//! Game client.
//!
//! ```text
//! game                         start menu
//! game --save NAME             play a local world directly
//! game --host [PORT]           play a local world that friends can join
//! game --connect ADDR[:PORT]   join a dedicated server or host
//! ```
//! Common options: `--name NAME`, `--password PASSWORD`, `--map MAP`, `--no-save`.

// Release builds on Windows run without a console window.
#![cfg_attr(all(windows, not(debug_assertions)), windows_subsystem = "windows")]

mod hud;
mod input;
mod machine;
mod menu;
mod profile;
mod render;
mod saves;
mod session;
mod ui;

use bevy::{prelude::*, window::WindowResolution};
use bevy_replicon::prelude::*;
use bevy_replicon_renet::RepliconRenetPlugins;
use game_core::CorePlugin;

use crate::{
    profile::Profile,
    session::{AppState, SessionRequest, SessionTarget},
};

fn main() -> AppExit {
    let mut profile = Profile::load();
    let (request, map) = parse_args(&mut profile);
    let mut app = App::new();
    let assets = game_core::assets_dir();
    app.add_plugins((
        DefaultPlugins
            .set(AssetPlugin {
                file_path: assets.to_string_lossy().into_owned(),
                ..default()
            })
            .set(ImagePlugin::default_nearest())
            .set(WindowPlugin {
                primary_window: Some(Window {
                    title: "Station".to_owned(),
                    resolution: WindowResolution::new(1280, 800),
                    ..default()
                }),
                ..default()
            }),
        RepliconPlugins,
        RepliconRenetPlugins,
        CorePlugin,
    ))
    .insert_resource(profile)
    .insert_resource(menu::StartMap(map))
    .insert_resource(ClearColor(Color::srgb(0.02, 0.02, 0.05)))
    .add_plugins((
        ui::UiFrameworkPlugin,
        session::SessionPlugin,
        menu::MenuPlugin,
        hud::HudPlugin,
        machine::MachinePlugin,
        render::RenderPlugin,
        input::InputPlugin,
    ));
    if let Some(request) = request {
        app.insert_resource(request);
        app.world_mut()
            .resource_mut::<NextState<AppState>>()
            .set(AppState::Connecting);
    }
    app.run()
}

/// Returns the session to start right away (skipping the menu), if any, and the map for new worlds.
fn parse_args(profile: &mut Profile) -> (Option<SessionRequest>, String) {
    let mut host = None;
    let mut connect = None;
    let mut save = None;
    let mut no_save = false;
    let mut password = String::new();
    let mut map = game_core::DEFAULT_MAP.to_owned();
    let mut args = std::env::args().skip(1).peekable();
    while let Some(arg) = args.next() {
        let mut value = |what: &str| {
            args.next()
                .unwrap_or_else(|| usage(&format!("{arg} needs {what}")))
        };
        match arg.as_str() {
            "--host" => {
                host = Some(match args.peek() {
                    Some(p) if !p.starts_with("--") => args
                        .next()
                        .unwrap()
                        .parse()
                        .unwrap_or_else(|_| usage("invalid port")),
                    _ => game_core::DEFAULT_PORT,
                });
            }
            "--connect" => connect = Some(value("an address")),
            "--name" => profile.name = value("a name"),
            "--password" => password = value("a password"),
            "--save" => save = Some(value("a save name")),
            "--no-save" => no_save = true,
            "--map" => map = value("a map path"),
            "-h" | "--help" => usage(""),
            other => usage(&format!("unknown argument `{other}`")),
        }
    }
    if !game_server::players::valid_name(&profile.name) {
        usage("names may only contain letters, digits, spaces, `_` and `-` (max 24)");
    }
    let target = match (connect, host) {
        (Some(_), Some(_)) => usage("--connect and --host can't be combined"),
        (Some(address), None) => {
            if save.is_some() || no_save {
                usage("--save and --no-save only apply to local worlds");
            }
            SessionTarget::Remote { address }
        }
        (None, host) if host.is_some() || save.is_some() || no_save => SessionTarget::Local {
            storage: (!no_save).then(|| saves::storage(save.as_deref().unwrap_or("singleplayer"))),
            map: map.clone(),
            host: host.map(|port| (port, password.clone())),
        },
        _ => return (None, map),
    };
    let request = SessionRequest {
        target,
        name: profile.name.clone(),
        password,
    };
    (Some(request), map)
}

fn usage(error: &str) -> ! {
    if !error.is_empty() {
        eprintln!("error: {error}\n");
    }
    eprintln!(
        "usage: game [--save NAME | --no-save] [--host [PORT]] [--connect ADDR[:PORT]]\n            \
         [--name NAME] [--password PASSWORD] [--map MAP]\n\n\
         (no options)  show the start menu\n\
         --save        play the local world NAME (created if missing), stored in {saves}\n\
         --no-save     play a local world that is not saved\n\
         --host        let others join your local world (default port {port}, password from --password)\n\
         --connect     join a server (default port {port})\n\
         --name        character name; characters persist per world\n\
         --password    server password (joining) or password for others (hosting)\n\
         --map         Tiled map for new worlds (default {map})",
        port = game_core::DEFAULT_PORT,
        map = game_core::DEFAULT_MAP,
        saves = saves::saves_dir().display(),
    );
    std::process::exit(if error.is_empty() { 0 } else { 2 })
}