From cc58260943e3cf3fcbc5a933ff5f7b89d25e10d1 Mon Sep 17 00:00:00 2001
From: Pavel Lutskov <pavel.lutskov@gmail.com>
Date: Wed, 17 Nov 2021 22:15:00 +0100
Subject: [PATCH] Refactor Piece

---
 rs/src/main.rs | 75 +++++++++++++++++++++++++++++++-------------------
 1 file changed, 47 insertions(+), 28 deletions(-)

diff --git a/rs/src/main.rs b/rs/src/main.rs
index e46caf2..2702e1e 100644
--- a/rs/src/main.rs
+++ b/rs/src/main.rs
@@ -1,9 +1,29 @@
-use std::marker::PhantomData;
 enum Color {
     Black,
     White,
 }
 
+impl Color {
+    fn get_home_row(&self) -> Row {
+        match self {
+            Color::Black => Row::_8,
+            Color::White => Row::_1,
+        }
+    }
+    fn get_pawn_row(&self) -> Row {
+        match self {
+            Color::Black => Row::_7,
+            Color::White => Row::_2,
+        }
+    }
+    fn get_direction(&self) -> i8 {
+        match self {
+            Color::Black => -1,
+            Color::White => 1,
+        }
+    }
+}
+
 struct Position {
     row: Row,
     column: Column,
@@ -108,10 +128,14 @@ impl GridAxis for Column {
     }
 }
 
-struct Piece<T> {
+enum PieceType {
+    Pawn,
+}
+
+struct Piece {
     position: Position,
     color: Color,
-    piece_type: PhantomData<T>,
+    piece_type: PieceType,
 }
 
 trait Movement {
@@ -119,9 +143,19 @@ trait Movement {
     fn get_captures(&self) -> Vec<Position>;
 }
 
-struct Pawn {}
-
-impl<T> Piece<T> {
+impl Piece {
+    fn get_moves(&self) -> Vec<Position> {
+        let deltas = match self.piece_type {
+            PieceType::Pawn => self._pawn_get_move_deltas(),
+        };
+        self.deltas_to_valid_positions(&deltas)
+    }
+    fn get_captures(&self) -> Vec<Position> {
+        let deltas = match self.piece_type {
+            PieceType::Pawn => self._pawn_get_capture_deltas(),
+        };
+        self.deltas_to_valid_positions(&deltas)
+    }
     fn deltas_to_valid_positions(
         &self,
         deltas: &Vec<(i8, i8)>,
@@ -133,32 +167,17 @@ impl<T> Piece<T> {
             })
             .collect()
     }
-}
-
-impl Piece<Pawn> {
-    fn get_home_row_direction(&self) -> (Row, i8) {
-        match self.color {
-            Color::Black => (Row::_7, -1),
-            Color::White => (Row::_2, 1),
-        }
-    }
-}
-
-impl Movement for Piece<Pawn> {
-    fn get_moves(&self) -> Vec<Position> {
-        let (home_row, direction) = self.get_home_row_direction();
-        let deltas: Vec<(i8, i8)> = if self.position.row == home_row {
+    fn _pawn_get_move_deltas(&self) -> Vec<(i8, i8)> {
+        let direction = self.color.get_direction();
+        if self.position.row == self.color.get_pawn_row() {
             vec![(1 * direction, 0), (2 * direction, 0)]
         } else {
             vec![(1 * direction, 0)]
-        };
-        self.deltas_to_valid_positions(&deltas)
+        }
     }
-    fn get_captures(&self) -> Vec<Position> {
-        let (_, direction) = self.get_home_row_direction();
-        let deltas: Vec<(i8, i8)> =
-            vec![(1 * direction, 1), (1 * direction, -1)];
-        self.deltas_to_valid_positions(&deltas)
+    fn _pawn_get_capture_deltas(&self) -> Vec<(i8, i8)> {
+        let direction = self.color.get_direction();
+        vec![(1 * direction, 1), (1 * direction, -1)]
     }
 }