//! Headless dedicated server.
//!
//! Configured by a TOML file (default `server.toml`, created on first start) and
//! command line options, which override the file for one run. Run with `--help`
//! for the options. Commands (`help`, `save`, `config set`, ...) can be typed into
//! the terminal.

use std::{path::PathBuf, time::Duration};

use bevy::{app::ScheduleRunnerPlugin, log::LogPlugin, prelude::*, state::app::StatesPlugin};
use bevy_replicon::prelude::*;
use bevy_replicon_renet::RepliconRenetPlugins;
use clap::Parser;
use game_core::CorePlugin;
use game_server::{
    GameServerPlugin, NetworkServerPlugin,
    config::{ConfigFile, DEFAULT_CONFIG_PATH, ServerConfig},
    console::ConsolePlugin,
};

/// Station dedicated server.
#[derive(Parser, Debug)]
#[command(
    version,
    about,
    after_help = "Options override the config file for this run only."
)]
struct Cli {
    /// Configuration file, created with defaults if missing.
    #[arg(short, long, value_name = "FILE", default_value = DEFAULT_CONFIG_PATH)]
    config: PathBuf,
    /// UDP port to listen on.
    #[arg(short, long)]
    port: Option<u16>,
    /// Password players need to join (empty for none).
    #[arg(long)]
    password: Option<String>,
    #[arg(long, value_name = "N")]
    max_players: Option<usize>,
    /// Database URL: sqlite://FILE or postgres://USER:PASSWORD@HOST/DB.
    #[arg(long, value_name = "URL")]
    database: Option<String>,
    /// World name (created if missing) or UUID.
    #[arg(long, value_name = "NAME|UUID")]
    world: Option<String>,
    /// Don't persist the world.
    #[arg(long)]
    no_save: bool,
    /// Tiled map for new worlds, relative to the assets directory.
    #[arg(long)]
    map: Option<String>,
    /// Seconds between autosaves.
    #[arg(long, value_name = "SECS")]
    autosave: Option<u64>,
    #[arg(long)]
    motd: Option<String>,
    /// Grant admin rights to a player id (repeatable).
    #[arg(long, value_name = "ID")]
    admin: Vec<String>,
    /// Only allow whitelisted players.
    #[arg(long)]
    whitelist: bool,
    /// Print the effective configuration and exit.
    #[arg(long)]
    print_config: bool,
}

impl Cli {
    fn apply(self, config: &mut ServerConfig) {
        let Cli {
            port,
            password,
            max_players,
            database,
            world,
            no_save,
            map,
            autosave,
            motd,
            admin,
            whitelist,
            ..
        } = self;
        macro_rules! set {
            ($($field:ident).+ = $value:expr) => {
                if let Some(value) = $value {
                    config.$($field).+ = value;
                }
            };
        }
        set!(port = port);
        set!(password = password);
        set!(max_players = max_players);
        set!(database.url = database);
        set!(database.world = world);
        set!(map = map);
        set!(autosave_secs = autosave);
        set!(motd = motd);
        if no_save {
            config.database.save = false;
        }
        if whitelist {
            config.access.whitelist_enabled = true;
        }
        config.access.admins.extend(admin);
    }
}

fn main() -> AppExit {
    let cli = Cli::parse();
    let (file, mut config, created) = match ConfigFile::load_or_create(&cli.config) {
        Ok(loaded) => loaded,
        Err(e) => {
            eprintln!("error: {e}");
            return AppExit::error();
        }
    };
    let print = cli.print_config;
    cli.apply(&mut config);
    if print {
        print!("{}", toml::to_string(&config).expect("config serializes"));
        return AppExit::Success;
    }

    let mut app = App::new();
    app.add_plugins((
        MinimalPlugins.set(ScheduleRunnerPlugin::run_loop(Duration::from_secs_f64(
            1.0 / 60.0,
        ))),
        StatesPlugin,
        LogPlugin::default(),
        bevy::app::TerminalCtrlCHandlerPlugin,
        RepliconPlugins,
        RepliconRenetPlugins,
        CorePlugin,
        GameServerPlugin {
            settings: config.settings(),
        },
        NetworkServerPlugin { config },
        ConsolePlugin,
    ));
    if created {
        info!("created config file `{}`", file.path.display());
    } else {
        info!("loaded config file `{}`", file.path.display());
    }
    app.insert_resource(file);
    app.run()
}