#include <zephyr.h>
#include <zephyr/device.h>
#include <zephyr/devicetree.h>
#include <zephyr/drivers/sensor.h>
#include <bluetooth/bluetooth.h>
#include <bluetooth/gatt.h>
#include <bluetooth/uuid.h>
#include <zephyr/sys/printk.h>
#include <stdio.h>

static float flow_data = 0.00; //variable to save flow meter value
static float pressure_data = 0.00;//variable to save preasure sensor value

struct sensor_value voltage, current;

//************Device Pointers*******************************

const struct device *ads = DEVICE_DT_GET_ONE(ti_ads1100);
const struct device *ina = DEVICE_DT_GET_ONE(ti_ina219b);

//************Bluetooth*******************************

static struct bt_uuid_128 flow_char_uuid = BT_UUID_INIT_128(
    BT_UUID_128_ENCODE(0x9c85a726, 0xb7f1, 0x11ec, 0xb909, 0x0242ac120002)); //Characteristics UUIDs

static struct bt_uuid_128 pressure_char_uuid = BT_UUID_INIT_128(
    BT_UUID_128_ENCODE(0x2f516d79, 0x77ca, 0x45e2, 0x8fa0, 0x93ab5e5691e0)); //Characteristics UUIDs

#define FM_SERVICE_UUID_VAL \
  BT_UUID_128_ENCODE(0xf7547938, 0x68ba, 0x11ec, 0x90d6, 0x0242ac120003) 

static struct bt_uuid_128 fm_svc_uuid = BT_UUID_INIT_128(FM_SERVICE_UUID_VAL); //Flow meter Service UUID

// Advertisement Data that nrf52833DK will advertise
static const struct bt_data ad[] = {
    BT_DATA_BYTES(BT_DATA_FLAGS, (BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR)),
    BT_DATA_BYTES(BT_DATA_UUID128_ALL, FM_SERVICE_UUID_VAL),
};

// GAP callbacks
static void connected(struct bt_conn *conn, uint8_t err) {
  if (err) {
    printk("Connection failed (err 0x%02x)\n", err);
  } else {
    printk("Connected\n");
  }
}

static void disconnected(struct bt_conn *conn, uint8_t reason) {
  printk("Disconnected (reason 0x%02x)\n", reason);
}

BT_CONN_CB_DEFINE(conn_callbacks) = {
    .connected = connected,
    .disconnected = disconnected,
};

//Mapping from voltage/currentr to pressure/flow
static float maping(double in, float in_min, float in_max, float out_min, float out_max)
{
    return (in - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}

// GATT Access Callbacks :: Allow the server (Mobile Phone) to read flow data from client(nrf52833DK)
static ssize_t read_flow_data(struct bt_conn *conn,
                              const struct bt_gatt_attr *attr, void *buf,
                              uint16_t len, uint16_t offset) {
  int ret = sensor_sample_fetch(ina);
  if (ret) {
  	printf("Could not fetch data from INA219.\n");
  }
  ret = sensor_channel_get(ina, SENSOR_CHAN_CURRENT, &current);
  if (ret) {
  	printf("Could not fetch data from INA219B.\n");
  }
  flow_data = sensor_value_to_double(&current);
  flow_data = flow_data*1000;
  if (flow_data>=4.00)
  {
    flow_data = maping(flow_data, 4.00, 20.00, 0.00, 300.00);
  }
  const float *value = attr->user_data;
  return bt_gatt_attr_read(conn, attr, buf, len, offset, value, sizeof(*value));
}

// GATT Access Callbacks :: Allow the server (Mobile Phone) to read flow data from client(nrf52833DK)
static ssize_t read_pressure_data(struct bt_conn *conn,
                              const struct bt_gatt_attr *attr, void *buf,
                              uint16_t len, uint16_t offset){
  double volt;
  //double volt_a [3];

  sensor_sample_fetch(ads);
  sensor_channel_get(ads, SENSOR_CHAN_VOLTAGE, &voltage);
  volt = sensor_value_to_double(&voltage);
  //printk("%f\n", volt);
  pressure_data = maping(volt, 5.00, 0.00, 0.00, 160.00);
  pressure_data = pressure_data - 0.00489;
  const float *value = attr->user_data;
  return bt_gatt_attr_read(conn, attr, buf, len, offset, value, sizeof(*value));
}

// Attribute Table: Declare services and charecteristics with attritubutes and permissions (Read/Write)
BT_GATT_SERVICE_DEFINE(
    flow_svc, BT_GATT_PRIMARY_SERVICE(&fm_svc_uuid),
    BT_GATT_CHARACTERISTIC(&flow_char_uuid.uuid,
                           BT_GATT_CHRC_READ,
                           BT_GATT_PERM_READ,
                           read_flow_data,NULL, &flow_data), 
	BT_GATT_CHARACTERISTIC(&pressure_char_uuid.uuid,
                           BT_GATT_CHRC_READ,
                           BT_GATT_PERM_READ,
                           read_pressure_data,NULL, &pressure_data));

void main(void)
{
  int err;

	if (ads == NULL) {
		printf("\n Error: ADS1100 Node not found.\n");
	} 
	if (ina == NULL) {
		printf("\n Error: INA219 Node not found.\n");
	} 
	if (!device_is_ready(ads)) {
		printf("\n Error: Device \"%s\" is not ready; ", ads->name);
	}
	if (!device_is_ready(ina)) {
		printf("\n Error: Device \"%s\" is not ready; ", ina->name);
	}
  err = bt_enable(NULL);
  if (err) {
    printk("Bluetooth init failed (err %d)\n", err);
    return;
  }
  printk("Bluetooth initialized\n");

  // start avertising
  err = bt_le_adv_start(BT_LE_ADV_CONN_NAME, ad, ARRAY_SIZE(ad), NULL, 0);
  if (err) {
    printk("Advertising failed to start (err %d)\n", err);
    return;
  }
	if (err==0) {
    printk("Advertising successfully started\n");
  }
}