use crate::chat_error::ChatError;
use crate::chat_user::ChatUser;
use crate::config::ConfigArgs;
use chrono::{DateTime, Utc};
use std::collections::BTreeMap;
use std::io::Write;
use std::net::TcpStream;

pub struct ChatServer {
    pub config: ConfigArgs,
    user_map: BTreeMap<u64, ChatUser>,
    user_id_counter: u64,
}

impl ChatServer {
    pub fn new(config: ConfigArgs) -> Self {
        Self {
            config,
            user_map: BTreeMap::new(),
            user_id_counter: 1,
        }
    }

    pub fn get_user_count(&self) -> usize {
        self.user_map.len()
    }

    /// register a client by creating a ChatUser for it and assigning it a user id
    pub fn register(&mut self, name: String, socket: TcpStream) -> u64 {
        let chat_user = ChatUser::new(self.user_id_counter, name, socket);
        let client_id = chat_user.id;
        self.user_map.insert(chat_user.id, chat_user);
        self.user_id_counter += 1;

        client_id
    }

    pub fn deregister(&mut self, client_id: u64) -> Option<ChatUser> {
        self.user_map.remove(&client_id)
    }

    pub fn send_to_all(&mut self, msg: &str) -> Result<(), ChatError> {
        let now: DateTime<Utc> = Utc::now();
        let time_msg = format!("[{}] {}", now.format("%H:%M:%S"), msg);
        let mut broken_clients = vec![];
        for (user_id, user) in self.user_map.iter_mut() {
            if write!(user.socket, "{}\n", time_msg).is_err() {
                broken_clients.push((*user_id, user.name.clone()));
            }
        }

        // remove users from map
        for (user_id, _) in broken_clients.iter() {
            self.deregister(*user_id);
        }

        // send out the news
        for (_, name) in broken_clients.iter() {
            self.send_to_all(&format!("* {} has left the chat (broken pipe)", name))?;
        }

        Ok(())
    }

    pub fn is_nick_in_use(&self, name: &str) -> bool {
        self.user_map.values().any(|client| client.name == name)
    }
}