git.scottworley.com Git - pluta-lesnura/blob - src/lib.rs

   1 use rand::Rng;
   2
   3 pub const NUM_RANKS: usize = 13;
   4 pub const NUM_SUITS: usize = 4;
   5 pub const NUM_JOKERS: usize = 2;
   6 pub const NUM_CARDS: usize = NUM_RANKS * NUM_SUITS + NUM_JOKERS;
   7
   8 #[derive(Clone, Copy, Eq, PartialEq)]
   9 pub struct Rank(u8);
  10 impl Rank {
  11     #[must_use]
  12     pub fn value(&self) -> u8 {
  13         self.0 + 1
  14     }
  15 }
  16
  17 #[derive(Clone, Copy, Eq, PartialEq)]
  18 pub struct Suit(u8);
  19
  20 #[derive(Clone, Copy, Eq, PartialEq)]
  21 pub struct Card(u8);
  22 impl Card {
  23     #[must_use]
  24     pub fn is_joker(&self) -> bool {
  25         usize::from(self.0) >= NUM_RANKS * NUM_SUITS
  26     }
  27     #[must_use]
  28     pub fn rank(&self) -> Option<Rank> {
  29         (!self.is_joker()).then_some(Rank(self.0 >> 2))
  30     }
  31     #[must_use]
  32     pub fn suit(&self) -> Option<Suit> {
  33         (!self.is_joker()).then_some(Suit(self.0 & 3))
  34     }
  35 }
  36
  37 #[derive(Clone, Copy)]
  38 pub enum WithOrWithoutJokers {
  39     WithJokers,
  40     WithoutJokers,
  41 }
  42
  43 #[must_use]
  44 pub fn deck(j: WithOrWithoutJokers) -> Vec<Card> {
  45     let limit = u8::try_from(match j {
  46         WithOrWithoutJokers::WithJokers => NUM_CARDS,
  47         WithOrWithoutJokers::WithoutJokers => NUM_SUITS * NUM_RANKS,
  48     })
  49     .expect("Too many cards?");
  50     (0..limit).map(Card).collect()
  51 }
  52
  53 #[derive(Clone, Copy)]
  54 pub struct PathLength(Rank);
  55
  56 #[derive(Clone, Copy, Default)]
  57 pub struct PathLengthInfo(u16);
  58 impl PathLengthInfo {
  59     #[must_use]
  60     pub fn is_showing(&self, i: Rank) -> bool {
  61         (self.0 >> i.0) & 1 == 1
  62     }
  63     fn reveal(&mut self, i: Rank) {
  64         self.0 |= 1 << i.0;
  65     }
  66     pub fn reveal_random(&mut self, true_length: PathLength) -> Option<Rank> {
  67         let showing = usize::try_from(self.0.count_ones()).expect("There aren't that many bits");
  68         let not_showing = NUM_RANKS - showing;
  69         if not_showing <= 1 {
  70             return None;
  71         }
  72
  73         let mut show = rand::thread_rng().gen_range(0..not_showing - 1);
  74         for i in 0..NUM_RANKS {
  75             let r = Rank(u8::try_from(i).expect("Too many cards?"));
  76             if !self.is_showing(r) && r != true_length.0 {
  77                 if show == 0 {
  78                     self.reveal(r);
  79                     return Some(r);
  80                 }
  81                 show -= 1;
  82             }
  83         }
  84         unreachable!()
  85     }
  86 }
  87
  88 #[cfg(test)]
  89 mod tests {
  90     use super::*;
  91
  92     #[test]
  93     fn path_length_info_random_reveal() {
  94         let length = PathLength(Rank(7));
  95         let mut pli = PathLengthInfo::default();
  96         for _ in 0..12 {
  97             let old_pli = PathLengthInfo::clone(&pli);
  98             match pli.reveal_random(length) {
  99                 None => panic!("Nothing revealed?"),
 100                 Some(r) => {
 101                     assert!(!old_pli.is_showing(r));
 102                     assert!(pli.is_showing(r));
 103                 }
 104             }
 105             assert_eq!(pli.0.count_ones(), 1 + old_pli.0.count_ones());
 106         }
 107         assert!(pli.reveal_random(length).is_none());
 108     }
 109
 110     #[test]
 111     fn test_deck() {
 112         use WithOrWithoutJokers::*;
 113         let d = deck(WithoutJokers);
 114         let rank_sum: u32 = d
 115             .iter()
 116             .map(Card::rank)
 117             .flatten()
 118             .map(|r| u32::from(r.value()))
 119             .sum();
 120         assert_eq!(rank_sum, 364);
 121         let _dj = deck(WithJokers);
 122     }
 123 }