use slab;

use crate::utils;

use super::{

    client::HWClient, room::HWRoom, actions, handlers,

    coretypes::{ClientId, RoomId},

    actions::{Destination, PendingMessage}

};

use crate::protocol::messages::*;

use rand::{RngCore, thread_rng};

use base64::{encode};

type Slab<T> = slab::Slab<T>;

pub struct HWServer {

    pub clients: Slab<HWClient>,

    pub rooms: Slab<HWRoom>,

    pub lobby_id: RoomId,

    pub output: Vec<(Vec<ClientId>, HWServerMessage)>,

    pub removed_clients: Vec<ClientId>,

}

impl HWServer {

    pub fn new(clients_limit: usize, rooms_limit: usize) -> HWServer {

        let rooms = Slab::with_capacity(rooms_limit);

        let clients = Slab::with_capacity(clients_limit);

        let mut server = HWServer {

            clients, rooms,

            lobby_id: 0,

            output: vec![],

            removed_clients: vec![]

        };

        server.lobby_id = server.add_room();

        server

    }

    pub fn add_client(&mut self) -> ClientId {

        let key: ClientId;

        {

            let entry = self.clients.vacant_entry();

            key = entry.key();

            let mut salt = [0u8; 18];

            thread_rng().fill_bytes(&mut salt);

            let client = HWClient::new(entry.key(), encode(&salt));

            entry.insert(client);

        }

        self.send(key, &Destination::ToSelf, HWServerMessage::Connected(utils::PROTOCOL_VERSION));

        key

    }

    pub fn client_lost(&mut self, client_id: ClientId) {

        actions::run_action(self, client_id,

                            actions::Action::ByeClient("Connection reset".to_string()));

    }

    pub fn add_room(&mut self) -> RoomId {

        let entry = self.rooms.vacant_entry();

        let key = entry.key();

        let room = HWRoom::new(entry.key());

        entry.insert(room);

        key

    }

    pub fn handle_msg(&mut self, client_id: ClientId, msg: HWProtocolMessage) {

        debug!("Handling message {:?} for client {}", msg, client_id);

        if self.clients.contains(client_id) {

            handlers::handle(self, client_id, msg);

        }

    }

    fn get_recipients(&self, client_id: ClientId, destination: &Destination) -> Vec<ClientId> {

        let mut ids = match *destination {

            Destination::ToSelf => vec![client_id],

            Destination::ToId(id) => vec![id],

            Destination::ToAll {room_id: Some(id), ..} =>

                self.room_clients(id),

            Destination::ToAll {protocol: Some(proto), ..} =>

                self.protocol_clients(proto),

            Destination::ToAll {..} =>

                self.clients.iter().map(|(id, _)| id).collect::<Vec<_>>()

        };

        if let Destination::ToAll {skip_self: true, ..} = destination {

            if let Some(index) = ids.iter().position(|id| *id == client_id) {

                ids.remove(index);

            }

        }

        ids

    }

    pub fn send(&mut self, client_id: ClientId, destination: &Destination, message: HWServerMessage) {

        let ids = self.get_recipients(client_id, &destination);

        self.output.push((ids, message));

    }

    pub fn react(&mut self, client_id: ClientId, actions: Vec<actions::Action>) {

        for action in actions {

            actions::run_action(self, client_id, action);

        }

    }

    pub fn lobby(&self) -> &HWRoom { &self.rooms[self.lobby_id] }

    pub fn has_room(&self, name: &str) -> bool {

        self.rooms.iter().any(|(_, r)| r.name == name)

    }

    pub fn find_room(&self, name: &str) -> Option<&HWRoom> {

        self.rooms.iter().find(|(_, r)| r.name == name).map(|(_, r)| r)

    }

    pub fn find_room_mut(&mut self, name: &str) -> Option<&mut HWRoom> {

        self.rooms.iter_mut().find(|(_, r)| r.name == name).map(|(_, r)| r)

    }

    pub fn find_client(&self, nick: &str) -> Option<&HWClient> {

        self.clients.iter().find(|(_, c)| c.nick == nick).map(|(_, c)| c)

    }

    pub fn find_client_mut(&mut self, nick: &str) -> Option<&mut HWClient> {

        self.clients.iter_mut().find(|(_, c)| c.nick == nick).map(|(_, c)| c)

    }

    pub fn select_clients<F>(&self, f: F) -> Vec<ClientId>

        where F: Fn(&(usize, &HWClient)) -> bool {

        self.clients.iter().filter(f)

            .map(|(_, c)| c.id).collect()

    }

    pub fn room_clients(&self, room_id: RoomId) -> Vec<ClientId> {

        self.select_clients(|(_, c)| c.room_id == Some(room_id))

    }

    pub fn protocol_clients(&self, protocol: u16) -> Vec<ClientId> {

        self.select_clients(|(_, c)| c.protocol_number == protocol)

    }

    pub fn other_clients_in_room(&self, self_id: ClientId) -> Vec<ClientId> {

        let room_id = self.clients[self_id].room_id;

        self.select_clients(|(id, c)| *id != self_id && c.room_id == room_id )

    }

    pub fn client_and_room(&mut self, client_id: ClientId) -> (&mut HWClient, Option<&mut HWRoom>) {

        let c = &mut self.clients[client_id];

        if let Some(room_id) = c.room_id {

            (c, Some(&mut self.rooms[room_id]))

        } else {

            (c, None)

        }

    }

    pub fn room(&mut self, client_id: ClientId) -> Option<&mut HWRoom> {

        self.client_and_room(client_id).1

    }

}