/** @file
 *  @brief HTS Service sample
 */

/*
 * Copyright (c) 2020 SixOctets Systems
 * Copyright (c) 2019 Aaron Tsui <aaron.tsui@outlook.com>
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <stdio.h>
#include <stddef.h>
#include <string.h>
#include <errno.h>

#include <zephyr.h>
#include <drivers/sensor.h>
#include <sys/printk.h>
#include <sys/byteorder.h>

#include <bluetooth/bluetooth.h>
#include <bluetooth/hci.h>
#include <bluetooth/conn.h>
#include <bluetooth/uuid.h>
#include <bluetooth/gatt.h>

static struct device *temp_dev;

static u8_t simulate_htm;
static u8_t indicating;
static struct bt_gatt_indicate_params ind_params;

static void htmc_ccc_cfg_changed(const struct bt_gatt_attr *attr,
				 u16_t value)
{
	simulate_htm = (value == BT_GATT_CCC_INDICATE) ? 1 : 0;
}

static void indicate_cb(struct bt_conn *conn, const struct bt_gatt_attr *attr,
			u8_t err)
{
	printk("Indication %s\n", err != 0U ? "fail" : "success");
	indicating = 0U;
}

/* Heart Rate Service Declaration */
BT_GATT_SERVICE_DEFINE(hts_svc,
	BT_GATT_PRIMARY_SERVICE(BT_UUID_HTS),
	BT_GATT_CHARACTERISTIC(BT_UUID_HTS_MEASUREMENT, BT_GATT_CHRC_INDICATE,
			       BT_GATT_PERM_NONE, NULL, NULL, NULL),
	BT_GATT_CCC(htmc_ccc_cfg_changed,
		    BT_GATT_PERM_READ | BT_GATT_PERM_WRITE),
	/* more optional Characteristics */
);

void hts_init(void)
{
	temp_dev = device_get_binding("TEMP_0");

	if (!temp_dev) {
		printk("error: no temp device\n");
		return;
	}

	printk("temp device is %p, name is %s\n", temp_dev,
	       temp_dev->name);
}

void hts_indicate(void)
{
	/* Temperature measurements simulation */
	struct sensor_value temp_value;

	if (simulate_htm) {
		static u8_t htm[5];
		static double temperature = 20U;
		u32_t mantissa;
		u8_t exponent;
		int r;

		if (indicating) {
			return;
		}

		if (!temp_dev) {
			temperature++;
			if (temperature == 30U) {
				temperature = 20U;
			}

			goto gatt_indicate;
		}

		r = sensor_sample_fetch(temp_dev);
		if (r) {
			printk("sensor_sample_fetch failed return: %d\n", r);
		}

		r = sensor_channel_get(temp_dev, SENSOR_CHAN_DIE_TEMP,
				       &temp_value);
		if (r) {
			printk("sensor_channel_get failed return: %d\n", r);
		}

		temperature = sensor_value_to_double(&temp_value);

gatt_indicate:
		printf("temperature is %gC\n", temperature);

		mantissa = (u32_t)(temperature * 100);
		exponent = (u8_t)-2;

		htm[0] = 0; /* temperature in celcius */
		sys_put_le24(mantissa, (u8_t *)&htm[1]);
		htm[4] = exponent;

		ind_params.attr = &hts_svc.attrs[2];
		ind_params.func = indicate_cb;
		ind_params.data = &htm;
		ind_params.len = sizeof(htm);

		if (bt_gatt_indicate(NULL, &ind_params) == 0) {
			indicating = 1U;
		}
	}
}