#include <WiFi.h>
#include <WiFiClient.h>
#include <ESP32Servo.h>
#include "ThingSpeak.h"
#include <LiquidCrystal_I2C.h>


LiquidCrystal_I2C lcd(0x27, 20, 4);
#define Second 1000
#define Dry_Echo 18
#define Dry_Trig 19
#define Wet_Echo 4
#define Wet_Trig 23
#define SoilMoisture 33
#define ServoMotor 21

const char* WIFI_NAME = "Wokwi-GUEST"; // WiFi SSID
const char* WIFI_PASSWORD = ""; // WiFI Password
const int myChannelNumber = 2520070; // ThingSpeak channel number
const char* myApiKey = "6EZGVRB1XQV3261X"; // ThingSpeak API key
const char* server = "api.thingspeak.com"; // ThingSpeak server address
WiFiClient client;
// functions
float calculate_distance(int Trig, int Echo, char can);
bool is_full(int Trig, int Echo, char can);
float calibrate(int moisture);

// global variables
char ssid[] = "Wokwi-GUEST";
char pass[] = "";
bool dry_full = 0;
bool wet_full = 0;
int servo_pos = 90;
int max_moisture = 4095;
int min_moisture = 1095;
float threshold = calibrate(4000);
Servo servo;

void setup() {
  // Wifi setup
  Serial.begin(115200);
  WiFi.begin(WIFI_NAME, WIFI_PASSWORD);
  while (WiFi.status() != WL_CONNECTED){
      delay(1000);
      Serial.println("Wifi not connected");
  }
  Serial.println("Wifi connected !");
  Serial.println("Local IP: " + String(WiFi.localIP()));
  WiFi.mode(WIFI_STA);
  ThingSpeak.begin(client);

  // LCD initialization
  lcd.init();

  lcd.backlight();
  lcd.clear();
  lcd.setCursor(5,0);
  lcd.print("Welcome to waste management system");
  Serial.begin(115200);
  pinMode(Dry_Trig, OUTPUT);
  pinMode(Dry_Echo, INPUT);
  pinMode(Wet_Trig, OUTPUT);
  pinMode(Wet_Echo, INPUT);
  pinMode(SoilMoisture, INPUT);
  servo.attach(ServoMotor, 500, 2400);
}
void loop() {
  Serial.println("______________________");

  // manage trash
  int moisture_value = analogRead(SoilMoisture);
  float moisture = calibrate(moisture_value);
  Serial.print("Moisture : ");
  Serial.print(moisture_value);
  Serial.print(" ----> calibrated : ");
  Serial.print(moisture);
  Serial.println("%");
  bool wet_trash = moisture > threshold;
  ThingSpeak.setField(3, moisture_value);
  if(wet_trash){
    Serial.print("The trash is wet! (threshold = ");
    Serial.print(threshold);
    Serial.println("%)");
    ThingSpeak.setField(3, 1);
    // open gate
    for (servo_pos = 90; servo_pos >= 0; servo_pos -= 1) {
      servo.write(servo_pos);
      delay(15);
    }
    delay(5 * Second);
    // close gate
    for (servo_pos = 0; servo_pos <= 90; servo_pos += 1) {
      servo.write(servo_pos);
      delay(15);
    }
    int status = ThingSpeak.writeFields(myChannelNumber, myApiKey);
  }
  else{
    ThingSpeak.setField(3, 0);
  }
  lcd.clear();  
  // manage can
  dry_full = is_full(Dry_Trig, Dry_Echo, 'D');
  wet_full = is_full(Wet_Trig, Wet_Echo, 'W');
  if (dry_full && wet_full){
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Dry can and wet can is full");
  }
  else if (dry_full){
    Serial.println("The dry can is full.");
    lcd.clear();
    lcd.setCursor(5, 1);
    lcd.print("Dry can is full");
  }
  else if (wet_full){
    Serial.println("The wet can is full.");
    lcd.clear();
    lcd.setCursor(5, 1);
    lcd.print("Wet can is full");
  }
  else{
    lcd.clear();
    lcd.setCursor(5, 1);
    lcd.print("Cans are empty");
  }

  delay(10 * Second);
}


float calculate_distance(int Trig, int Echo, char can){
  digitalWrite(Trig, LOW);
  delay(2);
  digitalWrite(Trig, HIGH);
  delay(10);
  digitalWrite(Trig, LOW);

  int duration = pulseIn(Echo, HIGH);
  float distance = duration * 0.034 /2;

  Serial.print(can);
  if(can=='D'){
    ThingSpeak.setField(1, distance);
  }else{
    ThingSpeak.setField(2, distance);
  }
  Serial.print(" free space : ");
  Serial.print(distance);
  Serial.println(" CM");
  
  return distance;
}

bool is_full(int Trig, int Echo, char can){
  float distance = calculate_distance(Trig, Echo, can);
  return distance < 4;
}

float calibrate(int moisture){
  int x = (max_moisture - min_moisture)/100;
  return (max_moisture - moisture)/x;
}