import React from 'react'
import {connect} from 'react-redux'

import * as Actions from '../common/actions'

/* This component reads the local storage store and adds them to the Redux store.
 * Local storage is read during the componentDidMount lifecycle method.
 * Local storage is written during the componentWillReceiveProps lifecycle method.
*/

// an app-specific name for the localStorage state
const stateName = 'dubdiff_state'

// return a new object with the given keys, each assigned to the cooresponding value
// from the given object
const copyKeys = (obj, keys) => keys.reduce((acc, p) => { acc[p] = obj[p]; return acc }, {})

// utility method for retrieving json data from the local store
/*
function getLocalState (keys) {
  if (window.localStorage.getItem(stateName)) {
    const localState = JSON.parse(window.localStorage.getItem(stateName))
    return copyKeys(localState, keys)
  } else {
    return copyKeys({}, keys)
  }
}
*/

// utility method for writing json data to the local store
function setLocalState (state, keys) {
  let toSave = copyKeys(state, keys)
  window.localStorage.setItem(stateName, JSON.stringify(toSave))
}

const mapStateToProps = (state) => ({
  input: state.input
  // the loading/empty/clean state
})

const mapDispatchToProps = dispatch => ({
  onChangeOriginal: (text) => dispatch(Actions.updateOriginalInput(text)),
  onChangeFinal: (text) => dispatch(Actions.updateFinalInput(text))
})

class LocalStorage extends React.Component {

  // load the state from the local storage
  componentDidMount () {
    // only if the status is EMPTY
/*
    if (this.props.input.original=='' && this.props.input.final == '') {
      const localState = getLocalState(['input'])
      if (localState.input && localState.input.original)
        this.props.onChangeOriginal(localState.input.original)
      if (localState.input && localState.input.final)
        this.props.onChangeFinal(localState.input.final)
    }
*/
  }
  // save the state to local storage
  componentWillReceiveProps (nextProps) {
    setLocalState(nextProps, ['input'])
  }

  render () {
    return this.props.children
  }
}

export default connect(mapStateToProps, mapDispatchToProps)(LocalStorage)