From 60728060a31939fe1b6fc977b4563ea8f2e896bd Mon Sep 17 00:00:00 2001
From: Rhys Lloyd <krakow20@gmail.com>
Date: Sat, 30 May 2026 09:59:58 -0700
Subject: [PATCH] serde for Card, Stack, Pile

---
 Cargo.lock           |  2 ++
 card_game/Cargo.toml |  6 ++++++
 card_game/src/lib.rs | 50 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 58 insertions(+)

diff --git a/Cargo.lock b/Cargo.lock
index 343cacc..f91f9e5 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -25,6 +25,8 @@ name = "card_game"
 version = "0.4.0"
 dependencies = [
  "arrayvec",
+ "serde",
+ "serde_derive",
 ]
 
 [[package]]
diff --git a/card_game/Cargo.toml b/card_game/Cargo.toml
index 051d596..64feed5 100644
--- a/card_game/Cargo.toml
+++ b/card_game/Cargo.toml
@@ -10,6 +10,12 @@ keywords = ["card", "cards", "solitaire", "klondike"]
 
 [dependencies]
 arrayvec = { version = "0.7.6", registry = "Quaternions", features = ["len_u8"], default-features = false }
+serde = { version = "1.0.228", default-features = false, optional = true }
+serde_derive = { version = "1.0.228", default-features = false, optional = true }
 
 [lints]
 workspace = true
+
+[features]
+default = ["serde"]
+serde = ["dep:serde", "dep:serde_derive"]
diff --git a/card_game/src/lib.rs b/card_game/src/lib.rs
index ab698e0..70f16a0 100644
--- a/card_game/src/lib.rs
+++ b/card_game/src/lib.rs
@@ -146,6 +146,11 @@ impl Rank {
 /// 2 bits for suit ID
 /// 4 bits for card Value
 #[derive(Clone, Debug, Eq, Hash, PartialEq)]
+#[cfg_attr(
+	feature = "serde",
+	derive(serde_derive::Deserialize, serde_derive::Serialize),
+	serde(transparent)
+)]
 pub struct Card(core::num::NonZeroU8);
 impl Card {
 	pub const fn new(deck: Deck, suit: Suit, rank: Rank) -> Self {
@@ -229,9 +234,54 @@ impl<const CAP: usize> IntoIterator for Stack<CAP> {
 		self.0.into_iter()
 	}
 }
+#[cfg(feature = "serde")]
+impl<'de, const CAP: usize> serde::Deserialize<'de> for Stack<CAP> {
+	fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+	where
+		D: serde::Deserializer<'de>,
+	{
+		struct StackVisitor<const CAP: usize>;
+		impl<'de, const CAP: usize> serde::de::Visitor<'de> for StackVisitor<CAP> {
+			type Value = Stack<CAP>;
+			fn expecting(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+				write!(f, "Card Stack")
+			}
+			fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
+			where
+				A: serde::de::SeqAccess<'de>,
+			{
+				let mut stack = Stack::new();
+				while let Some(card) = seq.next_element()? {
+					// TODO: Error
+					stack.try_push(card).unwrap();
+				}
+				Ok(stack)
+			}
+		}
+		deserializer.deserialize_seq(StackVisitor)
+	}
+}
+#[cfg(feature = "serde")]
+impl<const CAP: usize> serde::Serialize for Stack<CAP> {
+	fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+	where
+		S: serde::Serializer,
+	{
+		use serde::ser::SerializeSeq;
+		let mut seq = serializer.serialize_seq(Some(self.len()))?;
+		for card in self.as_slice() {
+			seq.serialize_element(card)?;
+		}
+		seq.end()
+	}
+}
 
 /// A pile is a stack of face down cards and a stack of face up cards.
 #[derive(Clone, Debug, Default, Eq, Hash, PartialEq)]
+#[cfg_attr(
+	feature = "serde",
+	derive(serde_derive::Deserialize, serde_derive::Serialize)
+)]
 pub struct Pile<const DN: usize, const UP: usize> {
 	face_down: Stack<DN>,
 	face_up: Stack<UP>,