// https://randomnerdtutorials.com/esp32-pir-motion-sensor-interrupts-timers/
#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <DHT.h>

// defining functions
void cleardisplay ();
void printdata (float i, float j, float k);


#define SCREEN_WIDTH 128            // SSD1306 definition
#define SCREEN_HEIGHT 64
#define OLED_RESET     -1 // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

#define timeSeconds 2              // past 3 sec PIR active
#define DHTPIN 4
#define DHTTYPE DHT22

const int led = 26;
const int motionSensor = 27;

DHT dht(DHTPIN, DHTTYPE);

unsigned long now = millis();
unsigned long lastTrigger = 0;
boolean startTimer = false;
boolean motion = false;
boolean showstatus = false;
boolean f;
float h, t;

// ISR - Interrupt Service Routine - activated throughout "interrupt"
// interrupt function - needs no call for activation
// activation through RISING current on pin "motionSensor"
// IRAM_ATTR: would be too slow if it was stored in flash memory
void IRAM_ATTR detectsMovement() {     // Checks if motion was detected
  digitalWrite(led, HIGH);             // led  HIGH
  motion = true;
  startTimer = true;                   // start the timer
  lastTrigger = millis();
}                                      // IRAM-ATTR = interrupt code in RAM


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

  dht.begin();
  
  
  // PIR Motion Sensor mode INPUT_PULLUP
  pinMode(motionSensor, INPUT_PULLUP);
  // Set motionSensor pin as interrupt, assign interrupt function and set RISING mode
  attachInterrupt(digitalPinToInterrupt(motionSensor), detectsMovement, RISING);
  // arguments: 1) motionSensor-pin, 2) function to execute, 3) when: RISING
  // LOW	Triggers the interrupt whenever the pin is LOW
  // HIGH	Triggers the interrupt whenever the pin is HIGH
  // CHANGE	Triggers the interrupt whenever the pin changes value, from HIGH to LOW or LOW to HIGH
  // FALLING	Triggers the interrupt when the pin goes from HIGH to LOW
  // RISING	Triggers the interrupt when the pin goes from LOW to HIGH
  pinMode(led, OUTPUT);           // led-pin HIGH & motion false are
  digitalWrite(led, LOW);         // triggers

  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {     // display setup
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }
  display.display();
  delay (1000);
  display.setTextSize(1);
  display.setTextColor(WHITE, BLACK);

  cleardisplay ();
}


// ------------------  l o o p  --------------------
void loop() {

h = dht.readHumidity();
t = dht.readTemperature();
f = dht.readTemperature(true);

if (isnan(h) || isnan(t) || isnan(f)) {
    Serial.println(F("Failed to read from DHT sensor!"));
    return;
}

  now = millis();
  if((digitalRead(led) == HIGH) && (motion == true)) {
    Serial.println("MOTION DETECTED!");
    cleardisplay ();
    printdata (t,h,5);
    delay ((timeSeconds+1)*1000);
    cleardisplay ();
    // motion = true;
  }
  // Turn off the LED after the number of seconds defined in the timeSeconds variable
  if(startTimer && (now - lastTrigger > (timeSeconds*1000))) {
    Serial.println("Motion stopped...");
    digitalWrite(led, LOW);
    startTimer = false;
    motion = false;
  }
}



void printdata (float i, float j, float k) {
  const int border = 2;
  const int leftborder = 6;
  const int texthight = 10;

  display.drawRect(border, border, SCREEN_WIDTH-border, SCREEN_HEIGHT-border, WHITE);
      
  display.setCursor(leftborder, 2*texthight); 
  display.print("Temp.:  ");       
  display.print(i); 
  display.print(" °C");

  display.setCursor(leftborder, 3*texthight);
  display.print("Humid.:  ");       
  display.print(j);
  display.print(" %");

  display.setCursor(leftborder, 4*texthight);
  display.print("Press.:  ");       
  display.print(k);
  display.println(" hPa");
  display.display();                    // 4. set display active
}



void cleardisplay ()  {
  display.clearDisplay();     // clears display buffer   1) first step
  display.display();          // sets output active      2) second step
}