use std::{
	collections::*,
	path::PathBuf,
};

use fltk::{
	app,
	button::Button, 
	enums::CallbackTrigger,
	frame::Frame,
	input::*,
	prelude::*, 
	window::Window
};

use tokio::{
	sync::{
		mpsc,
		oneshot,
	},
};

struct ServerInstance {
	task: tokio::task::JoinHandle <()>,
	shutdown_tx: oneshot::Sender <()>,
}

#[derive (Clone, Copy)]
enum Message {
	Hit,
	RunServer,
	StopServer,
}

fn main () 
{
	let rt = tokio::runtime::Runtime::new ().unwrap ();
	
	tracing_subscriber::fmt::init ();
	
	let mut server_instance = None;
	
	// let shutdown_rx = ptth_core::graceful_shutdown::init ();
	
	let (fltk_tx, fltk_rx) = app::channel::<Message> ();
	
	let app = app::App::default();
	let mut wind = Window::new (100, 100, 500, 180, "PTTH server");
	
	let config_file_opt = match ptth_server::load_toml::load::<ConfigFile, _> ("./config/ptth_server.toml") {
		Ok (x) => Some (x),
		Err (e) => {
			eprintln! ("Error in `./config/ptth_server.toml`: {:?}", e);
			None
		},
	};
	
	let (hit_tx, mut hit_rx) = mpsc::channel (1);
	{
		let fltk_tx = fltk_tx;
		
		rt.spawn (async move {
			while hit_rx.recv ().await.is_some () {
				fltk_tx.send (Message::Hit);
			}
		});
	}
	
	let mut gui = Gui::new (fltk_tx, config_file_opt.as_ref ());
	gui.set_server_running (false);
	
	wind.end ();
	wind.show ();
	
	while app.wait () {
		match fltk_rx.recv () {
			Some (Message::Hit) => {
				gui.hits += 1;
				gui.refresh_label ();
			},
			Some (Message::RunServer) => {
				let (shutdown_tx, shutdown_rx) = tokio::sync::oneshot::channel ();
				
				let roots = match &config_file_opt {
					None => Default::default (),
					Some (cf) => match &cf.file_server_roots {
						None => Default::default (),
						Some (x) => x.clone (),
					},
				};
				
				// `git grep JRY5NXZU` # duplicated code?
				
				let config_file = ptth_server::ConfigFile {
					name: gui.input_name.value ().to_string (),
					api_key: gui.input_api_key.value ().to_string (),
					relay_url: gui.input_relay_url.value ().to_string (),
					file_server_root: PathBuf::from (gui.input_file_server_root.value ()),
					file_server_roots: roots,
					throttle_upload: false,
					client_keys: Default::default (),
					allow_any_client: true,
					index_directories: true,
				};
				
				let hit_tx = hit_tx.clone ();
				let task = rt.spawn (async {
					if let Err (e) = ptth_server::run_server (
						config_file, 
						shutdown_rx,
						None,
						None,
						Some (hit_tx),
					).await
					{
						tracing::error! ("ptth_server crashed: {}", e);
					}
				});
				
				server_instance.replace (Some (ServerInstance {
					task,
					shutdown_tx,
				}));
				
				gui.set_server_running (true);
			},
			Some (Message::StopServer) => {
				server_instance.replace (None);
				
				gui.set_server_running (false);
			},
			None => (),
		}
	}
}

struct Gui {
	frame: Frame,
	but_run: Button,
	but_stop: Button,
	input_name: Input,
	input_relay_url: Input,
	input_file_server_root: Input,
	input_api_key: SecretInput,
	
	server_is_running: bool,
	hits: u64,
}

#[derive (Default, serde::Deserialize)]
pub struct ConfigFile {
	pub name: Option <String>,
	pub api_key: String,
	pub relay_url: Option <String>,
	pub file_server_root: Option <PathBuf>,
	pub file_server_roots: Option <BTreeMap <String, PathBuf>>,
}

impl Gui {
	fn new (
		fltk_tx: app::Sender <Message>,
		config_file_opt: Option <&ConfigFile>,
	) 
	-> Self 
	{
		let mut input_name = Input::new (200, 10, 290, 20, "name");
		input_name.set_value ("my_ptth_server");
		
		let mut input_relay_url = Input::new (200, 40, 290, 20, "relay_url");
		input_relay_url.set_value ("http://127.0.0.1:4000/7ZSFUKGV");
		
		let mut input_file_server_root = Input::new (200, 70, 290, 20, "file_server_root");
		input_file_server_root.set_value ("/home/user");
		
		let mut input_api_key = SecretInput::new (200, 100, 290, 20, "api_key");
		input_api_key.set_value ("");
		
		let mut but_run = Button::new (10, 130, 90, 40, "Run");
		but_run.set_trigger (CallbackTrigger::Changed);
		but_run.emit (fltk_tx, Message::RunServer);
		
		let frame = Frame::new (110, 130, 280, 40, "");
			
		let mut but_stop = Button::new (400, 130, 90, 40, "Stop");
		but_stop.set_trigger (CallbackTrigger::Changed);
		but_stop.emit (fltk_tx, Message::StopServer);
		
		if let Some (config_file) = config_file_opt
		{
			if let Some (v) = config_file.name.as_ref () {
				input_name.set_value (v);
			}
			input_api_key.set_value (&config_file.api_key);
			if let Some (v) = config_file.relay_url.as_ref () {
				input_relay_url.set_value (v);
			}
			if let Some (v) = config_file.file_server_root.as_ref () {
				if let Some (v) = v.to_str () {
					input_file_server_root.set_value (v);
				}
			}
		}
		
		Self {
			frame,
			but_run,
			but_stop,
			input_name,
			input_relay_url,
			input_file_server_root,
			input_api_key,
			
			server_is_running: false,
			hits: 0,
		}
	}
	
	fn set_server_running (&mut self, b: bool) {
		self.server_is_running = b;
		
		self.refresh_label ();
		
		set_active (&mut self.but_run, ! b);
		set_active (&mut self.but_stop, b);
		self.but_run.set (b);
		self.but_stop.set (! b);
		
		set_active (&mut self.input_name, ! b);
		set_active (&mut self.input_relay_url, ! b);
		set_active (&mut self.input_file_server_root, ! b);
		set_active (&mut self.input_api_key, ! b);
	}
	
	fn refresh_label (&mut self) {
		let s = 
		if self.server_is_running {
			format! ("Running. Requests: {}", self.hits)
		}
		else {
			"Stopped".to_string ()
		};
		
		self.frame.set_label (&s);
	}
}

fn set_active <W: WidgetExt> (w: &mut W, b: bool) {
	if b {
		w.activate ();
	}
	else {
		w.deactivate ();
	}
}