/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * Copyright (C) 2008 Imendio AB
 *
 * This program 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 of the
 * License, or (at your option) any later version.
 *
 * This program 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 program; if not, see <https://www.gnu.org/licenses>
 */

#include <config.h>

#include <string.h>
#ifdef HAVE_ASYNCNS
#include <asyncns.h>
#define freeaddrinfo(x) asyncns_freeaddrinfo(x)

/* Needed on Mac OS X */
#if HAVE_ARPA_NAMESER_COMPAT_H
#include <arpa/nameser_compat.h>
#endif

#include <arpa/nameser.h>
#include <resolv.h>

#include "lm-debug.h"
#include "lm-error.h"
#include "lm-internals.h"
#include "lm-marshal.h"
#include "lm-misc.h"
#include "lm-asyncns-resolver.h"

#define GET_PRIV(obj) (G_TYPE_INSTANCE_GET_PRIVATE ((obj), LM_TYPE_ASYNCNS_RESOLVER, LmAsyncnsResolverPriv))

typedef struct LmAsyncnsResolverPriv LmAsyncnsResolverPriv;
struct LmAsyncnsResolverPriv {
    GSource     *watch_resolv;
    asyncns_query_t *resolv_query;
    asyncns_t   *asyncns_ctx;
    GIOChannel  *resolv_channel;
};

static void     asyncns_resolver_finalize      (GObject     *object);
static void     asyncns_resolver_lookup        (LmResolver  *resolver);
static void     asyncns_resolver_cancel        (LmResolver  *resolver);

G_DEFINE_TYPE (LmAsyncnsResolver, lm_asyncns_resolver, LM_TYPE_RESOLVER)

static void
lm_asyncns_resolver_class_init (LmAsyncnsResolverClass *class)
{
    GObjectClass    *object_class = G_OBJECT_CLASS (class);
    LmResolverClass *resolver_class = LM_RESOLVER_CLASS (class);

    object_class->finalize = asyncns_resolver_finalize;

    resolver_class->lookup = asyncns_resolver_lookup;
    resolver_class->cancel = asyncns_resolver_cancel;

    g_type_class_add_private (object_class, sizeof (LmAsyncnsResolverPriv));
}

static void
lm_asyncns_resolver_init (LmAsyncnsResolver *asyncns_resolver)
{
    (void) GET_PRIV (asyncns_resolver);
}

static void
asyncns_resolver_finalize (GObject *object)
{
    (void) GET_PRIV (object);

    (G_OBJECT_CLASS (lm_asyncns_resolver_parent_class)->finalize) (object);
}

static void
asyncns_resolver_cleanup (LmResolver *resolver)
{
    LmAsyncnsResolverPriv *priv = GET_PRIV (resolver);

    if (priv->resolv_channel != NULL) {
        g_io_channel_unref (priv->resolv_channel);
        priv->resolv_channel = NULL;
    }

    if (priv->watch_resolv) {
        g_source_destroy (priv->watch_resolv);
        priv->watch_resolv = NULL;
    }

    if (priv->asyncns_ctx) {
        asyncns_free (priv->asyncns_ctx);
        priv->asyncns_ctx = NULL;
    }

    priv->resolv_query = NULL;
}

static void
asyncns_resolver_done (LmResolver *resolver)
{
    LmAsyncnsResolverPriv *priv = GET_PRIV (resolver);
    struct addrinfo       *ans;
    int                err;

    err = asyncns_getaddrinfo_done (priv->asyncns_ctx, priv->resolv_query, &ans);
    priv->resolv_query = NULL;
    /* Signal that we are done */

    g_object_ref (resolver);

    if (err) {
        _lm_resolver_set_result (resolver,
                                 LM_RESOLVER_RESULT_FAILED,
                                 NULL);
    } else {
        _lm_resolver_set_result (resolver,
                                 LM_RESOLVER_RESULT_OK,
                                 ans);
    }

    asyncns_resolver_cleanup (resolver);

    g_object_unref (resolver);
}

typedef gboolean  (* LmAsyncnsResolverCallback) (LmResolver *resolver);

static gboolean
asyncns_resolver_io_cb (GSource      *source,
                        GIOCondition  condition,
                        LmResolver   *resolver)
{
    LmAsyncnsResolverPriv     *priv = GET_PRIV (resolver);
    LmAsyncnsResolverCallback  func;

    asyncns_wait (priv->asyncns_ctx, FALSE);

    if (!asyncns_isdone (priv->asyncns_ctx, priv->resolv_query)) {
        return TRUE;
    }

    func = (LmAsyncnsResolverCallback) asyncns_getuserdata (priv->asyncns_ctx,
                                                            priv->resolv_query);
    return func (resolver);
}

static gboolean
asyncns_resolver_prep (LmResolver *resolver, GError **error)
{
    LmAsyncnsResolverPriv *priv = GET_PRIV (resolver);
    GMainContext          *context;

    if (priv->asyncns_ctx) {
        return TRUE;
    }

    priv->asyncns_ctx = asyncns_new (1);
    if (priv->asyncns_ctx == NULL) {
        g_set_error (error,
                     LM_ERROR,
                     LM_ERROR_CONNECTION_FAILED,
                     "can't initialise libasyncns");
        return FALSE;
    }

    priv->resolv_channel =
        g_io_channel_unix_new (asyncns_fd (priv->asyncns_ctx));

    g_object_get (resolver, "context", &context, NULL);

    priv->watch_resolv =
        lm_misc_add_io_watch (context,
                              priv->resolv_channel,
                              G_IO_IN,
                              (GIOFunc) asyncns_resolver_io_cb,
                              resolver);

    return TRUE;
}

static void
asyncns_resolver_lookup_host (LmResolver *resolver)
{
    LmAsyncnsResolverPriv *priv = GET_PRIV (resolver);
    gchar               *host;
    struct addrinfo      req;

    g_object_get (resolver, "host", &host, NULL);

    memset (&req, 0, sizeof(req));
    req.ai_family   = AF_UNSPEC;
    req.ai_socktype = SOCK_STREAM;
    req.ai_protocol = IPPROTO_TCP;

    if (!asyncns_resolver_prep (resolver, NULL)) {
        g_log (LM_LOG_DOMAIN, LM_LOG_LEVEL_NET, "Signal error\n");
        g_free (host);
        return;
    }

    priv->resolv_query =
        asyncns_getaddrinfo (priv->asyncns_ctx,
                             host,
                             NULL,
                             &req);

    asyncns_setuserdata (priv->asyncns_ctx,
                         priv->resolv_query,
                         (gpointer) asyncns_resolver_done);

    g_free (host);
}

static void
asyncns_resolver_srv_done (LmResolver *resolver)
{
    LmAsyncnsResolverPriv *priv = GET_PRIV (resolver);
    unsigned char         *srv_ans;
    int                    srv_len;
    gboolean               result = FALSE;

    g_log (LM_LOG_DOMAIN, LM_LOG_LEVEL_NET, "srv_done callback\n");

    srv_len = asyncns_res_done (priv->asyncns_ctx,
                                priv->resolv_query, &srv_ans);

    priv->resolv_query = NULL;

    if (srv_len <= 0) {
        /* FIXME: Report error */
        g_log (LM_LOG_DOMAIN, LM_LOG_LEVEL_NET,
               "Failed to read srv request results");
    } else {
        gchar *new_server;
        guint  new_port;

        g_log (LM_LOG_DOMAIN, LM_LOG_LEVEL_NET,
               "trying to parse srv response\n");

        result = _lm_resolver_parse_srv_response (srv_ans, srv_len,
                                                  &new_server,
                                                  &new_port);
        if (result == TRUE) {
            g_log (LM_LOG_DOMAIN, LM_LOG_LEVEL_NET,
                   "worked, new host/post is %s/%d\n",
                   new_server, new_port);

            g_object_set (resolver,
                          "host", new_server,
                          "port", new_port,
                          NULL);
            g_free (new_server);
        }

        /* TODO: Check whether srv_ans needs freeing */
    }

    asyncns_resolver_cleanup (resolver);

    g_object_ref (resolver);
    if (result == TRUE) {
        _lm_resolver_set_result (LM_RESOLVER (resolver), LM_RESOLVER_RESULT_OK, NULL);
    } else {
        _lm_resolver_set_result (LM_RESOLVER (resolver), LM_RESOLVER_RESULT_FAILED, NULL);
    }
    g_object_unref (resolver);
}

static void
asyncns_resolver_lookup_service (LmResolver *resolver)
{
    LmAsyncnsResolverPriv *priv = GET_PRIV (resolver);
    gchar                 *domain;
    gchar                 *service;
    gchar                 *protocol;
    gchar                 *srv;

    g_object_get (resolver,
                  "domain", &domain,
                  "service", &service,
                  "protocol", &protocol,
                  NULL);

    srv = _lm_resolver_create_srv_string (domain, service, protocol);

    g_log (LM_LOG_DOMAIN, LM_LOG_LEVEL_NET,
           "ASYNCNS: Looking up service: %s %s %s [%s]\n",
           domain, service, protocol, srv);

    if (!asyncns_resolver_prep (resolver, /* Use GError? */ NULL)) {
        g_log (LM_LOG_DOMAIN, LM_LOG_LEVEL_NET,
               "Failed to initiate the asyncns library");
        /* FIXME: Signal error */
        g_free (srv);
        g_free (domain);
        g_free (service);
        g_free (protocol);
        return;
    }

    priv->resolv_query =
        asyncns_res_query (priv->asyncns_ctx, srv, C_IN, T_SRV);

    asyncns_setuserdata (priv->asyncns_ctx,
                         priv->resolv_query,
                         (gpointer) asyncns_resolver_srv_done);

    g_free (srv);
    g_free (domain);
    g_free (service);
    g_free (protocol);
}

static void
asyncns_resolver_lookup (LmResolver *resolver)
{
    gint type;

    /* Start the DNS querying */

    /* Decide if we are going to lookup a srv or host */
    g_object_get (resolver, "type", &type, NULL);

    switch (type) {
    case LM_RESOLVER_HOST:
        asyncns_resolver_lookup_host (resolver);
        break;
    case LM_RESOLVER_SRV:
        asyncns_resolver_lookup_service (resolver);
        break;
    };

    /* End of DNS querying */
}

static void
asyncns_resolver_cancel (LmResolver *resolver)
{
    LmAsyncnsResolverPriv *priv;

    g_return_if_fail (LM_IS_ASYNCNS_RESOLVER (resolver));

    priv = GET_PRIV (resolver);

    if (priv->asyncns_ctx) {
        if (priv->resolv_query) {
            asyncns_cancel (priv->asyncns_ctx, priv->resolv_query);
            priv->resolv_query = NULL;
        }

        _lm_resolver_set_result (resolver,
                                 LM_RESOLVER_RESULT_CANCELLED,
                                 NULL);
    }
}

#endif //HAVE_ASYNCNS
