use crate::components::{Position, Renderable};
use crate::map;
use rltk::{Console, Rltk};
use specs::{Join, ReadExpect, ReadStorage, System};

pub struct DrawRenderables<'r> {
    pub ctx: &'r mut Rltk,
}

impl<'a, 'r> System<'a> for DrawRenderables<'r> {
    type SystemData = (
        ReadStorage<'a, Position>,
        ReadStorage<'a, Renderable>,
        ReadExpect<'a, map::Map>,
    );

    fn run(&mut self, (positions, renderables, map): Self::SystemData) {
        let points = iproduct!(0..map::MAPHEIGHT, 0..map::MAPWIDTH);
        for (idx, (tile, (y, x))) in map.tiles.iter().zip(points).enumerate() {
            // Render a tile depending upon the tile type

            if map.revealed_tiles[idx] {
                let fg = if map.visible_tiles[idx] {
                    tile.color()
                } else {
                    tile.color().to_greyscale()
                };
                self.ctx.set(
                    x as i32,
                    y as i32,
                    fg,
                    rltk::RGB::from_f32(0., 0., 0.),
                    tile.glyph(),
                );
            }
        }

        for (pos, render) in (&positions, &renderables).join() {
            let idx = map.xy_idx(pos.x, pos.y);
            if map.visible_tiles[idx] {
                self.ctx
                    .set(pos.x, pos.y, render.fg, render.bg, render.glyph);
            }
        }
    }
}