use glam::IVec2;

use crate::{
    config::{CELLS_IN_CHUNK, CHUNK_SIZE},
    content::materials::{MaterialForm, MaterialId},
    sim::{cell::Cell, lib::marching_squares::Marchable},
};

pub struct Chunk {
    pub cells: Box<[Cell; CELLS_IN_CHUNK]>,
    pub sleeping: bool,
    pub needs_texture_update: bool,
}

impl Chunk {
    #[inline]
    pub fn get_cell_at_local_position(&self, x: u8, y: u8) -> Cell {
        self.cells[x as usize + y as usize * CHUNK_SIZE as usize]
    }
    #[inline]
    pub fn set_cell_at_local_position(&mut self, x: u8, y: u8, cell: Cell) {
        self.cells[x as usize + y as usize * CHUNK_SIZE as usize] = cell;
    }

    pub fn void() -> Self {
        Chunk {
            cells: Box::new([Cell::void(); CELLS_IN_CHUNK]),
            sleeping: true,
            needs_texture_update: true,
        }
    }

    pub fn floor() -> Self {
        let mut c = Chunk {
            cells: Box::new([Cell::void(); CELLS_IN_CHUNK]),
            sleeping: true,
            needs_texture_update: true,
        };

        for dy in 1..5 {
            for x in 0..CHUNK_SIZE {
                c.set_cell_at_local_position(
                    x as u8,
                    CHUNK_SIZE as u8 - dy,
                    Cell::from_material(MaterialId::Steel),
                );
            }
        }

        c
    }
}

impl Marchable for Chunk {
    fn occupied(&self, pos: IVec2) -> bool {
        if pos.x < 0 || pos.x >= CHUNK_SIZE || pos.y < 0 || pos.y >= CHUNK_SIZE {
            false
        } else {
            // we only build a path for solid cells or settled powder cells
            let cell = self.get_cell_at_local_position(pos.x as u8, pos.y as u8);
            let material = cell.material.def();
            material.form == MaterialForm::Solid
                || material.form == MaterialForm::Powder && cell.settled() > 4
        }
    }
    fn size(&self) -> IVec2 {
        IVec2::new(CHUNK_SIZE, CHUNK_SIZE)
    }
}