import { EventEmitter } from  'events'
import { BehaviorSubject, from } from 'rxjs'
import { distinctUntilChanged, skip} from 'rxjs/operators'
// ** nested object access **
import _get from 'get-value'
import _set from '@uci-utils/set-value'
import _del from 'unset-value'
// *********************
import equal from 'deep-equal'
import traverse from 'traverse'
import isPlainObject from 'is-plain-object'

export default class RxClass extends EventEmitter {
  constructor(opts={}){
    super(opts)
    const rxopts = opts._rx_||{}
    this._rx_ = {
      event: rxopts.event  || 'changed',
      handler: rxopts.handler,
      props: {},
      amendValue: rxopts.amendValue,
      emit_path : rxopts.emit_path,
      hooks: [], // will add to all setters
      root: '', // root path/namespace to added to all get/set paths
      operators:[],  // will add to all pipes
      skip: rxopts.skip == null ? 0 : rxopts.skip
    }
  }
  // pass '__parent__' when getting objects for creating reactive prop
  // otherwise it gets the rx prop object and/or one of it's props
  _rxGetObj(path,prop) {
    path = this.formatObjPath(path)
    path = path.split('.')
    const name = path.pop()
    path = path.join('.')
    let parent = path ? this.$get(path) : this  // if path is empty string return this
    // console.log(name,path,parent)
    if (parent === null) parent = {}
    if (prop==='__parent__') return {name:name, parent:parent, parentPath:path}
    const rx = this.$get(['_rx_.props',path,name])
    // console.log(['_rx_.props',path,name],rx)
    return prop ? (rx || {})[prop] : rx
  }

  // if property exists it moves value to _ version and creates getter and setter and behavior subject
  rxAdd(opath,opts={}) {
    const path = this.formatObjPath(opath)
    if (opts.traverse) {
      const obj = opts.values ? opts.values : this.$get(path)
      const self = this
      // console.log('object to traverse', obj)
      traverse(obj).map(function () {
        if (this.isLeaf) {
          const lpath = this.path
          lpath.unshift(path)
          // console.log(`${!opts.values ? 'existing':'new'} leaf on path '${lpath}' with value: ${this.node}`)
          self.rxAdd(lpath,{value:this.node})
        }
      }
      )
      return true
    } // end traverse
    if (this.isRx(path)) return true
    const value = this.$get(path)
    if (value === undefined ) {
      // console.log ('no current property or value for',path,'creating temporary null')
      this.$set(path,null)
    }
    const {parent,name} = this._rxGetObj(path,'__parent__')
    this.$set(['_rx_.props',path],{new:true})
    let rx = this.$get(this.formatObjPath(['_rx_.props',path]))

    // console.log('moving',opts.value != null ? opts.value : value,path)
    rx.value = opts.value != null ? opts.value : value
    rx.path = path
    rx.amendValue =  opts.amendValue || this._rx_.amendValue || ((val) => val)
    if (opts.emit_path || this._rx_.emit_path) rx.amendValue = (value,path) => {return {value:value, path: path}}
    rx.obs = from(new BehaviorSubject(rx.amendValue(rx.value,rx.path)).pipe(
    // rx.obs = from(new ReplaySubject(1).pipe(
      skip(this._rx_.skip),
      distinctUntilChanged()
      // ,
      // takeUntil($get(this.$deleted,path))
    ))
    // console.log(path,'---------------\n',Object.getOwnPropertyNames(Object.getPrototypeOf(rx.obs)),rx.obs.subscribe)
    rx.subs = {}
    rx.hooks = []
    this.rxSubscribe(rx,'_default',this._rx_.handler,)
    this.rxSubscribe(rx,(opts.subscribe || {}).name,(opts.subscribe ||{}).handler)
    const self = this
    Object.defineProperty(parent, name, {
      configurable: true,
      enumerable: true,
      get () {
        return rx.value
      },
      set (value) {
        // console.log('in setter', path,value)
        rx.value = value
        value = rx.amendValue(value,path)
        rx.obs.next(value)
        self.emit(opts.event || self._rx_.event,value)
        self.emit(path,value)
        // any hook function that already bound will use that context
        self._rx_.hooks.forEach(hook=>hook.call(self,value))
        rx.hooks.forEach(hook=>hook.call(self,value))
      }
    })
    return true
  }

  // if name is only passed remove
  rxHook(func,name) {
    this._rx_.hooks[name]=func
  }

  rxAmendValue(path,func) {
    let rx = {}
    if (arguments.length === 0 ) {this._rx_.amendValue= null;return}
    if (typeof path === 'function') {this._rx_.amendValue=path;return}
    rx = (typeof path === 'string') ? this._rxGetObj(path) : path
    if (!rx) return false
    func = func ? func : (val => val )
    console.log('amend', func)
    rx.amendValue = func === 'path' ? (value,path) => {return {value:value, path: path}} : func
    return !!rx.amendValue
  }

  // if name is only passed remove
  rxOperator(func,name) {
    this._rx_.operators[name]=func
  }

  // removes obser, subscriptions, and getter and setter and make back into plain value
  rxRemove(path,opts={}) {
    if (!opts.confirm) return false  // must confirm to remove
    if (!this.isRx(path) && isPlainObject(this.$get(path))) {
      const self = this
      traverse(this.$get(path)).map(function () {
        if (this.isLeaf) {
          const lpath = this.path
          lpath.unshift(path)
          if(self.isRx(lpath)) self.rxRemove(lpath,{confirm:true})
        }
      })
      // all done removing the leaves so remove branch
      this.$del(['_rx_.props',path],true)
      return true
    }
    let { parent, name, parentPath } = this._rxGetObj(path,'__parent__')
    const rxparent = this.$get(['_rx_.props',parentPath])
    const rx = rxparent[name]
    if (!rx) return true  //  // not reactive nothing to remove
    Object.values(rx.subs).forEach(sub=>sub.unsubscribe())
    delete parent[name]
    parent[name] = rx.value
    delete rxparent[name]
    // console.log('removed rx from', path)
    return true
  }

  // pass rx as object or path
  rxSubscribe(rxObj,name,handler){
    // if (name ==='ha') {
    //   console.log(this.id,'making subscription',name,rxObj.path || rxObj,!!handler)
    // }
    if (typeof name !== 'string') return false
    rxObj = (typeof rxObj === 'string' || Array.isArray(rxObj) ) ? this._rxGetObj(rxObj) : rxObj
    // if (name && name!=='_default' && (rxObj||{}).path) console.log('rx object for',rxObj.path)
    if ((rxObj||{}).path) {
      if (typeof handler==='function') {
        // console.log('-----------subscription made-----------')
        return rxObj.subs[name] = rxObj.obs.subscribe(handler)
      }
    }
    return false
    // else {
    // if (name && name!=='_default') {
    //   console.log('*********no rx object at that path*******')
    //   console.log('================================')
    // }
    // }
  }

  // takes several formats for a path to an objects property and return only the . string
  formatObjPath(path) {
    if (path==null) return path
    if (Array.isArray(path)) {
      path = path.filter(Boolean).join('.')  // Boolean filter strips empty strings or null/undefined
    }
    path = path.replace(/\/:,/g, '.')  // replaces /:, with .
    return path
  }

  // checks for getter and the corresponding rx object
  isRx(path) {
    if (this.$get(path)===undefined) return false
    path = this.formatObjPath(path)
    const { parent, name, parentPath } = this._rxGetObj(path,'__parent__')
    const rxparent = this.$get(['_rx_.props',parentPath]) || {}
    const rx = rxparent[name]
    // console.log (path, 'rxparent,rx', !!parent, !!name, !!rxparent, !!rx)
    if (!rx) return false
    // console.log(Object.getOwnPropertyDescriptor(parent, name)['get'] )
    return !!Object.getOwnPropertyDescriptor(parent, name)['get']
  }

  $set () {
    let args = [...arguments]
    if (args.length < 2) return false
    if (args.length === 2) args.unshift(this)
    else if (!args[0]) return false
    args[1] = this.formatObjPath(args[1])
    // console.log('in $set',args[1],args[2])
    return _set(...args)
  }
  $get () {
    let args = [...arguments]
    if (args.length === 1) args.unshift(this)
    args[1] = this.formatObjPath(args[1])
    return _get(...args)
  }
  $del () {
    let args = [...arguments]
    if (args.length < 2) return false
    if (args[args.length-1]!==true) return false
    if (args.length === 2) args.unshift(this)
    args[1] = this.formatObjPath(args[1])
    return _del(...args)
  }

  get(path){
    path = this.formatObjPath(path)
    const value = this.$get(path)
    if (!isPlainObject(value)) return value
    let obj = {}  // return a copy with actual values instead of getters
    const self = this
    traverse(this.$get(path)).map(function () {
      if (this.isLeaf) {
        self.$set(obj,this.path,this.node)
      }
    }
    )
    return obj
  }

  set(path,value,opts={}){
    // console.log(path,value,opts,!this.isRx(path))
    if (!opts.noRx && !this.isRx(path)) {
      opts = Object.assign(isPlainObject(value) ? {values:value,traverse:true} : {value:value},opts)
      this.rxAdd(path,opts)
    } else {
      const curValue = this.$get(path)
      if (!equal(curValue,value) && value!==undefined) {
        // console.log('in set', path,value)
        this.$set(path,value)
      // console.log('value that was set',this.$get(path))
      }
      return this.$get(path)
    }
  }

}  // end  class