/*
We need your help to stop forest fires and bake tasty cookies!

See `requirements.md` for how to help.

Then check `notes.md`.
*/
#include "api.h"


static boolean retrigger_igniter = true;//represents if the igniter is need to re-trigger
static int time_igniter_on = 0;//count how long have been passed since the igniter turn on

void setup() {
  Serial.begin(115200);
  setup_api();

  Serial.println("Elf oven 2000 starting up.");
  serial_printf("Days without fire incident: %i\n", 0);

  //Unit test:
  //test function: is_safe_temperature(float temp)
  float test_min_temperature = -10.0;
  float test_max_temperature = 180.0;
  float random = ((float) rand()) / (float) RAND_MAX;
  float test_in_range_temperature = random * 190 - 10.0;
  float test_below_min_temperature = -10.00001;//Assumption: temperature < -10,
  float test_above_max_temperature = 180.00001;
  boolean test1_result = is_safe_temperature(test_min_temperature);
  if(test1_result){Serial.println("is_safe_temperature()function works well @ -10 Celsius");}
  test1_result = is_safe_temperature(test_max_temperature);
  if(test1_result){Serial.println("is_safe_temperature()function works well @ 180 Celsius");}
  test1_result = is_safe_temperature(test_in_range_temperature);
  if(test1_result){Serial.println("is_safe_temperature()function works well @ in-range temperature");}
  test1_result = is_safe_temperature(test_below_min_temperature);
  if(!test1_result){Serial.println("is_safe_temperature()function works well @ -10.00001 Celsius");}
  test1_result = is_safe_temperature(test_above_max_temperature);
  if(!test1_result){Serial.println("is_safe_temperature()function works well @ 180.00001 Celsius");}
}

void loop() {
  //Read sensor voltage and sensor vref voltage
  uint16_t sensor_voltage = read_voltage(TEMPERATURE_SENSOR);
  uint16_t sensor_voltage_ref = read_voltage(TEMPERATURE_SENSOR_REFERENCE);
  sensor_voltage_ref = get_vref(sensor_voltage_ref);
  //calculation temperature and print measurement
  float temperature = get_temperature(sensor_voltage, sensor_voltage_ref);
  print_measurements( sensor_voltage, sensor_voltage_ref, temperature);

  //check if oven is working under safe temperature, decide to turn on or turn off
  boolean at_safe_temper = is_safe_temperature(temperature);
  if(!at_safe_temper){
    turn_off_oven();
  }else if(at_safe_temper && (!is_open_door())){
    turn_on_oven();
  }

  //Check and automatically turn off igniter, once it turn on more than 5 seconds
  auto_off_igniter(); 

  delay(1000); // TODO: reduce time of the delay, let oven react faster
}

/*------Function to turn on oven---------------------------------------------------------*/
void turn_on_oven(){
  if(retrigger_igniter == true) set_output(IGNITER, HIGH);   
  set_output(GAS_VALVE, HIGH);   
}
/*------Function to turn off oven--------------------------------------------------------*/
void turn_off_oven(){
  set_output(IGNITER, LOW);  
  set_output(GAS_VALVE, LOW);   
}

/*------Function to check if temperature is safe(< 180 Celsius)--------------------------*/
bool is_safe_temperature(float temp){
  if(int(ceil(temp)) > 180) return false;
  if(int(floor(temp))< -10) return false;
  return true;
}

/*------Function: Interrupt handler,handle the situation for DOOR open/off---------------*/
void door_sensor_interrupt_handler(bool voltage_high)
{
  retrigger_igniter = true;
  time_igniter_on = 0;
  if(!is_open_door()){
    turn_on_oven(); 
  }
  if(is_open_door()){
    turn_off_oven(); 
  }
}

/*------Function: to calculate actual reference voltage---------------*/
int get_vref(int sensor_vol_ref){
  //Assumption: 0V vref input represents 4.5V, 5V vref represents 5.5V
  int vref = 4500 + (sensor_vol_ref/5);
  return vref;
}

//Caculate the temperature by voltage and reference voltage
float get_temperature(int sensor_vol, int sensor_vol_ref){
    float dif = (float(sensor_vol) / float(sensor_vol_ref));
    
    //TODO: Remove magic numbers here
    float temp = -10.0 + 3.875*(dif-0.1)*100.0;
    return temp;
}

/*-------------Function to print Measurements-----------------------------------------------/
1.oven temperature sensor `vref` voltage
2.oven temperature sensor signal voltage
3. oven temperature in degrees Celsius
*/
void print_measurements(int sensor_vol, int sensor_vol_ref, float temp){
  serial_printf("sensor voltage    = %i mV\n", sensor_vol);
  serial_printf("reference voltage = %i mV\n", sensor_vol_ref);

  //Print temperature
  if(floor(temp) < -10 || ceil(temp) > 300){
    Serial.print("temperature       =  ??????\n");
  }else{
    //Assumption: Temperature print in int format
    serial_printf("temperature       =  %i Celsius\n", (ceil(temp) > 0)?int(ceil(temp)):int(floor(temp)));    
    /*Print accurate termerature
    Serial.print("temperature =  ");
    Serial.print(temp);
    serial_printf(" Celsius\n");
    */
  }  
}

/*------------Function: count 5 seconds, than turn off the igniter---------*/
void auto_off_igniter(){
  
   serial_printf("time@igniter turn on =  %i sec\n", time_igniter_on);
    if (digitalRead(OUT_IGNITER) == HIGH){
    time_igniter_on = time_igniter_on + 1;
    if(time_igniter_on == 5){
      time_igniter_on = 0;
      set_output(IGNITER, LOW);
      retrigger_igniter = false;
    }

    if (digitalRead(OUT_IGNITER) == LOW){
      time_igniter_on = 0;
    }
  }
}