use std::f64::consts::PI;
use tui::style::Color;
use tui::widgets::canvas::{Painter, Shape};

pub struct Circle {
    pub x: f64,
    pub y: f64,
    pub r: f64,
    pub start: u16,
    pub stop: u16,
    pub color: Color,
}

impl Default for Circle {
    fn default() -> Self {
        Self {
            x: 0.0,
            y: 0.0,
            r: 1.0,
            start: 0,
            stop: 360,
            color: Color::White,
        }
    }
}

impl Shape for Circle {
    fn draw(&self, painter: &mut Painter) {
        let (x, y) = (self.x, self.y - self.r);

        for angle in (self.start..self.stop).map(|n| n as f64 / 180.0 * PI) {
            let (x, y) = rotate(x, y, angle);
            if let Some((x, y)) = painter.get_point(x, y) {
                painter.paint(x, y, self.color);
            }
        }
    }
}

fn rotate(x: f64, y: f64, a: f64) -> (f64, f64) {
    ((x * a.cos() - y * a.sin()), (x * a.sin() + y * a.cos()))
}