const readline = require('readline');

const random = (lo, hi) => lo + Math.floor(Math.random() * (hi - lo));
const sleep = (ms) => new Promise((resolve) => setTimeout(resolve, ms));
const rsleep = (lo, hi) => sleep(random(lo, hi));

const interface = readline.createInterface({
	input: process.stdin,
	output: process.stdout,
});

const prompt = (question) =>
	new Promise((resolve) =>
		interface.question(`${blue(question)}\n> `, resolve));

const coloured = (colour) => (str) => `${colour}${reset(str)}`;
const yellow = coloured("\x1b[33m");
const blue = coloured("\x1b[34m");
const green = coloured("\x1b[32m");
const reset = (str) => `${str}\x1b[0m`;

const add = (a, b) => compute(a, b, "+");

const hedges = [
	"um. okay. so,",
	"right. next. uh,",
	"hmm",
	"okay. so,",
	"um. okay.",
	"uh okay..",
	"so..",
];
const confirmations = [
	"o right. ofc.",
	"nice.",
	"thank u.",
	"thanks.",
	"um right. yes.",
	"right.",
];
const innumerables = [
	"yeah i don't think we can do that one",
	"that's not great for fib",
	"um no sorry i can't help with that one",
	"um????? no my b i can't help with that one",
	"oh no my bad no i can't help u with that",
	"sorry not that one",
	"yaaa not that one though",
];
const dones = [
	"we're done aren't we?",
	"oh! that's it..?",
	"all ... done??????",
	"i think it's over",
	"no more computation?",
	"oh!",
	"wait you did it all.",
	"oh that's it?",
];
const thinkings = [
	"let me just think a second..",
	"hold on..",
	"i just need a moment",
	"uh wait",
	"just looking at the data",
	"sorry - looking over things",
	"got everything just one sec",
	"let me look at things",
	"let me think a moment",
	"just thinking ...",
];
const rarray = (array) => array[random(0, array.length)];
const hedge = () => rarray(hedges);
const confirmation = () => rarray(confirmations);
const innumerable = () => rarray(innumerables);
const done = () => rarray(dones);
const thinking = () => rarray(thinkings);

const rentries = (map) => rarray(Array.from(map.entries()));

const say = (msg, before, after) =>
	sleep(before)
		.then(() => console.log(...msg))
		.then(() => sleep(after));

const fast = (...msg) => say(msg, random(30, 100), random(30, 100));
const slow = (...msg) => say(msg, random(400, 2000), random(200, 1000));

const compute = (a, b, op) =>
	slow(hedge())
		.then(() => prompt(`what is ${a} ${op} ${b}?`))
		.then((value) => slow(confirmation()).then(() => value));

const build = (n, map) => {
	if (n <= 0) {
		const zero = () => Promise.resolve();
		map.set(zero, 0);
		return zero;
	} else if (n === 1) {
		const one = () => Promise.resolve();
		map.set(one, 1);
		return one;
	} else {
		const sub1 = build(n - 1, map);
		const sub2 = build(n - 2, map);
		const nth = () =>
			(map.get(nth) === null && (map.get(sub1) !== null && map.get(sub2) !== null))
				? add(map.get(sub2), map.get(sub1))
					.then((value) => Promise.resolve(map.set(nth, value)).then(() => value))
				: Promise.resolve();
		map.set(nth, null);
		return nth;
	};
};

const fill = (map, top) =>
	map.get(top) === null
		? rentries(map)[0]().then(() => fill(map, top))
		: Promise.resolve(map.get(top));

const hitlfib = (n) =>
	Promise.resolve(new Map())
		.then((map) => Promise.resolve(build(n, map))
			.then((top) => fill(map, top)));

const hitlfibiter = (n, a = 0, b = 1) =>
	n === 0
		? Promise.resolve(a)
		: n === 1
			? Promise.resolve(b)
			: add(a, b).then((result) => hitlfibiter(n - 1, b, result));

const number = () =>
	prompt("give me a number")
		.then((str) => str.trim())
		.then((trimmed) => Promise.resolve(Number(trimmed))
			.then((n) => (trimmed !== "" && n !== null && isFinite(n))
				? n
				: slow(hedge()).then(() => slow(innumerable())).then(number)));

const choose = () =>
	prompt("would you like to use my iteration optimization??? yes???? .. or.. no?")
		.then((response) => Promise.resolve(["yes", "no", "y", "n"].includes(response.trim().toLowerCase()))
			.then((formed) => !formed
				? slow("um. sorry. one more time..").then(choose)
				: ["yes", "y"].includes(response.trim().toLowerCase())
					? fast("yes!").then(() => hitlfibiter)
					: fast("oh.").then(() => slow("okay.")).then(() => slow("we can take it slow.")).then(() => hitlfib)));

const optimize = (n) =>
	n < 4
		? hitlfib
		: n > 25 
			? slow(hedge())
				.then(() => fast("acutally.."))
				.then(() => fast("i need to use my iteration optimization for this."))
				.then(() => slow("i hope that's okay."))
				.then(() => hitlfibiter)
			: choose();

const flow = () =>
	slow("\nwhat's the fib you'd like to compute? i can help u out")
		.then(number)
		.then((n) => slow(confirmation())
			.then(() => fast(hedge()))
			.then(() => slow(`i will help u compute ${green(`fib ${n}`)}`))
			.then(() => optimize(n))
			.then((fib) => fib(n))
			.then((fibn) => slow(hedge())
				.then(() => fast(done()))
				.then(() => fast(thinking()))
				.then(() => rsleep(Math.min(1000, n * 100), Math.max(n * 500, 1000)))
				.then(() => slow(green(`fib ${n} is ${fibn}`)))))
		.then(() => rsleep(1000, 4000));

const loop = () => flow().then(loop);

loop();