[Piece] Implement Piece::fromSymbol

Piece.cpp

@@ -6,10 +6,37 @@ Piece::Piece(PieceColor color, PieceType type) : _color(color), _type(type) {
 }
 
 Piece::Optional Piece::fromSymbol(char symbol) {
-    (void)symbol;
+    PieceType type;
+    PieceColor color = std::isupper(symbol) ? PieceColor::White : PieceColor::Black;
+
+    auto tryType = static_cast<PieceType>(toupper(symbol));
+
+    switch (tryType) {
+        case PieceType::Pawn:
+            type = PieceType::Pawn;
+            break;
+        case PieceType::Knight:
+            type = PieceType::Knight;
+            break;
+        case PieceType::Bishop:
+            type = PieceType::Bishop;
+            break;
+        case PieceType::Rook:
+            type = PieceType::Rook;
+            break;
+        case PieceType::Queen:
+            type = PieceType::Queen;
+            break;
+        case PieceType::King:
+            type = PieceType::King;
+            break;
+        default:
             return std::nullopt;
     }
 
+    return Piece(color, type);
+}
+
 PieceColor Piece::color() const {
     return _color;
 }

Piece.hpp

@@ -10,12 +10,12 @@ enum class PieceColor {
 };
 
 enum class PieceType {
-    Pawn,
+    Pawn = 'P',
-    Knight,
+    Knight = 'N',
-    Bishop,
+    Bishop = 'B',
-    Rook,
+    Rook = 'R',
-    Queen,
+    Queen = 'Q',
-    King
+    King = 'K'
 };
 
 class Piece {