use bevy::{
    image::{
        ImageArrayLayout,
        ImageLoaderSettings,
    },
    prelude::*,
    sprite_render::{
        TileData,
        TilemapChunk,
        TilemapChunkTileData,
    },
};
use bevy_rapier2d::prelude::*;

use crate::meters;

const TILEMAP_PATH: &'static str = "sprites/level/tilemap.png";
const TILE_DISPLAY_SIZE: UVec2 = UVec2::splat(meters(1.) as u32);

#[derive(Component, Debug, PartialEq, Eq, Default, Clone, Copy, Reflect)]
#[reflect(Component, Debug, PartialEq, Default, Clone)]
pub struct Tilemap;

pub fn tilemap_bundle(
    asset_server: &Res<AssetServer>,
    tiles: Vec<(u16, URect)>,
) -> impl Bundle {
    let mut size = uvec2(0, 0);
    for tile in tiles.iter() {
        size.x = size.x.max(tile.1.max.x + 1);
        size.y = size.y.max(tile.1.max.y + 1);
    }
    let tile_data: Vec<Option<TileData>> = (0..size.element_product()).map(|xy| {
        if let Some((id, _)) = tiles.iter().find(|(_, rect)| rect.contains(uvec2(xy % size.x, xy / size.x))) {
            Some(TileData::from_tileset_index(*id))
        } else { None }
    }).collect();
    (
        Tilemap,
        TilemapChunk {
            chunk_size: size,
            tile_display_size: TILE_DISPLAY_SIZE,
            tileset: asset_server.load_with_settings(
                TILEMAP_PATH,
                |settings: &mut ImageLoaderSettings| {
                    settings.array_layout = Some(ImageArrayLayout::RowCount { rows: 3 })
                },
            ),
            ..default()
        },
        Transform::from_xyz(
            meters(0.5) * size.x as f32,
            meters(0.5) * size.y as f32 - meters(1.),
            0.,
        ),
        TilemapChunkTileData(tile_data),
        Children::spawn(SpawnIter(tiles.into_iter().map(move |(_, rect)| {
            let mut rect = rect.as_rect();
            rect.max = vec2(rect.max.x + 1., rect.max.y + 1.);

            let (width, height) = (rect.width(), rect.height());
            let offset = rect.center();
            (
                Collider::cuboid(meters(width * 0.5), meters(height * 0.5)),
                Transform::from_xyz(
                    meters(offset.x - size.x as f32 * 0.5),
                    meters(offset.y - size.y as f32 * 0.5),
                    0.,
                ),
            )}
        ))),
    )
}