From 99b49e629e2372962b082325503c33e20a458818 Mon Sep 17 00:00:00 2001
From: funman300 <funman300@gmail.com>
Date: Mon, 8 Jun 2026 11:20:39 -0700
Subject: [PATCH] feat(klondike): add optional serde feature for
 instruction/pile serialization

Adds serde Serialize/Deserialize derives (behind the `serde` feature flag)
to Tableau, Foundation, KlondikePile, SkipCards, TableauStack,
KlondikePileStack, DstFoundation, DstTableau, and KlondikeInstruction.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 klondike/Cargo.toml | 4 ++++
 klondike/src/lib.rs | 9 +++++++++
 2 files changed, 13 insertions(+)

diff --git a/klondike/Cargo.toml b/klondike/Cargo.toml
index 1c55cb4..344a6bf 100644
--- a/klondike/Cargo.toml
+++ b/klondike/Cargo.toml
@@ -3,9 +3,13 @@ name = "klondike"
 version = "0.3.0"
 edition = "2024"
 
+[features]
+serde = ["dep:serde"]
+
 [dependencies]
 card_game.workspace = true
 rand = { version = "0.10.1", default-features = false, features = ["std_rng"] }
+serde = { version = "1", optional = true, default-features = false, features = ["derive"] }
 
 [lints]
 workspace = true
diff --git a/klondike/src/lib.rs b/klondike/src/lib.rs
index 48b491d..8c2a7b4 100644
--- a/klondike/src/lib.rs
+++ b/klondike/src/lib.rs
@@ -121,6 +121,7 @@ impl KlondikeStats {
 }
 
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub enum Tableau {
 	Tableau1,
 	Tableau2,
@@ -147,6 +148,7 @@ impl Tableau {
 }
 
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub enum Foundation {
 	Foundation1,
 	Foundation2,
@@ -167,6 +169,7 @@ impl Foundation {
 }
 
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub enum KlondikePile {
 	Tableau(Tableau),
 	Stock,
@@ -200,6 +203,7 @@ impl From<Foundation> for KlondikePile {
 }
 
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub enum SkipCards {
 	Skip0,
 	Skip1,
@@ -238,6 +242,7 @@ impl SkipCards {
 }
 
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct TableauStack {
 	pub tableau: Tableau,
 	pub skip_cards: SkipCards,
@@ -271,6 +276,7 @@ impl TableauStack {
 }
 
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub enum KlondikePileStack {
 	Tableau(TableauStack),
 	Stock,
@@ -294,6 +300,7 @@ impl KlondikePileStack {
 }
 
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct DstFoundation {
 	pub src: KlondikePile,
 	pub foundation: Foundation,
@@ -317,6 +324,7 @@ impl DstFoundation {
 }
 
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct DstTableau {
 	pub src: KlondikePileStack,
 	pub tableau: Tableau,
@@ -340,6 +348,7 @@ impl DstTableau {
 }
 
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub enum KlondikeInstruction {
 	DstFoundation(DstFoundation),
 	DstTableau(DstTableau),