// Stdlib dependencies:
pub(crate) use std::error::Error;
pub(crate) use std::io::{stdout};
pub(crate) use std::thread::{spawn, JoinHandle};
pub(crate) use std::time::Duration;
pub(crate) use std::collections::BTreeMap;
pub(crate) use std::sync::atomic::{Ordering, AtomicBool, AtomicUsize};
pub(crate) use std::sync::{
    Arc,
    Mutex, MutexGuard,
    RwLock, LockResult, TryLockResult, RwLockReadGuard, RwLockWriteGuard
};

// Non-stdlib dependencies:
pub(crate) use microxdg::XdgApp;
pub(crate) use ratatui::prelude::*;
pub(crate) use midly::{MidiMessage, live::LiveEvent, num::u7};
pub(crate) use crossterm::{ExecutableCommand};
pub(crate) use crossterm::event::{Event, KeyEvent, KeyCode, KeyModifiers};
use better_panic::{Settings, Verbosity};
use crossterm::terminal::{
    EnterAlternateScreen, LeaveAlternateScreen,
    enable_raw_mode, disable_raw_mode
};

/// Define and reexport submodules.
#[macro_export] macro_rules! submod {
    ($($name:ident)*) => { $(mod $name; pub use self::$name::*;)* };
}

submod!( handle midi render time );

/// Standard result type.
pub type Usually<T> = Result<T, Box<dyn Error>>;

/// A UI component.
pub trait Component: Render + Handle + Sync {
    /// Perform type erasure for collecting heterogeneous components.
    fn boxed (self) -> Box<dyn Component> where Self: Sized + 'static {
        Box::new(self)
    }
}

/// Anything that implements `Render` + `Handle` can be used as a UI component.
impl<T: Render + Handle + Sync> Component for T {}

/// A UI component that may be associated with a JACK client by the `Jack` factory.
pub trait Device: Render + Handle + Process + Send + Sync {
    /// Perform type erasure for collecting heterogeneous devices.
    fn boxed (self) -> Box<dyn Device> where Self: Sized + 'static {
        Box::new(self)
    }
}

/// All things that implement the required traits can be treated as `Device`.
impl<T: Render + Handle + Process + Send + Sync> Device for T {}

// Reexport macros:
pub use crate::{submod, render, handle, process, phrase, keymap, key, ports};

// Reexport JACK proto-lib:
pub use crate::jack::*;

impl<T: Render + Handle + Send + Sync + Sized + 'static> Run for T {}

pub trait Run: Render + Handle + Send + Sync + Sized + 'static {
    fn run (self, init: Option<impl FnOnce(Arc<RwLock<Self>>)->Usually<()>>) -> Usually<()> {
        let app = Arc::new(RwLock::new(self));
        let exited = Arc::new(AtomicBool::new(false));
        let _input_thread = input_thread(&exited, &app);
        terminal_setup()?;
        panic_hook_setup();
        let main_thread = main_thread(&exited, &app)?;
        if let Some(init) = init {
            init(app)?;
        }
        main_thread.join().unwrap();
        terminal_teardown()?;
        Ok(())
    }
}

/// Set up panic hook
pub fn panic_hook_setup () {
    let better_panic_handler = Settings::auto().verbosity(Verbosity::Full).create_panic_handler();
    std::panic::set_hook(Box::new(move |info: &std::panic::PanicInfo|{
        stdout().execute(LeaveAlternateScreen).unwrap();
        disable_raw_mode().unwrap();
        better_panic_handler(info);
    }));
}

/// Set up terminal
pub fn terminal_setup () -> Usually<()> {
    stdout().execute(EnterAlternateScreen)?;
    enable_raw_mode()?;
    Ok(())
}
/// Cleanup
pub fn terminal_teardown () -> Usually<()> {
    stdout().execute(LeaveAlternateScreen)?;
    disable_raw_mode()?;
    Ok(())
}

/// Main thread render loop
pub fn main_thread (
    exited: &Arc<AtomicBool>,
    device: &Arc<RwLock<impl Render + Send + Sync + 'static>>
) -> Usually<JoinHandle<()>> {
    let exited = exited.clone();
    let device = device.clone();
    let mut terminal = ratatui::Terminal::new(CrosstermBackend::new(stdout()))?;
    let sleep = Duration::from_millis(16);
    Ok(spawn(move || loop {

        terminal.draw(|frame|{
            let area   = frame.size();
            let buffer = frame.buffer_mut();
            device.read().unwrap()
                .render(buffer, area)
                .expect("Failed to render content");
        }).expect("Failed to render frame");

        if exited.fetch_and(true, Ordering::Relaxed) {
            break
        }

        std::thread::sleep(sleep);

    }))
}

/// Spawn thread that listens for user input
pub fn input_thread (
    exited: &Arc<AtomicBool>,
    device: &Arc<RwLock<impl Handle + Send + Sync + 'static>>
) -> JoinHandle<()> {
    let poll = Duration::from_millis(100);
    let exited = exited.clone();
    let device = device.clone();
    spawn(move || loop {
        // Exit if flag is set
        if exited.fetch_and(true, Ordering::Relaxed) {
            break
        }
        // Listen for events and send them to the main thread
        if ::crossterm::event::poll(poll).is_ok() {
            let event = ::crossterm::event::read().unwrap();
            match event {
                Event::Key(KeyEvent {
                    code:      KeyCode::Char('c'),
                    modifiers: KeyModifiers::CONTROL,
                    ..
                }) => {
                    exited.store(true, Ordering::Relaxed);
                },
                _ => if device.write().unwrap().handle(&AppEvent::Input(event)).is_err() {
                    break
                }
            }
        }
    })
}