use super::{

    client::HwClient,

    indexslab::IndexSlab,

    room::HwRoom,

    types::{ClientId, RoomId, ServerVar},

};

use crate::{protocol::messages::HwProtocolMessage::Greeting, utils};

use crate::core::server::JoinRoomError::WrongProtocol;

use bitflags::*;

use log::*;

use slab;

use std::{borrow::BorrowMut, collections::HashSet, iter, num::NonZeroU16};

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

pub enum CreateRoomError {

    InvalidName,

    AlreadyExists,

}

pub enum JoinRoomError {

    DoesntExist,

    WrongProtocol,

    Full,

    Restricted,

}

pub struct AccessError();

pub struct HwAnteClient {

    pub nick: Option<String>,

    pub protocol_number: Option<NonZeroU16>,

    pub server_salt: String,

    pub is_checker: bool,

    pub is_local_admin: bool,

}

pub struct HwAnteroom {

    pub clients: IndexSlab<HwAnteClient>,

}

impl HwAnteroom {

    pub fn new(clients_limit: usize) -> Self {

        let clients = IndexSlab::with_capacity(clients_limit);

        HwAnteroom { clients }

    }

    pub fn add_client(&mut self, client_id: ClientId, salt: String, is_local_admin: bool) {

        let client = HwAnteClient {

            nick: None,

            protocol_number: None,

            server_salt: salt,

            is_checker: false,

            is_local_admin,

        };

        self.clients.insert(client_id, client);

    }

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

        let client = self.clients.remove(client_id);

        client

    }

}

pub struct ServerGreetings {

    pub for_latest_protocol: String,

    pub for_old_protocols: String,

}

impl ServerGreetings {

    fn new() -> Self {

        Self {

            for_latest_protocol: "\u{1f994} is watching".to_string(),

            for_old_protocols: "\u{1f994} is watching".to_string(),

        }

    }

}

bitflags! {

    pub struct ServerFlags: u8 {

        const REGISTERED_ONLY = 0b0000_1000;

    }

}

pub struct HwServer {

    pub clients: IndexSlab<HwClient>,

    pub rooms: Slab<HwRoom>,

    pub anteroom: HwAnteroom,

    pub latest_protocol: u16,

    pub flags: ServerFlags,

    pub greetings: ServerGreetings,

}

impl HwServer {

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

        let rooms = Slab::with_capacity(rooms_limit);

        let clients = IndexSlab::with_capacity(clients_limit);

        Self {

            clients,

            rooms,

            anteroom: HwAnteroom::new(clients_limit),

            greetings: ServerGreetings::new(),

            latest_protocol: 58,

            flags: ServerFlags::empty(),

        }

    }

    pub fn add_client(&mut self, client_id: ClientId, data: HwAnteClient) {

        if let (Some(protocol), Some(nick)) = (data.protocol_number, data.nick) {

            let mut client = HwClient::new(client_id, protocol.get(), nick);

            client.set_is_checker(data.is_checker);

            #[cfg(not(feature = "official-server"))]

            client.set_is_admin(data.is_local_admin);

            self.clients.insert(client_id, client);

        }

    }

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

        self.clients.remove(client_id);

    }

            &self.greetings.for_old_protocols

        } else {

            &self.greetings.for_latest_protocol

        }

    }

    #[inline]

    pub fn get_client_nick(&self, client_id: ClientId) -> &str {

        &self.clients[client_id].nick

    }

    #[inline]

    pub fn create_room(

        &mut self,

        creator_id: ClientId,

        name: String,

        password: Option<String>,

    ) -> Result<(&HwClient, &HwRoom), CreateRoomError> {

        use CreateRoomError::*;

        if utils::is_name_illegal(&name) {

            Err(InvalidName)

        } else if self.has_room(&name) {

            Err(AlreadyExists)

        } else {

            Ok(create_room(

                &mut self.clients[creator_id],

                &mut self.rooms,

                name,

                password,

            ))

        }

    }

    pub fn join_room(

        &mut self,

        client_id: ClientId,

        room_id: RoomId,

    ) -> Result<(&HwClient, &HwRoom, impl Iterator<Item = &HwClient> + Clone), JoinRoomError> {

        use JoinRoomError::*;

        let room = &mut self.rooms[room_id];

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

        if client.protocol_number != room.protocol_number {

            Err(WrongProtocol)

        } else if room.is_join_restricted() {

            Err(Restricted)

        } else if room.players_number == u8::max_value() {

            Err(Full)

        } else {

            move_to_room(client, room);

            let room_id = room.id;

            Ok((

                &self.clients[client_id],

                &self.rooms[room_id],

                self.clients.iter().map(|(_, c)| c),

            ))

        }

    }

    #[inline]

    pub fn join_room_by_name(

        &mut self,

        client_id: ClientId,

        room_name: &str,

    ) -> Result<(&HwClient, &HwRoom, impl Iterator<Item = &HwClient> + Clone), JoinRoomError> {

        use JoinRoomError::*;

        let room = self.rooms.iter().find(|(_, r)| r.name == room_name);

        if let Some((_, room)) = room {

            let room_id = room.id;

            self.join_room(client_id, room_id)

        } else {

            Err(DoesntExist)

        }

    }

    #[inline]

    pub fn set_var(&mut self, client_id: ClientId, var: ServerVar) -> Result<(), AccessError> {

        if self.clients[client_id].is_admin() {

            match var {

                ServerVar::MOTDNew(msg) => self.greetings.for_latest_protocol = msg,

                ServerVar::MOTDOld(msg) => self.greetings.for_old_protocols = msg,

                ServerVar::LatestProto(n) => self.latest_protocol = n,

            }

            Ok(())

        } else {

            Err(AccessError())

        }

    }

    #[inline]

    pub fn get_vars(&self, client_id: ClientId) -> Result<[ServerVar; 3], AccessError> {

        if self.clients[client_id].is_admin() {

            Ok([

                ServerVar::MOTDNew(self.greetings.for_latest_protocol.clone()),

                ServerVar::MOTDOld(self.greetings.for_old_protocols.clone()),

                ServerVar::LatestProto(self.latest_protocol),

            ])

        } else {

            Err(AccessError())

        }

    }

    pub fn get_used_protocols(&self, client_id: ClientId) -> Result<Vec<u16>, AccessError> {

        if self.clients[client_id].is_admin() {

            let mut protocols: HashSet<_> = self

                .clients

                .iter()

                .map(|(_, c)| c.protocol_number)

                .chain(self.rooms.iter().map(|(_, r)| r.protocol_number))

                .collect();

            let mut protocols: Vec<_> = protocols.drain().collect();

            protocols.sort();

            Ok(protocols)

        } else {

            Err(AccessError())

        }

    }

    #[inline]

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

        self.find_room(name).is_some()

    }

    #[inline]

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

        self.rooms

            .iter()

            .find_map(|(_, r)| Some(r).filter(|r| r.name == name))

    }

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

        self.rooms

            .iter_mut()

            .find_map(|(_, r)| Some(r).filter(|r| r.name == name))

    }

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

        self.clients

            .iter()

            .find_map(|(_, c)| Some(c).filter(|c| c.nick == nick))

    }

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

        self.clients

            .iter_mut()

            .find_map(|(_, c)| Some(c).filter(|c| c.nick == nick))

    }

    pub fn all_clients(&self) -> impl Iterator<Item = ClientId> + '_ {

        self.clients.iter().map(|(id, _)| id)

    }

    pub fn filter_clients<'a, F>(&'a self, f: F) -> impl Iterator<Item = ClientId> + 'a

    where

        F: Fn(&(usize, &HwClient)) -> bool + 'a,

    {

        self.clients.iter().filter(f).map(|(_, c)| c.id)

    }

    pub fn filter_rooms<'a, F>(&'a self, f: F) -> impl Iterator<Item = RoomId> + 'a

    where

        F: Fn(&(usize, &HwRoom)) -> bool + 'a,

    {

        self.rooms.iter().filter(f).map(|(_, c)| c.id)

    }

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

    where

        F: Fn(&(usize, &HwClient)) -> bool,

    {

        self.filter_clients(f).collect()

    }

    pub fn collect_nicks<F>(&self, f: F) -> Vec<String>

    where

        F: Fn(&(usize, &HwClient)) -> bool,

    {

        self.clients

            .iter()

            .filter(f)

            .map(|(_, c)| c.nick.clone())

            .collect()

    }

    pub fn lobby_clients(&self) -> impl Iterator<Item = ClientId> + '_ {

        self.filter_clients(|(_, c)| c.room_id == None)

    }

    pub fn room_clients(&self, room_id: RoomId) -> impl Iterator<Item = ClientId> + '_ {

        self.filter_clients(move |(_, c)| c.room_id == Some(room_id))

    }

    pub fn protocol_clients(&self, protocol: u16) -> impl Iterator<Item = ClientId> + '_ {

        self.filter_clients(move |(_, c)| c.protocol_number == protocol)

    }

    pub fn protocol_rooms(&self, protocol: u16) -> impl Iterator<Item = RoomId> + '_ {

        self.filter_rooms(move |(_, r)| r.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.collect_clients(|(id, c)| *id != self_id && c.room_id == room_id)

    }

    pub fn is_registered_only(&self) -> bool {

        self.flags.contains(ServerFlags::REGISTERED_ONLY)

    }

    pub fn set_is_registered_only(&mut self, value: bool) {

        self.flags.set(ServerFlags::REGISTERED_ONLY, value)

    }

}

fn allocate_room(rooms: &mut Slab<HwRoom>) -> &mut HwRoom {

    let entry = rooms.vacant_entry();

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

    entry.insert(room)

}

fn create_room<'a, 'b>(

    client: &'a mut HwClient,

    rooms: &'b mut Slab<HwRoom>,

    name: String,

    password: Option<String>,

) -> (&'a HwClient, &'b HwRoom) {

    let room = allocate_room(rooms);

    room.master_id = Some(client.id);

    room.name = name;

    room.password = password;

    room.protocol_number = client.protocol_number;

    room.players_number = 1;

    room.ready_players_number = 1;

    client.room_id = Some(room.id);

    client.set_is_master(true);

    client.set_is_ready(true);

    client.set_is_joined_mid_game(false);

    (client, room)

}

fn move_to_room(client: &mut HwClient, room: &mut HwRoom) {

    debug_assert!(client.room_id != Some(room.id));

    room.players_number += 1;

    client.room_id = Some(room.id);

    client.set_is_joined_mid_game(room.game_info.is_some());

    client.set_is_in_game(room.game_info.is_some());

    if let Some(ref mut info) = room.game_info {

        let teams = info.client_teams(client.id);

        client.teams_in_game = teams.clone().count() as u8;

        client.clan = teams.clone().next().map(|t| t.color);

        let team_names: Vec<_> = teams.map(|t| t.name.clone()).collect();

        if !team_names.is_empty() {

            info.left_teams.retain(|name| !team_names.contains(&name));

            info.teams_in_game += team_names.len() as u8;

            room.teams = info

                .teams_at_start

                .iter()

                .filter(|(_, t)| !team_names.contains(&t.name))

                .cloned()

                .collect();

        }

    }

}