use bevy::prelude::*;
use common::prelude::network::*;
use common::prelude::*;
use lightyear::prelude::*;

use bevy::asset::AssetMetaCheck;
use bevy::window::WindowResolution;
use lightyear::prelude::input::native::InputMarker;
use lightyear::prelude::server::Started;

mod args;
mod assets;
mod input;
mod placement;
mod ui;

use args::*;
use placement::*;

use input::is_cursor_grabbed;

#[derive(States, Clone, Copy, PartialEq, Eq, Hash, Debug)]
pub enum Screen {
    Loading,
    Gameplay,
}

fn main() -> Result {
    let args = Args::parse();
    let mut app = App::new();

    app.insert_resource(args);
    app.insert_state(Screen::Loading);

    app.add_plugins(
        DefaultPlugins
            .set(WindowPlugin {
                primary_window: Some(Window {
                    title: "bevy-bloxel-classic".into(),
                    // Steam Deck: DPI appears pretty high, causing everything to be scaled up.
                    //             Setting `scale_factor_override` prevents this from happening.
                    resolution: WindowResolution::new(1280, 720).with_scale_factor_override(1.0),
                    // WEB: Fit canvas to parent element, so `Window` resizes automatically.
                    fit_canvas_to_parent: true,
                    // WEB: Don't override default event handling like browser hotkeys while focused.
                    prevent_default_event_handling: false,
                    ..default()
                }),
                ..default()
            })
            .set(AssetPlugin {
                // WEB: Don't check for `.meta` files since we don't use them.
                meta_check: AssetMetaCheck::Never,
                ..default()
            }),
    );

    app.add_plugins((
        bevy_fix_cursor_unlock_web::FixPointerUnlockPlugin,
        common::asset_loading::plugin,
        common::network::plugin,
        assets::plugin,
        input::plugin,
        ui::plugin,
    ));

    app.add_systems(
        OnEnter(Screen::Gameplay),
        (setup_scene, start_server_or_connect),
    );

    // `place_break_blocks` requires the camera's `GlobalTransform`.
    // For a most up-to-date value, run it after that's been updated.
    app.add_systems(
        PostUpdate,
        place_break_blocks
            .after(TransformSystems::Propagate)
            .run_if(in_state(Screen::Gameplay).and(is_cursor_grabbed)),
    );

    app.add_observer(spawn_initial_blocks);
    app.add_observer(handle_predicted_player_spawn);

    app.run();
    Ok(())
}

fn setup_scene(mut commands: Commands) {
    commands.spawn((
        PointLight {
            shadows_enabled: true,
            ..default()
        },
        Transform::from_xyz(4.0, 8.0, 4.0),
    ));
}

fn start_server_or_connect(args: Res<Args>, mut commands: Commands) -> Result {
    let mode = args.mode.as_ref();
    let default = Mode::default();
    match mode.unwrap_or(&default) {
        Mode::Local => {
            commands.queue(StartLocalServerCommand);
        }
        #[cfg(not(target_family = "wasm"))]
        Mode::Host { port } => {
            commands.queue(StartWebTransportServerCommand::new(*port));
        }
        Mode::Connect { address, digest } => {
            commands.queue(ConnectWebTransportCommand::new(&address, digest.clone())?);
        }
    }
    // NOTE: When setting up a local server, a host-client is automatically
    //       connected to it thanks to the `autoconnect_host_client` observer.
    Ok(())
}

/// When the server is started, spawn the initial blocks the world is made of.
fn spawn_initial_blocks(_event: On<Add, Started>, mut blocks: Blocks) {
    for x in -8..8 {
        for z in -8..8 {
            blocks.spawn(IVec3::new(x, 0, z));
        }
    }
}

/// When the `Predicted` player we control is being spawned, insert necessary components.
fn handle_predicted_player_spawn(event: On<Add, Predicted>, mut commands: Commands) {
    let player = event.entity;
    commands.entity(player).insert((
        // Handle inputs on this entity.
        InputMarker::<Inputs>::default(),
        // TODO: Attach camera to player head eventually.
        Camera3d::default(),
    ));
}