From 124e5c0f7f5ba42374557456075135f83335ebc7 Mon Sep 17 00:00:00 2001
From: Gleb Koval <gleb@koval.net>
Date: Sun, 7 Aug 2022 19:20:56 +0000
Subject: [PATCH] initial o-x-rust implementation complete

---
 wasm/o-x-rust/Cargo.lock |  2 +-
 wasm/o-x-rust/Cargo.toml |  2 +-
 wasm/o-x-rust/src/lib.rs | 56 ++++++++++++++++++++++++++++++++++++++--
 3 files changed, 56 insertions(+), 4 deletions(-)

diff --git a/wasm/o-x-rust/Cargo.lock b/wasm/o-x-rust/Cargo.lock
index ff1f126..8eecd9c 100644
--- a/wasm/o-x-rust/Cargo.lock
+++ b/wasm/o-x-rust/Cargo.lock
@@ -25,7 +25,7 @@ dependencies = [
 
 [[package]]
 name = "o-x-rust"
-version = "0.0.2"
+version = "0.0.3"
 dependencies = [
  "wasm-bindgen",
 ]
diff --git a/wasm/o-x-rust/Cargo.toml b/wasm/o-x-rust/Cargo.toml
index daca615..6ce2416 100644
--- a/wasm/o-x-rust/Cargo.toml
+++ b/wasm/o-x-rust/Cargo.toml
@@ -4,7 +4,7 @@ description = "Naughts and crosses WASM algorithms"
 repository = "https://git.koval.net/cyclane/game-algorithms/src/branch/main/wasm/o-x-rust"
 license = "GNU GPLv3"
 readme = "README.md"
-version = "0.0.2"
+version = "0.0.3"
 edition = "2021"
 
 [lib]
diff --git a/wasm/o-x-rust/src/lib.rs b/wasm/o-x-rust/src/lib.rs
index 74b3078..e6a9a84 100644
--- a/wasm/o-x-rust/src/lib.rs
+++ b/wasm/o-x-rust/src/lib.rs
@@ -1,6 +1,58 @@
 use wasm_bindgen::prelude::wasm_bindgen;
 
 #[wasm_bindgen]
-pub fn add(a: usize, b: usize) -> usize {
-    a + b
+pub fn find_winner(board: &[u8]) -> u8 {
+	for i in 0..3 {
+		let h = i*3;
+		if board[h] == board[h + 1] && board[h + 1] == board[h + 2] {
+			return board[h];
+		}
+		if board[i] == board[i + 3] && board[i + 3] == board[i + 6] {
+			return board[i];
+		}
+	}
+	if board[0] == board[4] && board[4] == board[8] {
+		return board[0];
+	}
+	if board[2] == board[4] && board[4] == board[6] {
+		return board[2];
+	}
+	0
+}
+
+#[wasm_bindgen]
+pub fn count_empty(board: &[u8]) -> usize {
+	board.iter().filter(|&n| *n == 0).count()
+}
+
+#[wasm_bindgen]
+pub fn get_turn(me: u8, other: u8, first: bool, empty: usize) -> u8 {
+	if empty % 2 == if first { 1 } else { 0 } {
+		me
+	} else {
+		other
+	}
+}
+
+#[wasm_bindgen]
+pub fn get_score(me: u8, other: u8, first: bool, board: &[u8]) -> i32 {
+	let winner = find_winner(board);
+	if winner != 0 {
+		return if winner == me { 1 } else { -1 };
+	}
+	let empty = count_empty(board);
+	if empty == 0 {
+		return 0;
+	}
+	let mut score = 0;
+	for i in 0..9 {
+		if board[i] != 0 {
+			continue;
+		}
+		let copy = &mut [0u8; 9];
+		copy.copy_from_slice(board);
+		copy[i] = get_turn(me, other, first, empty);
+		score += get_score(me, other, first, copy);
+	}
+	score
 }