/*****************************************************************************
 * Copyright ©2017-2019 Gemalto – a Thales Company. All rights Reserved.
 *
 * This copy is 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 or https://www.apache.org/licenses/LICENSE-2.0.html 
 *
 * 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
 * $Author$
 * $Revision$
 * $Date$
 *
 * libse-gto to dialog with device T=1 protocol over SPI.
 *
 * This library is not thread safe on same context.
 */

#ifndef LIBSE_GTO_H
#define LIBSE_GTO_H

#ifdef __cplusplus
extern "C" {
#endif

#define LOG_TAG "THALES_HAL"

/**
 * library user context - reads the config and system
 * environment, user variables, allows custom logging.
 *
 * Default struct se_gto_ctx log to stderr file stream.
 * Content is opaque to user.
 */
struct se_gto_ctx;

/** Function callback to display log line.
 * @s nul terminated string.
 */

typedef void se_gto_log_fn (struct se_gto_ctx *ctx, const char *s);


/********************************* Core *************************************/

/** Create se-gto library context.
 *
 * This fills in the default values. Device node for eSE GTO is "@c /dev/gto".
 *
 * Use environment variable SE_GTO_LOG to alter default log level globally.
 * SE_GTO_LOG=n with n from 0 to 4, or choice of SE_GTO_LOG to err, info, debug.
 *
 * @returns a new se-gto library context
 */
int se_gto_new(struct se_gto_ctx **ctx);

/** Allocates resources from environment and kernel.
 *
 * @c errno is set on error.
 *
 * @return -1 on error, 0 otherwise.
 */
int se_gto_open(struct se_gto_ctx *ctx);

/** Release resources.
 *
 * @c errno is set on error.
 * @return -1 on error, 0 otherwise.
 */
int se_gto_close(struct se_gto_ctx *ctx);

/******************************* Facilities *********************************/

/** Returns current log level.
 *
 * @param ctx: se-gto library context
 *
 * @returns the current logging level
 **/
int se_gto_get_log_level(struct se_gto_ctx *ctx);

/**
 * Set the current logging level.
 *
 * @param ctx   se-gto library context
 * @param level the new logging level
 *
 * @c level controls which messages are logged:
 *   0 : error
 *   1 : warning
 *   2 : notice
 *   3 : info
 *   4 : debug
 **/
void se_gto_set_log_level(struct se_gto_ctx *ctx, int level);

/** Get current function callback for log entries.
 *
 * Use this function if you want to chain log entries and replace current
 * function by yours.
 *
 * @param ctx se-gto library context.
 *
 * @return current function for log string.
 */
se_gto_log_fn *se_gto_get_log_fn(struct se_gto_ctx *ctx);

/** Set function callback for log entries.
 *
 * @param ctx se-gto library context.
 * @param fn Function to dump nul terminated string.
 */
void se_gto_set_log_fn(struct se_gto_ctx *ctx, se_gto_log_fn *fn);

void *se_gto_get_userdata(struct se_gto_ctx *ctx);

/** Store custom userdata in the library context.
 *
 * @param ctx      se-gto library context
 * @param userdata data pointer
 **/
void se_gto_set_userdata(struct se_gto_ctx *ctx, void *userdata);

/**************************** HW configuration ******************************/

/** Returns current device node for eSE.
 *
 * Returned string must not be modified. Copy returned string if you need to
 * use it later.
 *
 * @param ctx se-gto library context.
 *
 * @returns nul terminated string.
 */
const char *se_gto_get_gtodev(struct se_gto_ctx *ctx);

/** Set device node used for eSE.
 *
 * @c gtodev is copied se-gto library. You can use a volatile string.
 *
 * @param ctx    se-gto library context.
 * @param gtodev full path to device node.
 */
void se_gto_set_gtodev(struct se_gto_ctx *ctx, const char *gtodev);

/****************************** APDU protocol *******************************/

/** Send reset command to Secure Element and return ATR bytes.
 *
 * @param ctx se-gto library context
 * @param atr byte buffer to receive ATR content
 * @param r   length of ATR byte buffer.
 *
 * @c errno is set on error.
 *
 * @returns number of bytes in @c atr buffer or -1 on error.
 */
int se_gto_reset(struct se_gto_ctx *ctx, void *atr, size_t r);

/** Transmit APDU to Secure Element
 *
 * If needed to comply with request from command, multiple ISO7816 Get
 * Response can be emitted to collect the full response.
 *
 * @param ctx  se-gto library context
 * @param apdu APDU command to send
 * @param n    length of APDU command
 * @param resp Response buffer
 * @param r    length of response buffer.
 *
 * @c errno is set on error.
 *
 * @returns number of bytes filled in @c resp buffer. -1 on error.
 *
 * @resp buffer last two bytes are SW1 and SW2 respectively. Response length
 * will always be at least 2 bytes. Maximum response size will be 257 bytes.
 *
 * Slave timeout is used waiting for APDU response. Each Extension Time packet
 * will restart response timeout.
 */
int se_gto_apdu_transmit(struct se_gto_ctx *ctx, const void *apdu, int n, void *resp, int r);

#ifdef __cplusplus
} /* extern "C" */
#endif

#endif /* ifndef LIBSE_GTO_H */