// Copyright 2017 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.

#include <atomic>
#include <mutex>
#include <thread>
#include "common/assert.h"
#include "enet/enet.h"
#include "network/room_member.h"

namespace Network {

constexpr u32 ConnectionTimeoutMs = 5000;

class RoomMember::RoomMemberImpl {
public:
    ENetHost* client = nullptr; ///< ENet network interface.
    ENetPeer* server = nullptr; ///< The server peer the client is connected to

    std::atomic<State> state{State::Idle}; ///< Current state of the RoomMember.
    void SetState(const State new_state);
    bool IsConnected() const;

    std::string nickname; ///< The nickname of this member.

    std::mutex network_mutex; ///< Mutex that controls access to the `client` variable.
    /// Thread that receives and dispatches network packets
    std::unique_ptr<std::thread> receive_thread;
    void ReceiveLoop();
    void StartLoop();
};

// RoomMemberImpl
void RoomMember::RoomMemberImpl::SetState(const State new_state) {
    state = new_state;
    // TODO(B3N30): Invoke the callback functions
}

bool RoomMember::RoomMemberImpl::IsConnected() const {
    return state == State::Joining || state == State::Joined;
}

void RoomMember::RoomMemberImpl::ReceiveLoop() {
    // Receive packets while the connection is open
    while (IsConnected()) {
        std::lock_guard<std::mutex> lock(network_mutex);
        ENetEvent event;
        if (enet_host_service(client, &event, 1000) > 0) {
            if (event.type == ENET_EVENT_TYPE_RECEIVE) {
                switch (event.packet->data[0]) {
                // TODO(B3N30): Handle the other message types
                case IdNameCollision:
                    SetState(State::NameCollision);
                    enet_packet_destroy(event.packet);
                    enet_peer_disconnect(server, 0);
                    enet_peer_reset(server);
                    return;
                    break;
                case IdMacCollision:
                    SetState(State::MacCollision);
                    enet_packet_destroy(event.packet);
                    enet_peer_disconnect(server, 0);
                    enet_peer_reset(server);
                    return;
                    break;
                default:
                    break;
                }
                enet_packet_destroy(event.packet);
            }
        }
    }
};

void RoomMember::RoomMemberImpl::StartLoop() {
    receive_thread = std::make_unique<std::thread>(&RoomMember::RoomMemberImpl::ReceiveLoop, this);
}

// RoomMember
RoomMember::RoomMember() : room_member_impl{std::make_unique<RoomMemberImpl>()} {
    room_member_impl->client = enet_host_create(nullptr, 1, NumChannels, 0, 0);
    ASSERT_MSG(room_member_impl->client != nullptr, "Could not create client");
}

RoomMember::~RoomMember() {
    ASSERT_MSG(!IsConnected(), "RoomMember is being destroyed while connected");
    enet_host_destroy(room_member_impl->client);
}

RoomMember::State RoomMember::GetState() const {
    return room_member_impl->state;
}

void RoomMember::Join(const std::string& nick, const char* server_addr, u16 server_port,
                      u16 client_port) {
    ENetAddress address{};
    enet_address_set_host(&address, server_addr);
    address.port = server_port;

    room_member_impl->server =
        enet_host_connect(room_member_impl->client, &address, NumChannels, 0);

    if (!room_member_impl->server) {
        room_member_impl->SetState(State::Error);
        return;
    }

    ENetEvent event{};
    int net = enet_host_service(room_member_impl->client, &event, ConnectionTimeoutMs);
    if (net > 0 && event.type == ENET_EVENT_TYPE_CONNECT) {
        room_member_impl->nickname = nick;
        room_member_impl->SetState(State::Joining);
        room_member_impl->StartLoop();
        // TODO(B3N30): Send a join request with the nickname to the server
    } else {
        room_member_impl->SetState(State::CouldNotConnect);
    }
}

bool RoomMember::IsConnected() const {
    return room_member_impl->IsConnected();
}

void RoomMember::Leave() {
    ASSERT_MSG(room_member_impl->receive_thread != nullptr, "Must be in a room to leave it.");
    {
        std::lock_guard<std::mutex> lock(room_member_impl->network_mutex);
        enet_peer_disconnect(room_member_impl->server, 0);
        room_member_impl->SetState(State::Idle);
    }
    room_member_impl->receive_thread->join();
    room_member_impl->receive_thread.reset();
    enet_peer_reset(room_member_impl->server);
}

} // namespace Network