[explorer, moves, position] Implement a moves command in explorer

The moves command writes all possible moves to the terminal.

Move the previous implementation of the moves command, which marked squares that
a piece could move to, to a 'movement' command.

position/src/lib.rs

@@ -11,4 +11,5 @@ mod macros;
 mod testing;
 
 pub use chessfriend_board::{fen, PlacePieceError, PlacePieceStrategy};
+pub use chessfriend_moves::GeneratedMove;
 pub use position::{Position, ValidateMove};

position/src/position.rs

@@ -4,6 +4,13 @@ mod captures;
 mod make_move;
 mod unmake_move;
 
+use chessfriend_moves::{
+    generators::{
+        AllPiecesMoveGenerator, BishopMoveGenerator, KingMoveGenerator, KnightMoveGenerator,
+        PawnMoveGenerator, QueenMoveGenerator, RookMoveGenerator,
+    },
+    GeneratedMove,
+};
 pub use make_move::{MakeMoveError, ValidateMove};
 
 use crate::move_record::MoveRecord;
@@ -12,7 +19,7 @@ use chessfriend_bitboard::BitBoard;
 use chessfriend_board::{
     display::DiagramFormatter, fen::ToFenStr, Board, PlacePieceError, PlacePieceStrategy,
 };
-use chessfriend_core::{Color, Piece, Square};
+use chessfriend_core::{Color, Piece, Shape, Square};
 use std::{cell::OnceCell, fmt};
 
 #[must_use]
@@ -79,6 +86,33 @@ impl Position {
     }
 }
 
+impl Position {
+    pub fn all_moves(&self, color: Option<Color>) -> AllPiecesMoveGenerator {
+        AllPiecesMoveGenerator::new(&self.board, color)
+    }
+
+    #[must_use]
+    pub fn moves_for_piece(
+        &self,
+        square: Square,
+    ) -> Option<Box<dyn Iterator<Item = GeneratedMove>>> {
+        self.get_piece(square)
+            .map(|piece| Self::generator(&self.board, piece))
+    }
+
+    #[must_use]
+    fn generator(board: &Board, piece: Piece) -> Box<dyn Iterator<Item = GeneratedMove>> {
+        match piece.shape {
+            Shape::Pawn => Box::new(PawnMoveGenerator::new(board, Some(piece.color))),
+            Shape::Knight => Box::new(KnightMoveGenerator::new(board, Some(piece.color))),
+            Shape::Bishop => Box::new(BishopMoveGenerator::new(board, Some(piece.color))),
+            Shape::Rook => Box::new(RookMoveGenerator::new(board, Some(piece.color))),
+            Shape::Queen => Box::new(QueenMoveGenerator::new(board, Some(piece.color))),
+            Shape::King => Box::new(KingMoveGenerator::new(board, Some(piece.color))),
+        }
+    }
+}
+
 impl Position {
     pub fn active_sight(&self) -> BitBoard {
         self.board.active_sight()