#include <Adafruit_GFX.h> // Hardware-specific library
#include <MCUFRIEND_kbv.h>
MCUFRIEND_kbv tft;

#define BLACK   0x0000
#define BLUE    0x001F
#define RED     0xF800
#define GREEN   0x07E0
#define CYAN    0x07FF
#define MAGENTA 0xF81F
#define YELLOW  0xFFE0
#define WHITE   0xFFFF

String a = "";
unsigned int lastStringLength = a.length();

// work in line numbers.  Font height in ht
int16_t ht = 8, top = 1, line, lines = 38, scroll;

void setup()
{
    Serial.begin(115200);
    tft.reset();
    uint16_t id = tft.readID();
    tft.begin(id);
    tft.setRotation(2);
    tft.fillScreen(BLACK);
    tft.setTextColor(YELLOW, BLACK);
    tft.setTextSize(1);     // System font is 8 pixels.  ht = 8*2=16
    tft.setCursor(60, 0);
    tft.print("*** Serial-Console ***");
    //tft.println(id, HEX);

    tft.setCursor(0, 0);
    //for (line = 1; line < 41; line++) tft.println(String(line) + ": ");

}

void loop()
{
   while (Serial.available()) {
    a = Serial.readString(); // read the incoming data as string
    int len = a.length();
    Serial.println(String(len));
    if (len >= 520) {    // check lines for word wrap
      tft.setCursor(0, ((scroll) + top) * ht);
      if (++scroll >= lines) scroll = 0;
      tft.vertScroll(top * ht, lines * ht, (scroll) * ht);
      Serial.println(a);
    tft.println("Line too long: " + String(len));
    }
    if (len >= 480) {    // check lines for word wrap
      tft.setCursor(0, ((scroll) + top) * ht);
      if (++scroll >= lines) scroll = 0;
      tft.vertScroll(top * ht, lines * ht, (scroll+13) * ht);

      Serial.println(a);
    tft.println(a);
    }
    else if (len >= 440) {    // check lines for word wrap
      tft.setCursor(0, ((scroll) + top) * ht);
      if (++scroll >= lines) scroll = 0;
      tft.vertScroll(top * ht, lines * ht, (scroll+12) * ht);

      Serial.println(a);
    tft.println(a);
    }
    else if (len >= 400) {    // check lines for word wrap
      tft.setCursor(0, ((scroll) + top) * ht);
      if (++scroll >= lines) scroll = 0;
      tft.vertScroll(top * ht, lines * ht, (scroll+11) * ht);

      Serial.println(a);
    tft.println(a);
    }
    else if (len >= 360) {    // check lines for word wrap
      tft.setCursor(0, ((scroll) + top) * ht);
      if (++scroll >= lines) scroll = 0;
      tft.vertScroll(top * ht, lines * ht, (scroll+10) * ht);

      Serial.println(a);
    tft.println(a);
    }
    else if (len >= 320) {    // check lines for word wrap
      tft.setCursor(0, ((scroll) + top) * ht);
      if (++scroll >= lines) scroll = 0;
      tft.vertScroll(top * ht, lines * ht, (scroll+9) * ht);

      Serial.println(a);
    tft.println(a);
    }
    else if (len >= 280) {    // check lines for word wrap
      tft.setCursor(0, ((scroll) + top) * ht);
      if (++scroll >= lines) scroll = 0;
      tft.vertScroll(top * ht, lines * ht, (scroll+8) * ht);

      Serial.println(a);
    tft.println(a);
    }
    else if (len >= 240) {    // check lines for word wrap
      tft.setCursor(0, ((scroll) + top) * ht);
      if (++scroll >= lines) scroll = 0;
      tft.vertScroll(top * ht, lines * ht, (scroll+7) * ht);

      Serial.println(a);
    tft.println(a);
    }
    else if (len >= 200) {
      tft.setCursor(0, ((scroll) + top) * ht);
      if (++scroll >= lines) scroll = 0;
      tft.vertScroll(top * ht, lines * ht, (scroll+6) * ht);

      Serial.println(a);
    tft.println(a);
    }
    else if (len >= 160) {
      tft.setCursor(0, ((scroll) + top) * ht);
      if (++scroll >= lines) scroll = 0;
      tft.vertScroll(top * ht, lines * ht, (scroll+5) * ht);

      Serial.println(a);
    tft.println(a);
    }
    else if (len >= 120) {
      tft.setCursor(0, ((scroll) + top) * ht);
      if (++scroll >= lines) scroll = 0;
      tft.vertScroll(top * ht, lines * ht, (scroll+4) * ht);

      Serial.println(a);
    tft.println(a);
    }
    else if (len >= 80 ) {
      tft.setCursor(0, ((scroll) + top) * ht);
      if (++scroll >= lines) scroll = 0;
      tft.vertScroll(top * ht, lines * ht, (scroll+3) * ht);

      Serial.println(a);
    tft.println(a);
    }
    else if (len > 39) {
      tft.setCursor(0, ((scroll) + top) * ht);
      if (++scroll >= lines) scroll = 0;
      tft.vertScroll(top * ht, lines * ht, (scroll+2) * ht);
      Serial.println("len: > 40");
      Serial.println(a);
    tft.println(a);
    tft.println(" ");
    }
    else if (len < 40) {
    tft.setCursor(0, (scroll + top) * ht);
    if (++scroll >= lines) scroll = 0;
    tft.vertScroll(top * ht, lines * ht, (scroll) * ht);

    Serial.println(a);
    tft.println(a);
    }

    //delay(100);


  }

}