const { pipe, map, filter } = rubico

const isOdd = number => number % 2 == 1

const asyncSquare = async number => number ** 2

const numbers = [1, 2, 3, 4, 5]

pipe(numbers, [
  filter(isOdd),
  map(asyncSquare),
  console.log, // [1, 9, 25]
])

// import rubico core globally
require('rubico/global')

// import rubico core as rubico
const rubico = require('rubico')

// import an operator from rubico core
const pipe = require('rubico/pipe')

// import rubico/x as x
const x = require('rubico/x')

// import an operator from rubico/x
const defaultsDeep = require('rubico/x/defaultsDeep')

// import rubico's Transducer module
const Transducer = require('rubico/Transducer')

const {
  // compose functions
  pipe, compose, tap,

  // control flow
  switchCase,

  // handle errors
  tryCatch,

  // compose data
  all, assign, get, set, pick, omit,

  // iterate
  forEach,

  // transform data
  map, filter, reduce, transform, flatMap,

  // compose predicates
  and, or, not, some, every,

  // comparison operators
  eq, gt, lt, gte, lte,

  // partial application
  thunkify, always, curry, __,
} = rubico

const helloPromise = Promise.resolve('hello')

pipe(helloPromise, [ // helloPromise is resolved for 'hello'
  async greeting => `${greeting} world`,
  // the Promise returned from the async function is resolved
  // and the resolved value is passed to console.log

  console.log, // hello world
])

const myObj = { a: 1, b: 2, c: 3 }

// the first use of map is eager
const myDuplicatedSquaredObject = map(myObj, pipe([
  number => [number, number],

  // the second use of map is lazy
  map(number => number ** 2),
]))

console.log(myDuplicatedSquaredObject)
// { a: [1, 1], b: [4, 4], c: [9, 9] }

const { pipe, tap, map, filter } = rubico

const toTodosUrl = id => `https://jsonplaceholder.typicode.com/todos/${id}`

const todoIDs = [1, 2, 3, 4, 5]

pipe(todoIDs, [

  // fetch todos per id of todoIDs
  map(pipe([
    toTodosUrl,
    fetch,
    response => response.json(),

    tap(console.log),
    // { userId: 1, id: 4, title: 'et porro tempora', completed: true }
    // { userId: 1, id: 1, title: 'delectus aut autem', completed: false }
    // { userId: 1, id: 3, title: 'fugiat veniam minus', completed: false }
    // { userId: 1, id: 2, title: 'quis ut nam facilis...', completed: false }
    // { userId: 1, id: 5, title: 'laboriosam mollitia...', completed: false }
  ])),

  // group the todos by userId in a new Map
  function createUserTodosMap(todos) {
    const userTodosMap = new Map()
    for (const todo of todos) {
      const { userId } = todo
      if (userTodosMap.has(userId)) {
        userTodosMap.get(userId).push(todo)
      } else {
        userTodosMap.set(userId, [todo])
      }
    }
    return userTodosMap
  },

  // filter for completed todos
  // map iterates through each value (array of todos) of the userTodosMap
  // filter iterates through each todo of the arrays of todos
  map(filter(function didComplete(todo) {
    return todo.completed
  })),

  tap(console.log),
  // Map(1) {
  //   1 => [ { userId: 1, id: 4, title: 'et porro tempora', completed: true } ]
  // }
])

const isOdd = number => number % 2 == 1

const asyncSquare = async number => number ** 2

const generateNumbers = function* () {
  yield 1
  yield 2
  yield 3
  yield 4
  yield 5
}

pipe(generateNumbers(), [
  transform(compose([
    Transducer.filter(isOdd),
    Transducer.map(asyncSquare),
  ]), []),
  console.log, // [1, 9, 25]
])