/*
 * Copyright (C) 2014 The Android Open Source Project
 *
 * 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 <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>

#include <cutils/android_reboot.h>
#include <cutils/klog.h>
#include <cutils/misc.h>
#include <cutils/uevent.h>
#include <cutils/properties.h>

#include <pthread.h>
#include <linux/android_alarm.h>
#include <sys/timerfd.h>
#include <linux/rtc.h>

#include <healthd/healthd.h>

#define LOGE(x...) do { KLOG_ERROR("charger", x); } while (0)
#define LOGI(x...) do { KLOG_INFO("charger", x); } while (0)
#define LOGV(x...) do { KLOG_DEBUG("charger", x); } while (0)

enum alarm_time_type {
    ALARM_TIME,
    RTC_TIME,
};

/*
 * shouldn't be changed after
 * reading from alarm register
 */
static time_t alm_secs;

static int alarm_get_time(enum alarm_time_type time_type,
                          time_t *secs)
{
    struct tm tm;
    unsigned int cmd;
    int rc, fd = -1;

    if (!secs)
        return -1;

    fd = open("/dev/rtc0", O_RDONLY);
    if (fd < 0) {
        LOGE("Can't open rtc devfs node\n");
        return -1;
    }

    switch (time_type) {
        case ALARM_TIME:
            cmd = RTC_ALM_READ;
            break;
        case RTC_TIME:
            cmd = RTC_RD_TIME;
            break;
        default:
            LOGE("Invalid time type\n");
            goto err;
    }

    rc = ioctl(fd, cmd, &tm);
    if (rc < 0) {
        LOGE("Unable to get time\n");
        goto err;
    }

    *secs = mktime(&tm) + tm.tm_gmtoff;
    if (*secs < 0) {
        LOGE("Invalid seconds = %ld\n", *secs);
        goto err;
    }

    close(fd);
    return 0;

err:
    close(fd);
    return -1;
}

#define ERR_SECS 2
static int alarm_is_alm_expired()
{
    int rc;
    time_t rtc_secs;

    rc = alarm_get_time(RTC_TIME, &rtc_secs);
    if (rc < 0)
        return 0;

    return (alm_secs >= rtc_secs - ERR_SECS &&
            alm_secs <= rtc_secs + ERR_SECS) ? 1 : 0;
}

static int timerfd_set_reboot_time_and_wait(time_t secs)
{
    int fd;
    int ret = -1;
    fd = timerfd_create(CLOCK_REALTIME_ALARM, 0);
    if (fd < 0) {
        LOGE("Can't open timerfd alarm node\n");
        goto err_return;
    }

    struct itimerspec spec;
    memset(&spec, 0, sizeof(spec));
    spec.it_value.tv_sec = secs;

    if (timerfd_settime(fd, 0 /* relative */, &spec, NULL)) {
        LOGE("Can't set timerfd alarm\n");
        goto err_close;
    }

    uint64_t unused;
    if (read(fd, &unused, sizeof(unused)) < 0) {
       LOGE("Wait alarm error\n");
       goto err_close;
    }

    ret = 0;
err_close:
    close(fd);
err_return:
    return ret;
}

static int alarm_set_reboot_time_and_wait(time_t secs)
{
    int rc, fd;
    struct timespec ts;

    fd = open("/dev/alarm", O_RDWR);
    if (fd < 0) {
        LOGE("Can't open alarm devfs node, trying timerfd\n");
        return timerfd_set_reboot_time_and_wait(secs);
    }

    /* get the elapsed realtime from boot time to now */
    rc = ioctl(fd, ANDROID_ALARM_GET_TIME(
                      ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP), &ts);
    if (rc < 0) {
        LOGE("Unable to get elapsed realtime\n");
        goto err;
    }

    /* calculate the elapsed time from boot time to reboot time */
    ts.tv_sec += secs;
    ts.tv_nsec = 0;

    rc = ioctl(fd, ANDROID_ALARM_SET(
                      ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP), &ts);
    if (rc < 0) {
        LOGE("Unable to set reboot time to %ld\n", secs);
        goto err;
    }

    do {
        rc = ioctl(fd, ANDROID_ALARM_WAIT);
    } while ((rc < 0 && errno == EINTR) || !alarm_is_alm_expired());

    if (rc <= 0) {
        LOGE("Unable to wait on alarm\n");
        goto err;
    }

    close(fd);
    return 0;

err:
    if (fd >= 0)
        close(fd);
    return -1;
}

static void *alarm_thread(void *)
{
    time_t rtc_secs, rb_secs;
    int rc;

    /*
     * to support power off alarm, the time
     * stored in alarm register at latest
     * shutdown time should be some time
     * earlier than the actual alarm time
     * set by user
     */
    rc = alarm_get_time(ALARM_TIME, &alm_secs);
    if (rc < 0 || !alm_secs)
        goto err;

    rc = alarm_get_time(RTC_TIME, &rtc_secs);
    if (rc < 0)
        goto err;

    /*
     * calculate the reboot time after which
     * the phone will reboot
     */
    rb_secs = alm_secs - rtc_secs;
    if (rb_secs <= 0)
        goto err;

    rc = alarm_set_reboot_time_and_wait(rb_secs);
    if (rc < 0)
        goto err;

    LOGI("Exit from power off charging, reboot the phone!\n");
    android_reboot(ANDROID_RB_RESTART, 0, 0);

err:
    LOGE("Exit from alarm thread\n");
    return NULL;
}

void healthd_board_init(struct healthd_config*)
{
    pthread_t tid;
    int rc;
    char value[PROP_VALUE_MAX];

    property_get("ro.bootmode", value, "");
    if (!strcmp("charger", value)) {
        rc = pthread_create(&tid, NULL, alarm_thread, NULL);
        if (rc < 0)
            LOGE("Create alarm thread failed\n");
    }
}

int healthd_board_battery_update(struct android::BatteryProperties*)
{
    // return 0 to log periodic polled battery status to kernel log
    return 1;
}

void healthd_board_mode_charger_draw_battery(struct android::BatteryProperties*)
{

}

void healthd_board_mode_charger_battery_update(struct android::BatteryProperties*)
{

}

void healthd_board_mode_charger_set_backlight(bool)
{

}

void healthd_board_mode_charger_init()
{

}
