use wasm_bindgen::prelude::*;

pub type DrawResult<T> = Result<T, Box<dyn std::error::Error>>;

/// Result of screen to chart coordinates conversion.
#[wasm_bindgen]
pub struct Point {
    pub x: f32,
    pub y: f32,
}

#[wasm_bindgen]
impl Point {
    pub fn new(x: f32, y: f32) -> Self { Self { x, y } }
}

#[wasm_bindgen]
pub struct Chart {
    pub(crate) convert: Box<dyn Fn((i32, i32)) -> Option<(f32, f32)>>,
    pub(crate) area: f32,
}

#[wasm_bindgen]
impl Chart {
    pub fn get_area(&self) -> f32 { self.area }

    pub fn coord(&self, x: i32, y: i32) -> Option<Point> {
        (self.convert)((x, y)).map(|(x, y)| Point::new(x, y))
    }
}