From 06aeab55c9ec91f8bfb8c3570297ee26f321bbf5 Mon Sep 17 00:00:00 2001
From: Kjetil Orbekk <kj@orbekk.com>
Date: Mon, 5 Sep 2022 14:34:55 -0400
Subject: Add card sorting utility

---
 webapp/src/card.rs | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 70 insertions(+), 3 deletions(-)

(limited to 'webapp/src')

diff --git a/webapp/src/card.rs b/webapp/src/card.rs
index 248b9b5..825694f 100644
--- a/webapp/src/card.rs
+++ b/webapp/src/card.rs
@@ -1,11 +1,13 @@
+use anyhow::anyhow;
 use rand::prelude::SliceRandom;
 use rand::Rng;
 use std::fmt;
+use strum::EnumCount;
 use strum::IntoEnumIterator;
+use strum_macros::EnumCount;
 use strum_macros::EnumIter;
-use anyhow::anyhow;
 
-#[derive(PartialOrd, Ord, PartialEq, Eq, Clone, Copy, EnumIter)]
+#[derive(PartialOrd, Ord, PartialEq, Eq, Clone, Copy, EnumIter, EnumCount)]
 pub enum Suit {
     Club,
     Diamond,
@@ -159,11 +161,71 @@ fn make_deck() -> Vec<Card> {
     result
 }
 
+#[derive(Default, PartialEq, Eq)]
+pub enum RankOrder {
+    #[default]
+    Descending,
+    Ascending,
+}
+
+pub fn sort_cards<Suits: Iterator<Item = Suit>>(suits: Suits, ord: RankOrder, cards: &mut [Card]) {
+    let mut score: [u8; Suit::COUNT] = [0; Suit::COUNT];
+    for (i, suit) in suits.enumerate() {
+        score[suit as usize] = i as u8;
+    }
+    cards.sort_by(|&Card(s1, r1), &Card(s2, r2)| {
+        let order = {
+            if s1 == s2 {
+                r1.cmp(&r2)
+            } else {
+                score[s2 as usize].cmp(&score[s1 as usize])
+            }
+        };
+        if ord == RankOrder::Descending {
+            order.reverse()
+        } else {
+            order
+        }
+    });
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
     use log::info;
 
+    #[test]
+    fn sorting_cards() {
+        let card = |s: &str| s.parse::<Card>().unwrap();
+        assert_eq!([card("♥2"), card("♥3"), card("♥4"),], {
+            let mut cards = [card("♥2"), card("♥4"), card("♥3")];
+            sort_cards(
+                [Suit::Heart, Suit::Spade, Suit::Club, Suit::Diamond].into_iter(),
+                RankOrder::Ascending,
+                &mut cards,
+            );
+            cards
+        });
+        assert_eq!([card("♥A"), card("♥3"), card("♥2"),], {
+            let mut cards = [card("♥2"), card("♥A"), card("♥3")];
+            sort_cards(
+                [Suit::Heart, Suit::Spade, Suit::Club, Suit::Diamond].into_iter(),
+                RankOrder::Descending,
+                &mut cards,
+            );
+            cards
+        });
+        assert_eq!([card("♠A"), card("♥A"), card("♣A"), card("♦A"),], {
+            let mut cards = [card("♣A"), card("♠A"), card("♥A"), card("♦A"),];
+            sort_cards(
+                [Suit::Spade, Suit::Heart, Suit::Club, Suit::Diamond].into_iter(),
+                RankOrder::Descending,
+                &mut cards,
+            );
+            cards
+        });
+    }
+
     #[test]
     fn string_conversion() {
         crate::tests::test_setup();
@@ -197,5 +259,10 @@ where
     let west = deck.by_ref().take(13).cloned().collect();
     let south = deck.by_ref().take(13).cloned().collect();
     let east = deck.by_ref().take(13).cloned().collect();
-    Deal { north, west, south, east }
+    Deal {
+        north,
+        west,
+        south,
+        east,
+    }
 }
-- 
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