use std::net::SocketAddr;

use packet::{ClientboundPacket, Packet, PacketError, ServerboundPacket};
use pumpkin_config::{RCONConfig, ADVANCED_CONFIG};
use std::sync::Arc;
use tokio::io::{AsyncReadExt, AsyncWriteExt};

use crate::server::Server;

mod packet;

pub struct RCONServer;

impl RCONServer {
    pub async fn new(config: &RCONConfig, server: Arc<Server>) -> Result<Self, std::io::Error> {
        let listener = tokio::net::TcpListener::bind(config.address).await.unwrap();

        let password = Arc::new(config.password.clone());

        let mut connections = 0;
        loop {
            // Asynchronously wait for an inbound socket.
            let (connection, address) = listener.accept().await?;

            if config.max_connections != 0 && connections >= config.max_connections {
                continue;
            }

            connections += 1;
            let mut client = RCONClient::new(connection, address);

            let password = password.clone();
            let server = server.clone();
            tokio::spawn(async move { while !client.handle(&server, &password).await {} });
            log::debug!("closed RCON connection");
            connections -= 1;
        }
    }
}

pub struct RCONClient {
    connection: tokio::net::TcpStream,
    address: SocketAddr,
    logged_in: bool,
    incoming: Vec<u8>,
    closed: bool,
}

impl RCONClient {
    #[must_use]
    pub const fn new(connection: tokio::net::TcpStream, address: SocketAddr) -> Self {
        Self {
            connection,
            address,
            logged_in: false,
            incoming: Vec::new(),
            closed: false,
        }
    }

    /// Returns if client is closed or not
    pub async fn handle(&mut self, server: &Arc<Server>, password: &str) -> bool {
        if !self.closed {
            match self.read_bytes().await {
                // Stream closed, so we can't reply, so we just close everything.
                Ok(true) => return true,
                Ok(false) => {}
                Err(e) => {
                    log::error!("could not read packet: {e}");
                    return true;
                }
            }
            // If we get a close here, we might have a reply, which we still want to write.
            let _ = self.poll(server, password).await.map_err(|e| {
                log::error!("RCON error: {e}");
                self.closed = true;
            });
        }
        self.closed
    }

    async fn poll(&mut self, server: &Arc<Server>, password: &str) -> Result<(), PacketError> {
        let Some(packet) = self.receive_packet().await? else {
            return Ok(());
        };
        let config = &ADVANCED_CONFIG.rcon;
        match packet.get_type() {
            ServerboundPacket::Auth => {
                if packet.get_body() == password {
                    self.send(ClientboundPacket::AuthResponse, packet.get_id(), "")
                        .await?;
                    if config.logging.log_logged_successfully {
                        log::info!("RCON ({}): Client logged in successfully", self.address);
                    }
                    self.logged_in = true;
                } else {
                    if config.logging.log_wrong_password {
                        log::info!("RCON ({}): Client has tried wrong password", self.address);
                    }
                    self.send(ClientboundPacket::AuthResponse, -1, "").await?;
                    self.closed = true;
                }
            }
            ServerboundPacket::ExecCommand => {
                if self.logged_in {
                    let output = tokio::sync::Mutex::new(Vec::new());
                    let dispatcher = server.command_dispatcher.clone();
                    dispatcher
                        .handle_command(
                            &mut crate::command::CommandSender::Rcon(&output),
                            server,
                            packet.get_body(),
                        )
                        .await;
                    let output = output.lock().await;
                    for line in output.iter() {
                        if config.logging.log_commands {
                            log::info!("RCON ({}): {}", self.address, line);
                        }
                        self.send(ClientboundPacket::Output, packet.get_id(), line)
                            .await?;
                    }
                }
            }
        }
        Ok(())
    }

    async fn read_bytes(&mut self) -> std::io::Result<bool> {
        let mut buf = [0; 1460];
        let n = self.connection.read(&mut buf).await?;
        if n == 0 {
            return Ok(true);
        }
        self.incoming.extend_from_slice(&buf[..n]);
        Ok(false)
    }

    async fn send(
        &mut self,
        packet: ClientboundPacket,
        id: i32,
        body: &str,
    ) -> Result<(), PacketError> {
        let buf = packet.write_buf(id, body);
        self.connection
            .write(&buf)
            .await
            .map_err(PacketError::FailedSend)?;
        Ok(())
    }

    async fn receive_packet(&mut self) -> Result<Option<Packet>, PacketError> {
        Packet::deserialize(&mut self.incoming).await
    }
}