martian-chess/src/game.rs

use crate::prelude::*;

pub struct GamePlugin;

impl Plugin for GamePlugin {
    fn build(&self, app: &mut App) {
        app.add_systems(Startup, setup_board);
    }
}

#[derive(Debug, Component)]
pub(crate) enum Piece {
    Pawn,
    Drone,
    Queen,
}

// manually for the type.
impl std::fmt::Display for Piece {
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        match self {
            Piece::Queen => write!(f, "@"),
            Piece::Drone => write!(f, "^"),
            Piece::Pawn => write!(f, "*"),
        }
    }
}

/// The board is setup like this:
/// ```text
///       0  1  2  3  4  5  6  7
///     +--+--+--+--+--+--+--+--+
/// a   |  |  |  |  I  | d| Q| Q|
///     +--+--+--+--+--+--+--+--+
/// b   |d |p |p |  I  | p| d| Q|
///     +--+--+--+--+--+--+--+--+
/// c   |Q |d |p |  I  | p| p| d|
///     +--+--+--+--+--+--+--+--+
/// d   |Q |Q |d |  I  |  |  |  |
///     +--+--+--+--+--+--+--+--+
/// ````
#[derive(Debug, Resource)]
pub(crate) struct Board {
    pub inner: Vec<Vec<Option<Entity>>>,
}

fn setup_board(mut commands: Commands) {
    let a5d = commands
        .spawn((SpatialBundle { ..default() }, Piece::Drone))
        .id();
    let a6q = commands
        .spawn((SpatialBundle { ..default() }, Piece::Queen))
        .id();
    let a7q = commands
        .spawn((SpatialBundle { ..default() }, Piece::Queen))
        .id();
    let b0d = commands
        .spawn((SpatialBundle { ..default() }, Piece::Drone))
        .id();
    let b1p = commands
        .spawn((SpatialBundle { ..default() }, Piece::Pawn))
        .id();
    let b2p = commands
        .spawn((SpatialBundle { ..default() }, Piece::Pawn))
        .id();
    let c5p = commands
        .spawn((SpatialBundle { ..default() }, Piece::Pawn))
        .id();
    let b5p = commands
        .spawn((SpatialBundle { ..default() }, Piece::Pawn))
        .id();
    let b6d = commands
        .spawn((SpatialBundle { ..default() }, Piece::Drone))
        .id();
    let b7q = commands
        .spawn((SpatialBundle { ..default() }, Piece::Queen))
        .id();
    let c0q = commands
        .spawn((SpatialBundle { ..default() }, Piece::Queen))
        .id();
    let c1d = commands
        .spawn((SpatialBundle { ..default() }, Piece::Drone))
        .id();
    let c2p = commands
        .spawn((SpatialBundle { ..default() }, Piece::Pawn))
        .id();
    let c6p = commands
        .spawn((SpatialBundle { ..default() }, Piece::Pawn))
        .id();
    let c7d = commands
        .spawn((SpatialBundle { ..default() }, Piece::Drone))
        .id();
    let d0q = commands
        .spawn((SpatialBundle { ..default() }, Piece::Queen))
        .id();
    let d1q = commands
        .spawn((SpatialBundle { ..default() }, Piece::Queen))
        .id();
    let d2d = commands
        .spawn((SpatialBundle { ..default() }, Piece::Drone))
        .id();

    commands.insert_resource(Board {
        inner: vec![
            vec![
                None,
                None,
                None,
                None,
                None,
                Some(a5d),
                Some(a6q),
                Some(a7q),
            ],
            vec![
                Some(b0d),
                Some(b1p),
                Some(b2p),
                None,
                None,
                Some(b5p),
                Some(b6d),
                Some(b7q),
            ],
            vec![
                Some(c0q),
                Some(c1d),
                Some(c2p),
                None,
                None,
                Some(c5p),
                Some(c6p),
                Some(c7d),
            ],
            vec![
                Some(d0q),
                Some(d1q),
                Some(d2d),
                None,
                None,
                None,
                None,
                None,
            ],
        ],
    });
}