#include <WiFi.h>
#include <WiFiClient.h>
#include <HTTPClient.h>
#include <ArduinoJson.h>

// Pins
const int trigPin = 5;
const int echoPin = 4;

// Wi-Fi credentials
const char* SSID = "Wokwi-GUEST";
// const char* PASSWORD = "";

// Server
const String SERVER = "https://equipped-immense-parakeet.ngrok-free.app";

// last filled level
long lastInches = 0;
int lastCM = 0;

// max depth 
long maxInches = 0;
long maxCM = 0;

const float maxPercentage = 75.0; // max percentage level

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  Serial.begin(9600);
  delay(500);

  Serial.print("Connecting to Wi-Fi");
  WiFi.begin(SSID, "", 6);
  delay(5000);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.print("\nConnected to Wi-Fi with IP ");
  Serial.println(WiFi.localIP());

  setMaximumDepth(trigPin, echoPin);
}

void loop() {
  long t, inches;
  int cm;

  // pulse output
  digitalWrite(trigPin, LOW);
  delayMicroseconds(4);

  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);

  digitalWrite(trigPin, LOW);

  t = pulseIn(echoPin, HIGH);
  inches = t / 74 / 2;
  cm = t / 29 / 2;

  Serial.print(inches);
  Serial.print(" inches, ");
  Serial.print(cm);
  Serial.println(" cm");

  float percentage = getPercentage(maxInches, maxCM, inches, cm);
  Serial.print(percentage);
  Serial.println("% filled");

  // update fill level when bin is filled or emptied
  if (lastInches > inches || lastInches < inches || lastCM > cm || lastCM < cm) {
    Serial.println("Updating fill level ...");
    sendReq(SERVER + "/update", percentage, inches, cm, maxInches, maxCM);
    delay(1000);
  }

  // if greater or less than the last filled level, send a request to store or update
  if (lastInches > inches && lastCM > cm && percentage >= maxPercentage && percentage <= 100.0f) {
    Serial.println("Sending notification ...");
    sendReq(SERVER + "/update?notification=true", percentage, inches, cm, maxInches, maxCM);
    delay(1000);
  }

  lastInches = inches;
  lastCM = cm;

  delay(1000);
}

// set maximum depth
void setMaximumDepth(int trigPin, int echoPin) {
  long inches, t;
  int cm, counter = 10;

  while (counter >= 0) {

    digitalWrite(trigPin, LOW);
    delayMicroseconds(4);

    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);

    digitalWrite(trigPin, LOW);

    t = pulseIn(echoPin, HIGH);
    inches = t / 74 / 2;
    cm = t / 29 / 2;

    if (counter == 0) {
      counter = -1;
      maxInches = inches;
      maxCM = cm;
      Serial.print("Max depth: ");
      Serial.print(maxInches);
      Serial.print(" inch(es), ");
      Serial.print(maxCM);
      Serial.println(" cm");
    }
    --counter;
    delay(200);
  }
}

// check if level is filled or crossed
float getPercentage(long maxInches, int maxCM, long inches, int cm) {
  float totalDepthCM = (maxInches * 2.54) + maxCM;
  float totalCM = (inches * 2.54) + cm;
  float filledCM = abs(totalDepthCM - totalCM);
  float percentage = (filledCM / totalDepthCM) * 100.0;
  return percentage;
}

void sendReq(String Server_URI, float percentage, long inches, int cm, long maxInches, int maxCM) {
  if (WiFi.status() == WL_CONNECTED) {
    WiFiClient client;
    HTTPClient http;
    String length_str, max_depth, json;
    DynamicJsonDocument doc(1024);

    length_str = String(inches) + "." + String(cm);
    max_depth = String(maxInches) + "." + String(maxCM);

    doc["bin_id"] = 101;
    doc["percentage"] = percentage;
    doc["max_depth"] = max_depth;
    doc["level"] = length_str;
    doc["location"] = "Oriental University";

    serializeJson(doc, json);

    http.begin(client, Server_URI);
    http.addHeader("Content-Type", "application/json");

    int httpResponseCode = http.POST(json);
    String response = http.getString();
    http.end();

    Serial.println(httpResponseCode);
    Serial.println(response);
  }
}