path: root/ui/src/main.rs

use model::{CheckersBitBoard, PieceColor, PossibleMoves, SquareCoordinate};
use tetra::graphics::{self, Color, DrawParams, Texture};
use tetra::input::MouseButton;
use tetra::math::Vec2;
use tetra::{input, Context, ContextBuilder, State};

const WINDOW_WIDTH: f32 = 640.0;
const WINDOW_HEIGHT: f32 = 480.0;
const DARK_SLATE_BLUE: Color = Color::rgb(0.2823529, 0.2392157, 0.5450980);

struct GameState {
	chess_board: Texture,
	possible_move_square: Texture,
	dark_piece: Texture,
	light_piece: Texture,
	dark_king: Texture,
	light_king: Texture,
	bit_board: CheckersBitBoard,
	selected_square: Option<SquareCoordinate>,
	possible_moves: Vec<SquareCoordinate>,
}

impl GameState {
	fn new(ctx: &mut Context) -> tetra::Result<Self> {
		Ok(GameState {
			chess_board: Texture::new(ctx, "./ui/resources/chess_board.png")?,
			possible_move_square: Texture::new(ctx, "./ui/resources/possible_move.png")?,
			dark_piece: Texture::new(ctx, "./ui/resources/red_piece.png")?,
			light_piece: Texture::new(ctx, "./ui/resources/white_piece.png")?,
			dark_king: Texture::new(ctx, "./ui/resources/red_king.png")?,
			light_king: Texture::new(ctx, "./ui/resources/white_king.png")?,
			bit_board: CheckersBitBoard::starting_position(),
			selected_square: None,
			possible_moves: Vec::new(),
		})
	}
}

impl GameState {
	fn draw_highlighted_square(&self, ctx: &mut Context, square: SquareCoordinate) {
		let square_draw_params = DrawParams::new()
			.position(Vec2::new(
				120.0 + (50.0 * square.file() as f32),
				390.0 - (50.0 * square.rank() as f32),
			))
			.scale(Vec2::new(0.5, 0.5));

		self.possible_move_square.draw(ctx, square_draw_params);
	}
}

impl State for GameState {
	fn update(&mut self, ctx: &mut Context) -> tetra::Result {
		if input::is_mouse_button_released(ctx, MouseButton::Left) {
			let x = input::get_mouse_x(ctx);
			let y = input::get_mouse_y(ctx);

			if x > 120.0 && y > 40.0 && x < 520.0 && y < 440.0 {
				let file = ((x - 140.0) / 50.0).round();
				let rank = ((410.0 - y) / 50.0).round();
				let square = SquareCoordinate::new(rank as u8, file as u8);
				self.selected_square = Some(square);

				let moves = PossibleMoves::moves(self.bit_board);
				self.possible_moves = moves
					.into_iter()
					.filter(|m| SquareCoordinate::from_value(m.start() as usize) == square)
					.map(|m| SquareCoordinate::from_value(m.end_position()))
					.collect()
			}
		}

		Ok(())
	}

	fn draw(&mut self, ctx: &mut Context) -> tetra::Result {
		graphics::clear(ctx, DARK_SLATE_BLUE);

		let board_draw_params = DrawParams::new()
			.position(Vec2::new(120.0, 40.0))
			.scale(Vec2::new(0.4938272, 0.4938272));

		self.chess_board.draw(ctx, board_draw_params);

		if let Some(square) = self.selected_square {
			self.draw_highlighted_square(ctx, square);
		}

		for square in &self.possible_moves {
			self.draw_highlighted_square(ctx, *square);
		}

		for row in 0..8 {
			for col in 0..8 {
				if let Some(piece) = self.bit_board.get_at_row_col(row, col) {
					let piece_draw_params = DrawParams::new()
						.position(Vec2::new(
							130.0 + (50.0 * col as f32),
							400.0 - (50.0 * row as f32),
						))
						.scale(Vec2::new(0.3, 0.3));

					match piece.color() {
						PieceColor::Dark => {
							if piece.is_king() {
								self.dark_king.draw(ctx, piece_draw_params)
							} else {
								self.dark_piece.draw(ctx, piece_draw_params)
							}
						}
						PieceColor::Light => {
							if piece.is_king() {
								self.light_king.draw(ctx, piece_draw_params)
							} else {
								self.light_piece.draw(ctx, piece_draw_params)
							}
						}
					}
				}
			}
		}

		Ok(())
	}
}

fn main() -> tetra::Result {
	let title = "Checkers with Ampere";
	let mut builder = ContextBuilder::new(title, WINDOW_WIDTH as i32, WINDOW_HEIGHT as i32);

	builder.show_mouse(true);
	builder.quit_on_escape(true);

	if cfg!(debug_assertions) {
		builder.debug_info(true);
	} else {
		builder.debug_info(false);
	}

	builder.build()?.run(GameState::new)
}