/*
 * Copyright (C) 2019,2020 by Sukchan Lee <acetcom@gmail.com>
 *
 * This file is part of Open5GS.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#include "namf-build.h"

static char* ogs_guti_to_string(amf_ue_t *amf_ue)
{
    ogs_plmn_id_t plmn_id;
    char plmn_id_buff[OGS_PLMNIDSTRLEN];
    char *amf_id = NULL;
    char *tmsi = NULL;
    char *guti = NULL;

    memset(&plmn_id, 0, sizeof(plmn_id));
    ogs_nas_to_plmn_id(&plmn_id, &amf_ue->current.guti.nas_plmn_id);

    amf_id = ogs_amf_id_to_string(&amf_ue->current.guti.amf_id);
    tmsi = ogs_uint32_to_0string(*(amf_ue->current.m_tmsi));

    guti = ogs_msprintf("5g-guti-%s%s%s",
            ogs_plmn_id_to_string(&plmn_id, plmn_id_buff),
            amf_id,
            tmsi);

    /* TS29.518 6.1.3.2.2 Guti pattern (27 or 28 characters):
    "5g-guti-[0-9]{5,6}[0-9a-fA-F]{14}" */
    ogs_assert(strlen(guti) == (OGS_MAX_5G_GUTI_LEN - 1) ||
            (strlen(guti)) == OGS_MAX_5G_GUTI_LEN);

    ogs_free(amf_id);
    ogs_free(tmsi);

    return guti;
}

static char* amf_ue_to_context_id(amf_ue_t *amf_ue)
{
    char *ue_context_id = NULL;

    if (amf_ue->supi) {
        ue_context_id = ogs_strdup(amf_ue->supi);
    } else {
        ue_context_id = ogs_guti_to_string(amf_ue);
    }

    return ue_context_id;
}

ogs_sbi_request_t *amf_namf_comm_build_ue_context_transfer(
        amf_ue_t *amf_ue, void *data)
{
    ogs_sbi_message_t message;
    ogs_sbi_request_t *request = NULL;
    OpenAPI_ue_context_transfer_req_data_t UeContextTransferReqData;
    char *ue_context_id = NULL;

    ogs_assert(amf_ue);

    ue_context_id = amf_ue_to_context_id(amf_ue);
    ogs_assert(ue_context_id);

    memset(&UeContextTransferReqData, 0, sizeof(UeContextTransferReqData));
    UeContextTransferReqData.access_type = amf_ue->nas.access_type;
    UeContextTransferReqData.reason = amf_ue->nas.registration.value;

    memset(&message, 0, sizeof(message));
    message.h.method = (char *)OGS_SBI_HTTP_METHOD_POST;
    message.h.service.name = (char *)OGS_SBI_SERVICE_NAME_NAMF_COMM;
    message.h.api.version = (char *)OGS_SBI_API_V1;
    message.h.resource.component[0] =
            (char *)OGS_SBI_RESOURCE_NAME_UE_CONTEXTS;
    message.h.resource.component[1] = ue_context_id;
    message.h.resource.component[2] =
            (char *)OGS_SBI_RESOURCE_NAME_TRANSFER;
    message.UeContextTransferReqData = &UeContextTransferReqData;

    request = ogs_sbi_build_request(&message);
    ogs_expect(request);

    if (ue_context_id)
        ogs_free(ue_context_id);

    return request;
}