use crate::board::{BOARD_AREA, BOARD_SIZE};
use bitvec::prelude::*;
use static_assertions::const_assert;

// BitBoard should be big enough to fit all points on the board
const_assert!(std::mem::size_of::<BitBoard>() * 8 >= BOARD_AREA);

/// Backing Type of BitBoard
type BBBaseType = u64;

#[derive(Copy, Clone, PartialEq, Eq)]
pub struct BitBoard(BitArr!(for BOARD_AREA, in BBBaseType, Lsb0));

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

impl BitBoard {
    pub const fn new() -> Self {
        Self(bitarr!(BBBaseType, Lsb0; 0; BOARD_AREA))
    }

    const fn get_index(row: usize, col: usize) -> usize {
        row * BOARD_SIZE + col
    }

    pub fn get(&self, row: usize, col: usize) -> bool {
        self.0[Self::get_index(row, col)]
    }

    pub fn set(&mut self, row: usize, col: usize, value: bool) {
        self.0.set(Self::get_index(row, col), value);
    }

    pub fn count(&self) -> usize {
        self.0.count_ones()
    }
}

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn set_and_get() {
        let mut b = BitBoard::new();
        assert!(!b.get(2, 4));
        b.set(2, 4, true);
        assert!(b.get(2, 4));
        b.set(2, 4, false);
        assert!(!b.get(2, 4));
    }
}