#include <fstream>
#include <cryptopp/dh.h>
#include <cryptopp/dsa.h>
#include <boost/lexical_cast.hpp>
#include "CryptoConst.h"
#include "RouterContext.h"
#include "util/Timestamp.h"
#include "I2NPProtocol.h"
#include "NetDb.h"
#include "util/util.h"
#include "version.h"

namespace i2p
{
    RouterContext context;

    RouterContext::RouterContext ():
        m_LastUpdateTime (0), m_AcceptsTunnels (true), m_IsFloodfill (false), 
        m_StartupTime (0), m_Status (eRouterStatusOK )
    {
    }

    void RouterContext::Init ()
    {
        m_StartupTime = i2p::util::GetSecondsSinceEpoch ();
        if (!Load ())
            CreateNewRouter ();
        UpdateRouterInfo ();
    }

    void RouterContext::CreateNewRouter ()
    {
        m_Keys = i2p::data::CreateRandomKeys ();
        SaveKeys ();
        NewRouterInfo ();
    }

    void RouterContext::NewRouterInfo ()
    {
        i2p::data::RouterInfo routerInfo;
        routerInfo.SetRouterIdentity (GetIdentity ());
        int port = i2p::util::config::GetArg("-port", 0);
        if (!port)
            port = m_Rnd.GenerateWord32 (9111, 30777); // I2P network ports range
        routerInfo.AddSSUAddress (i2p::util::config::GetCharArg("-host", "127.0.0.1"), port, routerInfo.GetIdentHash ());
        routerInfo.AddNTCPAddress (i2p::util::config::GetCharArg("-host", "127.0.0.1"), port);
        routerInfo.SetCaps (i2p::data::RouterInfo::eReachable | 
            i2p::data::RouterInfo::eSSUTesting | i2p::data::RouterInfo::eSSUIntroducer); // LR, BC
        routerInfo.SetProperty ("coreVersion", I2P_VERSION);
        routerInfo.SetProperty ("netId", "2");
        routerInfo.SetProperty ("router.version", I2P_VERSION);
        routerInfo.SetProperty ("stat_uptime", "90m");
        routerInfo.CreateBuffer (m_Keys);
        m_RouterInfo.Update (routerInfo.GetBuffer (), routerInfo.GetBufferLen ());
    }

    void RouterContext::UpdateRouterInfo ()
    {
        m_RouterInfo.CreateBuffer (m_Keys);
        m_RouterInfo.SaveToFile (i2p::util::filesystem::GetFullPath (ROUTER_INFO));
        m_LastUpdateTime = i2p::util::GetSecondsSinceEpoch ();
    }   

    void RouterContext::UpdatePort (int port)
    {
        bool updated = false;
        for (auto& address : m_RouterInfo.GetAddresses ())
        {
            if (address.port != port)
            {   
                address.port = port;
                updated = true;
            }   
        }   
        if (updated)
            UpdateRouterInfo ();
    }

    void RouterContext::UpdateAddress (const boost::asio::ip::address& host)
    {
        bool updated = false;
        for (auto& address : m_RouterInfo.GetAddresses ())
        {
            if (address.host != host && address.IsCompatible (host))
            {   
                address.host = host;
                updated = true;
            }   
        }   
        auto ts = i2p::util::GetSecondsSinceEpoch ();
        if (updated || ts > m_LastUpdateTime + ROUTER_INFO_UPDATE_INTERVAL)
            UpdateRouterInfo ();
    }

    bool RouterContext::AddIntroducer (const i2p::data::RouterInfo& routerInfo, uint32_t tag)
    {
        bool ret = false;
        auto address = routerInfo.GetSSUAddress ();
        if (address)
        {   
            ret = m_RouterInfo.AddIntroducer (address, tag);
            if (ret)
                UpdateRouterInfo ();
        }   
        return ret;
    }   

    void RouterContext::RemoveIntroducer (const boost::asio::ip::udp::endpoint& e)
    {
        if (m_RouterInfo.RemoveIntroducer (e))
            UpdateRouterInfo ();
    }   
    
    void RouterContext::SetFloodfill (bool floodfill)
    {
        m_IsFloodfill = floodfill;
        if (floodfill)
            m_RouterInfo.SetCaps (m_RouterInfo.GetCaps () | i2p::data::RouterInfo::eFloodfill);
        else
        {
            m_RouterInfo.SetCaps (m_RouterInfo.GetCaps () & ~i2p::data::RouterInfo::eFloodfill);
            // we don't publish number of routers and leaseset for non-floodfill
            m_RouterInfo.DeleteProperty (ROUTER_INFO_PROPERTY_LEASESETS);
            m_RouterInfo.DeleteProperty (ROUTER_INFO_PROPERTY_ROUTERS);
        }
        UpdateRouterInfo ();
    }

    void RouterContext::SetHighBandwidth ()
    {
        if (!m_RouterInfo.IsHighBandwidth ())
        {
            m_RouterInfo.SetCaps (m_RouterInfo.GetCaps () | i2p::data::RouterInfo::eHighBandwidth);
            UpdateRouterInfo ();
        }
    }

    void RouterContext::SetLowBandwidth ()
    {
        if (m_RouterInfo.IsHighBandwidth ())
        {
            m_RouterInfo.SetCaps (m_RouterInfo.GetCaps () & ~i2p::data::RouterInfo::eHighBandwidth);
            UpdateRouterInfo ();
        }
    }

    bool RouterContext::IsUnreachable () const
    {
        return m_RouterInfo.GetCaps () & i2p::data::RouterInfo::eUnreachable;
    }   
        
    void RouterContext::SetUnreachable ()
    {
        // set caps
        m_RouterInfo.SetCaps (i2p::data::RouterInfo::eUnreachable | i2p::data::RouterInfo::eSSUTesting); // LU, B
        // remove NTCP address
        auto& addresses = m_RouterInfo.GetAddresses ();
        for (size_t i = 0; i < addresses.size (); i++)
        {
            if (addresses[i].transportStyle == i2p::data::RouterInfo::eTransportNTCP)
            {
                addresses.erase (addresses.begin () + i);
                break;
            }
        }   
        // delete previous introducers
        for (auto& addr : addresses)
            addr.introducers.clear ();
    
        // update
        UpdateRouterInfo ();
    }

    void RouterContext::SetReachable ()
    {
        // update caps
        uint8_t caps = m_RouterInfo.GetCaps ();
        caps &= ~i2p::data::RouterInfo::eUnreachable;
        caps |= i2p::data::RouterInfo::eReachable;
        caps |= i2p::data::RouterInfo::eSSUIntroducer;
        if (m_IsFloodfill)
            caps |= i2p::data::RouterInfo::eFloodfill;
        m_RouterInfo.SetCaps (caps);
        
        // insert NTCP back
        auto& addresses = m_RouterInfo.GetAddresses ();
        for (size_t i = 0; i < addresses.size (); i++)
        {
            if (addresses[i].transportStyle == i2p::data::RouterInfo::eTransportSSU)
            {
                // insert NTCP address with host/port form SSU
                m_RouterInfo.AddNTCPAddress (addresses[i].host.to_string ().c_str (), addresses[i].port);
                break;
            }
        }       
        // delete previous introducers
        for (auto& addr : addresses)
            addr.introducers.clear ();
        
        // update
        UpdateRouterInfo ();
    }   
        
    void RouterContext::SetSupportsV6 (bool supportsV6)
    {
        if (supportsV6)
            m_RouterInfo.EnableV6 ();
        else
            m_RouterInfo.DisableV6 ();
        UpdateRouterInfo ();
    }   

    void RouterContext::UpdateNTCPV6Address (const boost::asio::ip::address& host)
    {
        bool updated = false, found = false;    
        int port = 0;
        auto& addresses = m_RouterInfo.GetAddresses ();
        for (auto& addr : addresses)
        {
            if (addr.host.is_v6 () && addr.transportStyle == i2p::data::RouterInfo::eTransportNTCP)
            {
                if (addr.host != host)
                {
                    addr.host = host;
                    updated = true;
                }
                found = true;   
            }   
            else
                port = addr.port;   
        }   
        if (!found)
        {
            // create new address
            m_RouterInfo.AddNTCPAddress (host.to_string ().c_str (), port);
            auto mtu = i2p::util::net::GetMTU (host);
            if (mtu)
            {   
                LogPrint ("Our v6 MTU=", mtu);
                if (mtu > 1472) mtu = 1472; 
            }   
            m_RouterInfo.AddSSUAddress (host.to_string ().c_str (), port, GetIdentHash (), mtu ? mtu : 1472); // TODO
            updated = true;
        }
        if (updated)
            UpdateRouterInfo ();
    }

    void RouterContext::UpdateStats ()
    {
        if (m_IsFloodfill)
        {
            // update routers and leasesets
            m_RouterInfo.SetProperty (ROUTER_INFO_PROPERTY_LEASESETS, boost::lexical_cast<std::string>(i2p::data::netdb.GetNumLeaseSets ()));
            m_RouterInfo.SetProperty (ROUTER_INFO_PROPERTY_ROUTERS, boost::lexical_cast<std::string>(i2p::data::netdb.GetNumRouters ()));
            UpdateRouterInfo (); 
        }
    }
        
    bool RouterContext::Load ()
    {
        std::ifstream fk (i2p::util::filesystem::GetFullPath (ROUTER_KEYS).c_str (), std::ifstream::binary | std::ofstream::in);
        if (!fk.is_open ()) return false;
        
        i2p::data::Keys keys;   
        fk.read ((char *)&keys, sizeof (keys));
        m_Keys = keys;

        i2p::data::RouterInfo routerInfo(i2p::util::filesystem::GetFullPath (ROUTER_INFO)); // TODO
        m_RouterInfo.Update (routerInfo.GetBuffer (), routerInfo.GetBufferLen ());
        m_RouterInfo.SetProperty ("coreVersion", I2P_VERSION);
        m_RouterInfo.SetProperty ("router.version", I2P_VERSION);

        if (IsUnreachable ())
            SetReachable (); // we assume reachable until we discover firewall through peer tests
        
        return true;
    }

    void RouterContext::SaveKeys ()
    {   
        std::ofstream fk (i2p::util::filesystem::GetFullPath (ROUTER_KEYS).c_str (), std::ofstream::binary | std::ofstream::out);
        i2p::data::Keys keys;
        memcpy (keys.privateKey, m_Keys.GetPrivateKey (), sizeof (keys.privateKey));
        memcpy (keys.signingPrivateKey, m_Keys.GetSigningPrivateKey (), sizeof (keys.signingPrivateKey));
        auto& ident = GetIdentity ().GetStandardIdentity ();    
        memcpy (keys.publicKey, ident.publicKey, sizeof (keys.publicKey));
        memcpy (keys.signingKey, ident.signingKey, sizeof (keys.signingKey));
        fk.write ((char *)&keys, sizeof (keys));    
    }

    std::shared_ptr<i2p::tunnel::TunnelPool> RouterContext::GetTunnelPool () const
    {
        return i2p::tunnel::tunnels.GetExploratoryPool (); 
    }   
        
    void RouterContext::HandleI2NPMessage (const uint8_t * buf, size_t len, std::shared_ptr<i2p::tunnel::InboundTunnel> from)
    {
        i2p::HandleI2NPMessage (CreateI2NPMessage (buf, GetI2NPMessageLength (buf), from));
    }

    void RouterContext::ProcessGarlicMessage (std::shared_ptr<I2NPMessage> msg)
    {
        std::unique_lock<std::mutex> l(m_GarlicMutex);
        i2p::garlic::GarlicDestination::ProcessGarlicMessage (msg);
    }   
            
    void RouterContext::ProcessDeliveryStatusMessage (std::shared_ptr<I2NPMessage> msg)
    {
        std::unique_lock<std::mutex> l(m_GarlicMutex);
        i2p::garlic::GarlicDestination::ProcessDeliveryStatusMessage (msg);
    }   
        
    uint32_t RouterContext::GetUptime () const
    {
        return i2p::util::GetSecondsSinceEpoch () - m_StartupTime;
    }   
}