use rltk::{GameState, Rltk, VirtualKeyCode, RGB};
use specs::prelude::*;
use specs_derive::Component;
use std::cmp::{max, min};

#[derive(Component)]
struct Position {
    x: i32,
    y: i32,
}

#[derive(Component)]
struct Renderable {
    glyph: rltk::FontCharType,
    fg: RGB,
    bg: RGB,
}

struct State {
    ecs: World,
}

impl GameState for State {
    fn tick(&mut self, ctx: &mut Rltk) {
        ctx.cls();
        ctx.print(1, 1, "Hello Rust World");
    }
}

fn main() -> rltk::BError {
    use rltk::RltkBuilder;

    let context = RltkBuilder::simple80x50()
        .with_title("Roguelike Tutorial")
        .build()?;

    let mut gs = State { ecs: World::new() };

    gs.ecs.register::<Position>();
    gs.ecs.register::<Renderable>();

    gs.ecs
        .create_entity()
        .with(Position { x: 40, y: 25 })
        .with(Renderable {
            glyph: rltk::to_cp437('@'),
            fg: RGB::named(rltk::YELLOW),
            bg: RGB::named(rltk::BLACK),
        })
        .build();

    rltk::main_loop(context, gs)
}