import useLocalStorage from './useLocalStorage';
import set from 'lodash.set'
import unset from 'lodash.unset'
import cloneDeep from 'lodash.cloneDeep'
import defaultSettings from 'shared/components/workbench/default-settings.js'
import {useState} from 'react'

// Generates a default design gist to start from
export const defaultGist = (design, locale='en') => {
  const gist = {
  design: design.config.name,
  version: design.config.version,
  ...defaultSettings,
  _state: {view: 'draft'}
  }
  if (locale) gist.locale = locale

  return gist
}

// generate the gist state and its handlers
export function useGist(design, app) {
	// get the localstorage state and setter
	const [gist, _setGist, gistReady] = useLocalStorage(`${design.config.name}_gist`, defaultGist(design, app.locale));
	const [gistHistory, setGistHistory] = useState([]);
	const [gistFuture, setGistFuture] = useState([]);

	const setGist = (newGist, addToHistory=true) => {
		let oldGist
		_setGist((gistState) => {
			// have to clone it or nested objects will be referenced instead of copied, which defeats the purpose
			if (addToHistory) oldGist = cloneDeep(gistState)

			return typeof newGist === 'function' ? newGist(cloneDeep(gistState)) : newGist
		})

		if (addToHistory) {
			setGistHistory((history) => {
				return [...history, oldGist]
			})
			setGistFuture([])
		}
	}

	/** update a single gist value */
	const updateGist = (path, value, addToHistory=true) => {
		setGist((gistState) => {
			const newGist = {...gistState};
			set(newGist, path, value);
			return newGist;
		}, addToHistory)
	}

	/** unset a single gist value */
	const unsetGist = (path, addToHistory=true) => {
    setGist((gistState) => {
    	const newGist = {...gistState};
    	unset(newGist, path);
    	return newGist;
    }, addToHistory)
  }

  const undoGist = () => {
  	_setGist((gistState) => {
	  	let prevGist;
	  	setGistHistory((history) => {
		  	const newHistory = [...history]
	  		prevGist = newHistory.pop() || defaultGist(design, app.locale);
	  		return newHistory;
	  	})
	  	setGistFuture((future) => [gistState, ...future]);

	  	return {...prevGist}
  	})
  }

  const redoGist = () => {
  	const newHistory = [...gistHistory, gist]
  	const newFuture = [...gistFuture]
  	const newGist = newFuture.shift()
  	setGistHistory(newHistory)
  	setGistFuture(newFuture)
  	_setGist(newGist)
  }

  const resetGist = () => setGist(defaultGist(design, app.locale))

  return {gist, setGist, unsetGist, gistReady, updateGist, undoGist, redoGist, resetGist};
}