//! System info

use std::{sync::Mutex, time::Duration};

use anyhow::Context;
use sysinfo::{CpuRefreshKind, SystemExt};

use crate::debian;

pub struct Info {
    system: sysinfo::System,
    updates: Vec<String>,
}

impl Info {
    pub fn new() -> Self {
        Self {
            system: sysinfo::System::new(),
            updates: Vec::new(),
        }
    }

    pub fn refresh_resources(&mut self) {
        self.system.refresh_specifics(
            sysinfo::RefreshKind::new()
                .with_disks_list()
                .with_memory()
                .with_cpu(CpuRefreshKind::new().with_cpu_usage()),
        );
    }

    pub fn refresh_updates(&mut self) -> anyhow::Result<()> {
        debian::update_package_index().context("while fetching the package index")?;

        let updates =
            debian::get_available_updates().context("while fetching available updates")?;

        self.updates = updates;

        Ok(())
    }

    pub fn system(&self) -> &sysinfo::System {
        &self.system
    }

    pub fn updates(&self) -> &Vec<String> {
        &self.updates
    }
}

impl Default for Info {
    fn default() -> Self {
        Self::new()
    }
}

/// Spawns a new thread that forever gathers system information.
pub fn spawn_info_subsystem() -> &'static Mutex<Info> {
    const REFRESH_RESOURCES_INTERVAL: Duration = Duration::from_secs(5);
    const REFRESH_UPDATES_INTERVAL: Duration = Duration::from_secs(3600);

    let info = Box::new(Mutex::new(Info::new()));
    let info = Box::leak(info);

    std::thread::spawn(|| loop {
        tracing::debug!("refreshing system resources");

        #[allow(clippy::mut_mutex_lock)]
        info.lock().unwrap().refresh_resources();

        std::thread::sleep(REFRESH_RESOURCES_INTERVAL);
    });

    std::thread::spawn(|| loop {
        tracing::debug!("refreshing available system updates");

        #[allow(clippy::mut_mutex_lock)]
        if let Err(err) = info.lock().unwrap().refresh_updates() {
            tracing::warn!(?err, "failed to refresh updates");
        }

        std::thread::sleep(REFRESH_UPDATES_INTERVAL);
    });

    info
}