You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: mod.rs
    path of file: ./repos/kingslayer/src/cli
    
    the code of the file until where you have to start completion: use std::{
    cell::{Cell, RefCell},
    fs::{self, File},
    io::{self, BufReader, Read, Write},
};

use serde::{Deserialize, Serialize};

use crate::{
    entity::{Element, Enemy, Entity, Item},
    input::{read_line, CmdTokens, Lexer, Parser},
    player::Player,
    types::{Action, Class, CmdResult, Race},
    world::World,
};

/// The Cli type provides a simple way to interface into the mechanics of Kingslayer with custom worlds
#[derive(Clone, Debug, Default, Deserialize, Serialize)]
pub struct Cli {
    #[serde(default)]
    running: Cell<bool>,
    #[serde(default)]
    num_moves: Cell<u32>,
    #[serde(default)]
    last_cmd_res: RefCell<CmdResult>,
    #[serde(default)]
    last_successful_cmd: RefCell<CmdTokens>,
    #[serde(default)]
    player: RefCell<Box<Player>>,
    world: RefCell<Box<World>>,
}

impl Cli {
    /// Construct from a RON file
    pub fn from_file(path: &str) -> Result<Self, io::Error> {
        let metadata = fs::metadata(path)?;
        let world_file = File::open(path)?;
        let mut world_file_reader = BufReader::new(world_file);
        let mut data = String::with_capacity(metadata
    
    fn combat(&self) -> String {
        let mut events_str =
            String::with_capacity(50 * self.world.borrow().get_curr_room().enemies().len());

        for enemy in self.world.borrow_mut().get_curr_room_mut().enemies_mut() {
            if enemy.is_angry() && enemy.is_alive() {
                let enemy_damage = enemy.damage();

                events_str.push_str(
                    &self
                        .player
                        .borrow_mut()
                        .take_damage(enemy.name(), enemy_damage),
                );

                self.player.borrow_mut().engage_combat();
            }
            if !enemy.is_alive() {
                format!("{}\nYou gained {} XP.", events_str, enemy.xp());
                self.player.borrow_mut().disengage_combat();
                self.player.borrow_mut().gain_xp(enemy.xp());
            }
        }
        self.world.borrow_mut().clear_dead_enemies();

        if !self.player.borrow().is_alive() {
            events_str.push_str("\n\nYou died. Farewell.");
        } else {
            events_str.push_str(&self.player.borrow_mut().level_up());
        }
        events_str.shrink_to_fit();
        events_str
    }