use clap::{arg, App};
use rdev::{
  Event,
  EventType::{
    KeyPress,
    KeyRelease,
  },
  Key,
};
use nix::unistd::{Group, Uid};
use once_cell::sync::OnceCell;
use std::{
    thread,
    sync::{
      Mutex,
      mpsc::{
        sync_channel,
        SyncSender,
        Receiver
      },
    },
    collections::HashMap,
    env, fs,
    io::prelude::*,
    os::unix::net::UnixStream,
    os::unix::net::UnixListener,
    path::Path,
    process::{exit, id},
    thread::sleep,
    time::Duration,
    time::SystemTime,
};
use sysinfo::{ProcessExt, System, SystemExt};

mod config;

#[derive(PartialEq)]
pub struct LastHotkey {
    hotkey: config::Hotkey,
    ran_at: SystemTime,
}

static STATE_MODE: OnceCell<Mutex<String>> = OnceCell::new();
static MODE_SOCK: &str = "/tmp/odilia-mode.sock";

fn listen_for_mode_change() -> std::io::Result<()> {
  log::trace!("Mode change listener started!");
  let listener = UnixListener::bind(MODE_SOCK)?;
  match listener.accept() {
    Ok((mut socket, _addr)) => {
        let mut response = String::new();
        socket.read_to_string(&mut response)?;
        log::trace!("reponse from odilia-mode.sock: '{}'", response);
        let mode_m = STATE_MODE.get();
        match mode_m {
          Some(mm) => {
            let mut mode = mm.lock();
            match mode {
              Ok(mut m) => {
                *m = response;
                println!("Mode updated to '{}'", m);
                log::trace!("Mode updated to '{}'", m);
              },
              Err(e) => log::error!("Could not lock mode."),
            }
          },
          _ => log::error!("Could not get static STATE_MODE."),
        }
    },
    Err(e) => log::error!("accept function failed: {:?}", e),
  }
  Ok(())
}

pub fn key_listener() {
    let args = set_flags().get_matches();
    env::set_var("RUST_LOG", "swhkd=warn");

    if args.is_present("debug") {
        env::set_var("RUST_LOG", "swhkd=trace");
    }

    log::trace!("Logger initialized.");

    match STATE_MODE.set(Mutex::new(String::new())) {
      Err(e) => log::error!("could not initialize STATE_MODE"),
      _ => log::trace!("STATE_MODE initialized"),
    }

    let pidfile: String = String::from("/tmp/swhkd.pid");
    if Path::new(&pidfile).exists() {
       log::trace!("Reading {} file and checking for running instances.", pidfile);
        let swhkd_pid = match fs::read_to_string(&pidfile) {
            Ok(swhkd_pid) => swhkd_pid,
            Err(e) => {
                log::error!("Unable to read {} to check all running instances", e);
                exit(1);
            }
        };
        log::debug!("Previous PID: {}", swhkd_pid);

        let mut sys = System::new_all();
        sys.refresh_all();
        for (pid, process) in sys.processes() {
            if pid.to_string() == swhkd_pid && process.exe() == env::current_exe().unwrap() {
                log::error!("Swhkd is already running!");
                exit(1);
            }
        }
    }

    match fs::write(&pidfile, id().to_string()) {
        Ok(_) => {}
        Err(e) => {
            log::error!("Unable to write to {}: {}", pidfile, e);
            exit(1);
        }
    }

    permission_check();

    let config_file_path: std::path::PathBuf;
    if args.is_present("config") {
        config_file_path = Path::new(args.value_of("config").unwrap()).to_path_buf();
    } else {
        config_file_path = check_config_xdg();
    }
    log::debug!("Using config file path: {:#?}", config_file_path);

    if !config_file_path.exists() {
        log::error!("{:#?} doesn't exist", config_file_path);
        exit(1);
    }

    let hotkeys = match config::load(config_file_path) {
        Err(e) => {
            log::error!("Config Error: {}", e);
            exit(1);
        }
        Ok(out) => out,
    };

    for hotkey in &hotkeys {
        log::debug!("hotkey: {:#?}", hotkey);
    }

    let modifiers_map: HashMap<Key, config::Modifier> = HashMap::from([
        (Key::MetaLeft, config::Modifier::Super),
        (Key::MetaRight, config::Modifier::Super),
        (Key::Alt, config::Modifier::Alt),
        (Key::AltGr, config::Modifier::Alt),
        (Key::ControlLeft, config::Modifier::Control),
        (Key::ControlRight, config::Modifier::Control),
        (Key::ShiftLeft, config::Modifier::Shift),
        (Key::ShiftRight, config::Modifier::Shift),
    ]);

    let mut possible_hotkeys: Vec<config::Hotkey> = Vec::new();

    let default_test_modifier: Vec<config::Modifier> = vec![config::Modifier::Super];
    let mut last_hotkey = LastHotkey {
        // just a dummy last_hotkey so I don't need to mess with Option<T>. TODO: Change this to Option<T>
        hotkey: config::Hotkey::new(
            Some("".to_string()),
            Key::KeyA,
            default_test_modifier,
            String::from("notify-send \"it works\""),
            false,
        ),
        ran_at: SystemTime::now(),
    };

    loop {
       // TODO 
    }

}

pub fn main() {
  env_logger::init();
  let key_handler = thread::spawn(|| {
    key_listener();
  });
  /*
  let mode_updater = thread::spawn(|| {
    let res = listen_for_mode_change();
    match res {
      Ok(listener) => log::trace!("Finished mode changer!"),
      Err(e) => log::error!("Error setting up mode socket: {}", e),
    }
  });
  */
  log::trace!("Threads set up");
  //mode_updater.join().unwrap();
  key_handler.join().unwrap();
}

pub fn permission_check() {
    if !Uid::current().is_root() {
        let groups = nix::unistd::getgroups();
        for (_, groups) in groups.iter().enumerate() {
            for group in groups {
                let group = Group::from_gid(*group);
                if group.unwrap().unwrap().name == "input" {
                    log::error!("Note: INVOKING USER IS IN INPUT GROUP!!!!");
                    log::error!("THIS IS A HUGE SECURITY RISK!!!!");
                }
            }
        }
        log::error!("Consider using `pkexec swhkd ...`");
    } else {
        log::warn!("Running swhkd as root!");
    }
}

pub fn set_flags() -> App<'static> {
    let app = App::new("swhkd")
        .version(env!("CARGO_PKG_VERSION"))
        .author(env!("CARGO_PKG_AUTHORS"))
        .about("Simple Wayland HotKey Daemon")
        .arg(
            arg!(-c --config <CONFIG_FILE_PATH>)
                .required(false)
                .takes_value(true)
                .help("Set a custom config file path."),
        )
        .arg(
            arg!(-C --cooldown <COOLDOWN_IN_MS>)
                .required(false)
                .takes_value(true)
                .help("Set a custom repeat cooldown duration. Default is 250ms."),
        )
        .arg(arg!(-d - -debug).required(false).help("Enable debug mode."));
    app
}

pub fn check_config_xdg() -> std::path::PathBuf {
    let config_file_path: std::path::PathBuf;
    match env::var("XDG_CONFIG_HOME") {
        Ok(val) => {
            config_file_path = Path::new(&val).join("swhkd/swhkdrc");
            log::debug!("XDG_CONFIG_HOME exists: {:#?}", val);
            return config_file_path;
        }
        Err(_) => {
            log::error!("XDG_CONFIG_HOME has not been set.");
            config_file_path = Path::new("/etc/swhkd/swhkdrc").to_path_buf();
            log::warn!(
                "Note: Due to the design of the application, the invoking user is always root."
            );
            log::warn!("You can set a custom config file with the -c option.");
            log::warn!("Adding your user to the input group could solve this.");
            log::warn!("However that's a massive security flaw and basically defeats the purpose of using wayland.");
            log::warn!("The following issue may be addressed in the future, but it is certainly not a priority right now.");
        }
    }
    config_file_path
}

fn sock_send(command: &str) -> std::io::Result<()> {
    let mut stream = UnixStream::connect("/tmp/swhkd.sock")?;
    stream.write_all(command.as_bytes())?;
    Ok(())
}