<T extends typeof ApiResource>(
    model: T,
    instance: InstanceType<T>,
  ): InstanceType<T> {
    return new model(instance) as InstanceType<T>
  }

  /**
   * Return the model class with the given entity name
   *
   * @param entityName
   */
  public async getModelFor(entityName: string): Promise<typeof ApiResource> {
    if (!Object.prototype.hasOwnProperty.call(modelsIndex, entityName)) {
      throw new Error("No model found for entity name '" + entityName + "'")
    }
    return await modelsIndex[entityName]()
  }

  /**
   * Return the model class from an Opentalent Api IRI
   *
   * @param iri An IRI of the form .../api/<entity>/...
   */
  public async getModelFromIri(iri: string): Promise<typeof ApiResource> {
    const matches = iri.match(/^\/api\/(\w+)\/.*/)
    if (!matches || !matches[1]) {
      throw new Error('cannot parse the IRI')
    }
    return await this.getModelFor(matches[1])
  }

  /**
   * Create a new instance of the given model
   *
   * @param model
   * @param properties
   */
  public newInstance<T extends typeof ApiResource>(
    model: T,
    properties: object = {},
  ): InstanceType<T> {
    const repository = this.getRepository(model)

    const instance = repository.make(properties)

    if (
      !Object.prototype.hasOwnProperty.call(properties, 'id') ||
      // @ts-expect-error Si la première condition passe, on sait que id existe
      !properties.id
    ) {
      // Object has no id yet, we give him a temporary one
      instance.id = 'tmp' + uuid4()
    }

    return this.save(instance, true)
  }

  /**
   * Save the model instance into the store
   *
   * @param instance
   * @param permanent Is the change already persisted in the datasource? If this is the case, the initial state of this
   *                  record is also updated.
   */
  public save<T extends ApiResource>(
    instance: T,
    permanent: boolean = false,
  ): T {
    const model = this.getModel(instance)

    this.validateEntity(instance)

    if (permanent) {
      this.saveInitialState(model, instance)
    }

    return this.getRepository(model).save(instance) as T
  }

  /**
   * Find the model instance in the store
   * TODO: comment réagit la fonction si l'id n'existe pas dans le store?
   *
   * @param model
   * @param id
   */
  public find<T extends typeof ApiResource>(model: T, id: number | string): T {
    const repository = this.getRepository(model)
    return repository.find(id) as T
  }

  /**
   * Fetch an ApiModel / ApiResource by its id, save it to the store and returns it
   *
   * @param model  Model of the object to fetch
   * @param id   Id of the object to fetch
   */
  public async fetch<T extends typeof ApiResource>(
    model: T,
    id?: number | null,
  ): Promise<InstanceType<T>> {
    // Else, get the object from the API
    const url = UrlUtils.join('api', model.entity, id ? String(id) : '')
    const response = await this.apiRequestService.get(url)

    // deserialize the response
    const attributes = HydraNormalizer.denormalize(response, model)
      .data as object

    return this.newInstance(model, attributes)
  }

  /**
   * Fetch a collection of model instances
   *
   * @param model
   * @param parent
   * @param query
   */
  public async fetchCollection<T extends typeof ApiResource>(
    model: T,
    parent: T | null,
    query: Query | null = null,
  ): Promise<ComputedRef<Collection<InstanceType<T>>>> {
    let url

    if (parent !== null) {
      url = UrlUtils.join('api', parent.entity, '' + parent.id, model.entity)
    } else {
      url = UrlUtils.join('api', model.entity)
    }

    if (query) {
      url += '?' + query.getUrlQuery()
    }

    const response = await this.apiRequestService.get(url)

    // deserialize the response
    const apiCollection = HydraNormalizer.denormalize(response, model)

    apiCollection.data.map((attributes: object) => {
      return this.newInstance(model, attributes)
    })

    let piniaOrmQuery = this.getQuery(model)
    if (query) {
      piniaOrmQuery = query.applyToPiniaOrmQuery(piniaOrmQuery)
    }
    const res = computed(() => {
      const items: PiniaOrmCollection<InstanceType<T>> = piniaOrmQuery.get()

      return {
        items,
        totalItems: apiCollection.metadata.totalItems,
        pagination: {
          first: apiCollection.metadata.first || 1,
          last: apiCollection.metadata.last || 1,
          next: apiCollection.metadata.next || undefined,
          previous: apiCollection.metadata.previous || undefined,
        },
      }
    })

    // @ts-expect-error Needed to avoid 'Cannot stringify non POJO' occasional bugs
    res.toJSON = () => {
      return 'Computed result from fetchCollection at : ' + url
    }

    return res
  }

  /**
   * Persist the model instance as it is in the store into the data source via the API
   *
   * @param instance
   */
  public async persist(instance: ApiModel) {
    const model = this.getModel(instance)

    let url = UrlUtils.join('api', model.entity)
    let response

    this.validateEntity(instance)

    const data: AnyJson = HydraNormalizer.normalizeEntity(instance)

    const headers = { profileHash: await this.makeProfileHash() }

    if (!instance.isNew()) {
      if (!model.isIdLess()) {
        url = UrlUtils.join(url, String(instance.id))
      }
      response = await this.apiRequestService.patch(url, data, null, headers)
    } else {
      delete data.id
      response = await this.apiRequestService.post(url, data, null, headers)
    }

    const hydraResponse = HydraNormalizer.denormalize(response, model)

    const newInstance = this.newInstance(model, hydraResponse.data)

    // Si l'instance était nouvelle avant d'être persistée, elle vient désormais de recevoir un id définitif. On
    // peut donc supprimer l'instance temporaire.
    if (instance.isNew()) {
      this.removeTempAfterPersist(model, instance.id)
    }

    return newInstance
  }

  /**
   * Send an update request (PATCH) to the API with the given data on an existing model instance
   *
   * @param model
   * @param id
   * @param data
   */
  public async patch(
    model: typeof ApiModel,
    id: number,
    data: AssociativeArray,
  ) {
    const url = UrlUtils.join('api', model.entity, '' + id)

    const body = JSON.stringify(data)
    const response = await this.apiRequestService.patch(url, body)

    const hydraResponse = HydraNormalizer.denormalize(response, model)

    return this.newInstance(model, hydraResponse.data)
  }

  /**
   * Delete the model instance from the datasource via the API
   *
   * @param instance
   * @param instance
   */
  public async delete<T extends ApiResource>(instance: T) {
    const model = this.getModel(instance)
    instance = this.cast(model, instance) as T

    console.log('delete', instance)

    this.validateEntity(instance)

    const repository = this.getRepository(model)

    this.validateEntity(instance)

    // If object has been persisted to the datasource, send a delete request
    if (!instance.isNew()) {
      const url = UrlUtils.join('api', model.entity, String(instance.id))
      await this.apiRequestService.delete(url)
    }

    // reactiveUpdate the store
    repository.destroy(instance.id)
  }

  /**
   * Reset the model instance to its initial state (i.e. the state it had when it was fetched from the API)
   *
   * @param model
   * @param instance
   */
  public reset<T extends ApiResource>(instance: T) {
    const model = this.getModel(instance)

    const initialInstance = this.getInitialStateOf(model, instance.id)
    if (initialInstance === null) {
      throw new Error(
        'no initial state recorded for this object - abort [' +
          model.entity +
          '/' +
          instance.id +
          ']',
      )
    }

    const repository = this.getRepository(model)
    repository.save(initialInstance)

    return initialInstance
  }

  /**
   * Delete all records in the repository of the model
   *
   * @param model
   */
  public flush<T extends typeof ApiResource>(model: T) {
    const repository = this.getRepository(model)
    repository.flush()
  }

  /**
   * Is the model instance a new one, or does it already exist in the data source (=API)
   *
   * This is a convenient way of testing a model instance you did not already fetch, else prefer the use of the
   * isNew() method of ApiResource
   *
   * @param model
   * @param id
   */
  public isNewInstance<T extends typeof ApiResource>(
    model: T,
    id: number | string,
  ): boolean {
    const repository = this.getRepository(model)

    const item = repository.find(id)
    if (!item || typeof item === 'undefined') {
      // TODO: est-ce qu'il ne faudrait pas lever une erreur ici plutôt?
      console.error(model.entity + '/' + id + ' does not exist!')
      return false
    }

    return item.isNew()
  }

  /**
   * Save the state of the model instance in the store, so this state could be restored later
   *
   * @param model
   * @param instance
   * @private
   */
  protected saveInitialState<T extends typeof ApiResource>(
    model: T,
    instance: InstanceType<T>,
  ) {
    const repository = this.getRepository(model)

    // Clone and prefix id
    const clone = _.cloneDeep(instance)
    clone.id = this.CLONE_PREFIX + clone.id

    repository.save(clone)
  }

  /**
   * Return the saved state of the model instance from the store
   *
   * @param model
   * @param id
   * @private
   */
  protected getInitialStateOf<T extends typeof ApiResource>(
    model: T,
    id: string | number,
  ): InstanceType<T> | null {
    const repository = this.getRepository(model)

    // Find the clone by id
    const instance = repository.find(this.CLONE_PREFIX + id)
    if (instance === null) {
      return null
    }

    // Restore the initial id
    instance.id = id
    return instance
  }

  /**
   * Delete the temporary model instance from the repo after it was persisted via the api, replaced by the instance
   * that has been returned by the api with is definitive id.
   *
   * @param model
   * @param tempInstanceId
   * @private
   */
  protected removeTempAfterPersist<T extends typeof ApiResource>(
    model: T,
    tempInstanceId: number | string,
  ) {
    const repository = this.getRepository(model)

    const instance = repository.find(tempInstanceId)
    if (!instance || typeof instance === 'undefined') {
      // TODO: il vaudrait peut-être mieux lever une erreur ici?
      console.error(model.entity + '/' + tempInstanceId + ' does not exist!')
      return
    }
    if (!instance.isNew()) {
      throw new Error('Error: Can not remove a non-temporary model instance')
    }

    repository.destroy(tempInstanceId)
    repository.destroy(this.CLONE_PREFIX + tempInstanceId)
  }

  protected async makeProfileHash(): Promise<string> {
    const mask = this._getProfileMask()
    return await ObjectUtils.hash(mask)
  }

  /**
   * Validate the entity, and throw an error if it's not correctly defined.
   * @param instance
   * @protected
   */
  protected validateEntity(instance: unknown): void {
    if (Object.prototype.hasOwnProperty.call(instance, 'id')) {
      // @ts-expect-error At this point, we're sure there is an id property
      const id = instance.id

      if (
        !(typeof id === 'number') &&
        !(typeof id === 'string' && id.startsWith('tmp'))
      ) {
        // The id is a pinia orm Uid, the entity has been created using the `new` keyword (not supported for now)
        throw new Error(
          'Definition error for the entity, did you use the entityManager.newInstance(...) method?\n' +
            JSON.stringify(instance),
        )
      }
    }
  }
}

export default EntityManager