/***
    Copyright (C) 2021 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: Net.hpp
    Date: 2021-6-9
    Author: Reece
***/
#pragma once

namespace Aurora::IO::Net
{
    enum TransportProtocol
    {
        kProtocolUDP,
        kProtocolTCP
    };

    enum IPProtocol
    {
        kIPProtocolV4,
        kIPProtocolV6
    };

    struct IPAddress
    {
        IPProtocol ip;
        bool hasIP;
        AuString address;
        union
        {
            AuUInt8 v4[4];
            AuUInt16 v6[8];
        };

        AUKN_SYM AuString toString();
    };

    struct Endpoint
    {
        TransportProtocol protocol;
        IPAddress address;
        AuUInt16 port;

        // 0 - destination is a stateless datagram server
        // 1 - destination is a psuedo-stateful server
        AuUInt UDPTimeout;

        AUKN_SYM AuString toString();
    };

    class INetworkStream;
    class IBasicSocket;
    class IClientSocket;

    using StreamHasData_cb = std::function<bool(AuSPtr<IClientSocket> socket)>; // DTLS/UDP/TCP/TLS -> TRUE = expects another frame or stream buffer, FALSE = end of socket life
    using InitializeSocket_cb = std::function<bool(AuSPtr<IClientSocket> socket)>;
    using ShutdownSocket_cb = std::function<void(AuSPtr<IBasicSocket> socket)>;

    using Error_t = std::error_code;

    class IBasicSocket
    {
    public:
        virtual bool    IsActive()     = 0;
        virtual Error_t GetLastError() = 0;
        virtual void    Shutdown()     = 0;
        virtual bool    GetLocalEndpoint(Endpoint &out) = 0;
    };

    class IClientSocket : public IBasicSocket
    {
    public:
        // called during loop pump
        struct ClientCallbacks
        {
            StreamHasData_cb hasData;                 // on data available
            ShutdownSocket_cb onShutdown;             // Socket shutdown or otherwise dead
            ShutdownSocket_cb onStreamOverSaturation; // DoS?
            ShutdownSocket_cb onTLSHandshakeAbort;
        };

        virtual bool Initialize(const ClientCallbacks &callbacks) = 0;
        virtual bool Initialize() = 0;

        virtual bool GetRemoteEndpoint(Endpoint &out) = 0;

        virtual bool ReadAsync(AuUInt8 *buffer, bool all, AuUInt32 &length) = 0;
        virtual bool WriteAsync(const AuUInt8 *buffer, AuUInt32 length) = 0;
        virtual bool WriteAsync(const AuUInt8 *buffer, AuUInt32 length, std::function<void(bool)>) = 0;

        virtual AuUInt GetInternalRecvBuffer() = 0;
        virtual bool   SetInternalRecvBuffer(AuUInt bytes) = 0;
    };

    class ILocalClientSocket : public IClientSocket
    {
    public:
        using ConnectCallback_cb = std::function<void(bool success)>;
        virtual bool Connect() = 0;
        virtual void ConnectAsync(ConnectCallback_cb cb) = 0;
    };

    struct TlsConnect
    {
        Aurora::Crypto::X509::Certificate serverCertificate;
        AuSPtr<IBasicSocket> socket;
    };

    using TlsConnect_cb = std::function<bool(const TlsConnect &info)>;

    struct ServerInfo
    {
        Endpoint listen;
    };

    struct TLSServerInfo : ServerInfo
    {
        Aurora::Crypto::RSAPair cert;
    };

    struct ClientInfo
    {
        Endpoint socket;
        AuString service;
    };

    struct TLSClientInfo : ClientInfo
    {
        TlsConnect_cb pinning;
    };

    class IServer : public IBasicSocket
    {
    public:
        virtual bool AddAcceptCallback(const InitializeSocket_cb &accept) = 0; // on accept*
        virtual bool AddExitCallback(const ShutdownSocket_cb &accept) = 0; // server shutdown*

        virtual void GetClients(AuList<AuSPtr<IClientSocket>> &soccies) = 0;
        virtual bool Listen() = 0;
    };

    class INetworkingPool
    {
    public:
        /**
            Supported thread models:
            while (true)
            {
                // read from sockets pre-frame
                PumpSOL();

                // process other async network logic here

                // process writes and a few early reads before we sleep
                PumpEOL();

                // yield
                Yield();
            }

            while (true)
            {
                // process other async network logic here

                // run
                Run()
            }

        */
        virtual void PumpSOL() = 0;
        virtual void PumpEOL() = 0;

        virtual void Run() = 0;

        virtual bool NewServer(const ServerInfo &listen, IServer *&out) = 0;
        virtual bool NewTlsServer(const TLSServerInfo &keys, IServer *&out) = 0;
        virtual void DeleteServer(IServer *socket) = 0;

        virtual bool NewClient(const ClientInfo &info, ILocalClientSocket *&out) = 0;
        virtual bool NewTlsClient(const TLSClientInfo &info, ILocalClientSocket *&out) = 0;
        virtual void DeleteClient(ILocalClientSocket *socket) = 0;
    };
}