use crate::wayland::{shm::ShmPool, wl_shm::wl_buffer};
use super::drawable::{Drawable, color_blend};

// x and y are center of circle
pub struct Circle {
    x: usize,
    y: usize,
    radius: usize,
    color: u32,
}

impl Circle {
    pub fn new(x: usize, y: usize, radius: usize, color: u32) -> Self {
        Circle { x, y, radius, color }
    }
}

impl Drawable for Circle {
    fn update(&mut self) {
        // self.x += 1;
    }

    fn draw(&self, buffer: &wl_buffer, shm_pool: &mut ShmPool) {
        for l_row in 1..self.radius { 
            let inner_diff = (((self.radius-1).pow(2) - l_row.pow(2)) as f64).sqrt();
            let outer_diff = ((self.radius.pow(2) - l_row.pow(2)) as f64).sqrt();
            shm_pool.write(self.color, (self.y-l_row)*buffer.width + self.x - inner_diff.floor() as usize + buffer.offset, 2*(inner_diff.floor() as usize));
            shm_pool.write(self.color, (self.y+l_row-1)*buffer.width + self.x - inner_diff.floor() as usize + buffer.offset, 2*(inner_diff.floor() as usize));
            for l_col in (inner_diff.floor() as usize+1)..(outer_diff.ceil() as usize) {
                let distance = ((l_row.pow(2) + l_col.pow(2)) as f64).sqrt();
                let offset = (self.y-l_row)*buffer.width + self.x - l_col + buffer.offset;
                shm_pool.write_pixel(color_blend(self.color, 0, distance.fract()), offset);
                let offset = (self.y-l_row)*buffer.width + self.x + l_col-1 + buffer.offset;
                shm_pool.write_pixel(color_blend(self.color, 0, distance.fract()), offset);
                let offset = (self.y+l_row-1)*buffer.width + self.x - l_col + buffer.offset;
                shm_pool.write_pixel(color_blend(self.color, 0, distance.fract()), offset);
                let offset = (self.y+l_row-1)*buffer.width + self.x + l_col-1 + buffer.offset;
                shm_pool.write_pixel(color_blend(self.color, 0, distance.fract()), offset);
            }
        }
    }
}

impl Into<Box<dyn Drawable>> for Circle {
    fn into(self) -> Box<dyn Drawable> {
        Box::new(self)
    }
}