/*
 * Copyright 2017 resin.io
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

'use strict'

const _ = require('lodash')
const errors = require('./errors')

/**
 * @summary Minimum percentage value
 * @constant
 * @public
 * @type {Number}
 */
exports.PERCENTAGE_MINIMUM = 0

/**
 * @summary Maximum percentage value
 * @constant
 * @public
 * @type {Number}
 */
exports.PERCENTAGE_MAXIMUM = 100

/**
 * @summary Check if a percentage is valid
 * @function
 * @public
 *
 * @param {Number} percentage - percentage
 * @returns {Boolean} whether the percentage is valid
 *
 * @example
 * if (utils.isValidPercentage(85)) {
 *   console.log('The percentage is valid');
 * }
 */
exports.isValidPercentage = (percentage) => {
  return _.every([
    _.isNumber(percentage),
    percentage >= exports.PERCENTAGE_MINIMUM,
    percentage <= exports.PERCENTAGE_MAXIMUM
  ])
}

/**
 * @summary Convert a percentage to a float
 * @function
 * @public
 *
 * @param {Number} percentage - percentage
 * @returns {Number} float percentage
 *
 * @example
 * const value = utils.percentageToFloat(50);
 * console.log(value);
 * > 0.5
 */
exports.percentageToFloat = (percentage) => {
  if (!exports.isValidPercentage(percentage)) {
    throw errors.createError({
      title: `Invalid percentage: ${percentage}`
    })
  }

  return percentage / exports.PERCENTAGE_MAXIMUM
}

/**
 * @summary Memoize a function
 * @function
 * @private
 *
 * @description
 * This workaround is needed to avoid AngularJS from getting
 * caught in an infinite digest loop when using `ngRepeat`
 * over a function that returns a mutable version of an
 * ImmutableJS object.
 *
 * The problem is that every time you call `myImmutableObject.toJS()`
 * you will get a new object, whose reference is different from
 * the one you previously got, even if the data is exactly the same.
 *
 * @param {Function} func - function that returns an ImmutableJS list
 * @param {Function} comparer - function to compare old and new args and state
 * @returns {Function} memoized function
 *
 * @example
 * const getList = () => {
 *   return Store.getState().toJS().myList;
 * };
 *
 * const memoizedFunction = memoize(getList, angular.equals);
 */
exports.memoize = (func, comparer) => {
  let previousTuples = []

  return (...restArgs) => {
    let areArgsInTuple = false
    let state = Reflect.apply(func, this, restArgs)

    previousTuples = _.map(previousTuples, ([ oldArgs, oldState ]) => {
      if (comparer(oldArgs, restArgs)) {
        areArgsInTuple = true

        if (comparer(state, oldState)) {
          // Use the previously memoized state for this argument
          state = oldState
        }

        // Update the tuple state
        return [ oldArgs, state ]
      }

      // Return the tuple unchanged
      return [ oldArgs, oldState ]
    })

    // Add the state associated with these args to be memoized
    if (!areArgsInTuple) {
      previousTuples.push([ restArgs, state ])
    }

    return state
  }
}

/**
 * @summary Check if obj has one or many specific props
 * @function
 * @public
 *
 * @param {Object} obj - object
 * @param {Array<String>} props - properties
 *
 * @returns {Boolean}
 *
 * @example
 * const doesIt = hasProps({ foo: 'bar' }, [ 'foo' ]);
 */
exports.hasProps = (obj, props) => {
  return _.every(props, (prop) => {
    return _.has(obj, prop)
  })
}