import {compose, merge, mergeDiff, Property} from '@avocado/core';
import {Vector} from '@avocado/math';
import {Synchronized} from '@avocado/state';

const decorate = compose(
  Synchronized,
);

export class Trait extends decorate(class {}) {

  constructor(entity, params, state) {
    super();
    this.entity = entity;
    const ctor = this.constructor;
    this._memoizedListeners = undefined;
    this.params = Object.assign({}, ctor.defaultParams(), params);
    this.state = Object.assign({}, ctor.defaultState(), state);
    this.previousState = JSON.parse(JSON.stringify(this.state));
    if (this.tick) {
      this.tick = this.tick.bind(this);
    }
    if (this.renderTick) {
      this.renderTick = this.renderTick.bind(this);
    }
  }

  createTraitPacketUpdates(Packet) {
    const packets = [];
    if (this.isDirty) {
      packets.push(new Packet(this.state, this.entity));
      this.makeClean();
    }
    return packets;
  }

  destroy() {}

  hooks() {
    return {};
  }

  hydrate() {
    return Promise.resolve();
  }

  get isDirty() {
    for (const key in this.state) {
      if (this.state[key] !== this.previousState[key]) {
        return true;
      }
    }
    return false;
  }

  label() {
    return this.constructor.name;
  }

  listeners() {
    return {};
  }

  makeClean() {
    for (const key in this.state) {
      this.previousState[key] = this.state[key];
    }
  }

  memoizedListeners() {
    if (!this._memoizedListeners) {
      this._memoizedListeners = this.listeners();
    }
    return this._memoizedListeners;
  }

  methods() {
    return {};
  }

  toJSON() {
    return {
      params: this.params,
      state: this.state,
    };
  }

  transformPatchValue(key, value) {
    return value;
  }

  static contextType() {
    return {};
  }

  static defaultJSON() {
    return {
      params: this.defaultParams(),
      state: this.defaultState(),
    };
  }

  static defaultParams() {
    return {};
  }

  static defaultState() {
    return {};
  }

  static dependencies() {
    return [];
  }

}

export function StateProperty(key, meta = {}) {
  let transformedProperty;
  if (meta.transformProperty) {
    transformedProperty = meta.transformProperty(key);
  }
  else {
    transformedProperty = `$$avocado_state_property_${key}`;
  }
  return (Superclass) => {
    meta.emit = meta.emit || function(...args) {
      this.entity.emit(...args);
    };
    meta.initialize = meta.initialize || function() {
      this[transformedProperty] = this.state[key];
    }
    meta.get = meta.get || new Function(`
      return this.${transformedProperty};
    `);
    meta.set = meta.set || new Function('value', `
      this.${transformedProperty} = value;
      this.state['${key}'] = value;
    `);
    return Property(key, meta)(Superclass);
  }
}