minimax/src/main.rs

use std::cmp::Ordering;

use anyhow::{bail, Result};
use termion::color::{self};

mod agents;
mod board;
mod util;
use board::Board;
use util::{Player, Symb};

fn play(
	maxi: &mut dyn agents::MaximizerAgent,
	maxi_player: Player,
	mini: &mut dyn agents::MinimizerAgent,
	mini_player: Player,
) -> Result<Board> {
	let mut board = Board::new();
	let mut is_first_turn = true;
	let mut is_maxi_turn = true;

	while !board.is_done() {
		// Print board
		println!(
			"\r{}{}{}{}",
			" ".repeat(6),
			if is_first_turn { '╓' } else { '║' },
			board.prettyprint()?,
			if is_first_turn { '╖' } else { '║' },
		);
		is_first_turn = false;

		// Take action
		let action = if is_maxi_turn {
			maxi.step_max(&board)?
		} else {
			mini.step_min(&board)?
		};

		if !board.play(
			action,
			if is_maxi_turn {
				maxi_player
			} else {
				mini_player
			},
		) {
			bail!("agent made invalid move")
		}

		is_maxi_turn = !is_maxi_turn;
	}

	println!("\r{}║{}║", " ".repeat(6), board.prettyprint()?);
	println!("\r{}╙{}╜", " ".repeat(6), " ".repeat(board.size()));
	Ok(board)
}

fn main() -> Result<()> {
	rayon::ThreadPoolBuilder::new()
		.num_threads(4)
		.build_global()
		.unwrap();

	let mut maxi = agents::PlayerAgent::new(Player::Human);
	let mut mini = agents::Diffuse {};

	let a = play(&mut maxi, Player::Human, &mut mini, Player::Computer)?;
	if a.is_done() {
		println!(
			"\r\n{}Your score:{} {:.2}\n\n",
			color::Fg(Player::Human.color()),
			color::Fg(color::Reset),
			a.evaluate().unwrap()
		);
	} else {
		println!(
			"\r\n{}Quitting{}\r\n",
			color::Fg(color::Red),
			color::Fg(color::Reset),
		);
		return Ok(());
	}

	let mut mini = agents::PlayerAgent::new(Player::Human);
	let mut maxi = agents::Diffuse {};

	let b = play(&mut maxi, Player::Computer, &mut mini, Player::Human)?;
	if b.is_done() {
		println!(
			"\r\n{}Computer score:{} {:.2}\n\n",
			color::Fg(Player::Human.color()),
			color::Fg(color::Reset),
			b.evaluate().unwrap()
		);
	} else {
		println!(
			"\r\n{}Quitting{}\r\n",
			color::Fg(color::Red),
			color::Fg(color::Reset),
		);
		return Ok(());
	}

	match a.evaluate().partial_cmp(&b.evaluate()) {
		Some(Ordering::Equal) => {
			println!("\r\nTie");
		}
		Some(Ordering::Greater) => {
			println!(
				"\r\n{}Human wins{}",
				color::Fg(Player::Human.color()),
				color::Fg(color::Reset),
			);
		}
		Some(Ordering::Less) => {
			println!(
				"\r\n{}Computer wins{}",
				color::Fg(Player::Computer.color()),
				color::Fg(color::Reset),
			);
		}
		None => {
			println!(
				"\r\n{}Error{}",
				color::Fg(color::Red),
				color::Fg(color::Reset),
			);
		}
	}

	Ok(())
}