From 4f3469b3e3fd61561cbd6982728e2e4c79c1441b Mon Sep 17 00:00:00 2001
From: Pavel Lutskov <pavel.lutskov@gmail.com>
Date: Sun, 5 Dec 2021 15:42:07 +0100
Subject: [PATCH] Change Board state to HashMap

---
 rs/src/board.rs | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

diff --git a/rs/src/board.rs b/rs/src/board.rs
index da6bd2a..bfdb25b 100644
--- a/rs/src/board.rs
+++ b/rs/src/board.rs
@@ -1,3 +1,5 @@
+use std::collections::HashMap;
+
 #[derive(Clone)]
 enum Color {
     Black,
@@ -25,7 +27,7 @@ impl Color {
     }
 }
 
-#[derive(Clone)]
+#[derive(PartialEq, Eq, Hash, Clone)]
 pub struct Position {
     rank: Rank,
     file: File,
@@ -56,7 +58,7 @@ impl Position {
     }
 }
 
-#[derive(PartialEq, Clone, Copy)]
+#[derive(PartialEq, Eq, Hash, Clone, Copy)]
 pub enum Rank {
     _1,
     _2,
@@ -68,7 +70,7 @@ pub enum Rank {
     _8,
 }
 
-#[derive(PartialEq, Clone, Copy)]
+#[derive(PartialEq, Eq, Hash, Clone, Copy)]
 pub enum File {
     A,
     B,
@@ -204,17 +206,22 @@ impl Piece {
 }
 
 pub struct Board {
-    state: [[Option<Piece>; File::ALL_VALUES.len()]; Rank::ALL_VALUES.len()],
+    state: HashMap<Position, Piece>,
 }
 
 impl Board {
-    pub fn get_at(&self, position: &Position) -> &Option<Piece> {
-        &self.state[position.rank.get_index() as usize]
-            [position.file.get_index() as usize]
+    pub fn get_at(&self, position: &Position) -> Option<&Piece> {
+        return self.state.get(position);
     }
-    fn set_at(&mut self, position: &Position, piece_or_empty: Option<Piece>) {
-        self.state[position.rank.get_index() as usize]
-            [position.file.get_index() as usize] = piece_or_empty;
+    pub fn set_at(
+        &mut self,
+        position: Position,
+        piece_or_empty: Option<Piece>,
+    ) {
+        match piece_or_empty {
+            Some(piece) => self.state.insert(position, piece),
+            None => self.state.remove(&position),
+        };
     }
     pub fn new() -> Board {
         let mut board = Board {
@@ -222,9 +229,12 @@ impl Board {
         };
         for piece_type in &[PieceType::Pawn] {
             for (piece, position) in piece_type.initial_setup() {
-                board.set_at(&position, Some(piece));
+                board.set_at(position, Some(piece));
             }
         }
         board
     }
+    pub fn iter(&self) -> impl Iterator<Item = (&Position, &Piece)> {
+        self.state.iter()
+    }
 }