use crate::{
    board::{Board, Color},
    fen::from_fen,
};
use String as FenError;

#[derive(Debug, PartialEq, Eq)]
pub struct Game {
    pub board: Board,
}

impl Game {
    pub const fn new() -> Self {
        Self {
            board: Board::new(),
        }
    }

    pub fn new_from_fen(fen: &str) -> Result<Self, FenError> {
        from_fen(fen)
    }

    pub const fn run(&self) {
        Board::new();
    }
}

impl Default for Game {
    fn default() -> Self {
        Self::new()
    }
}

#[derive(Debug, PartialEq, Eq, Clone, Copy)]
pub struct State {
    side_to_move: Color,
    castling_ability: u8,
    en_passant_target_square: Option<u8>,
    halfmove_clock: u8,
    fullmove_counter: u8,
}

impl State {
    pub const fn new() -> Self {
        Self {
            side_to_move: Color::White,
            castling_ability: 0b1111,
            en_passant_target_square: None,
            halfmove_clock: 0,
            fullmove_counter: 1,
        }
    }

    pub const fn load_state(
        side_to_move: Color,
        castling_ability: u8,
        en_passant_target_square: Option<u8>,
        halfmove_clock: u8,
        fullmove_counter: u8,
    ) -> Self {
        Self {
            side_to_move,
            castling_ability,
            en_passant_target_square,
            halfmove_clock,
            fullmove_counter,
        }
    }

    pub const fn get_en_passant_target_square(&self) -> Option<u8> {
        self.en_passant_target_square
    }

    pub const fn get_castling_ability(&self) -> u8 {
        self.castling_ability
    }
}

use std::fmt;

impl fmt::Display for State {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        writeln!(f,
            "side_to_move: {:?}\ncastling_ability: {:b}\nen_passant_target_square: {:b}\nhalfmove_clock: {}\nfullmove_counter: {}\n",
            self.side_to_move, self.castling_ability, 1_u64 << self.en_passant_target_square.unwrap_or(0), self.halfmove_clock, self.fullmove_counter)
    }
}

impl Default for State {
    fn default() -> Self {
        Self::new()
    }
}

pub enum CastlingRights {
    Short,
    Long,
    Both,
    None,
}