better iter order

This reverts commit 5a52f2ab7a.

Cargo.lock

@@ -11,8 +11,8 @@ checksum = "7f202df86484c868dbad7eaa557ef785d5c66295e41b460ef922eca0723b842c"
 [[package]]
 name = "arrayvec"
 version = "0.7.6"
-source = "sparse+https://git.aleshym.co/api/packages/Quaternions/cargo/"
-checksum = "813440870d646c57c222c1d713dc4e3ddcb2919c3801564d767d85d7bf2afee4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7c02d123df017efcdfbd739ef81735b36c5ba83ec3c59c80a9d7ecc718f92e50"
 
 [[package]]
 name = "bitflags"

card_game/Cargo.toml

@@ -9,7 +9,7 @@ authors = ["Rhys Lloyd <krakow20@gmail.com>"]
 keywords = ["card", "cards", "solitaire", "klondike"]
 
 [dependencies]
-arrayvec = { version = "0.7.6", registry = "Quaternions", features = ["len_u8"], default-features = false }
+arrayvec = "0.7.6"
 
 [lints]
 workspace = true

card_game/src/lib.rs

@@ -6,10 +6,10 @@ struct ReadmeDoctests;
 use core::ops::RangeBounds;
 
 // TODO: pub struct ValidInstruction<I>(I);
-pub trait Game {
-	type Stats;
-	type Config;
-	type Instruction;
+pub trait Game: Clone + core::fmt::Debug {
+	type Stats: Clone + core::fmt::Debug;
+	type Config: Clone + core::fmt::Debug;
+	type Instruction: Clone + core::fmt::Debug;
 	fn possible_instructions(&self) -> impl Iterator<Item = Self::Instruction> + use<Self>;
 	fn is_instruction_valid(&self, config: &Self::Config, instruction: Self::Instruction) -> bool;
 	fn process_instruction(
@@ -321,21 +321,33 @@ impl<S> SessionStats<S> {
 	}
 }
 
+#[derive(Clone, Debug)]
 pub struct Session<G: Game> {
 	stats: SessionStats<G::Stats>,
 	config: G::Config,
 	state: SessionState<G>,
 }
-#[derive(Clone, Eq, Hash, PartialEq)]
-pub struct SessionState<G: Game> {
-	seed: G,
+#[derive(Clone, Debug)]
+pub struct StateSnapshot<G: Game> {
 	state: G,
-	history: Vec<G::Instruction>,
+	instruction: G::Instruction,
+}
+impl<G: Game> StateSnapshot<G> {
+	pub const fn state(&self) -> &G {
+		&self.state
+	}
+	pub const fn instruction(&self) -> &G::Instruction {
+		&self.instruction
+	}
+}
+#[derive(Clone, Debug)]
+pub struct SessionState<G: Game> {
+	state: G,
+	history: Vec<StateSnapshot<G>>,
 }
 impl<G: Game + Clone> SessionState<G> {
 	fn new(state: G) -> Self {
 		Self {
-			seed: state.clone(),
 			state,
 			history: Vec::new(),
 		}
@@ -345,6 +357,7 @@ impl<G: Game> Session<G>
 where
 	G: Clone + Eq + core::hash::Hash,
 	G::Stats: Clone + Default,
+	G::Config: Clone,
 	G::Instruction: Clone + Eq + core::hash::Hash,
 {
 	pub fn new(state: G, config: G::Config) -> Self {
@@ -369,7 +382,7 @@ where
 	pub const fn config(&self) -> &G::Config {
 		&self.config
 	}
-	pub fn history(&self) -> &[G::Instruction] {
+	pub fn history(&self) -> &[StateSnapshot<G>] {
 		&self.state.history
 	}
 	pub fn undo(&mut self) {
@@ -389,12 +402,61 @@ where
 	pub fn is_win(&self) -> bool {
 		self.state.is_win()
 	}
+	pub fn is_winnable(&self) -> Option<Vec<StateSnapshot<G>>> {
+		let mut state_moves = std::collections::HashMap::new();
+		let mut state = self.clone();
+		while !state.is_win() {
+			// Continue existing iterator if it exists
+			let it = state_moves
+				.entry(state.state().clone())
+				.or_insert_with(|| state.state().possible_instructions());
+
+			// Run one possible move
+			if let Some(instruction) = it.next() {
+				state.process_instruction(instruction);
+				continue;
+			}
+
+			// No more moves. If we can't undo we're done
+			if state.history().is_empty() {
+				return None;
+			} else {
+				state.undo();
+			}
+		}
+
+		// history includes cycles
+		let mut state_index: std::collections::HashMap<_, _> = state
+			.history()
+			.iter()
+			.enumerate()
+			.map(|(i, snapshot)| (snapshot.state().clone(), i))
+			.collect();
+
+		// find the longest range where the start and end are the same state
+		while let Some(longest_range) = state
+			.history()
+			.iter()
+			.enumerate()
+			.filter_map(|(index, snapshot)| {
+				let &last_index = state_index.get(snapshot.state())?;
+				let longness = last_index - index;
+				(longness != 0).then_some(index..last_index)
+			})
+			.max_by_key(|range| range.len())
+		{
+			state.state.history.drain(longest_range);
+			for (i, snapshot) in state.history().iter().enumerate() {
+				state_index.insert(snapshot.state().clone(), i);
+			}
+		}
+
+		Some(state.state.history)
+	}
 }
 impl<G: Game> Game for SessionState<G>
 where
-	G: Clone,
 	G::Stats: Default,
-	G::Instruction: Clone,
 {
 	type Stats = SessionStats<G::Stats>;
 	type Config = G::Config;
@@ -420,19 +482,16 @@ where
 	) {
 		match instruction {
 			SessionInstruction::Undo => {
-				// replay the entire history of the game except one move
-				self.history.pop();
-				let mut inner_stats = G::Stats::default();
-				let mut state = self.seed.clone();
-				for instruction in &self.history {
-					state.process_instruction(&mut inner_stats, config, instruction.clone());
-				}
-				self.state = state;
-				stats.inner_stats = inner_stats;
+				if let Some(snapshot) = self.history.pop() {
+					self.state = snapshot.state;
 					stats.increment_undos();
 				}
+			}
 			SessionInstruction::InnerInstruction(instruction) => {
-				self.history.push(instruction.clone());
+				self.history.push(StateSnapshot {
+					state: self.state.clone(),
+					instruction: instruction.clone(),
+				});
 				self.state
 					.process_instruction(&mut stats.inner_stats, config, instruction);
 			}

klondike-cli/src/main.rs

@@ -4,8 +4,8 @@ use klondike::{
 	KlondikePile, KlondikePileStack, KlondikeStats, SkipCards, Tableau, TableauStack,
 };
 
-// #[cfg(test)]
-// mod test;
+#[cfg(test)]
+mod test;
 
 use std::fmt::Display;
 struct Displayed<T>(T);

klondike-cli/src/test.rs

@@ -1,33 +1,15 @@
-use klondike::Klondike;
 use card_game::Session;
+use klondike::Klondike;
 #[test]
 fn test_is_winnable() {
 	// is winnable
-	let is_winnable = Session::new_default(Klondike::with_seed(123)).is_winnable();
-	println!("is_winnable = {is_winnable:?}");
-}
-#[test]
-fn test_klondike() {
-	// create game session
-	let game = Klondike::with_seed(123);
-	let mut session = Session::new_default(game);
-
-	// is winnable
-	let is_winnable = session.is_winnable();
-	println!("is_winnable = {is_winnable:?}");
-
-	// play game
-	while let Some(instruction) = session.possible_instructions().next() {
-		session.process_instruction(instruction);
+	let is_winnable = Session::new_default(Klondike::with_seed(124)).is_winnable();
+	if let Some(win_moves) = is_winnable {
+		// for (i, ins) in win_moves.into_iter().enumerate() {
+		// 	println!("{i} = {:?}", ins.instruction());
+		// }
+		println!("Game is winnable with {} moves", win_moves.len());
+	} else {
+		println!("Game is not winnable");
 	}
-
-	// did win
-	let is_win = session.is_win();
-
-	// print session history
-	for (i, instruction) in session.history().iter().enumerate() {
-		println!("move {i} = {instruction:?}");
-	}
-
-	println!("is_win = {is_win}");
 }

klondike/README.md

@@ -17,8 +17,8 @@ let mut session = Session::new_default(game);
 while let Some(instruction) = session.state().get_auto_move() {
 	session.process_instruction(instruction);
 
-	// quit after 200 moves or win
-	if session.is_win() || 200 < session.stats().stats().moves() {
+	// quit after 1000 moves
+	if 1000 < session.stats().stats().moves() {
 		break;
 	}
 }

klondike/src/lib.rs

@@ -137,6 +137,7 @@ impl From<Foundation> for KlondikePile {
 	}
 }
 
+#[repr(u8)]
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 pub enum SkipCards {
 	Skip0,
@@ -365,26 +366,15 @@ impl KlondikeState {
 	pub const fn tableau7(&self) -> &Pile<6, 13> {
 		&self.tableau7
 	}
-	pub fn tableau_face_down_cards(&self, tableau: Tableau) -> &[Card] {
+	pub fn is_tableau_face_down_empty(&self, tableau: Tableau) -> bool {
 		match tableau {
-			Tableau::Tableau1 => self.tableau1.face_down(),
-			Tableau::Tableau2 => self.tableau2.face_down(),
-			Tableau::Tableau3 => self.tableau3.face_down(),
-			Tableau::Tableau4 => self.tableau4.face_down(),
-			Tableau::Tableau5 => self.tableau5.face_down(),
-			Tableau::Tableau6 => self.tableau6.face_down(),
-			Tableau::Tableau7 => self.tableau7.face_down(),
-		}
-	}
-	pub fn tableau_face_up_cards(&self, tableau: Tableau) -> &[Card] {
-		match tableau {
-			Tableau::Tableau1 => self.tableau1.face_up(),
-			Tableau::Tableau2 => self.tableau2.face_up(),
-			Tableau::Tableau3 => self.tableau3.face_up(),
-			Tableau::Tableau4 => self.tableau4.face_up(),
-			Tableau::Tableau5 => self.tableau5.face_up(),
-			Tableau::Tableau6 => self.tableau6.face_up(),
-			Tableau::Tableau7 => self.tableau7.face_up(),
+			Tableau::Tableau1 => self.tableau1.face_down().is_empty(),
+			Tableau::Tableau2 => self.tableau2.face_down().is_empty(),
+			Tableau::Tableau3 => self.tableau3.face_down().is_empty(),
+			Tableau::Tableau4 => self.tableau4.face_down().is_empty(),
+			Tableau::Tableau5 => self.tableau5.face_down().is_empty(),
+			Tableau::Tableau6 => self.tableau6.face_down().is_empty(),
+			Tableau::Tableau7 => self.tableau7.face_down().is_empty(),
 		}
 	}
 	pub fn stack_bottom_card(&self, src: KlondikePileStack) -> Option<&Card> {
@@ -392,7 +382,15 @@ impl KlondikeState {
 			KlondikePileStack::Tableau(TableauStack {
 				tableau,
 				skip_cards,
-			}) => self.tableau_face_up_cards(tableau).get(skip_cards as usize),
+			}) => match tableau {
+				Tableau::Tableau1 => self.tableau1.face_up().get(skip_cards as usize),
+				Tableau::Tableau2 => self.tableau2.face_up().get(skip_cards as usize),
+				Tableau::Tableau3 => self.tableau3.face_up().get(skip_cards as usize),
+				Tableau::Tableau4 => self.tableau4.face_up().get(skip_cards as usize),
+				Tableau::Tableau5 => self.tableau5.face_up().get(skip_cards as usize),
+				Tableau::Tableau6 => self.tableau6.face_up().get(skip_cards as usize),
+				Tableau::Tableau7 => self.tableau7.face_up().get(skip_cards as usize),
+			},
 			KlondikePileStack::Foundation(foundation) => {
 				self.foundations[foundation as usize].last()
 			}
@@ -401,7 +399,15 @@ impl KlondikeState {
 	}
 	pub fn top_card<S: Into<KlondikePile>>(&self, src: S) -> Option<&Card> {
 		match src.into() {
-			KlondikePile::Tableau(tableau) => self.tableau_face_up_cards(tableau).last(),
+			KlondikePile::Tableau(tableau) => match tableau {
+				Tableau::Tableau1 => self.tableau1.face_up().last(),
+				Tableau::Tableau2 => self.tableau2.face_up().last(),
+				Tableau::Tableau3 => self.tableau3.face_up().last(),
+				Tableau::Tableau4 => self.tableau4.face_up().last(),
+				Tableau::Tableau5 => self.tableau5.face_up().last(),
+				Tableau::Tableau6 => self.tableau6.face_up().last(),
+				Tableau::Tableau7 => self.tableau7.face_up().last(),
+			},
 			KlondikePile::Foundation(foundation) => self.foundations[foundation as usize].last(),
 			KlondikePile::Stock => self.stock.face_up().last(),
 		}
@@ -527,6 +533,10 @@ impl Iterator for KlondikeIter {
 		instruction
 	}
 }
+#[test]
+fn test_klondike_iter() {
+	assert_eq!(KlondikeIter::new().count(), 721);
+}
 
 #[derive(Clone, Debug, Eq, Hash, PartialEq)]
 pub struct Klondike {
@@ -582,7 +592,7 @@ impl Klondike {
 	/// Check if the game should be auto-completed
 	pub fn is_win_trivial(&self) -> bool {
 		// all face down cards empty means win
-		self.state.stock.is_empty()
+		self.state.stock.face_down().is_empty()
 			&& self.state.tableau1.face_down().is_empty()
 			&& self.state.tableau2.face_down().is_empty()
 			&& self.state.tableau3.face_down().is_empty()
@@ -604,7 +614,7 @@ impl Klondike {
 				KlondikePileStack::Tableau(TableauStack {
 					tableau,
 					skip_cards: SkipCards::Skip0,
-				}) if !self.state().tableau_face_down_cards(tableau).is_empty()
+				}) if !self.state().is_tableau_face_down_empty(tableau)
 					|| self
 						.state()
 						.stack_bottom_card(dst_tableau.src)
@@ -619,18 +629,19 @@ impl Klondike {
 			KlondikeInstruction::RotateStock => 4,
 		}
 	}
+	pub fn iter(&self) -> impl Iterator<Item = KlondikeInstruction> + use<> {
+		let state = self.state.clone();
+		KlondikeIter::new().filter(move |&instruction| state.is_instruction_valid(instruction))
+	}
 	/// A single move that usually makes progress towards a winning game
 	pub fn get_auto_move(&self) -> Option<KlondikeInstruction> {
-		self.possible_instructions()
+		self.iter()
 			.filter(|ins| !ins.is_useless())
 			.min_by_key(|ins| self.instruction_priority(ins))
 	}
 	/// A list of possible moves with useless moves filtered out and sorted by a simple priority function
 	pub fn get_sorted_moves(&self) -> Vec<KlondikeInstruction> {
-		let mut useful_moves: Vec<_> = self
-			.possible_instructions()
-			.filter(|ins| !ins.is_useless())
-			.collect();
+		let mut useful_moves: Vec<_> = self.iter().filter(|ins| !ins.is_useless()).collect();
 		useful_moves.sort_by_key(|ins| self.instruction_priority(ins));
 		useful_moves
 	}
@@ -641,8 +652,7 @@ impl Game for Klondike {
 	type Config = KlondikeConfig;
 	type Instruction = KlondikeInstruction;
 	fn possible_instructions(&self) -> impl Iterator<Item = Self::Instruction> + use<> {
-		let state = self.state.clone();
-		KlondikeIter::new().filter(move |&instruction| state.is_instruction_valid(instruction))
+		self.get_sorted_moves().into_iter()
 	}
 	fn is_instruction_valid(&self, _config: &Self::Config, instruction: Self::Instruction) -> bool {
 		self.state.is_instruction_valid(instruction)