SeaBattle/sea_battle_backend/src/game.rs

use std::sync::Arc;

use actix::prelude::*;
use actix::{Actor, Context, Handler};
use uuid::Uuid;

use crate::data::*;

pub trait Player {
    fn get_name(&self) -> &str;

    fn get_uid(&self) -> Uuid;

    fn set_other_player_name(&self, name: &str);

    fn query_boats_layout(&self, rules: &GameRules);

    fn rejected_boats_layout(&self, errors: Vec<&'static str>);

    fn notify_other_player_ready(&self);

    fn notify_game_starting(&self);

    fn request_fire(&self, status: CurrentGameStatus);

    fn other_player_must_fire(&self, status: CurrentGameStatus);

    fn strike_result(&self, c: Coordinates, res: FireResult);

    fn other_player_strike_result(&self, c: Coordinates, res: FireResult);

    fn lost_game(&self, your_map: EndGameMap, opponent_map: EndGameMap);

    fn won_game(&self, your_map: EndGameMap, opponent_map: EndGameMap);
}

fn opponent(index: usize) -> usize {
    match index {
        0 => 1,
        1 => 0,
        _ => unreachable!(),
    }
}

#[derive(Default, Eq, PartialEq, Debug, Copy, Clone)]
enum GameStatus {
    #[default]
    Created,
    WaitingForBoatsDisposition,
    Started,
    Finished,
}

pub struct Game {
    rules: GameRules,
    players: Vec<Arc<dyn Player>>,
    status: GameStatus,
    map_0: Option<GameMap>,
    map_1: Option<GameMap>,
    turn: usize,
}

impl Game {
    pub fn new(rules: GameRules) -> Self {
        Self {
            rules,
            players: vec![],
            status: GameStatus::Created,
            map_0: None,
            map_1: None,
            turn: 0,
        }
    }

    /// Find the ID of a player from its UUID
    fn player_id_by_uuid(&self, uuid: Uuid) -> usize {
        self.players
            .iter()
            .enumerate()
            .find(|p| p.1.get_uid() == uuid)
            .expect("Player is not member of this game!")
            .0
    }

    /// Once the two player has been registered, the game may start
    fn query_boats_disposition(&mut self) {
        self.players[0].set_other_player_name(self.players[1].get_name());
        self.players[1].set_other_player_name(self.players[0].get_name());

        log::debug!("Query boats disposition");
        assert_eq!(self.status, GameStatus::Created);
        self.status = GameStatus::WaitingForBoatsDisposition;
        self.players[0].query_boats_layout(&self.rules);
        self.players[1].query_boats_layout(&self.rules);
    }

    /// Start fires exchange
    fn start_fire_exchanges(&mut self) {
        self.status = GameStatus::Started;
        log::debug!(
            "Start fire exchanges. Player {}#{} goes first",
            self.players[self.turn].get_name(),
            self.turn
        );

        self.request_fire();
    }

    fn request_fire(&self) {
        self.players[self.turn].request_fire(self.get_game_status_for_player(self.turn));
        self.players[opponent(self.turn)]
            .other_player_must_fire(self.get_game_status_for_player(opponent(self.turn)));
    }

    fn player_map(&self, id: usize) -> &GameMap {
        match id {
            0 => self.map_0.as_ref(),
            1 => self.map_1.as_ref(),
            _ => unreachable!(),
        }
        .unwrap()
    }

    fn player_map_mut(&mut self, id: usize) -> &mut GameMap {
        match id {
            0 => self.map_0.as_mut(),
            1 => self.map_1.as_mut(),
            _ => unreachable!(),
        }
        .unwrap()
    }

    /// Handle fire attempts
    fn handle_fire(&mut self, c: Coordinates) {
        let result = self.player_map_mut(opponent(self.turn)).fire(c);
        self.players[self.turn].strike_result(c, result);
        self.players[opponent(self.turn)].strike_result(c, result);

        // Easiest case : player missed his fire
        if result == FireResult::Missed {
            self.turn = opponent(self.turn);
            self.request_fire();
            return;
        }

        if result == FireResult::Sunk && self.player_map(opponent(self.turn)).are_all_boat_sunk() {
            self.status = GameStatus::Finished;

            let winner_map = self.player_map(self.turn).final_map();
            let looser_map = self.player_map(opponent(self.turn)).final_map();

            self.players[self.turn].won_game(winner_map.clone(), looser_map.clone());
            self.players[opponent(self.turn)].lost_game(looser_map, winner_map);

            return;
        }

        if (result == FireResult::Sunk || result == FireResult::Hit)
            && !self.rules.player_continue_on_hit
        {
            self.turn = opponent(self.turn);
        }

        self.request_fire();
    }

    /// Get current game status for a specific player
    fn get_game_status_for_player(&self, id: usize) -> CurrentGameStatus {
        CurrentGameStatus {
            rules: self.rules.clone(),
            your_map: self.player_map(id).current_map_status(false),
            opponent_map: self.player_map(opponent(id)).current_map_status(true),
        }
    }
}

impl Actor for Game {
    type Context = Context<Self>;
}

#[derive(Message)]
#[rtype(result = "()")]
pub struct AddPlayer<E>(pub E);

impl<E> Handler<AddPlayer<Arc<E>>> for Game
where
    E: Player + 'static,
{
    type Result = ();

    /// Add a new player to the game
    fn handle(&mut self, msg: AddPlayer<Arc<E>>, _ctx: &mut Self::Context) -> Self::Result {
        assert!(self.players.len() < 2);
        self.players.push(msg.0);

        if self.players.len() == 2 {
            self.query_boats_disposition();
        }
    }
}

#[derive(Message)]
#[rtype(result = "()")]
pub struct SetBoatsLayout(pub Uuid, pub BoatsLayout);

impl Handler<SetBoatsLayout> for Game {
    type Result = ();

    /// Receive game configuration of a player
    fn handle(&mut self, msg: SetBoatsLayout, _ctx: &mut Self::Context) -> Self::Result {
        if self.status != GameStatus::WaitingForBoatsDisposition {
            log::error!("Player attempted to set boat configuration on invalid step!");
            return;
        }

        let player_index = self.player_id_by_uuid(msg.0);

        let errors = msg.1.errors(&self.rules);
        if !errors.is_empty() {
            log::error!("Got invalid boats layout!");
            self.players[player_index].rejected_boats_layout(errors);
            self.players[player_index].query_boats_layout(&self.rules);
            return;
        }

        log::debug!("Got boat disposition for player {}", player_index);
        match player_index {
            0 => self.map_0 = Some(GameMap::new(self.rules.clone(), msg.1)),
            1 => self.map_1 = Some(GameMap::new(self.rules.clone(), msg.1)),
            _ => unreachable!(),
        }

        self.players[opponent(player_index)].notify_other_player_ready();

        if self.map_0.is_some() && self.map_1.is_some() {
            self.players.iter().for_each(|p| p.notify_game_starting());
            self.start_fire_exchanges();
        }
    }
}

#[derive(Message, Debug)]
#[rtype(result = "()")]
pub struct Fire(pub Uuid, pub Coordinates);

impl Handler<Fire> for Game {
    type Result = ();

    fn handle(&mut self, msg: Fire, _ctx: &mut Self::Context) -> Self::Result {
        if self.status != GameStatus::Started {
            log::error!("Player attempted to fire on invalid step!");
            return;
        }

        if msg.0 != self.players[self.turn].get_uid() {
            log::error!("Player attempted to fire when it was not its turn!");
            return;
        }

        self.handle_fire(msg.1)
    }
}