mc-proxy-controller/src/docker.rs

use std::time::Duration;

use anyhow::{Result, bail};
use bollard::Docker;
use tokio::sync::mpsc;
use tokio::time::Instant;

use crate::config::Config;
use crate::rcon;
use crate::state::{ServerState, SharedServerState};

#[derive(Debug, Clone, PartialEq, Eq)]
pub enum ContainerStatus {
    Running,
    Stopped,
    NotFound,
}

pub struct DockerManager {
    docker: Docker,
    container_name: String,
}

impl DockerManager {
    pub async fn new(container_name: String) -> Result<Self> {
        let docker = Docker::connect_with_socket_defaults()?;
        Ok(Self {
            docker,
            container_name,
        })
    }

    pub async fn get_container_status(&self) -> Result<ContainerStatus> {
        match self
            .docker
            .inspect_container(&self.container_name, None)
            .await
        {
            Ok(details) => {
                let Some(state) = details.state else {
                    bail!("No state in container details");
                };
                let running = state.running.unwrap_or(false);

                if running {
                    Ok(ContainerStatus::Running)
                } else {
                    Ok(ContainerStatus::Stopped)
                }
            }
            Err(bollard::errors::Error::DockerResponseServerError {
                status_code: 404, ..
            }) => Ok(ContainerStatus::NotFound),
            Err(e) => Err(e.into()),
        }
    }

    pub async fn start_container(&self) -> Result<()> {
        println!("Starting Docker container: {}", self.container_name);
        self.docker
            .start_container(&self.container_name, None)
            .await?;
        Ok(())
    }
}

pub async fn run_docker_lifecycle_manager(
    config: Config,
    state: SharedServerState,
    mut player_connect_rx: mpsc::Receiver<()>,
) -> Result<()> {
    let docker = DockerManager::new(config.container_name.clone()).await?;

    match docker.get_container_status().await {
        Ok(ContainerStatus::Running) => {
            println!(
                "Container '{}' is already running, checking for RCON availability...",
                config.container_name
            );
            state.transition_to_starting().await;
        }
        Ok(ContainerStatus::Stopped) => {
            println!(
                "Container '{}' is stopped, waiting for player connection...",
                config.container_name
            );
            state.transition_to_stopped().await;
        }
        Ok(ContainerStatus::NotFound) => {
            eprintln!("ERROR: Container '{}' not found!", config.container_name);
            bail!("Container not found");
        }
        Err(e) => {
            eprintln!("ERROR: Failed to connect to Docker: {}", e);
            return Err(e);
        }
    }

    let startup_timeout = Duration::from_secs(config.startup_timeout_secs);
    let stop_timeout = Duration::from_secs(30);

    loop {
        tokio::select! {
            Some(_) = player_connect_rx.recv() => {
                let current_state = state.get().await;
                if matches!(current_state, ServerState::Stopped | ServerState::Unknown) {
                    println!("Player connection detected, starting container...");
                    if let Err(e) = docker.start_container().await {
                        eprintln!("Failed to start container: {}", e);
                    } else {
                        state.transition_to_starting().await;
                    }
                } else {
                    println!("Player connection detected, but server is already in state {:?}", current_state);
                }
            }

            _ = tokio::time::sleep(Duration::from_millis(500)) => {
                let current_state = state.get().await;

                match current_state {
                    ServerState::Starting { started_at } => {
                        match docker.get_container_status().await {
                            Ok(ContainerStatus::Stopped) => {
                                eprintln!("Container stopped unexpectedly during startup (crashed/exited)");
                                state.transition_to_stopped().await;
                                continue;
                            }
                            Ok(ContainerStatus::NotFound) => {
                                eprintln!("Container disappeared during startup");
                                state.transition_to_stopped().await;
                                continue;
                            }
                            Err(e) => {
                                eprintln!("Failed to check container status: {}", e);
                            }
                            Ok(ContainerStatus::Running) => {
                            }
                        }

                        let rcon_available = rcon::connect_rcon(&config.rcon_addr, &config.rcon_password).await.is_ok();
                        if rcon_available {
                            let startup_duration = (Instant::now() - started_at).as_secs();
                            println!("RCON connection established, server is ready!");
                            state.record_startup_duration(startup_duration).await;
                            state.transition_to_running().await;
                        } else if Instant::now() - started_at > startup_timeout {
                            eprintln!(
                                "Server start timeout ({}s), transitioning back to Stopped",
                                startup_timeout.as_secs()
                            );
                            state.transition_to_stopped().await;
                        }
                    }
                    ServerState::Stopping { stop_requested_at } => {
                        match docker.get_container_status().await {
                            Ok(ContainerStatus::Stopped) => {
                                println!("Container stopped successfully");
                                state.transition_to_stopped().await;
                            }
                            _ => {
                                if Instant::now() - stop_requested_at > stop_timeout {
                                    eprintln!("Container stop timeout, forcing transition to Stopped");
                                    state.transition_to_stopped().await;
                                }
                            }
                        }
                    }
                    _ => {}
                }
            }
        }
    }
}