/**
 * @file
 * @brief BACnet PrivateTransfer encode and decode helper functions
 * @author Steve Karg <skarg@users.sourceforge.net>
 * @date 2009
 * @copyright SPDX-License-Identifier: GPL-2.0-or-later WITH GCC-exception-2.0
 */
#include <stdint.h>
/* BACnet Stack defines - first */
#include "bacnet/bacdef.h"
/* BACnet Stack API */
#include "bacnet/bacdcode.h"
#include "bacnet/ptransfer.h"

/* encode service */
static int pt_encode_apdu(uint8_t *apdu,
    uint16_t max_apdu,
    BACNET_PRIVATE_TRANSFER_DATA *private_data)
{
    int len = 0; /* length of each encoding */
    int apdu_len = 0; /* total length of the apdu, return value */
    /*
            Unconfirmed/ConfirmedPrivateTransfer-Request ::= SEQUENCE {
            vendorID               [0] Unsigned,
            serviceNumber          [1] Unsigned,
            serviceParameters      [2] ABSTRACT-SYNTAX.&Type OPTIONAL
        }
    */
    /* unused parameter */
    (void)max_apdu;
    if (apdu) {
        len =
            encode_context_unsigned(&apdu[apdu_len], 0, private_data->vendorID);
        apdu_len += len;
        len = encode_context_unsigned(
            &apdu[apdu_len], 1, private_data->serviceNumber);
        apdu_len += len;
        len = encode_opening_tag(&apdu[apdu_len], 2);
        apdu_len += len;
        for (len = 0; len < private_data->serviceParametersLen; len++) {
            apdu[apdu_len] = private_data->serviceParameters[len];
            apdu_len++;
        }
        len = encode_closing_tag(&apdu[apdu_len], 2);
        apdu_len += len;
    }

    return apdu_len;
}

int ptransfer_encode_apdu(uint8_t *apdu,
    uint8_t invoke_id,
    BACNET_PRIVATE_TRANSFER_DATA *private_data)
{
    int apdu_len = 0; /* total length of the apdu, return value */
    int len = 0;

    if (apdu) {
        apdu[0] = PDU_TYPE_CONFIRMED_SERVICE_REQUEST;
        apdu[1] = encode_max_segs_max_apdu(0, MAX_APDU);
        apdu[2] = invoke_id;
        apdu[3] = SERVICE_CONFIRMED_PRIVATE_TRANSFER;
        apdu_len = 4;
        len = pt_encode_apdu(
            &apdu[apdu_len], (uint16_t)(MAX_APDU - apdu_len), private_data);
        apdu_len += len;
    }

    return apdu_len;
}

int uptransfer_encode_apdu(
    uint8_t *apdu, BACNET_PRIVATE_TRANSFER_DATA *private_data)
{
    int apdu_len = 0; /* total length of the apdu, return value */
    int len = 0;

    if (apdu) {
        apdu[0] = PDU_TYPE_UNCONFIRMED_SERVICE_REQUEST;
        apdu[1] = SERVICE_UNCONFIRMED_PRIVATE_TRANSFER;
        apdu_len = 2;
        len = pt_encode_apdu(
            &apdu[apdu_len], (uint16_t)(MAX_APDU - apdu_len), private_data);
        apdu_len += len;
    }

    return apdu_len;
}

/* decode the service request only */
int ptransfer_decode_service_request(uint8_t *apdu,
    unsigned apdu_len,
    BACNET_PRIVATE_TRANSFER_DATA *private_data)
{
    int len = 0; /* return value */
    int decode_len = 0; /* return value */
    BACNET_UNSIGNED_INTEGER unsigned_value = 0;

    /* check for value pointers */
    if (apdu_len && private_data) {
        /* Tag 0: vendorID */
        decode_len = decode_context_unsigned(&apdu[len], 0, &unsigned_value);
        if (decode_len < 0) {
            return -1;
        }
        len = decode_len;
        private_data->vendorID = (uint16_t)unsigned_value;
        /* Tag 1: serviceNumber */
        decode_len = decode_context_unsigned(&apdu[len], 1, &unsigned_value);
        if (decode_len < 0) {
            return -1;
        }
        len += decode_len;
        private_data->serviceNumber = unsigned_value;
        /* Tag 2: serviceParameters */
        if (decode_is_opening_tag_number(&apdu[len], 2)) {
            /* a tag number of 2 is not extended so only one octet */
            len++;
            /* don't decode the serviceParameters here */
            private_data->serviceParameters = &apdu[len];
            private_data->serviceParametersLen =
                (int)apdu_len - len - 1 /*closing tag */;
            /* len includes the data and the closing tag */
            len = (int)apdu_len;
        } else {
            return -1;
        }
    }

    return len;
}

int ptransfer_error_encode_apdu(uint8_t *apdu,
    uint8_t invoke_id,
    BACNET_ERROR_CLASS error_class,
    BACNET_ERROR_CODE error_code,
    BACNET_PRIVATE_TRANSFER_DATA *private_data)
{
    int apdu_len = 0; /* total length of the apdu, return value */
    int len = 0; /* length of the part of the encoding */

    if (apdu) {
        apdu[0] = PDU_TYPE_ERROR;
        apdu[1] = invoke_id;
        apdu[2] = SERVICE_CONFIRMED_PRIVATE_TRANSFER;
        apdu_len = 3;
        /* service parameters */
        /*
                ConfirmedPrivateTransfer-Error ::= SEQUENCE {
                errorType       [0] Error,
                vendorID        [1] Unsigned,
                serviceNumber [2] Unsigned,
                errorParameters [3] ABSTRACT-SYNTAX.&Type OPTIONAL
            }
        */
        len = encode_opening_tag(&apdu[apdu_len], 0);
        apdu_len += len;
        len = encode_application_enumerated(&apdu[apdu_len], error_class);
        apdu_len += len;
        len = encode_application_enumerated(&apdu[apdu_len], error_code);
        apdu_len += len;
        len = encode_closing_tag(&apdu[apdu_len], 0);
        apdu_len += len;
        len =
            encode_context_unsigned(&apdu[apdu_len], 1, private_data->vendorID);
        apdu_len += len;
        len = encode_context_unsigned(
            &apdu[apdu_len], 2, private_data->serviceNumber);
        apdu_len += len;
        len = encode_opening_tag(&apdu[apdu_len], 3);
        apdu_len += len;
        for (len = 0; len < private_data->serviceParametersLen; len++) {
            apdu[apdu_len] = private_data->serviceParameters[len];
            apdu_len++;
        }
        len = encode_closing_tag(&apdu[apdu_len], 3);
        apdu_len += len;
    }

    return apdu_len;
}

/* decode the service request only */
int ptransfer_error_decode_service_request(uint8_t *apdu,
    unsigned apdu_len,
    BACNET_ERROR_CLASS *error_class,
    BACNET_ERROR_CODE *error_code,
    BACNET_PRIVATE_TRANSFER_DATA *private_data)
{
    int len = 0; /* return value */
    int decode_len = 0; /* return value */
    uint8_t tag_number = 0;
    uint32_t len_value_type = 0;
    uint32_t enum_value = 0;
    BACNET_UNSIGNED_INTEGER unsigned_value = 0;

    /* check for value pointers */
    if (apdu_len && private_data) {
        /* Tag 0: Error */
        if (decode_is_opening_tag_number(&apdu[len], 0)) {
            /* a tag number of 0 is not extended so only one octet */
            len++;
            /* error class */
            decode_len = decode_tag_number_and_value(
                &apdu[len], &tag_number, &len_value_type);
            len += decode_len;
            if (tag_number != BACNET_APPLICATION_TAG_ENUMERATED) {
                return 0;
            }
            decode_len =
                decode_enumerated(&apdu[len], len_value_type, &enum_value);
            len += decode_len;
            if (error_class) {
                *error_class = (BACNET_ERROR_CLASS)enum_value;
            }
            /* error code */
            decode_len = decode_tag_number_and_value(
                &apdu[len], &tag_number, &len_value_type);
            len += decode_len;
            if (tag_number != BACNET_APPLICATION_TAG_ENUMERATED) {
                return 0;
            }
            decode_len =
                decode_enumerated(&apdu[len], len_value_type, &enum_value);
            len += decode_len;
            if (error_code) {
                *error_code = (BACNET_ERROR_CODE)enum_value;
            }
            if (decode_is_closing_tag_number(&apdu[len], 0)) {
                /* a tag number of 0 is not extended so only one octet */
                len++;
            } else {
                return 0;
            }
        }
        /* Tag 1: vendorID */
        decode_len = decode_context_unsigned(&apdu[len], 1, &unsigned_value);
        if (decode_len < 0) {
            return -1;
        }
        len += decode_len;
        private_data->vendorID = (uint16_t)unsigned_value;
        /* Tag 2: serviceNumber */
        decode_len = decode_context_unsigned(&apdu[len], 2, &unsigned_value);
        if (decode_len < 0) {
            return -1;
        }
        len += decode_len;
        private_data->serviceNumber = (uint32_t)unsigned_value;
        /* Tag 3: serviceParameters */
        if (decode_is_opening_tag_number(&apdu[len], 3)) {
            /* a tag number of 2 is not extended so only one octet */
            len++;
            /* don't decode the serviceParameters here */
            private_data->serviceParameters = &apdu[len];
            private_data->serviceParametersLen =
                (int)apdu_len - len - 1 /*closing tag */;
        } else {
            return -1;
        }
        /* we could check for a closing tag of 3 */
    }

    return len;
}

int ptransfer_ack_encode_apdu(uint8_t *apdu,
    uint8_t invoke_id,
    BACNET_PRIVATE_TRANSFER_DATA *private_data)
{
    int len = 0; /* length of each encoding */
    int apdu_len = 0; /* total length of the apdu, return value */

    if (apdu) {
        apdu[0] = PDU_TYPE_COMPLEX_ACK; /* complex ACK service */
        apdu[1] = invoke_id; /* original invoke id from request */
        apdu[2] = SERVICE_CONFIRMED_PRIVATE_TRANSFER; /* service choice */
        apdu_len = 3;
        /* service ack follows */
        /*
                ConfirmedPrivateTransfer-ACK ::= SEQUENCE {
                vendorID               [0] Unsigned,
                serviceNumber          [1] Unsigned,
                resultBlock            [2] ABSTRACT-SYNTAX.&Type OPTIONAL
            }
        */
        len =
            encode_context_unsigned(&apdu[apdu_len], 0, private_data->vendorID);
        apdu_len += len;
        len = encode_context_unsigned(
            &apdu[apdu_len], 1, private_data->serviceNumber);
        apdu_len += len;
        len = encode_opening_tag(&apdu[apdu_len], 2);
        apdu_len += len;
        for (len = 0; len < private_data->serviceParametersLen; len++) {
            apdu[apdu_len] = private_data->serviceParameters[len];
            apdu_len++;
        }
        len = encode_closing_tag(&apdu[apdu_len], 2);
        apdu_len += len;
    }

    return apdu_len;
}

/* ptransfer_ack_decode_service_request() is the same as
       ptransfer_decode_service_request */