/* mbed Microcontroller Library
 * Copyright (c) 2006-2019 ARM Limited
 * SPDX-License-Identifier: Apache-2.0
 *
 * 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
 *
 * 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.
 */
#include "hal/rtc_api.h"

#include "platform/mbed_rtc_time.h"
#include "platform/SingletonPtr.h"
#include "platform/PlatformMutex.h"

static SingletonPtr<PlatformMutex> _mutex;

#if DEVICE_RTC

static void (*_rtc_init)(void) = rtc_init;
static int (*_rtc_isenabled)(void) = rtc_isenabled;
static time_t (*_rtc_read)(void) = rtc_read;
static void (*_rtc_write)(time_t t) = rtc_write;

#elif DEVICE_LPTICKER

#include "drivers/LowPowerTimer.h"

#define US_PER_SEC 1000000

static SingletonPtr<mbed::LowPowerTimer> _rtc_lp_timer;
static uint64_t _rtc_lp_base;
static bool _rtc_enabled;

static void _rtc_lpticker_init(void)
{
    _rtc_lp_timer->start();
    _rtc_enabled = true;
}

static int _rtc_lpticker_isenabled(void)
{
    return (_rtc_enabled == true);
}

static time_t _rtc_lpticker_read(void)
{
    return _rtc_lp_timer->read_high_resolution_us() / US_PER_SEC + _rtc_lp_base;
}

static void _rtc_lpticker_write(time_t t)
{
    _rtc_lp_timer->reset();
    _rtc_lp_base = t;
}

static void (*_rtc_init)(void) = _rtc_lpticker_init;
static int (*_rtc_isenabled)(void) = _rtc_lpticker_isenabled;
static time_t (*_rtc_read)(void) = _rtc_lpticker_read;
static void (*_rtc_write)(time_t t) = _rtc_lpticker_write;

#else /* DEVICE_LPTICKER */

static void (*_rtc_init)(void) = NULL;
static int (*_rtc_isenabled)(void) = NULL;
static time_t (*_rtc_read)(void) = NULL;
static void (*_rtc_write)(time_t t) = NULL;
#endif /* DEVICE_LPTICKER */

#ifdef __cplusplus
extern "C" {
#endif

int settimeofday(const struct timeval *tv, MBED_UNUSED const struct timezone *tz)
{
    _mutex->lock();
    if (_rtc_init != NULL) {
        _rtc_init();
    }
    if (_rtc_write != NULL) {
        _rtc_write(tv->tv_sec);
    }
    _mutex->unlock();

    return 0;
}

int gettimeofday(struct timeval *tv, MBED_UNUSED void *tz)
{
    _mutex->lock();
    if (_rtc_isenabled != NULL) {
        if (!(_rtc_isenabled())) {
            set_time(0);
        }
    }

    time_t t = (time_t) - 1;
    if (_rtc_read != NULL) {
        t = _rtc_read();
    }

    tv->tv_sec  = t;
    tv->tv_usec = 0;

    _mutex->unlock();

    return 0;
}

#if defined (__ICCARM__)
time_t __time32(time_t *timer)
#else
time_t time(time_t *timer)
#endif
{
    struct timeval tv;
    gettimeofday(&tv, NULL);

    if (timer != NULL) {
        *timer = tv.tv_sec;
    }

    return tv.tv_sec;
}


void set_time(time_t t)
{
    const struct timeval tv = { t, 0 };
    settimeofday(&tv, NULL);
}

void attach_rtc(time_t (*read_rtc)(void), void (*write_rtc)(time_t), void (*init_rtc)(void), int (*isenabled_rtc)(void))
{
    _mutex->lock();
    _rtc_read = read_rtc;
    _rtc_write = write_rtc;
    _rtc_init = init_rtc;
    _rtc_isenabled = isenabled_rtc;
    _mutex->unlock();
}


#ifdef __cplusplus
}
#endif
