import * as I from 'immutable';

import {nextStep} from './next-step';

export class Synchronizer {

  constructor(statefuls) {
    this._state = I.Map();
    this._statefuls = statefuls;
    this.updateState();
  }

  patchState(patch) {
    const stepMap = {};
    for (const step of patch) {
      const [key, substep] = nextStep(step)
      if (!stepMap[key]) {
        stepMap[key] = [];
      }
      stepMap[key].push(substep);
    }
    for (const key in stepMap) {
      const stateful = this._statefuls[key];
      if (!stateful) {
        continue;
      }
      stateful.patchState(stepMap[key]);
    }
  }

  setStateful(key, stateful) {
    this._statefuls[key] = stateful;
  }

  get state() {
    return this._state;
  }

  tick(elapsed) {
    for (const key in this._statefuls) {
      const stateful = this._statefuls[key];
      stateful.tick(elapsed);
    }
    this.updateState();
  }

  updateState() {
    if (AVOCADO_SERVER) {
      this._state = this._state.withMutations((state) => {
        for (const key in this._statefuls) {
          const stateful = this._statefuls[key];
          state.set(key, stateful.state);
        }
      });
    }
  }

}