import { Store } from 'data-store'
import { BehaviorSubject, Subject, from } from 'rxjs'
import { distinctUntilChanged, takeUntil } from 'rxjs/operators'
import _get from 'get-value'
import _set from 'set-value'
import _del from 'unset-value'
import equal from 'deep-equal'
// import autobind from 'auto-bind'

// ammend/react datastore class
export default class StoreRx extends Store {
  constructor(opts){
    // console.log('constructor', opts)
    super(opts)
    this.name = opts.name
    this._observers = {}
    this._deleted = {}
    this.emitter = opts.emitter
    this.event = opts.event || 'datastore'
    this.handler=opts.handler
    this.get = this.get.bind(this)
    this.set = this.set.bind(this)
  }

  // TODO manage all subscriptions

  getObs(path) {
    path = this.formatPath(path)
    return path ? _get(this._observers,path):this._observers
  }

  delObs(path) {
    // TODO support deleting all observers, would require traversing _observers
    path = this.formatPath(path)
    _get(this._deleted,path).next('deleted')
    _del(this._deleted,path)
    _del(this._observers,path)
  }

  setObs(path) {
    path = this.formatPath(path)
    const obs = this.getObs(path)
    if (obs) return obs
    _set(this._deleted,path,from(new Subject()))
    _set(this._observers,path,from(new BehaviorSubject(super.get(path))).pipe(
      distinctUntilChanged(),
      takeUntil(_get(this._deleted,path))
    ))
    return this.getObs(path)
  }

  get(path,handler){
    // console.log('get>>>>',path,handler)
    // console.log(this._observers)
    path = this.formatPath(path)
    if (typeof handler==='function') {
      let obs = this.getObs(path)
      if (!obs)  obs = this.setObs(path)
      // console.log(obs)
      return obs.subscribe(handler)
    }
    return super.get(path)
  }

  // TODO trap delete and delete observer too

  set(path,value){
    // TODO support path as object to merge per super.set
    // TODO if value not set del obs as well
    path = this.formatPath(path)
    const curValue = this.get(path)
    // console.log('set>>>>',path,curValue,value)
    if (!equal(curValue,value) || !value) {
      let obs = this.getObs(path)
      if (obs) obs.next(value)
      if (this.emit) this.emit(this.event,{path:path,key:path,value:value})
      // console.log('pushing in datastore set',path,value)
      if (this.handler) this.handler({path:path,key:path,value:value})
      return super.set(path,value)
    }
    return this
  }

  formatPath(path) {
    if (path==null) return path
    if (Array.isArray(path)) {
      path = path.filter(Boolean).join('.')
    } else path = path.replace(/\/:/g, '.')
    return path
  }

}  // end datastore class