/*
 * This file Copyright (C) Mnemosyne LLC
 *
 * This file is licensed by the GPL version 2. Works owned by the
 * Transmission project are granted a special exemption to clause 2 (b)
 * so that the bulk of its code can remain under the MIT license.
 * This exemption does not extend to derived works not owned by
 * the Transmission project.
 *
 * $Id$
 */

#include <assert.h>
#include <errno.h>

#ifdef SYSTEM_MINIUPNP
  #include <miniupnpc/miniupnpc.h>
  #include <miniupnpc/upnpcommands.h>
#else
  #include <miniupnp/miniupnpc.h>
  #include <miniupnp/upnpcommands.h>
#endif

#ifdef SYS_DARWIN
  #define HAVE_MINIUPNP_16 1
#endif

#include "transmission.h"
#include "log.h"
#include "port-forwarding.h"
#include "session.h"
#include "upnp.h"
#include "utils.h"

static const char *
getKey (void) { return _("Port Forwarding (UPnP)"); }

typedef enum
{
    TR_UPNP_IDLE,
    TR_UPNP_ERR,
    TR_UPNP_DISCOVER,
    TR_UPNP_MAP,
    TR_UPNP_UNMAP
}
tr_upnp_state;

struct tr_upnp
{
    bool               hasDiscovered;
    struct UPNPUrls    urls;
    struct IGDdatas    data;
    int                port;
    char               lanaddr[16];
    unsigned int       isMapped;
    tr_upnp_state      state;
};

/**
***
**/

tr_upnp*
tr_upnpInit (void)
{
    tr_upnp * ret = tr_new0 (tr_upnp, 1);

    ret->state = TR_UPNP_DISCOVER;
    ret->port = -1;
    return ret;
}

void
tr_upnpClose (tr_upnp * handle)
{
    assert (!handle->isMapped);
    assert ((handle->state == TR_UPNP_IDLE)
          || (handle->state == TR_UPNP_ERR)
          || (handle->state == TR_UPNP_DISCOVER));

    if (handle->hasDiscovered)
        FreeUPNPUrls (&handle->urls);
    tr_free (handle);
}

/**
***  Wrappers for miniupnpc functions
**/

static struct UPNPDev *
tr_upnpDiscover (int msec)
{
    struct UPNPDev * ret = NULL;

#if defined (HAVE_MINIUPNP_16)
    int err = UPNPDISCOVER_SUCCESS;
    ret = upnpDiscover (msec, NULL, NULL, 0, 0, &err);
    if (err != UPNPDISCOVER_SUCCESS)
#elif defined (HAVE_MINIUPNP_15)
    ret = upnpDiscover (msec, NULL, NULL, 0);
    if (ret == NULL)
#endif

        tr_logAddNamedDbg (getKey (), "upnpDiscover failed (errno %d - %s)", errno, tr_strerror (errno));

    return ret;
}

static int
tr_upnpGetSpecificPortMappingEntry (tr_upnp * handle, const char * proto)
{
    int err;
    char intClient[16];
    char intPort[16];
    char portStr[16];

    *intClient = '\0';
    *intPort = '\0';

    tr_snprintf (portStr, sizeof (portStr), "%d", (int)handle->port);

#if defined (HAVE_MINIUPNP_16)
    err = UPNP_GetSpecificPortMappingEntry (handle->urls.controlURL, handle->data.first.servicetype, portStr, proto, intClient, intPort, NULL, NULL, NULL);
#elif defined (HAVE_MINIUPNP_15)
    err = UPNP_GetSpecificPortMappingEntry (handle->urls.controlURL, handle->data.first.servicetype, portStr, proto, intClient, intPort);
#else
    err = UPNPCOMMAND_UNKNOWN_ERROR;
#endif

    return err;
}

static int
tr_upnpAddPortMapping (const tr_upnp * handle, const char * proto, tr_port port, const char * desc)
{
    int err;
    const int old_errno = errno;
    char portStr[16];
    errno = 0;

    tr_snprintf (portStr, sizeof (portStr), "%d", (int)port);

#if defined (HAVE_MINIUPNP_16)
    err = UPNP_AddPortMapping (handle->urls.controlURL, handle->data.first.servicetype, portStr, portStr, handle->lanaddr, desc, proto, NULL, NULL);
#elif defined (HAVE_MINIUPNP_15)
    err = UPNP_AddPortMapping (handle->urls.controlURL, handle->data.first.servicetype, portStr, portStr, handle->lanaddr, desc, proto, NULL);
#else
    err = UPNPCOMMAND_UNKNOWN_ERROR;
#endif

    if (err)
        tr_logAddNamedDbg (getKey (), "%s Port forwarding failed with error %d (errno %d - %s)", proto, err, errno, tr_strerror (errno));

    errno = old_errno;
    return err;
}

static void
tr_upnpDeletePortMapping (const tr_upnp * handle, const char * proto, tr_port port)
{
    char portStr[16];

    tr_snprintf (portStr, sizeof (portStr), "%d", (int)port);

    UPNP_DeletePortMapping (handle->urls.controlURL,
                            handle->data.first.servicetype,
                            portStr, proto, NULL);
}

/**
***
**/

enum
{
  UPNP_IGD_NONE = 0,
  UPNP_IGD_VALID_CONNECTED = 1,
  UPNP_IGD_VALID_NOT_CONNECTED = 2,
  UPNP_IGD_INVALID = 3
};

int
tr_upnpPulse (tr_upnp * handle,
              int       port,
              int       isEnabled,
              int       doPortCheck)
{
    int ret;

    if (isEnabled && (handle->state == TR_UPNP_DISCOVER))
    {
        struct UPNPDev * devlist;

        devlist = tr_upnpDiscover (2000);

        errno = 0;
        if (UPNP_GetValidIGD (devlist, &handle->urls, &handle->data,
                             handle->lanaddr, sizeof (handle->lanaddr)) == UPNP_IGD_VALID_CONNECTED)
        {
            tr_logAddNamedInfo (getKey (), _(
                         "Found Internet Gateway Device \"%s\""),
                     handle->urls.controlURL);
            tr_logAddNamedInfo (getKey (), _(
                         "Local Address is \"%s\""), handle->lanaddr);
            handle->state = TR_UPNP_IDLE;
            handle->hasDiscovered = 1;
        }
        else
        {
            handle->state = TR_UPNP_ERR;
            tr_logAddNamedDbg (
                 getKey (), "UPNP_GetValidIGD failed (errno %d - %s)",
                errno,
                tr_strerror (errno));
            tr_logAddNamedDbg (
                getKey (),
                "If your router supports UPnP, please make sure UPnP is enabled!");
        }
        freeUPNPDevlist (devlist);
    }

    if (handle->state == TR_UPNP_IDLE)
    {
        if (handle->isMapped && (!isEnabled || (handle->port != port)))
            handle->state = TR_UPNP_UNMAP;
    }

    if (isEnabled && handle->isMapped && doPortCheck)
    {
        if ((tr_upnpGetSpecificPortMappingEntry (handle, "TCP") != UPNPCOMMAND_SUCCESS) ||
          (tr_upnpGetSpecificPortMappingEntry (handle, "UDP") != UPNPCOMMAND_SUCCESS))
        {
            tr_logAddNamedInfo (getKey (), _("Port %d isn't forwarded"), handle->port);
            handle->isMapped = false;
        }
    }

    if (handle->state == TR_UPNP_UNMAP)
    {
        tr_upnpDeletePortMapping (handle, "TCP", handle->port);
        tr_upnpDeletePortMapping (handle, "UDP", handle->port);

        tr_logAddNamedInfo (getKey (),
                 _("Stopping port forwarding through \"%s\", service \"%s\""),
                 handle->urls.controlURL, handle->data.first.servicetype);

        handle->isMapped = 0;
        handle->state = TR_UPNP_IDLE;
        handle->port = -1;
    }

    if (handle->state == TR_UPNP_IDLE)
    {
        if (isEnabled && !handle->isMapped)
            handle->state = TR_UPNP_MAP;
    }

    if (handle->state == TR_UPNP_MAP)
    {
        int  err_tcp = -1;
        int  err_udp = -1;
        errno = 0;

        if (!handle->urls.controlURL || !handle->data.first.servicetype)
            handle->isMapped = 0;
        else
        {
            char desc[64];
            tr_snprintf (desc, sizeof (desc), "%s at %d", TR_NAME, port);

            err_tcp = tr_upnpAddPortMapping (handle, "TCP", port, desc);
            err_udp = tr_upnpAddPortMapping (handle, "UDP", port, desc);

            handle->isMapped = !err_tcp | !err_udp;
        }
        tr_logAddNamedInfo (getKey (),
                 _("Port forwarding through \"%s\", service \"%s\". (local address: %s:%d)"),
                 handle->urls.controlURL, handle->data.first.servicetype,
                 handle->lanaddr, port);
        if (handle->isMapped)
        {
            tr_logAddNamedInfo (getKey (), "%s", _("Port forwarding successful!"));
            handle->port = port;
            handle->state = TR_UPNP_IDLE;
        }
        else
        {
            tr_logAddNamedDbg (getKey (), "If your router supports UPnP, please make sure UPnP is enabled!");
            handle->port = -1;
            handle->state = TR_UPNP_ERR;
        }
    }

    switch (handle->state)
    {
        case TR_UPNP_DISCOVER:
            ret = TR_PORT_UNMAPPED; break;

        case TR_UPNP_MAP:
            ret = TR_PORT_MAPPING; break;

        case TR_UPNP_UNMAP:
            ret = TR_PORT_UNMAPPING; break;

        case TR_UPNP_IDLE:
            ret = handle->isMapped ? TR_PORT_MAPPED
                  : TR_PORT_UNMAPPED; break;

        default:
            ret = TR_PORT_ERROR; break;
    }

    return ret;
}