/******************************************************************************
 * Copyright (c) 2016 Parrot S.A.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *   * Neither the name of the Parrot Company nor the
 *     names of its contributors may be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE PARROT COMPANY BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * @file systimetools.h
 *
 * @brief drone system time tools.
 *
 ******************************************************************************/

#ifndef _SYSTIMETOOLS_H_
#define _SYSTIMETOOLS_H_

#ifndef __USE_XOPEN
#define __USE_XOPEN
#endif

#include <stdint.h>
#include <time.h>
#include <sys/time.h>

#ifdef __cplusplus
extern "C" {
#endif

/*
 * Context to track time configuration.
 *
 * Current public messages send the system time with two successive messages :
 * one to set the date (YYYY-MM-DD), one other to set the hour (HH-MM-SS).
 *
 * This context allows the configuration of the system time with these two
 * messages, regardless of the reception order.
 */
struct time_ctx {
	int fields;
	struct tm tm; /* tm.tm_isdst is ignored */
	int gmtoff;   /* for systems where it is not present in struct tm */
};

/**
 * @brief Initialize the time context
 *
 * @return 0 Initialization ok
 * @return -EINVAL Invalid parameter
 */
int time_ctx_init(struct time_ctx *ctx);

/**
 * @brief Set the date of the system
 *
 * @return 0 Both date and hour have been configured. The system has been
 *           configured.
 * @return -EINPROGRESS Date as been saved but hour has not been configured yet
 * @return -EINVAL Invalid parameter
 * @return -EEXIST The date has already been set
 */
int time_ctx_set_date(struct time_ctx *ctx, const char *str_date);

/**
 * @brief Set the hour of the system
 *
 * @return 0 Both date and hour have been configured. The system has been
 *           configured.
 * @return -EINPROGRESS Hour as been saved but date has not been configured yet
 * @return -EINVAL Invalid parameter
 * @return -EEXIST The hour has already been set
 */
int time_ctx_set_hour(struct time_ctx *ctx, const char *str_hour);

/**
 * @brief Set the time of the system
 *
 * @return 0 Both date and hour have been configured. The system has been
 *           configured.
 * @return -EINVAL Invalid parameter
 * @return -EEXIST The time has already been set
 */
int time_ctx_set_time(struct time_ctx *ctx, const char *str_time);

/**
 * @brief Get the stored local time
 *
 * @param epoch_sec      Number of seconds since january 1st 1970 00:00 UTC
 * @param utc_offset_sec Offset in seconds from UTC
 *
 * @return 0 If ctx contains a valid time
 * @return -EINPROGRESS If ctx is not completed
 */
int time_ctx_get_local(struct time_ctx *ctx, uint64_t *epoch_sec,
		int32_t *utc_offset_sec);

/**
 * System time API
 */

/**
 * @brief Set the local time of the system
 *        The system time is changed to epoch_sec (UTC)
 *
 *        + if build with libputils:
 *            the utc_offset_sec is saved in a boxinit property
 *        + if no build with libputils:
 *            the utc_offset_sec is ignored and will be considered 0
 *
 * @param epoch_sec      Number of seconds since january 1st 1970 00:00 UTC
 * @param utc_offset_sec Offset in seconds from UTC
 *
 * @return 0 on success
 */
int time_local_set(uint64_t epoch_sec, int32_t utc_offset_sec);

/**
 * @brief Get the local time of the system
 *       epoch_sec will be retrived from the current system time (UTC)
 *
 *       + if build with libputils:
 *           the utc_offset_sec will be retrieved from the boxinit property
 *       + if no build with libputils:
 *           utc_offset_sec will be 0
 *
 * @param epoch_sec      Number of seconds since january 1st 1970 00:00 UTC
 * @param utc_offset_sec Offset in seconds from UTC
 *
 * @return 0 in case of success, negative errno value in case of error.
 */
int time_local_get(uint64_t *epoch_sec, int32_t *utc_offset_sec);

/**
 * @brief Get the local time of the system (with milliseconds)
 *       epoch_sec will be retrived from the current system time (UTC)
 *
 *       + if build with libputils:
 *           the utc_offset_sec will be retrieved from the boxinit property
 *       + if no build with libputils:
 *           utc_offset_sec will be 0
 *
 * @param epoch_sec      Number of seconds since january 1st 1970 00:00 UTC
 * @param ms             Number of milliseconds in the current second
 * @param utc_offset_sec Offset in seconds from UTC
 *
 * @return 0 in case of success, negative errno value in case of error.
 */
int time_local_ms_get(uint64_t *epoch_sec, uint16_t *ms,
		int32_t *utc_offset_sec);

/**
 * @brief Fill a tm struct based on epoch_sec and utc_offset_sec
 *
 * @param epoch_sec      Number of seconds since january 1st 1970 00:00 UTC
 * @param utc_offset_sec Offset in seconds from UTC
 *
 * @return 0 on success
 * @return -EINVAL if tm is NULL
 */
int time_local_to_tm(uint64_t epoch_sec, int32_t utc_offset_sec,
		struct tm *tm);

/**
 * @brief Get local time contained in a tm struct as (epoch_sec/utc_offset_sec)
 *
 * @param tm             The tm struct containing the local time
 * @param epoch_sec      Number of seconds since january 1st 1970 00:00 UTC
 * @param utc_offset_sec Offset in seconds from UTC
 *
 * @return 0 in case of success, negative errno value in case of error
 */
int time_local_from_tm(const struct tm *tm, uint64_t *epoch_sec,
		int32_t *utc_offset_sec);

/* Time format for string representation */
enum time_fmt {
	TIME_FMT_SHORT,	/* 20180301T014814-1025 */
	TIME_FMT_ISO8601_SHORT = TIME_FMT_SHORT,
	TIME_FMT_LONG,	/* 2018-03-01T01:48:14-10:25 */
	TIME_FMT_ISO8601_LONG = TIME_FMT_LONG,
	TIME_FMT_RFC1123, /* Mon, 13 Aug 2018 13:39:55 GMT */
};

/**
 * @brief Get a formated representation of the local time
 * (ISO 8601 or RFC 1123).
 * @note If using RFC 1123, only UTC is supported, therefore utc_offset_sec
 * must be null.
 *
 * @param epoch_sec Number of seconds since january 1st 1970 00:00 UTC
 * @param utc_offset_sec Offset in seconds from UTC
 * @param fmt format to use (short or long)
 * @param s The string that will contain the formated date
 * @param n Max size of string
 *
 * @return 0 in case of success, negative errno value in case of error
 */
int time_local_format(uint64_t epoch_sec, int32_t utc_offset_sec,
		enum time_fmt fmt, char *s, size_t n);

/**
 * @brief Parse a formated representation of the local time.
 * @param s date/time as a string (ISO 8601 short or long)
 * @param epoch_sec Number of seconds since january 1st 1970 00:00 UTC
 * @param utc_offset_sec Offset in seconds from UTC
 *
 * @return 0 in case of success, negative errno value in case of error
 */
int time_local_parse(const char *s, uint64_t *epoch_sec,
	int32_t *utc_offset_sec);

#ifdef __cplusplus
}
#endif

#endif /* _SYSTIMETOOLS_H_ */