use bevy::{
    prelude::*,
    window::{PrimaryWindow, WindowMode, WindowResized},
};

use crate::material::CustomMaterial;

#[derive(Component)]
pub struct FullscreenQuad;

pub fn setup(
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<CustomMaterial>>,
    primary_window: Single<&Window, With<PrimaryWindow>>,
    mut commands: Commands,
) {
    commands.spawn(Camera2d);

    // quad that fills the whole window
    let screen_size = Vec2::new(
        primary_window.resolution.width(),
        primary_window.resolution.height(),
    );
    // create material with initial time = 0.0
    let material_handle = materials.add(CustomMaterial {
        time: 0.0,
        resolution: screen_size,
    });

    commands.spawn((
        Mesh2d(meshes.add(Rectangle::default())),
        MeshMaterial2d(material_handle),
        Transform::from_scale(Vec3::new(screen_size.x, screen_size.y, 1.0)),
        FullscreenQuad,
    ));
}

pub fn screen_resized(
    mut events: EventReader<WindowResized>,
    shader_data: Single<(&mut Transform, &MeshMaterial2d<CustomMaterial>), With<FullscreenQuad>>,
    mut materials: ResMut<Assets<CustomMaterial>>,
) {
    let (mut transform, material) = shader_data.into_inner();
    if let Some(event) = events.read().last() {
        transform.scale = Vec3::new(event.width, event.height, 1.0);
        materials.get_mut(&material.0).unwrap().resolution = Vec2::new(event.width, event.height);
    }
}

pub fn exit_app(mut exit: EventWriter<AppExit>) {
    exit.write(AppExit::Success);
}

pub fn toggle_fullscreen(mut primary_window: Single<&mut Window, With<PrimaryWindow>>) {
    primary_window.mode = match primary_window.mode {
        WindowMode::BorderlessFullscreen(_) => WindowMode::Windowed,
        WindowMode::Windowed => WindowMode::BorderlessFullscreen(MonitorSelection::Current),
        WindowMode::Fullscreen(_, _) => WindowMode::BorderlessFullscreen(MonitorSelection::Current),
    };
}