/*
 * Copyright (c) 2017-2019 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * \file interfaces/bonjour/bonjour.c
 * \brief Implementation of Bonjour interface
 *
 * TODO:
 *  - concurrent queries
 *  - interface binding
 */

#include <hicn/facemgr.h>
#include <hicn/util/log.h>
#include <hicn/util/map.h>

#include "../../common.h"
#include "../../interface.h"
#include "mdns/mdns.h"

#include "bonjour.h"

#define DEFAULT_BUFFER_SIZE 2048
#define SERVICE_STRING_SIZE 256

#define DEFAULT_SERVICE_NAME "hicn"
#define DEFAULT_SERVICE_PROTOCOL "udp"
#define DEFAULT_SERVICE_DOMAIN "local"

typedef struct {
    bonjour_cfg_t cfg;
    int sock;
    size_t buffer_size;
    void* buffer;

    /* The face being resolved, non-NULL values indicate interface is busy... */
    face_t * face;
} bj_data_t;

int bj_initialize(interface_t * interface, void * cfg)
{
    bj_data_t * data = malloc(sizeof(bj_data_t));
    if (!data)
        goto ERR_MALLOC;
    interface->data = data;

    if (cfg) {
#ifndef __linux__
        if (cfg->netdevice)
            WARN("Binding to interface is (currently) only supported on Linux");
#endif /* ! __linux__ */
        data->cfg = * (bonjour_cfg_t *) cfg;
    } else {
        memset(&data->cfg, 0, sizeof(bonjour_cfg_t));
    }

    if (!data->cfg.service_name)
        data->cfg.service_name = DEFAULT_SERVICE_NAME;

    if (!data->cfg.service_protocol)
        data->cfg.service_protocol = DEFAULT_SERVICE_PROTOCOL;

    if (!data->cfg.service_domain)
        data->cfg.service_domain = DEFAULT_SERVICE_DOMAIN;

    data->sock = mdns_socket_open_ipv4();
    if (data->sock < 0) {
        printf("Failed to open socket: %s\n", strerror(errno));
        goto ERR_SOCK;
    }

    /* Netdevice configuration */
#ifdef __linux__
#ifndef __ANDROID__
    if (IS_VALID_NETDEVICE(data->cfg.netdevice)) {
        int rc = setsockopt(data->sock, SOL_SOCKET, SO_BINDTODEVICE,
                &data->cfg.netdevice.name, strlen(data->cfg.netdevice.name) + 1);
        if (rc == -1) {
            ERROR("setsockopt");
            goto ERR_SOCK_OPT;
        }
    }
#endif
#endif /* __linux__ */

    data->buffer_size = DEFAULT_BUFFER_SIZE;
    data->buffer = malloc(data->buffer_size);
    if (!data->buffer)
        goto ERR_BUFFER;

#ifdef _WIN32
    WORD versionWanted = MAKEWORD(1, 1);
    WSADATA wsaData;
    WSAStartup(versionWanted, &wsaData);
#endif

    if (interface_register_fd(interface, data->sock, NULL) < 0) {
        ERROR("[bj_initialize] Error registering fd");
        goto ERR_FD;
    }

    return 0;

ERR_FD:
    free(data->buffer);
ERR_BUFFER:
#ifndef __ANDROID__
ERR_SOCK_OPT:
#endif
    mdns_socket_close(data->sock);
#ifdef _WIN32
    WSACleanup();
#endif
ERR_SOCK:
    free(data);
ERR_MALLOC:
    return -1;
}

/*
 * We reuse the callback to be triggered upon external events
 * TODO: move to a cleaner interface architecture later...
 */
int bj_on_event(interface_t * interface, const facelet_t * facelet)
{
    bj_data_t * data = (bj_data_t*)interface->data;

    /*
    printf("Sending DNS-SD discovery\n");
    if (mdns_discovery_send(sock)) {
            printf("Failed to send DNS-DS discovery: %s\n", strerror(errno));
            goto quit;
    }

    printf("Reading DNS-SD replies\n");
    for (int i = 0; i < 10; ++i) {
            records = mdns_discovery_recv(sock, buffer, capacity, callback,
                                          user_data);
            sleep(1);
    }
    */

    DEBUG("Sending mDNS query");
    char service_string[SERVICE_STRING_SIZE];

    int rc = snprintf(service_string, SERVICE_STRING_SIZE, "_%s._%s.%s.",
            data->cfg.service_name, data->cfg.service_protocol,
            data->cfg.service_domain);
    if (rc < 0)
        ; // error
    else if (rc >= SERVICE_STRING_SIZE)
        ; //truncated

    if (mdns_query_send(data->sock, MDNS_RECORDTYPE_PTR,
                        service_string,
                        strlen(service_string),
                        data->buffer, data->buffer_size)) {
            printf("Failed to send mDNS query: %s\n", strerror(errno));
            return -1;
    }
    return 0;
}

static char addrbuffer[64];
static char namebuffer[256];
static mdns_record_txt_t txtbuffer[128];

static mdns_string_t
ipv4_address_to_string(char* buffer, size_t capacity, const struct sockaddr_in* addr) {
	char host[NI_MAXHOST] = {0};
	char service[NI_MAXSERV] = {0};
	int ret = getnameinfo((const struct sockaddr*)addr, sizeof(struct sockaddr_in),
	                      host, NI_MAXHOST, service, NI_MAXSERV,
	                      NI_NUMERICSERV | NI_NUMERICHOST);
	int len = 0;
	if (ret == 0) {
		if (addr->sin_port != 0)
			len = snprintf(buffer, capacity, "%s:%s", host, service);
		else
			len = snprintf(buffer, capacity, "%s", host);
	}
	if (len >= (int)capacity)
		len = (int)capacity - 1;
	mdns_string_t str = {buffer, len};
	return str;
}

static mdns_string_t
ipv6_address_to_string(char* buffer, size_t capacity, const struct sockaddr_in6* addr) {
	char host[NI_MAXHOST] = {0};
	char service[NI_MAXSERV] = {0};
	int ret = getnameinfo((const struct sockaddr*)addr, sizeof(struct sockaddr_in6),
	                      host, NI_MAXHOST, service, NI_MAXSERV,
	                      NI_NUMERICSERV | NI_NUMERICHOST);
	int len = 0;
	if (ret == 0) {
		if (addr->sin6_port != 0)
			len = snprintf(buffer, capacity, "[%s]:%s", host, service);
		else
			len = snprintf(buffer, capacity, "%s", host);
	}
	if (len >= (int)capacity)
		len = (int)capacity - 1;
	mdns_string_t str = {buffer, len};
	return str;
}

static mdns_string_t
ip_address_to_string(char* buffer, size_t capacity, const struct sockaddr* addr) {
	if (addr->sa_family == AF_INET6)
		return ipv6_address_to_string(buffer, capacity, (const struct sockaddr_in6*)addr);
	return ipv4_address_to_string(buffer, capacity, (const struct sockaddr_in*)addr);
}

int
ip_address_set_sockaddr(ip_address_t * ip_address, struct sockaddr * sa)
{
    switch(sa->sa_family) {
        case AF_INET:
            ip_address->v4.as_inaddr = ((struct sockaddr_in *)sa)->sin_addr;
            break;
        case AF_INET6:
            ip_address->v6.as_in6addr = ((struct sockaddr_in6 *)sa)->sin6_addr;
            break;
        default:
            return -1;
    }

    return 0;
}

static int
callback(const struct sockaddr* from, mdns_entry_type_t entry, uint16_t type,
        uint16_t rclass, uint32_t ttl, const void* data, size_t size, size_t
        offset, size_t length, void* user_data)
{
    interface_t * interface = (interface_t*)user_data;
    bj_data_t * bj_data = (bj_data_t *)interface->data;

    struct sockaddr_storage addr;

    mdns_string_t fromaddrstr = ip_address_to_string(addrbuffer, sizeof(addrbuffer), from);
    const char* entrytype = (entry == MDNS_ENTRYTYPE_ANSWER) ? "answer" :
        ((entry == MDNS_ENTRYTYPE_AUTHORITY) ? "authority" : "additional");

    switch(type) {
        case MDNS_RECORDTYPE_A:
        {
            ip_address_t ip_address;
            mdns_record_parse_a(data, size, offset, length, (struct sockaddr_in*)&addr);
            ip_address_set_sockaddr(&ip_address, (struct sockaddr *)&addr);

            mdns_string_t addrstr = ipv4_address_to_string(namebuffer, sizeof(namebuffer), (struct sockaddr_in *)&addr);
            DEBUG("%.*s : %s A %.*s",
                    MDNS_STRING_FORMAT(fromaddrstr), entrytype,
                    MDNS_STRING_FORMAT(addrstr));

            facelet_t * facelet = facelet_create();
            facelet_set_netdevice(facelet, bj_data->cfg.netdevice);
            facelet_set_family(facelet, AF_INET);
            facelet_set_remote_addr(facelet, ip_address);
            //facelet_set_remote_port(facelet, ((struct sockaddr_in*)&addr)->sin_port);

            facelet_set_event(facelet, FACELET_EVENT_UPDATE);
            interface_raise_event(interface, facelet);
            break;
        }

        case MDNS_RECORDTYPE_AAAA:
        {
            ip_address_t ip_address;
            mdns_record_parse_aaaa(data, size, offset, length, (struct sockaddr_in6*)&addr);
            ip_address_set_sockaddr(&ip_address, (struct sockaddr *)&addr);

            mdns_string_t addrstr = ipv6_address_to_string(namebuffer,
                    sizeof(namebuffer), (struct sockaddr_in6*)&addr);
            DEBUG("%.*s : %s AAAA %.*s",
                    MDNS_STRING_FORMAT(fromaddrstr), entrytype,
                    MDNS_STRING_FORMAT(addrstr));

            facelet_t * facelet = facelet_create();
            facelet_set_netdevice(facelet, bj_data->cfg.netdevice);
            facelet_set_family(facelet, AF_INET6);
            facelet_set_remote_addr(facelet, ip_address);
            //facelet_set_remote_port(facelet, ((struct sockaddr_in6*)&addr)->sin6_port);

            facelet_set_event(facelet, FACELET_EVENT_UPDATE);
            interface_raise_event(interface, facelet);
            break;
        }

        case MDNS_RECORDTYPE_SRV: /* same port for both v4 and v6 */
        {
            mdns_record_srv_t srv = mdns_record_parse_srv(data, size, offset, length,
                    namebuffer, sizeof(namebuffer));

            DEBUG("%.*s : %s SRV %.*s priority %d weight %d port %d",
                    MDNS_STRING_FORMAT(fromaddrstr), entrytype,
                    MDNS_STRING_FORMAT(srv.name), srv.priority, srv.weight, srv.port);

            /* We raise both v4 and v6
             *
             * Unless we choose whether we query A and/or AAAA, this might leave
             * us with an unused pending facelet, eg. we might not have an IPv6
             * but we raise an IPv6 bonjour event...
             */

            facelet_t * facelet = facelet_create();
            facelet_set_netdevice(facelet, bj_data->cfg.netdevice);
            facelet_set_family(facelet, AF_INET);
            facelet_set_remote_port(facelet, srv.port);

            facelet_set_event(facelet, FACELET_EVENT_UPDATE);
            interface_raise_event(interface, facelet);

            facelet = facelet_create();
            facelet_set_netdevice(facelet, bj_data->cfg.netdevice);
            facelet_set_family(facelet, AF_INET6);
            facelet_set_remote_port(facelet, srv.port);

            facelet_set_event(facelet, FACELET_EVENT_UPDATE);
            interface_raise_event(interface, facelet);
            break;
        }

        case MDNS_RECORDTYPE_PTR:
        {
            mdns_string_t namestr = mdns_record_parse_ptr(data, size, offset, length,
                    namebuffer, sizeof(namebuffer));
            DEBUG("%.*s : %s PTR %.*s type %u rclass 0x%x ttl %u length %d",
                    MDNS_STRING_FORMAT(fromaddrstr), entrytype,
                    MDNS_STRING_FORMAT(namestr), type, rclass, ttl, (int)length);
            break;
        }

        case MDNS_RECORDTYPE_TXT:
        {
            size_t parsed = mdns_record_parse_txt(data, size, offset, length,
                    txtbuffer, sizeof(txtbuffer) / sizeof(mdns_record_txt_t));
            for (size_t itxt = 0; itxt < parsed; ++itxt) {
                if (txtbuffer[itxt].value.length) {
                    DEBUG("%.*s : %s TXT %.*s = %.*s",
                            MDNS_STRING_FORMAT(fromaddrstr), entrytype,
                            MDNS_STRING_FORMAT(txtbuffer[itxt].key),
                            MDNS_STRING_FORMAT(txtbuffer[itxt].value));
                }
                else {
                    DEBUG("%.*s : %s TXT %.*s",
                            MDNS_STRING_FORMAT(fromaddrstr), entrytype,
                            MDNS_STRING_FORMAT(txtbuffer[itxt].key));
                }
            }
            break;
        }

        default:
            /* Silently ignore the received record */
            DEBUG("%.*s : %s type %u rclass 0x%x ttl %u length %d",
                    MDNS_STRING_FORMAT(fromaddrstr), entrytype,
                    type, rclass, ttl, (int)length);
            return 0;
    }
    return 0;

}

/*
 * The fact we use a single fd does not allow us to get user_data associated to
 * the query.
 */
int bj_callback(interface_t * interface, int fd, void * unused)
{
    bj_data_t * data = (bj_data_t*)interface->data;
    DEBUG("Got an mDNS reply");
    /* size_t records = */ mdns_query_recv(data->sock, data->buffer, data->buffer_size, callback, interface, 1);

    return 0;
}

int bj_finalize(interface_t * interface)
{
    bj_data_t * data = (bj_data_t*)interface->data;

    free(data->buffer);
    mdns_socket_close(data->sock);

#ifdef _WIN32
    WSACleanup();
#endif

    return 0;

}

const interface_ops_t bonjour_ops = {
    .type = "bonjour",
    .initialize = bj_initialize,
    .on_event = bj_on_event,
    .callback = bj_callback,
    .finalize = bj_finalize,
  //  .on_event = NULL,
};