/*
BT module settings (AT mode):
+NAME=OBD2_BT
+VER=8.0.2,FSC-BT836B
+MAC=DC0D30000FA9
+BAUD=115200
+PIN=1189

HC-05 bluetooth module: 
  address: 5856:00:017A39
  IAC: 9E8B33

https://forum.arduino.cc/t/trying-to-connect-hc-05-to-bluetooth-obd2-interface-elm-327/643301/13
https://stackoverflow.com/questions/59125470/connecting-to-elm327-bt-with-hc05-stm32-not-as-simply-as-look-like
https://electronics.stackexchange.com/questions/101572/hc-05-bluetooth-module-not-responding-to-certain-commands


OBD2 INQ: 0010:CC:4F3603,0,FF9C,OBDII
AT+PAIR=0010,CC,4F3603,20

AT Commands to connect permanently to the OBD2 module:
    AT+RESET
    AT+ORGL (Set to original)
    AT+ROLE=1 (Set to Master)
    AT+CMODE=0 (Set connect to a specific address)
    AT+BIND=0010,CC,4F3603
    AT+INIT (Need to connect)
    AT+PAIR=0010,CC,4F3603,20 (,20 means 30 second timeout)
                                                            

Be sure to disconnect the TX and RX pins from the BT module when programming the arduino.
*/
#ifndef OBD2_ELM327_H
#define OBD2_ELM327_H

#include "ELMduino.h"

#ifdef __cplusplus
 extern "C" {
#endif

// #include <Arduino.h>
// #include "obd2_util.h"

/* pins */
#define PIN_BT_RX 19
#define PIN_BT_TX 18

#define BT_STATE_PIN 3 /* state connection pin from bluetooth module -> level high on connected */

#define BT_BAUD 115200
#define ELM327_BAUD 115200

#define BT_STATE_LENGTH 13 /* length of the string identifier used for the states */

#define ELM327_SERIAL Serial2

#define UPDATE_RPM_POS 0x00
#define UPDATE_THROTTLE_POS 0x01
#define UPDATE_COOLANT_TEMP_POS 0x02
#define UPDATE_INTAKE_AIR_TEMP_POS 0x03
#define UPDATE_AMBIENT_AIR_TEMP_POS 0x04
#define UPDATE_OIL_TEMP_POS 0x05
#define UPDATE_ENGINE_LOAD_POS 0x06
#define UPDATE_BATTERY_VOLTAGE_POS 0x07
#define UPDATE_FUEL_PRESSURE_POS 0x08
#define UPDATE_SPEED_POS 0x09
#define UPDATE_MANIFOLD_PRESSURE_POS 0x0A
#define UPDATE_FUEL_LEVEL_POS 0x0B

#define COOLANT_TEMP_MIN 0
#define COOLANT_TEMP_MAX 120
#define INTAKE_AIR_TEMP_MIN -40
#define INTAKE_AIR_TEMP_MAX 120
#define AMBIENT_AIR_TEMP_MIN -40
#define AMBIENT_AIR_TEMP_MAX 120
#define OIL_TEMP_MIN -40
#define OIL_TEMP_MAX 120
#define ENGINE_LOAD_MIN 0
#define ENGINE_LOAD_MAX 100
#define BATTERY_VOLTAGE_MIN 0
#define BATTERY_VOLTAGE_MAX 16
#define FUEL_PRESSURE_MIN 0
#define FUEL_PRESSURE_MAX 765
#define MANIFOLD_PRESSURE_MIN 0
#define MANIFOLD_PRESSURE_MAX 255
#define FUEL_LEVEL_MIN 0
#define FUEL_LEVEL_MAX 100

enum BluetoothState
{
    BT_INITIALISING = 0,
    BT_CONNECTED = 1
};

/**
 * @brief struct to hold bluetooth module data
 * 
 * @param state the current state of the bluetooth module
 * @param on_state_change function pointer to the function to be called when the state changes
 */
typedef struct obt2_elm327_tag
{
    ELM327 *elm327;
    enum BluetoothState bt_state;
    void (*on_state_change)();
    uint16_t value_updates;
    uint16_t rpm;
    uint8_t throttle_percent;
    uint8_t engine_coolant_temp;
    uint8_t intake_air_temp;
    uint8_t ambient_air_temp;
    uint16_t engine_oil_temp;
    uint8_t engine_load;
    float battery_voltage;
    uint16_t fuel_pressure;
    uint8_t speed;
    uint8_t manifold_pressure;
    uint16_t fuel_level;
} obd2_elm327_t;

/**
 * @brief initializes the bluetooth module driver   
 * 
 * @param elm327 pointer to struct holding bluetooth driver data
 * @returns 1 if successfully initialized, 0 if not.
 */
char obd2_elm327_init(obd2_elm327_t *elm327);

/**
 * @brief processes the bluetooth module communication with the OBD2 reader for variables that change quickly
 * 
 * @param bt pointer to struct holding bluetooth driver data
 */
void obd2_elm327_process_fast(obd2_elm327_t *elm327);

/**
 * @brief processes the bluetooth module communication with the OBD2 reader for variables that change slowly (checks every 5 seconds)
 * 
 * @param bt pointer to struct holding bluetooth driver data
 */
void obd2_elm327_process_slow(obd2_elm327_t *elm327);

void obd2_elm327_check_connection(obd2_elm327_t *elm327);

/**
 * @brief copies the current state of the bluetooth module to the state string
 * 
 * @param elm327 pointer to struct holding bluetooth driver data
 * @param state resulting string to hold the text representation of the state
 */
void obd2_elm327_get_state(obd2_elm327_t *elm327, char *state);

/**
 * @brief checks if a bit is set in the value_updates variable
 * 
 * @returns 1 if the bit is set, 0 if not
 */
char obd2_el327_is_bit_set(obd2_elm327_t *elm327, uint16_t pos);

/**
 * @brief sets a bit in the value_updates variable
 */
void obd2_el327_set_bit(obd2_elm327_t *elm327, uint16_t pos);

/**
 * @brief clears a bit in the value_updates variable
 */
void obd2_el327_clear_bit(obd2_elm327_t *elm327, uint16_t pos);

#ifdef __cplusplus
 }
#endif

#endif // OBD2_ELM327_H