//! Simple plot example derived from
//! [eframe](https://docs.rs/eframe/0.22.0/eframe/index.html#usage-native) and
//! [plotters](https://docs.rs/plotters/0.3.4/plotters/index.html#quick-start)

use eframe::egui::{self, CentralPanel, Visuals};
use egui_plotter::EguiBackend;
use plotters::prelude::*;

fn main() {
    let native_options = eframe::NativeOptions::default();
    eframe::run_native(
        "Simple Example",
        native_options,
        Box::new(|cc| Box::new(Simple::new(cc))),
    )
    .unwrap();
}

#[derive(Default)]
struct Simple {}

impl Simple {
    fn new(cc: &eframe::CreationContext<'_>) -> Self {
        // Disable feathering as it causes artifacts
        let context = &cc.egui_ctx;

        context.tessellation_options_mut(|tess_options| {
            tess_options.feathering = false;
        });

        // Also enable light mode
        context.set_visuals(Visuals::light());

        Self::default()
    }
}

impl eframe::App for Simple {
    fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
        CentralPanel::default().show(ctx, |ui| {
            let root = EguiBackend::new(ui).into_drawing_area();
            root.fill(&WHITE).unwrap();
            let mut chart = ChartBuilder::on(&root)
                .caption("y=x^2", ("sans-serif", 50).into_font())
                .margin(5)
                .x_label_area_size(30)
                .y_label_area_size(30)
                .build_cartesian_2d(-1f32..1f32, -0.1f32..1f32)
                .unwrap();

            chart.configure_mesh().draw().unwrap();

            chart
                .draw_series(LineSeries::new(
                    (-50..=50).map(|x| x as f32 / 50.0).map(|x| (x, x * x)),
                    &RED,
                ))
                .unwrap()
                .label("y = x^2")
                .legend(|(x, y)| PathElement::new(vec![(x, y), (x + 20, y)], &RED));

            chart
                .configure_series_labels()
                .background_style(&WHITE.mix(0.8))
                .border_style(&BLACK)
                .draw()
                .unwrap();

            root.present().unwrap();
        });
    }
}