use crate::{config::SETTLED_THRESOHLD, content::materials::MaterialId};

#[derive(Clone, Copy)]
pub struct Cell {
    pub material: MaterialId,
    pub flags: u8,
}

impl Cell {
    // only update the cell if this matches the parity of the seqno
    const FLAG_PARITY: u8 = 0b0000_0001;
    // is this cell owned by an entity?
    const FLAG_ENTITY_INTEGRATED: u8 = 0b0000_0010;
    // how close is the cell to settling?
    const MASK_SETTLED: u8 = 0b0001_1100;

    #[inline]
    pub fn parity(self) -> u8 {
        self.flags & Self::FLAG_PARITY
    }
    #[inline]
    pub fn flip_parity(&mut self) {
        self.flags ^= Self::FLAG_PARITY;
    }
    #[inline]
    pub fn match_parity(&mut self, seqno: u64) {
        let parity = !seqno.is_multiple_of(2);
        if parity {
            self.flags |= Self::FLAG_PARITY;
        } else {
            self.flags &= !Self::FLAG_PARITY
        }
    }

    #[inline]
    pub fn entity_integrated(self) -> bool {
        (self.flags & Self::FLAG_ENTITY_INTEGRATED) == Self::FLAG_ENTITY_INTEGRATED
    }
    #[inline]
    pub fn set_entity_integrated(&mut self, entity_integrated: bool) {
        if entity_integrated {
            self.flags |= Self::FLAG_ENTITY_INTEGRATED
        } else {
            self.flags &= !Self::FLAG_ENTITY_INTEGRATED
        }
    }

    #[inline]
    pub fn settled(self) -> u8 {
        (self.flags & Self::MASK_SETTLED) >> 2
    }
    #[inline]
    fn set_settled(&mut self, settled: u8) {
        debug_assert!(settled <= 7);
        self.flags = (settled << 2) | (self.flags & !Self::MASK_SETTLED);
    }
    #[inline]
    pub fn reset_settled(&mut self) {
        self.flags &= !Self::MASK_SETTLED;
    }

    #[inline]
    pub fn increment_settled(&mut self) {
        let s = self.settled();
        if s < SETTLED_THRESOHLD {
            self.set_settled(s + 1);
        }
    }
}

impl Cell {
    pub fn void() -> Cell {
        Cell {
            material: MaterialId::Void,
            flags: 0,
        }
    }
    pub fn from_material(material: MaterialId) -> Cell {
        Cell { material, flags: 0 }
    }
}