#include <Arduino.h>
#include <TFT_eSPI.h>
#include <SPI.h>

TFT_eSPI tft = TFT_eSPI();       // Invoke custom library
// pins are defined un User_Setup.h

const int BTN1_PIN = 25;
volatile bool btn1_pressed = false;
const int BTN2_PIN = 33;
volatile bool btn2_pressed = false;

// forward declarations
void IRAM_ATTR isr1();
void IRAM_ATTR isr2();

void setup() {
  tft.init();   // initialize a ST7735S chip

  // set up the buttons and the interrupts
  pinMode(BTN1_PIN, INPUT_PULLUP);
  attachInterrupt(BTN1_PIN, isr1, FALLING);
  pinMode(BTN2_PIN, INPUT_PULLUP);
  attachInterrupt(BTN2_PIN, isr2, FALLING);

  init_board();

  delay(100);
}

#define GRID_WIDTH   12
#define GRID_HEIGHT  18
#define BLOCK_SIZE   10
#define BLOCK_MARGIN  2

#define BLOCK_WIDTH    20
#define BLOCK_HEIGHT   30

uint32_t main_board[GRID_WIDTH][GRID_HEIGHT], offboard[GRID_WIDTH][GRID_HEIGHT];

void
init_board()
{
  tft.fillScreen(TFT_BLACK);

  for(int i = 0; i < GRID_WIDTH; i++)
    for(int j = 0; j < GRID_HEIGHT; j++)
      {
        main_board[i][j] = 0;
        offboard[i][j]  = 0;
      }  
}

void
draw_board()
{
  for(int i = 0; i < GRID_WIDTH; i++)
    for(int j = 0; j < GRID_HEIGHT; j++)
      {
        if (main_board[i][j] == offboard[i][j]) continue; // no need to redraw
        offboard[i][j] = main_board[i][j];
        tft.fillRect(i*BLOCK_SIZE+BLOCK_MARGIN,j*BLOCK_SIZE+BLOCK_MARGIN,
                     BLOCK_SIZE-BLOCK_MARGIN,BLOCK_SIZE-BLOCK_MARGIN,
                     main_board[i][j]);
      }
}

uint8_t blocks[2][4] =
  {
   {0,1,2,3},{0,1,4,5}
  };


// Draw a block of type TYPE with color COLOR, starting at coordinates X, Y.
// Updates the main_board directly
void
draw_block(int x, int y, int type, int color)
{
  for (int i = 0; i < 4; i++)
    {
      int v = blocks[type][i];
      int dx = v%4;
      int dy = v/4;
      main_board[x+dx][y+dy] = color;
    }
}

int px = 0, cx = 0;
int py = 0, cy = 0;
int cblock_ty = 0;
void loop() {
  // if (dy == 0) {
  //   dx = map(esp_random(), 0, 0xFFFFFFFF, 0, 128/5);
  // }
  cy++;
  if (cy >= GRID_HEIGHT) {
    cy = 0;
  }

  if (btn1_pressed)
    {
      btn1_pressed = false;
      cx--;
    }
  if (btn2_pressed)
    {
      btn2_pressed = false;
      cx++;
    }

  // clear the previous block
  if (cy != py || cx != px)
    {
      draw_block(px, py, cblock_ty, TFT_BLACK);
    }
  draw_block(cx, cy, cblock_ty, TFT_RED);

  draw_board();

  delay(350);

  px = cx;
  py = cy;
}

void IRAM_ATTR
isr1()
{
  btn1_pressed = true;
}

void IRAM_ATTR
isr2()
{
  btn2_pressed = true;
}