use super::{

    client::HwClient,

    indexslab::IndexSlab,

    room::HwRoom,

};

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

use bitflags::*;

use chrono::{offset, DateTime};

use log::*;

use slab::Slab;

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

#[derive(Debug)]

pub enum CreateRoomError {

    InvalidName,

    AlreadyExists,

}

#[derive(Debug)]

pub enum JoinRoomError {

    DoesntExist,

    WrongProtocol,

    Full,

    Restricted,

}

#[derive(Debug)]

pub enum LeaveRoomResult {

    RoomRemoved,

    RoomRemains {

        is_empty: bool,

        was_master: bool,

        was_in_game: bool,

        new_master: Option<ClientId>,

        removed_teams: Vec<String>,

    },

}

#[derive(Debug)]

pub enum LeaveRoomError {

    NoRoom,

}

#[derive(Debug)]

pub struct ChangeMasterResult {

    pub old_master_id: Option<ClientId>,

    pub new_master_id: ClientId,

}

#[derive(Debug)]

pub enum ChangeMasterError {

    NoAccess,

    AlreadyMaster,

    NoClient,

    ClientNotInRoom,

}

#[derive(Debug)]

pub enum ModifyTeamError {

    NoTeam,

    NotMaster,

}

#[derive(Debug)]

pub enum ModifyRoomNameError {

    AccessDenied,

    InvalidName,

    DuplicateName,

}

#[derive(Debug)]

pub enum StartGameError {

    NotEnoughClans,

    NotEnoughTeams,

    NotReady,

    AlreadyInGame,

}

#[derive(Debug)]

pub struct EndGameResult {

    pub joined_mid_game_clients: Vec<ClientId>,

    pub left_teams: Vec<String>,

    pub unreadied_nicks: Vec<String>,

}

#[derive(Debug)]

pub struct UninitializedError();

#[derive(Debug)]

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 is_registered: bool,

    pub is_admin: bool,

    pub is_contributor: bool,

}

struct Ipv4AddrRange {

    min: [u8; 4],

    max: [u8; 4],

}

impl Ipv4AddrRange {

    fn contains(&self, addr: [u8; 4]) -> bool {

        (0..4).all(|i| self.min[i] <= addr[i] && addr[i] <= self.max[i])

    }

}

struct BanCollection {

    ban_ips: Vec<Ipv4AddrRange>,

    ban_timeouts: Vec<DateTime<offset::Utc>>,

    ban_reasons: Vec<String>,

}

impl BanCollection {

    fn new() -> Self {

        Self {

            ban_ips: vec![],

            ban_timeouts: vec![],

            ban_reasons: vec![],

        }

    }

    fn find(&self, addr: [u8; 4]) -> Option<String> {

        let time = offset::Utc::now();

        self.ban_ips

            .iter()

            .enumerate()

            .find(|(i, r)| r.contains(addr) && time < self.ban_timeouts[*i])

            .map(|(i, _)| self.ban_reasons[i].clone())

    }

}

pub struct HwAnteroom {

    pub clients: IndexSlab<HwAnteClient>,

    bans: BanCollection,

}

impl HwAnteroom {

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

        let clients = IndexSlab::with_capacity(clients_limit);

        HwAnteroom {

            clients,

            bans: BanCollection::new(),

        }

    }

    pub fn find_ip_ban(&self, addr: [u8; 4]) -> Option<String> {

        self.bans.find(addr)

    }

    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,

            is_registered: false,

            is_admin: false,

            is_contributor: false,

        };

        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(),

        }

    }

    #[inline]

    pub fn client(&self, client_id: ClientId) -> &HwClient {

        &self.clients[client_id]

    }

    #[inline]

    fn client_mut(&mut self, client_id: ClientId) -> &mut HwClient {

        &mut self.clients[client_id]

    }

    #[inline]

    pub fn room(&self, room_id: RoomId) -> &HwRoom {

        &self.rooms[room_id]

    }

    #[inline]

    pub fn room_mut(&mut self, room_id: RoomId) -> &mut HwRoom {

        &mut self.rooms[room_id]

    }

    #[inline]

    pub fn client_and_room(&self, client_id: ClientId, room_id: RoomId) -> (&HwClient, &HwRoom) {

        (&self.clients[client_id], &self.rooms[room_id])

    }

    #[inline]

    pub fn client_and_room_mut(

        &mut self,

        client_id: ClientId,

        room_id: RoomId,

    }

    #[inline]

    pub fn is_admin(&self, client_id: ClientId) -> bool {

        self.clients

            .get(client_id)

            .map(|c| c.is_admin())

            .unwrap_or(false)

    }

    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);

            #[cfg(feature = "official-server")]

            {

                client.set_is_registered(info.is_registered);

                client.set_is_admin(info.is_admin);

                client.set_is_contributor(info.is_contributor);

            }

            self.clients.insert(client_id, client);

        }

    }

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

        self.clients.remove(client_id);

    }

    pub fn get_greetings(&self, client: &HwClient) -> &str {

        if client.protocol_number < self.latest_protocol {

            &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)

        }

    }

    pub fn leave_room(&mut self, client_id: ClientId) -> Result<LeaveRoomResult, LeaveRoomError> {

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

        if let Some(room_id) = client.room_id {

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

            room.players_number -= 1;

            client.room_id = None;

            let is_empty = room.players_number == 0;

            let is_fixed = room.is_fixed();

            let was_master = room.master_id == Some(client_id);

            let was_in_game = client.is_in_game();

            let mut removed_teams = vec![];

            if is_empty && !is_fixed {

                if client.is_ready() && room.ready_players_number > 0 {

                    room.ready_players_number -= 1;

                }

                removed_teams = room

                    .client_teams(client.id)

                    .map(|t| t.name.clone())

                    .collect();

                for team_name in &removed_teams {

                    room.remove_team(team_name);

                }

                if client.is_master() && !is_fixed {

                    client.set_is_master(false);

                    room.master_id = None;

                }

            }

            client.set_is_ready(false);

            client.set_is_in_game(false);

            if !is_fixed {

                if room.players_number == 0 {

                    self.rooms.remove(room_id);

                } else if room.master_id == None {

                    let new_master_id = self.room_clients(room_id).next();

                    if let Some(new_master_id) = new_master_id {

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

                        room.master_id = Some(new_master_id);

                        let new_master = &mut self.clients[new_master_id];

                        new_master.set_is_master(true);

                        if room.protocol_number < 42 {

                            room.name = new_master.nick.clone();

                        }

                        room.set_join_restriction(false);

                        room.set_team_add_restriction(false);

                        room.set_unregistered_players_restriction(true);

                    }

                }

            }

            if is_empty && !is_fixed {

                Ok(LeaveRoomResult::RoomRemoved)

            } else {

                Ok(LeaveRoomResult::RoomRemains {

                    is_empty,

                    was_master,

                    was_in_game,

                    new_master: self.rooms[room_id].master_id,

                    removed_teams,

                })

            }

        } else {

            Err(LeaveRoomError::NoRoom)

        }

    }

    pub fn change_master(

        &mut self,

        client_id: ClientId,

        room_id: RoomId,

        new_master_nick: String,

    ) -> Result<ChangeMasterResult, ChangeMasterError> {

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

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

        if client.is_admin() || room.master_id == Some(client_id) {

            let new_master_id = self

                .clients

                .iter()

                .find(|(_, c)| c.nick == new_master_nick)

                .map(|(id, _)| id);

            match new_master_id {

                Some(new_master_id) if new_master_id == client_id => {

                    Err(ChangeMasterError::AlreadyMaster)

                }

                Some(new_master_id) => {

                    let new_master = &mut self.clients[new_master_id];

                    if new_master.room_id == Some(room_id) {

                        self.clients[new_master_id].set_is_master(true);

                        let old_master_id = room.master_id;

                        if let Some(master_id) = old_master_id {

                            self.clients[master_id].set_is_master(false);