/*
  LwipIntfDev.h

  Arduino network template class for generic device

  Original Copyright (c) 2020 esp8266 Arduino All rights reserved.
  This file is part of the esp8266 Arduino core environment.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

#ifndef _LWIPINTFDEV_H
#define _LWIPINTFDEV_H

// TODO:
// unchain pbufs

#include <netif/ethernet.h>
#include <lwip/init.h>
#include <lwip/netif.h>
#include <lwip/etharp.h>
#include <lwip/dhcp.h>
#include <lwip/dns.h>
#include <lwip/apps/sntp.h>

#include <user_interface.h>  // wifi_get_macaddr()

#include "SPI.h"
#include "Schedule.h"
#include "LwipIntf.h"
#include "wl_definitions.h"

#ifndef DEFAULT_MTU
#define DEFAULT_MTU 1500
#endif

enum EthernetLinkStatus
{
    Unknown,
    LinkON,
    LinkOFF
};

template<class RawDev>
class LwipIntfDev: public LwipIntf, public RawDev
{
public:
    LwipIntfDev(int8_t cs = SS, SPIClass& spi = SPI, int8_t intr = -1) :
        RawDev(cs, spi, intr), _mtu(DEFAULT_MTU), _intrPin(intr), _started(false), _default(false)
    {
        memset(&_netif, 0, sizeof(_netif));
    }

    boolean config(const IPAddress& local_ip, const IPAddress& arg1, const IPAddress& arg2,
                   const IPAddress& arg3 = IPADDR_NONE, const IPAddress& dns2 = IPADDR_NONE);

    // default mac-address is inferred from esp8266's STA interface
    boolean begin(const uint8_t* macAddress = nullptr, const uint16_t mtu = DEFAULT_MTU);

    const netif* getNetIf() const
    {
        return &_netif;
    }

    IPAddress localIP() const
    {
        return IPAddress(ip4_addr_get_u32(ip_2_ip4(&_netif.ip_addr)));
    }
    IPAddress subnetMask() const
    {
        return IPAddress(ip4_addr_get_u32(ip_2_ip4(&_netif.netmask)));
    }
    IPAddress gatewayIP() const
    {
        return IPAddress(ip4_addr_get_u32(ip_2_ip4(&_netif.gw)));
    }

    // 1. Currently when no default is set, esp8266-Arduino uses the first
    //    DHCP client interface receiving a valid address and gateway to
    //    become the new lwIP default interface.
    // 2. Otherwise - when using static addresses - lwIP for every packets by
    //    defaults selects automatically the best suited output interface
    //    matching the destination address.  If several interfaces match,
    //    the first one is picked.  On esp8266/Arduno: WiFi interfaces are
    //    checked first.
    // 3. Or, use `::setDefault(true)` to force using this interface's gateway
    //    as default router.
    void setDefault(bool deflt = true);

    // true if interface has a valid IPv4 address
    // (and ethernet link status is not detectable or is up)
    bool connected()
    {
        return !!ip4_addr_get_u32(ip_2_ip4(&_netif.ip_addr))
               && (!RawDev::isLinkDetectable() || RawDev::isLinked());
    }

    bool routable()
    {
        return !ip_addr_isany(&_netif.gw);
    }

    // ESP8266WiFi API compatibility
    wl_status_t status();

    // Arduino Ethernet compatibility
    EthernetLinkStatus linkStatus();

protected:
    err_t netif_init();
    void  check_route();
    void  netif_status_callback();

    static err_t netif_init_s(netif* netif);
    static err_t linkoutput_s(netif* netif, struct pbuf* p);
    static void  netif_status_callback_s(netif* netif);

    // called on a regular basis or on interrupt
    err_t handlePackets();

    // members

    netif _netif;

    uint16_t _mtu;
    int8_t   _intrPin;
    uint8_t  _macAddress[6];
    bool     _started;
    bool     _default;
};

template<class RawDev>
boolean LwipIntfDev<RawDev>::config(const IPAddress& localIP, const IPAddress& gateway,
                                    const IPAddress& netmask, const IPAddress& dns1,
                                    const IPAddress& dns2)
{
    if (_started)
    {
        DEBUGV("LwipIntfDev: use config() then begin()\n");
        return false;
    }

    IPAddress realGateway, realNetmask, realDns1;
    if (!ipAddressReorder(localIP, gateway, netmask, dns1, realGateway, realNetmask, realDns1))
    {
        return false;
    }
    ip4_addr_set_u32(ip_2_ip4(&_netif.ip_addr), localIP.v4());
    ip4_addr_set_u32(ip_2_ip4(&_netif.gw), realGateway.v4());
    ip4_addr_set_u32(ip_2_ip4(&_netif.netmask), realNetmask.v4());

    if (realDns1.isSet())
    {
        // Set DNS1-Server
        dns_setserver(0, realDns1);
    }

    if (dns2.isSet())
    {
        // Set DNS2-Server
        dns_setserver(1, dns2);
    }
    return true;
}

template<class RawDev>
boolean LwipIntfDev<RawDev>::begin(const uint8_t* macAddress, const uint16_t mtu)
{
    if (mtu)
    {
        _mtu = mtu;
    }

    if (macAddress)
    {
        memcpy(_macAddress, macAddress, 6);
    }
    else
    {
        _netif.num = 2;
        for (auto n = netif_list; n; n = n->next)
            if (n->num >= _netif.num)
            {
                _netif.num = n->num + 1;
            }

#if 1
        // forge a new mac-address from the esp's wifi sta one
        // I understand this is cheating with an official mac-address
        wifi_get_macaddr(STATION_IF, (uint8*)_macAddress);
#else
        // https://serverfault.com/questions/40712/what-range-of-mac-addresses-can-i-safely-use-for-my-virtual-machines
        memset(_macAddress, 0, 6);
        _macAddress[0] = 0xEE;
#endif
        _macAddress[3] += _netif.num;  // alter base mac address
        _macAddress[0] &= 0xfe;        // set as locally administered, unicast, per
        _macAddress[0] |= 0x02;  // https://en.wikipedia.org/wiki/MAC_address#Universal_vs._local
    }

    if (!RawDev::begin(_macAddress))
    {
        return false;
    }

    // setup lwIP netif

    _netif.hwaddr_len = sizeof _macAddress;
    memcpy(_netif.hwaddr, _macAddress, sizeof _macAddress);

    // due to netif_add() api: ...
    ip_addr_t ip_addr, netmask, gw;
    ip_addr_copy(ip_addr, _netif.ip_addr);
    ip_addr_copy(netmask, _netif.netmask);
    ip_addr_copy(gw, _netif.gw);

    if (!netif_add(&_netif, ip_2_ip4(&ip_addr), ip_2_ip4(&netmask), ip_2_ip4(&gw), this,
                   netif_init_s, ethernet_input))
    {
        return false;
    }

    if (localIP().v4() == 0)
    {
        // IP not set, starting DHCP
        _netif.flags |= NETIF_FLAG_UP;
        switch (dhcp_start(&_netif))
        {
        case ERR_OK:
            break;

        case ERR_IF:
            return false;

        default:
            netif_remove(&_netif);
            return false;
        }
    }
    else
    {
        // IP is set, static config
        netif_set_link_up(&_netif);
        netif_set_up(&_netif);
    }

    _started = true;

    if (_intrPin >= 0)
    {
        if (RawDev::interruptIsPossible())
        {
            // attachInterrupt(_intrPin, [&]() { this->handlePackets(); }, FALLING);
        }
        else
        {
            ::printf((PGM_P)F(
                "lwIP_Intf: Interrupt not implemented yet, enabling transparent polling\r\n"));
            _intrPin = -1;
        }
    }

    if (_intrPin < 0
        && !schedule_recurrent_function_us(
            [&]()
            {
                this->handlePackets();
                return true;
            },
            100))
    {
        netif_remove(&_netif);
        return false;
    }

    return true;
}

template<class RawDev>
wl_status_t LwipIntfDev<RawDev>::status()
{
    return _started ? (connected() ? WL_CONNECTED : WL_DISCONNECTED) : WL_NO_SHIELD;
}

template<class RawDev>
EthernetLinkStatus LwipIntfDev<RawDev>::linkStatus()
{
    return RawDev::isLinkDetectable() ? _started && RawDev::isLinked() ? LinkON : LinkOFF : Unknown;
}

template<class RawDev>
err_t LwipIntfDev<RawDev>::linkoutput_s(netif* netif, struct pbuf* pbuf)
{
    LwipIntfDev* ths = (LwipIntfDev*)netif->state;

    if (pbuf->len != pbuf->tot_len || pbuf->next)
    {
        Serial.println("ERRTOT\r\n");
    }

    uint16_t len = ths->sendFrame((const uint8_t*)pbuf->payload, pbuf->len);

#if PHY_HAS_CAPTURE
    if (phy_capture)
    {
        phy_capture(ths->_netif.num, (const char*)pbuf->payload, pbuf->len, /*out*/ 1,
                    /*success*/ len == pbuf->len);
    }
#endif

    return len == pbuf->len ? ERR_OK : ERR_MEM;
}

template<class RawDev>
err_t LwipIntfDev<RawDev>::netif_init_s(struct netif* netif)
{
    return ((LwipIntfDev*)netif->state)->netif_init();
}

template<class RawDev>
void LwipIntfDev<RawDev>::netif_status_callback_s(struct netif* netif)
{
    ((LwipIntfDev*)netif->state)->netif_status_callback();
}

template<class RawDev>
err_t LwipIntfDev<RawDev>::netif_init()
{
    _netif.name[0]      = 'e';
    _netif.name[1]      = '0' + _netif.num;
    _netif.mtu          = _mtu;
    _netif.chksum_flags = NETIF_CHECKSUM_ENABLE_ALL;
    _netif.flags = NETIF_FLAG_ETHARP | NETIF_FLAG_IGMP | NETIF_FLAG_BROADCAST | NETIF_FLAG_LINK_UP;

    // lwIP's doc: This function typically first resolves the hardware
    // address, then sends the packet.  For ethernet physical layer, this is
    // usually lwIP's etharp_output()
    _netif.output = etharp_output;

    // lwIP's doc: This function outputs the pbuf as-is on the link medium
    // (this must points to the raw ethernet driver, meaning: us)
    _netif.linkoutput = linkoutput_s;

    _netif.status_callback = netif_status_callback_s;

    return ERR_OK;
}

template<class RawDev>
void LwipIntfDev<RawDev>::netif_status_callback()
{
    check_route();
    if (connected())
    {
        sntp_stop();
        sntp_init();
    }
}

template<class RawDev>
void LwipIntfDev<RawDev>::check_route()
{
    if (connected())
    {
        if (_default || (netif_default == nullptr && routable()))
        {
            // on user request,
            // or if there is no current default interface, but our gateway is valid
            netif_set_default(&_netif);
        }
    }
    else if (netif_default == &_netif)
    {
        netif_set_default(nullptr);
    }
}

template<class RawDev>
err_t LwipIntfDev<RawDev>::handlePackets()
{
    int pkt = 0;
    while (1)
    {
        if (++pkt == 10)
        // prevent starvation
        {
            return ERR_OK;
        }

        uint16_t tot_len = RawDev::readFrameSize();
        if (!tot_len)
        {
            return ERR_OK;
        }

        // from doc: use PBUF_RAM for TX, PBUF_POOL from RX
        // however:
        // PBUF_POOL can return chained pbuf (not in one piece)
        // and WiznetDriver does not have the proper API to deal with that
        // so in the meantime, we use PBUF_RAM instead which is currently
        // guarantying to deliver a continuous chunk of memory.
        // TODO: tweak the wiznet driver to allow copying partial chunk
        //       of received data and use PBUF_POOL.
        pbuf* pbuf = pbuf_alloc(PBUF_RAW, tot_len, PBUF_RAM);
        if (!pbuf || pbuf->len < tot_len)
        {
            if (pbuf)
            {
                pbuf_free(pbuf);
            }
            RawDev::discardFrame(tot_len);
            return ERR_BUF;
        }

        uint16_t len = RawDev::readFrameData((uint8_t*)pbuf->payload, tot_len);
        if (len != tot_len)
        {
            // tot_len is given by readFrameSize()
            // and is supposed to be honoured by readFrameData()
            // todo: ensure this test is unneeded, remove the print
            Serial.println("read error?\r\n");
            pbuf_free(pbuf);
            return ERR_BUF;
        }

        err_t err = _netif.input(pbuf, &_netif);

#if PHY_HAS_CAPTURE
        if (phy_capture)
        {
            phy_capture(_netif.num, (const char*)pbuf->payload, tot_len, /*out*/ 0,
                        /*success*/ err == ERR_OK);
        }
#endif

        if (err != ERR_OK)
        {
            pbuf_free(pbuf);
            return err;
        }
        // (else) allocated pbuf is now lwIP's responsibility
    }
}

template<class RawDev>
void LwipIntfDev<RawDev>::setDefault(bool deflt)
{
    _default = deflt;
    check_route();
}

#endif  // _LWIPINTFDEV_H