#include <MD_Parola.h>
#include <MD_MAX72xx.h>
#include <SPI.h>

const int sensorPin = A0;
const int sensorMin = 0;
const int sensorMax = 1023;

#define HARDWARE_TYPE MD_MAX72XX::PAROLA_HW
#define MAX_DEVICES 8
#define CLK_PIN  13
#define DATA_PIN 11
#define CS_PIN   10

MD_Parola P = MD_Parola(HARDWARE_TYPE, CS_PIN, MAX_DEVICES);

uint8_t scrollSpeed = 50;    // default frame delay value
textEffect_t scrollEffect = PA_SCROLL_LEFT;
textPosition_t scrollAlign = PA_LEFT;
uint16_t scrollPause = 1500; // in milliseconds

char curMessage[100] = "IOT Course";

void setup() {
  Serial.begin(9600);
  P.begin();
  P.displayText(curMessage, scrollAlign, scrollSpeed, scrollPause, scrollEffect, scrollEffect);
}

void loop() {
  int sensorReading = analogRead(sensorPin);
  int range = map(sensorReading, sensorMin, sensorMax, 0, 3);

  switch (range) {
    case 0:
      changeMessage("LOW");
      break;
    case 1:
      changeMessage("MEDIUM");
      break;
    case 2:
      changeMessage("UPPER");
      break;
    case 3:
      changeMessage("HIGH");
      break;
  }

  if (P.displayAnimate()) {
    readSerial();
  }
}

void changeMessage(const char* newMsg) {
  if (strcmp(curMessage, newMsg) != 0) {
    strcpy(curMessage, newMsg);
    P.displayText(curMessage, scrollAlign, scrollSpeed, scrollPause, scrollEffect, scrollEffect);
  }
}

void readSerial() {
  static char newMessage[100];
  static char *cp = newMessage;

  while (Serial.available()) {
    *cp = (char)Serial.read();
    if ((*cp == '\n') || (cp - newMessage >= sizeof(newMessage) - 2)) {
      *cp = '\0';
      cp = newMessage;
      changeMessage(newMessage);
    } else {
      cp++;
    }
  }
}