From b2e2d547ef233fa9358cb5821fb3071b13ad1f13 Mon Sep 17 00:00:00 2001
From: Wesley Irvin <wesley@wesirvin.com>
Date: Sun, 11 Jan 2026 16:25:37 -0500
Subject: [PATCH] Created Hand Type

Created a Hand type that can also calculate the sum of the cards in the
hand. Also wrote a display for it so that we can just print hands out.

Reviewed-on: https://git.wesirvin.com/wesley/blackjack/pulls/13
---
 src/hand.rs         | 82 +++++++++++++++++++++++++++++++++++++++++++++
 src/lib.rs          |  5 +++
 tests/hand_tests.rs | 40 ++++++++++++++++++++++
 3 files changed, 127 insertions(+)
 create mode 100644 tests/hand_tests.rs

diff --git a/src/hand.rs b/src/hand.rs
index e69de29..0693573 100644
--- a/src/hand.rs
+++ b/src/hand.rs
@@ -0,0 +1,82 @@
+use std::fmt;
+
+use super::card::Card;
+
+pub struct Hand {
+    cards: Vec<Card>,
+    is_dealer: bool,
+    show_all: bool,
+}
+
+impl Hand {
+    pub fn new(is_dealer: bool) -> Self {
+        let cards: Vec<Card> = Vec::new();
+
+        Self {
+            cards: cards,
+            is_dealer: is_dealer,
+            show_all: !is_dealer,
+        }
+    }
+
+    pub fn sum(&self) -> u8 {
+        let mut num_aces = 0;
+        let mut sum: u8 = 0;
+        if self.is_dealer && !self.show_all {
+            if self.cards[1].value + 1 > 10 {
+                return 10;
+            } else if self.cards[1].value + 1 == 1 {
+                return 11;
+            }
+            return self.cards[1].value + 1;
+        }
+
+        for card in 0..self.cards.len() {
+            match self.cards[card].value + 1 {
+                1 => {
+                    sum += 11;
+                    num_aces += 1;
+                }
+                2..=9 => sum += self.cards[card].value + 1,
+                10..=13 => sum += 10,
+                _ => sum += 0,
+            }
+        }
+
+        while num_aces > 0 && sum > 21 {
+            num_aces -= 1;
+            sum -= 10;
+        }
+
+        sum
+    }
+
+    pub fn get_new_card(&mut self, new_card: Card) {
+        self.cards.push(new_card);
+    }
+
+    pub fn set_show_all(&mut self, show_all: bool) {
+        if self.is_dealer {
+            self.show_all = show_all;
+        }
+    }
+}
+
+impl fmt::Display for Hand {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let mut display_string = String::new();
+
+        if self.show_all {
+            for card in 0..self.cards.len() {
+                display_string.push_str(&self.cards[card].to_string());
+                display_string.push_str(" ");
+            }
+        } else {
+            display_string.push_str("** ");
+            display_string.push_str(&self.cards[1].to_string());
+            display_string.push_str(" ");
+        }
+
+        write!(f, "{}", display_string)
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index ceb7cc4..61b0480 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,6 +1,9 @@
 use std::error::Error;
 
 mod card;
+
+pub use card::Card;
+
 mod deck;
 
 pub use deck::Deck;
@@ -8,6 +11,8 @@ pub use deck::Deck;
 mod gamestate;
 mod hand;
 
+pub use hand::Hand;
+
 pub fn run() -> Result<(), Box<dyn Error>> {
     println!("Hello, world!");
 
diff --git a/tests/hand_tests.rs b/tests/hand_tests.rs
new file mode 100644
index 0000000..5286d74
--- /dev/null
+++ b/tests/hand_tests.rs
@@ -0,0 +1,40 @@
+use blackjack::Card;
+use blackjack::Hand;
+
+const ACE_HEARTS: Card = Card { suit: 0, value: 0 };
+const ACE_SPADES: Card = Card { suit: 3, value: 0 };
+const KING_HEARTS: Card = Card { suit: 0, value: 12 };
+const KING_SPADES: Card = Card { suit: 3, value: 12 };
+
+#[test]
+fn test_double_ace() {
+    let mut hand = Hand::new(false);
+    hand.get_new_card(ACE_HEARTS);
+    hand.get_new_card(ACE_SPADES);
+
+    assert_eq!(12, hand.sum());
+}
+
+#[test]
+fn double_ace_double_face() {
+    let mut hand = Hand::new(false);
+    hand.get_new_card(ACE_HEARTS);
+    hand.get_new_card(ACE_SPADES);
+    hand.get_new_card(KING_HEARTS);
+    hand.get_new_card(KING_SPADES);
+
+    assert_eq!(22, hand.sum());
+}
+
+#[test]
+fn show_all_is_dealer() {
+    let mut hand = Hand::new(true);
+    hand.get_new_card(ACE_HEARTS);
+    hand.get_new_card(KING_SPADES);
+
+    assert_eq!(10, hand.sum());
+
+    hand.set_show_all(true);
+
+    assert_eq!(21, hand.sum());
+}