use mio;

use std::{collections::HashMap, io, io::Write};

use super::{

    actions::{Destination, DestinationRoom},

    core::HWServer,

    room::RoomSave,

};

use crate::{

    server::actions::PendingMessage,

    utils,

};

use base64::encode;

use log::*;

use rand::{thread_rng, RngCore};

mod checker;

mod common;

mod inroom;

mod lobby;

mod loggingin;

use self::loggingin::LoginResult;

use std::fmt::{Formatter, LowerHex};

#[derive(PartialEq)]

pub struct Sha1Digest([u8; 20]);

impl Sha1Digest {

    pub fn new(digest: [u8; 20]) -> Self {

        Self(digest)

    }

}

impl LowerHex for Sha1Digest {

    fn fmt(&self, f: &mut Formatter) -> Result<(), std::fmt::Error> {

        for byte in &self.0 {

            write!(f, "{:02x}", byte)?;

        }

        Ok(())

    }

}

pub struct AccountInfo {

    pub is_registered: bool,

    pub is_admin: bool,

    pub is_contributor: bool,

    pub server_hash: Sha1Digest,

}

pub enum IoTask {

    GetAccount {

        nick: String,

        protocol: u16,

        password_hash: String,

        client_salt: String,

        server_salt: String,

    },

}

pub enum IoResult {

    Account(Option<AccountInfo>),

}

pub struct Response {

    client_id: ClientId,

    messages: Vec<PendingMessage>,

    io_tasks: Vec<IoTask>,

    removed_clients: Vec<ClientId>,

}

impl Response {

    pub fn new(client_id: ClientId) -> Self {

        Self {

            client_id,

            messages: vec![],

            io_tasks: vec![],

            removed_clients: vec![],

        }

    }

    #[inline]

    pub fn is_empty(&self) -> bool {

        self.messages.is_empty() && self.removed_clients.is_empty() && self.io_tasks.is_empty()

    }

    #[inline]

    pub fn len(&self) -> usize {

        self.messages.len()

    }

    #[inline]

    pub fn client_id(&self) -> ClientId {

        self.client_id

    }

    #[inline]

    pub fn add(&mut self, message: PendingMessage) {

        self.messages.push(message)

    }

    #[inline]

    pub fn request_io(&mut self, task: IoTask) {

        self.io_tasks.push(task)

    }

    pub fn extract_messages<'a, 'b: 'a>(

        &'b mut self,

        server: &'a HWServer,

    ) -> impl Iterator<Item = (Vec<ClientId>, HWServerMessage)> + 'a {

        let client_id = self.client_id;

        self.messages.drain(..).map(move |m| {

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

            (ids, m.message)

        })

    }

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

        self.removed_clients.push(client_id);

    }

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

        self.removed_clients.drain(..)

    }

    pub fn extract_io_tasks(&mut self) -> impl Iterator<Item = IoTask> + '_ {

        self.io_tasks.drain(..)

    }

}

impl Extend<PendingMessage> for Response {

    fn extend<T: IntoIterator<Item = PendingMessage>>(&mut self, iter: T) {

        for msg in iter {

            self.add(msg)

        }

    }

}

fn get_recipients(

    server: &HWServer,

    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: DestinationRoom::Lobby,

            ..

        } => server.lobby_clients(),

        Destination::ToAll {

            room_id: DestinationRoom::Room(id),

            ..

        } => server.room_clients(id),

        Destination::ToAll {

            protocol: Some(proto),

            ..

        } => server.protocol_clients(proto),

        Destination::ToAll { .. } => server.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 handle(

    server: &mut HWServer,

    client_id: ClientId,

    response: &mut Response,

    message: HWProtocolMessage,

) {

    match message {

        HWProtocolMessage::Ping => response.add(Pong.send_self()),

        HWProtocolMessage::Malformed => warn!("Malformed/unknown message"),

        HWProtocolMessage::Empty => warn!("Empty message"),

        _ => {

            if server.anteroom.clients.contains(client_id) {

                match loggingin::handle(&mut server.anteroom, client_id, response, message) {

                    LoginResult::Unchanged => (),

                    LoginResult::Complete => {

                        if let Some(client) = server.anteroom.remove_client(client_id) {

                            server.add_client(client_id, client);

                        }

                    }

                    LoginResult::Exit => {

                        server.anteroom.remove_client(client_id);

                        response.remove_client(client_id);

                    }

                }

            } else {

                match message {

                    HWProtocolMessage::Quit(Some(msg)) => {

                        common::remove_client(server, response, "User quit: ".to_string() + &msg);

                    }

                    HWProtocolMessage::Quit(None) => {

                        common::remove_client(server, response, "User quit".to_string());

                    }

                    _ => match server.clients[client_id].room_id {

                        None => lobby::handle(server, client_id, response, message),

                        Some(room_id) => {

                            inroom::handle(server, client_id, response, room_id, message)

                        }

                    },

                }

            }

        }

    }

}

pub fn handle_client_accept(server: &mut HWServer, client_id: ClientId, response: &mut Response) {

    let mut salt = [0u8; 18];

    thread_rng().fill_bytes(&mut salt);

    server.anteroom.add_client(client_id, encode(&salt));

    response.add(HWServerMessage::Connected(utils::PROTOCOL_VERSION).send_self());

}

pub fn handle_client_loss(server: &mut HWServer, client_id: ClientId, response: &mut Response) {

    if server.anteroom.remove_client(client_id).is_none() {

        common::remove_client(server, response, "Connection reset".to_string());

    }

}

pub fn handle_io_result(

    server: &mut HWServer,

    client_id: ClientId,

    response: &mut Response,

    io_result: IoResult,

) {

    match io_result {

        IoResult::Account(Some(info)) => {

            response.add(ServerAuth(format!("{:x}", info.server_hash)).send_self());

            if let Some(client) = server.anteroom.remove_client(client_id) {

                server.add_client(client_id, client);

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

                client.set_is_admin(info.is_admin);

                client.set_is_contributor(info.is_admin)

            }

        }

        IoResult::Account(None) => {

            response.add(Error("Authentication failed.".to_string()).send_self());

            response.remove_client(client_id);

        }

    }

}