cbv2g_json_wrapper.h

/*
 * SPDX-License-Identifier: Apache-2.0
 * Copyright 2024 Contributors to EVerest
 *
 * cbv2g_json_wrapper.h - JSON-based API wrapper for libcbv2g
 *
 * This library provides a JSON-based interface to libcbv2g's EXI encoding/decoding
 * functionality, designed to replace the Java-based EXIficient codec in Josev.
 */

#ifndef CBV2G_JSON_WRAPPER_H
#define CBV2G_JSON_WRAPPER_H

#include <stdint.h>
#include <stddef.h>

#ifdef __cplusplus
extern "C" {
#endif

/* Version information */
#define CBV2G_JSON_WRAPPER_VERSION_MAJOR 1
#define CBV2G_JSON_WRAPPER_VERSION_MINOR 0
#define CBV2G_JSON_WRAPPER_VERSION_PATCH 0
#define CBV2G_JSON_WRAPPER_VERSION "1.0.0"

/* Error codes */
#define CBV2G_SUCCESS                    0
#define CBV2G_ERROR_INVALID_PARAM       -1
#define CBV2G_ERROR_BUFFER_TOO_SMALL    -2
#define CBV2G_ERROR_ENCODING_FAILED     -3
#define CBV2G_ERROR_DECODING_FAILED     -4
#define CBV2G_ERROR_UNKNOWN_NAMESPACE   -5
#define CBV2G_ERROR_JSON_PARSE          -6
#define CBV2G_ERROR_JSON_GENERATE       -7
#define CBV2G_ERROR_UNKNOWN_MESSAGE     -8
#define CBV2G_ERROR_INTERNAL            -9

/* Namespace constants matching Josev's Namespace enum */
#define NS_DIN_MSG_DEF          "urn:din:70121:2012:MsgDef"
#define NS_ISO_V2_MSG_DEF       "urn:iso:15118:2:2013:MsgDef"
#define NS_ISO_V20_BASE         "urn:iso:std:iso:15118:-20"
#define NS_ISO_V20_COMMON_MSG   "urn:iso:std:iso:15118:-20:CommonMessages"
#define NS_ISO_V20_AC           "urn:iso:std:iso:15118:-20:AC"
#define NS_ISO_V20_DC           "urn:iso:std:iso:15118:-20:DC"
#define NS_ISO_V20_WPT          "urn:iso:std:iso:15118:-20:WPT"
#define NS_ISO_V20_ACDP         "urn:iso:std:iso:15118:-20:ACDP"
#define NS_SAP                  "urn:iso:15118:2:2010:AppProtocol"

/**
 * @brief Encode a JSON message to EXI format
 *
 * @param json_message  JSON string containing the message to encode
 * @param namespace     Namespace string identifying the protocol/schema
 * @param output_buffer Buffer to receive the EXI-encoded bytes
 * @param buffer_size   Size of the output buffer
 * @param output_length Pointer to receive the actual length of encoded data
 *
 * @return CBV2G_SUCCESS on success, negative error code on failure
 */
int cbv2g_encode(const char* json_message,
                 const char* namespace,
                 uint8_t* output_buffer,
                 size_t buffer_size,
                 size_t* output_length);

/**
 * @brief Decode EXI data to JSON format
 *
 * @param exi_data      EXI-encoded byte array
 * @param exi_length    Length of the EXI data
 * @param namespace     Namespace string identifying the protocol/schema
 * @param output_json   Buffer to receive the JSON string
 * @param buffer_size   Size of the output buffer
 *
 * @return CBV2G_SUCCESS on success, negative error code on failure
 */
int cbv2g_decode(const uint8_t* exi_data,
                 size_t exi_length,
                 const char* namespace,
                 char* output_json,
                 size_t buffer_size);

/**
 * @brief Get the version string of this library
 *
 * @return Version string (e.g., "1.0.0")
 */
const char* cbv2g_get_version(void);

/**
 * @brief Get the last error message
 *
 * @return Error message string, or empty string if no error
 */
const char* cbv2g_get_last_error(void);

/**
 * @brief Clear the last error message
 */
void cbv2g_clear_error(void);

#ifdef __cplusplus
}
#endif

#endif /* CBV2G_JSON_WRAPPER_H */