/* IMPORT */

import { DIRTY_NO, DIRTY_MAYBE_NO, DIRTY_MAYBE_YES, DIRTY_YES } from '~/constants'
import { OWNER, SUPER_OWNER } from './superroot'
import { lazyArrayPush } from '~/lazy'
import { ObservablesArray, ObservablesSet } from '~/objects/observables'
import Owner from '~/objects/owner'
import type { IOwner, ObserverFunction, Contexts } from '~/types'
import { Stack } from '~/methods/debugger'

/* MAIN */

class Observer extends Owner {

  /* VARIABLES */

  parent: IOwner = OWNER;
  context: Contexts = OWNER.context;
  status: number = DIRTY_YES;
  observables: ObservablesArray | ObservablesSet
  sync?: boolean

  /* CONSTRUCTOR */

  constructor() {

    super()

    this.observables = new ObservablesArray(this)

    if (OWNER !== SUPER_OWNER) {

      lazyArrayPush(this.parent, 'observers', this)

    }

  }

  /* API */

  dispose(deep: boolean): void {

    this.observables.dispose(deep)

    super.dispose(deep)

  }

  refresh<T>(fn: ObserverFunction<T>, stack?: Stack): T {

    this.dispose(false)

    this.status = DIRTY_MAYBE_NO // Resetting the trip flag, we didn't re-execute just yet

    try {

      return this.wrap(fn, this, this, stack)

    } finally {

      this.observables.postdispose()

    }

  }

  run(stack?: Stack): void {

    throw new Error('Abstract method')

  }

  stale(status: number, stack?: Stack): void {

    throw new Error('Abstract method')

  }

  update(stack?: Stack): void {

    if (this.disposed) return // Disposed, it shouldn't be updated again

    if (this.status === DIRTY_MAYBE_YES) { // Maybe we are dirty, let's check with our observables, to be sure

      this.observables.update(stack)

    }

    if (this.status === DIRTY_YES) { // We are dirty, let's refresh

      this.status = DIRTY_MAYBE_NO // Trip flag, to be able to tell if we caused ourselves to be dirty again

      this.run(stack)

      if (this.status === DIRTY_MAYBE_NO) { // Not dirty anymore

        this.status = DIRTY_NO

      } else { // Maybe we are still dirty, let's check again

        this.update(stack)

      }

    } else { // Not dirty

      this.status = DIRTY_NO

    }

  }

}

/* EXPORT */

export default Observer