const _ = require('underscore');
const state = require('./state.js');

let cache = {};

function i (id) {
  return new Promise((resolve, reject) => {
    state.create(id);
    state.read(id)
      .then(data => {
        cache[id] = data;
        resolve();
      })
      .catch(err => reject(err));
  });
}
function c (id) {
  if(_.has(cache, id)) {
    state.update(id, cache[id]);
    console.info(`[${id}] Committed new state`);
  } else {
    console.error(`[${id}] Could not commit nonexistant state`);
  }
}
function r (id) {
  state.read(id)
    .then(data => {
      cache[id] = data
      console.info(`[${id}] Reverted state`);
    })
    .catch(console.error);
}
function e (id) {
  if(_.has(cache, id)) {
    delete cache[id];
    console.info(`[${id}] Erased state`);
    state.delete(id);
  } else {
    console.error(`[${id}] Could not erase nonexistant state`);
  }
}
function s (id) {
  return new Promise((resolve, reject) => {
    if(_.has(cache, id)) {
      resolve(cache[id]);
    } else {
      state.read(id)
        .then(data => {
          cache[id] = data;
          console.info(`[${id}] read and cached state`);
          resolve(cache[id]);
        })
        .catch(err => reject(err));
    }
  })
}

module.exports = {
  init: i,
  commit: c,
  revert: r,
  erase: e,
  state: s
}