use std::collections::HashMap;
use std::io;

use serde_json::{Value, json};
use unicode_categories::UnicodeCategories;

use crate::{
	controls::{Control, Action},
	server::Server,
	PlayerId,
	auth::{UserRegistry, LoaderError}
};

#[derive(Debug, Clone, PartialEq)]
enum Authentication {
	Guest,
	Tilde,
	Passtoken(String)
}

#[derive(Debug)]
enum Message {
	Auth(String, Authentication, bool),
	Chat(String),
	Input(Value)
}

struct MessageError {
	typ: String,
	text: String
}

macro_rules! merr {
	(name, $text: expr) => {merr!("invalidname", $text)};
	(action, $text: expr) => {merr!("invalidaction", $text)};
	(msg, $text: expr) => {merr!("invalidmessage", $text)};
	($typ: expr, $text: expr) => {MessageError{typ: $typ.to_string(), text: $text.to_string()}};
}


pub struct GameServer {
	players: HashMap<(usize, usize), PlayerId>,
	connections: HashMap<PlayerId, (usize, usize)>,
	users: Box<dyn UserRegistry>,
	servers: Vec<Box<dyn Server>>,
	admins: String
}

impl GameServer {
	pub fn new(servers: Vec<Box<dyn Server>>, users: Box<dyn UserRegistry>, admins: String) -> GameServer {
		GameServer {
			players: HashMap::new(),
			connections: HashMap::new(),
			servers,
			users,
			admins
		}
	}
	
	pub fn update(&mut self) -> Vec<Action>{
		for server in self.servers.iter_mut(){
			let _ = server.accept_pending_connections();
		}
		
		let mut actions: Vec<Action> = Vec::new();
		let mut input = Vec::new();
		for (serverid, server) in self.servers.iter_mut().enumerate(){
			let (messages, left) = server.recv_pending_messages();
			input.push((serverid, messages, left));
		}
		for (serverid, messages, left) in input {
			for (id, message) in messages {
				match parse_message(&message) {
					Ok(msg) => {
						match self.handle_message((serverid, id), msg){
							Ok(Some(action)) => {actions.push(action);}
							Ok(None) => {}
							Err(err) => {let _ = self.send_error((serverid, id), &err.typ, &err.text);}
						}
					}
					Err(err) => {
						{let _ = self.send_error((serverid, id), &err.typ, &err.text);}
					}
				}
			}
			for id in left {
				if let Some(player) = self.players.remove(&(serverid, id)){
					self.connections.remove(&player);
					self.broadcast_message(&format!("{} disconnected", player.name));
					actions.push(Action::Leave(player.clone()));
				}
			}
		}
		actions
	}
	
	fn send_error(&mut self, (serverid, connectionid): (usize, usize), errname: &str, err_text: &str) -> Result<(), io::Error>{
		self.servers[serverid].send(connectionid, &json!(["error", errname, err_text]).to_string().as_str())
	}
	
	pub fn broadcast_message(&mut self, text: &str){
		println!("m {}", text);
		self.broadcast_json(json!(["message", text, ""]));
	}
	
	pub fn broadcast_json(&mut self, value: Value){
		self.broadcast(value.to_string().as_str());
	}
	
	pub fn broadcast(&mut self, txt: &str){
		for (serverid, id) in self.players.keys() {
			let _ = self.servers[*serverid].send(*id, txt);
		}
	}
	
	pub fn send(&mut self, player: &PlayerId, value: Value) -> Result<(), io::Error> {
		match self.connections.get(player) {
			Some((serverid, id)) => {
				self.servers[*serverid].send(*id, value.to_string().as_str())
			}
			None => Err(io::Error::new(io::ErrorKind::Other, "unknown player name"))
		}
	}
	
	pub fn send_player_error(&mut self, player: &PlayerId, errname: &str, err_text: &str) -> Result<(), io::Error> {
		self.send(player, json!(["error", errname, err_text]))
	}
	
	fn handle_message(&mut self, (serverid, connectionid): (usize, usize), msg: Message) -> Result<Option<Action>, MessageError> {
		let id = (serverid, connectionid);
		match msg {
			Message::Auth(name, auth, join) => {
				if name.len() > 99 {
					return Err(merr!(name, "A name can not be longer than 99 bytes"));
				}
				if name.len() == 0 {
					return Err(merr!(name, "A name must have at least one character"));
				}
				if auth != Authentication::Tilde {
					for chr in name.chars() {
						if !(chr.is_letter() || chr.is_number() || chr.is_punctuation_connector()){
							return Err(merr!(name, "A name can only contain letters, numbers and underscores"));
						}
					}
				}
				if self.players.contains_key(&id) {
					return Err(merr!(action, "You can not change your name"));
				}
				let player = PlayerId{name};
				self.authenticate(&player, auth.clone(), id)?;
				if self.connections.contains_key(&player) {
					return Err(merr!("nametaken", "Another connection to this player exists already"));
				}
				self.broadcast_message(&format!("{} connected", player.name));
				self.players.insert(id, player.clone());
				self.connections.insert(player.clone(), id);
				if let Err(_) = self.send(&player, json!(["connected", format!("successfully connected as {}", &player.name)])){
					return Err(merr!("server", "unable to send connected message"))
				}
				if auth == Authentication::Guest {
					let _ = self.send(&player, json!([
						"message",
						format!("You are connected as guest account. Anyone could log in to this account. To register an account for yourself ask one of the server admins: {}", &self.admins),
						"server"
					]));
				}
				Ok(if join {
					Some(Action::Join(player))
				} else {
					None
				})
			}
			Message::Chat(text) => {
				let player = self.players.get(&id).ok_or(merr!(action, "Set a valid name before you send any other messages"))?;
				let name = player.name.clone();
				self.broadcast_message(&format!("{}: {}", name, text));
				Ok(None)
			}
			Message::Input(inp) => {
				let player = self.players.get(&id).ok_or(merr!(action, "Set a name before you send any other messages"))?;
				let control = Control::from_json(&inp).ok_or(merr!(action, &format!("unknown action: {}", inp)))?;
				Ok(Some(Action::Input(player.clone(), control)))
			}
		}
	}
	
	fn authenticate(&self, player: &PlayerId, auth: Authentication, (serverid, connectionid): (usize, usize)) -> Result<(), MessageError> {
		Ok(match auth {
			Authentication::Guest => {
				if self.users.user_exists(&player) {
					return Err(merr!("registered", "This name is registered. Use another name or authenticate for this name"))
				}
				()
			}
			Authentication::Tilde => {
				let (firstchar, username) = player.name.split_at(1);
				if firstchar == "~" {
					if Some(username.to_string()) != self.servers[serverid].get_name(connectionid) {
						return Err(merr!(name, "A tilde name must match your username"));
					}
				}
			}
			Authentication::Passtoken(token) => {
				match self.users.load_user(player) {
					Ok(user) => {
						if player.name != user.name {
							println!("Name mismatch: user entry for {:?} has name {}", player, user.name);
							return Err(merr!("server", "name mismatch"));
						}
						if !user.validate_token(&token) {
							return Err(merr!("invalidtoken", "invalid pass token"));
						}
						()
					}
					Err(LoaderError::InvalidResource(err)) => {
						println!("failed to load user data for user '{}': {}", player.name, err);
						return Err(merr!("server", "failed to load user data"))
					}
					Err(LoaderError::MissingResource(_)) => {
						return Err(merr!("unregistered", "this name is not registered"))
					}
				}
			}
		})
	}
}



fn parse_message(msg: &str) -> Result<Message, MessageError> {
	let data: Value = serde_json::from_str(msg).map_err(|e| merr!(msg, format!("Invalid JSON: {}", e)))?;
	let arr = data.as_array().ok_or(merr!(msg, "message not a json array"))?;
	if arr.len() < 2 {
		return Err(merr!(msg, "array not long enough"));
	}
	let arg = &arr[1];
	let msgtype = arr[0].as_str().ok_or(merr!(msg, "first message element not a string"))?;
	Ok(match msgtype {
		"name" => {
			let name = arg.as_str().ok_or(merr!(msg, "name not a string"))?.to_string();
			Message::Auth(
				name.clone(),
				if name.starts_with("~") {
					Authentication::Tilde
				} else {
					Authentication::Guest
				},
				true
			)
		}
		"chat" => {
			let text = arg.as_str().ok_or(merr!(msg, "chat text not a string"))?;
			Message::Chat(text.to_string())
		}
		"input" => {
			Message::Input(arg.clone())
		}
		"auth" => {
			let name = arg.get("name").ok_or(merr!(msg, "auth message does not have name"))?.as_str().ok_or(merr!(msg, "auth name not a string"))?.to_string();
			let typ = arg.get("type").ok_or(merr!(msg, "auth message does not have type"))?.as_str().ok_or(merr!(msg, "auth type not a string"))?;
			let join = arg.get("join").unwrap_or(&json!(true)).as_bool().ok_or(merr!(msg, "join flag not a bool"))?;
			Message::Auth(
				name,
				match typ {
					"guest" => Authentication::Guest,
					"tilde" => Authentication::Tilde,
					"passtoken" => Authentication::Passtoken(
						arg
						.get("passtoken")
						.ok_or(merr!(msg, "passtoken auth message does not have passtoken"))?
						.as_str()
						.ok_or(merr!(msg, "passtoken not a string"))?
						.to_string()
					),
					_ => {return Err(merr!(msg, "invalid authentication type"))}
				},
				join
			)
		}
		_ => {
			return Err(merr!(msg, format!("unknown messsage type {:?}", msgtype)))
		}
	})
}