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/* ************************************************************************** */
/* */
/* . */
/* scramble.rs / \ */
/* / \ */
/* By: charles <charles.cabergs@gmail.com> /o o \ */
/* / v \ */
/* Created: 2020/06/25 13:24:17 by charles / _ \ */
/* Updated: 2020/06/25 13:24:18 by charles '-----------' */
/* */
/* ************************************************************************** */
use std::fmt;
use std::str;
use rand::{
distributions::{Distribution, Standard},
Rng
};
pub struct Scramble(Vec<Move>);
impl Scramble {
pub fn new_rand(n: usize) -> Scramble {
let mut sequence: Vec<Move> = Vec::with_capacity(n);
while sequence.len() != n {
let direction = rand::random::<Direction>();
let modifier = rand::random::<Modifier>();
if let Some(l) = sequence.last() {
if l.direction == direction {
continue;
}
}
sequence.push(Move { direction, modifier });
}
Scramble(sequence)
}
}
impl fmt::Display for Scramble {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{}", self.0.iter().map(|m| m.to_string()).collect::<Vec<String>>().join(" "))
}
}
impl str::FromStr for Scramble {
type Err = &'static str;
fn from_str(s: &str) -> Result<Self, Self::Err> {
let strs = s.split(" ");
let mut scramble = Scramble(Vec::new());
for s in strs {
scramble.0.push(s.parse()?);
}
Ok(scramble)
}
}
impl str::FromStr for Move {
type Err = &'static str;
fn from_str(s: &str) -> Result<Self, Self::Err> {
use Direction::*;
use Modifier::*;
let mut cs = s.chars();
let direction = match cs.next() {
Some('F') => Front,
Some('B') => Back,
Some('D') => Down,
Some('U') => Up,
Some('R') => Right,
Some('L') => Left,
Some(_) => return Err("Move direction isn't valid"),
None => return Err("Move format is empty"),
};
let modifier = match cs.next() {
Some('\'') => Prime,
Some('2') => Twice,
Some(_) => return Err("Move modifier isn't valid"),
None => No,
};
if let Some(_) = cs.next() {
return Err("Unexpected character in move");
}
Ok(Move{ direction, modifier })
}
}
#[derive(PartialEq)]
enum Direction { Front, Back, Down, Up, Right, Left, }
enum Modifier { No, Twice, Prime, }
struct Move {
direction: Direction,
modifier: Modifier,
}
// https://stackoverflow.com/questions/48490049
impl Distribution<Direction> for Standard {
fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Direction {
use Direction::*;
match rng.gen_range(0, 6) {
0 => Front,
1 => Back,
2 => Down,
3 => Up,
4 => Right,
_ => Left,
}
}
}
impl Distribution<Modifier> for Standard {
fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Modifier {
use Modifier::*;
match rng.gen_range(0, 3) {
0 => No,
1 => Twice,
_ => Prime,
}
}
}
impl fmt::Display for Move {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
use Direction::*;
use Modifier::*;
let letter = match self.direction {
Front => "F",
Back => "B",
Down => "D",
Up => "U",
Right => "R",
Left => "L",
};
let modifier = match self.modifier {
No => "",
Twice => "2",
Prime => "'",
};
write!(f, "{}{}", letter, modifier)
}
}
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