import { createSelector } from '@reduxjs/toolkit'
import _difference from 'lodash/difference'

import { ActionType } from '../actions/types'
import { RootState } from '../store'

const selectSelf = (state: RootState) => state

/**
 * Select all workflow relations sequence correctly by ordered
 * @returns
 */
export const selectNormalizedActionRelationsSequence = () =>
  createSelector(selectSelf, (state: RootState) => {
    const { actions, relations } = state
    const [source] = actions.filter(({ type }) => type === ActionType.SOURCE)
    const [root] = relations.filter(({ actName }) => actName === source.name)

    let normalizedRelations = [root]
    let curr = root
    let i = 0

    while (i < relations.length) {
      const [next] = relations.filter(({ id }) => id === curr.rel[0])
      if (!next) break
      normalizedRelations = [...normalizedRelations, next]
      curr = next
      i++
    }

    return normalizedRelations
  })

/**
 * Select a normalized state snapshot
 * (actions, relations, pipeline is in correct order head -> tail)
 * @returns
 */
export const selectNormalizedState = () =>
  createSelector(selectSelf, (state: RootState) => {
    const relations = selectNormalizedActionRelationsSequence()(state)

    const actions = relations.map(relation => {
      return state.actions.filter(act => act.name === relation.actName)[0]
    })

    const pipeline = relations.map(relation => {
      return state.pipeline.filter(pl => pl.id === relation.id)[0]
    })

    return {
      actions,
      relations,
      pipeline,
    }
  })

/**
 * Select all missed or disconnected relations
 * @returns
 */
export const selectAllMissedActionRelations = () =>
  createSelector(selectSelf, (state: RootState) => {
    const relations = selectNormalizedActionRelationsSequence()(state)
    return _difference(state.relations, relations)
  })