backgammon 0.18.0

/*
 * BSD 2-Clause License
 *
 * Copyright (c) 2020-2026, Carlo Strub <cs@carlostrub.ch>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

use std::fmt;

///Represents a player in the game.
///
///This game is for two players only, called Player 0 and Player 1. The labels are arbitrary and do
/// not affect the game. We use 0 and 1 for convenience, as they match Rust tuple indexing. There is
/// a special case where nobody can move, such as when the game starts or ends. We define
/// this as the default.
#[derive(Debug, Clone, Copy, Eq, Ord, PartialEq, PartialOrd, Hash, Default)]
pub enum Player {
    /// None of the two players, e.g. at the start or end of the game.
    #[default]
    Nobody,
    /// Player 0
    Player0,
    /// Player 1
    Player1,
}

impl Player {
    /// Returns the other player, i.e. the player who is not the current player.
    pub fn other(&self) -> Self {
        match *self {
            Player::Nobody => Player::Nobody,
            Player::Player0 => Player::Player1,
            Player::Player1 => Player::Player0,
        }
    }
}

// Implement Display trait for Player
impl fmt::Display for Player {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            Player::Nobody => write!(f, "Nobody"),
            Player::Player0 => write!(f, "Player 0"),
            Player::Player1 => write!(f, "Player 1"),
        }
    }
}

// Test Display trait for Player
#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_display() {
        assert_eq!(format!("{}", Player::Nobody), "Nobody");
        assert_eq!(format!("{}", Player::Player0), "Player 0");
        assert_eq!(format!("{}", Player::Player1), "Player 1");
    }

    #[test]
    fn test_other() {
        assert_eq!(Player::Nobody.other(), Player::Nobody);
        assert_eq!(Player::Player0.other(), Player::Player1);
        assert_eq!(Player::Player1.other(), Player::Player0);
    }
}