#pragma once

#include "irc_command.hpp"
#include "ircmsg.hpp"
#include "snote.hpp"
#include "stream.hpp"

#include <boost/asio.hpp>
#include <boost/signals2.hpp>

#include <list>
#include <memory>
#include <string>

template <typename T, int(*UpRef)(T*), void(*Free)(T*)>
class Ref {
    struct Deleter { auto operator()(auto ptr) { Free(ptr); }};
    std::unique_ptr<T, Deleter> obj;
public:
    Ref() = default;
    Ref(T* t) : obj{t} { if (t) UpRef(t); }
    auto get() const -> T* { return obj.get(); }
};

struct ConnectSettings
{
    bool tls;
    std::string host;
    std::uint16_t port;

    Ref<X509, X509_up_ref, X509_free> client_cert;
    Ref<EVP_PKEY, EVP_PKEY_up_ref, EVP_PKEY_free> client_key;
    std::string verify;
    std::string sni;

    std::string socks_host;
    std::uint16_t socks_port;
    std::string socks_user;
    std::string socks_pass;
};

class Connection : public std::enable_shared_from_this<Connection>
{
private:
    Stream stream_;
    boost::asio::steady_timer watchdog_timer_;
    std::list<std::string> write_strings_;
    bool write_posted_;

    // Set true when watchdog triggers.
    // Set false when message received.
    bool stalled_;

    // AUTHENTICATE support
    std::string authenticate_buffer_;

    auto write_buffers() -> void;
    auto dispatch_line(char *line) -> void;

    static constexpr std::chrono::seconds watchdog_duration = std::chrono::seconds{30};
    auto watchdog() -> void;
    auto watchdog_activity() -> void;

    auto connect(ConnectSettings settings) -> boost::asio::awaitable<void>;
    auto on_authenticate(std::string_view) -> void;

    /// Build and send well-formed IRC message from individual parameters
    auto write_irc(std::string) -> void;
    auto write_irc(std::string, std::string_view) -> void;
    template <typename... Args>
    auto write_irc(std::string front, std::string_view next, Args... rest) -> void;

public:
    boost::signals2::signal<void()> sig_connect;
    boost::signals2::signal<void()> sig_disconnect;
    boost::signals2::signal<void(IrcCommand, const IrcMsg &)> sig_ircmsg;
    boost::signals2::signal<void(SnoteMatch &)> sig_snote;
    boost::signals2::signal<void(std::string_view)> sig_authenticate;

    Connection(boost::asio::io_context &io);

    /// Write bytes into the socket.
    auto write_line(std::string message) -> void;

    auto get_executor() -> boost::asio::any_io_executor
    {
        return stream_.get_executor();
    }

    auto start(ConnectSettings) -> void;
    auto close() -> void;

    auto send_ping(std::string_view) -> void;
    auto send_pong(std::string_view) -> void;
    auto send_pass(std::string_view) -> void;
    auto send_user(std::string_view, std::string_view) -> void;
    auto send_nick(std::string_view) -> void;
    auto send_join(std::string_view) -> void;
    auto send_cap_ls() -> void;
    auto send_cap_end() -> void;
    auto send_cap_req(std::string_view) -> void;
    auto send_privmsg(std::string_view, std::string_view) -> void;
    auto send_notice(std::string_view, std::string_view) -> void;
    auto send_authenticate(std::string_view message) -> void;
    auto send_authenticate_encoded(std::string_view message) -> void;
    auto send_authenticate_abort() -> void;
};

template <typename... Args>
auto Connection::write_irc(std::string front, std::string_view next, Args... rest) -> void
{
    using namespace std::literals;

    if (next.empty() || next.front() == ':' || next.find_first_of("\r\n \0"sv) != next.npos)
    {
        throw std::runtime_error{"bad irc argument"};
    }

    front += " ";
    front += next;
    write_irc(std::move(front), rest...);
}