//! Game client.
//!
//! ```text
//! game                         singleplayer (persistent local world)
//! game --host [PORT]           singleplayer world that friends can join
//! game --connect ADDR[:PORT]   join a dedicated server or host
//! ```
//! Common options: `--name NAME`, `--save FILE`, `--map MAP`.

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

mod input;
mod net;
mod render;
mod ui;

use std::{net::SocketAddr, path::PathBuf};

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

/// How this client runs.
#[derive(Clone, Debug)]
pub enum Mode {
    /// Server logic runs in-process without networking.
    Singleplayer,
    /// Server logic runs in-process and accepts remote players.
    Host { port: u16 },
    /// Pure client connected to a remote server.
    Join { addr: SocketAddr },
}

/// The local player's login name, used to find our character among replicated ones.
#[derive(Resource, Clone, Debug)]
pub struct LocalPlayer {
    pub name: String,
}

#[derive(Resource, Clone, Debug)]
pub struct ClientMode(pub Mode);

fn main() -> AppExit {
    let (mode, name, settings) = parse_args();
    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: format!("Station - {name}"),
                    resolution: WindowResolution::new(1280, 800),
                    ..default()
                }),
                ..default()
            }),
        RepliconPlugins,
        RepliconRenetPlugins,
        CorePlugin,
    ));

    match &mode {
        Mode::Singleplayer => {
            app.add_plugins(GameServerPlugin { settings });
        }
        Mode::Host { port } => {
            app.add_plugins((
                GameServerPlugin { settings },
                NetworkServerPlugin { port: *port },
            ));
        }
        Mode::Join { .. } => {}
    }

    app.insert_resource(LocalPlayer { name })
        .insert_resource(ClientMode(mode))
        .insert_resource(ClearColor(Color::srgb(0.02, 0.02, 0.05)))
        .add_plugins((
            net::NetPlugin,
            render::RenderPlugin,
            input::InputPlugin,
            ui::UiPlugin,
        ))
        .run()
}

fn parse_args() -> (Mode, String, ServerSettings) {
    let mut mode = Mode::Singleplayer;
    let mut name = std::env::var("USER")
        .ok()
        .filter(|n| game_server::players::valid_name(n))
        .unwrap_or_else(|| "Player".to_owned());
    let mut settings = ServerSettings {
        save_path: Some(PathBuf::from("saves/singleplayer.rsn")),
        ..default()
    };
    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" => {
                let port = match args.peek() {
                    Some(p) if !p.starts_with("--") => args
                        .next()
                        .unwrap()
                        .parse()
                        .unwrap_or_else(|_| usage("invalid port")),
                    _ => game_core::DEFAULT_PORT,
                };
                mode = Mode::Host { port };
            }
            "--connect" => {
                let addr = value("an address");
                let addr = if addr.contains(':') {
                    addr
                } else {
                    format!("{addr}:{}", game_core::DEFAULT_PORT)
                };
                let addr = std::net::ToSocketAddrs::to_socket_addrs(&addr)
                    .ok()
                    .and_then(|mut a| a.next())
                    .unwrap_or_else(|| usage(&format!("can't resolve `{addr}`")));
                mode = Mode::Join { addr };
            }
            "--name" => name = value("a name"),
            "--save" => settings.save_path = Some(value("a file").into()),
            "--no-save" => settings.save_path = None,
            "--map" => settings.map = value("a map path"),
            "-h" | "--help" => usage(""),
            other => usage(&format!("unknown argument `{other}`")),
        }
    }
    if !game_server::players::valid_name(&name) {
        usage("names may only contain letters, digits, spaces, `_` and `-` (max 24)");
    }
    (mode, name, settings)
}

fn usage(error: &str) -> ! {
    if !error.is_empty() {
        eprintln!("error: {error}\n");
    }
    eprintln!(
        "usage: game [--host [PORT] | --connect ADDR[:PORT]] [--name NAME] [--save FILE | --no-save] [--map MAP]\n\n\
         (no mode)  singleplayer, world saved to saves/singleplayer.rsn\n\
         --host     play your world and let others join (default port {port})\n\
         --connect  join a server (default port {port})\n\
         --name     character name; characters persist per world\n\
         --save     world file for singleplayer/host\n\
         --map      Tiled map for new worlds (default {map})",
        port = game_core::DEFAULT_PORT,
        map = game_core::DEFAULT_MAP,
    );
    std::process::exit(if error.is_empty() { 0 } else { 2 })
}