#include <wiringPi.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>


// define our pins :

#define Set_DIN(high) (high?(digitalWrite(7, HIGH)):(digitalWrite(7, LOW)))
#define Set_CS(high) (high?(digitalWrite(8, HIGH)):(digitalWrite(8, LOW)))
#define Set_CLK(high) (high?(digitalWrite(10, HIGH)):(digitalWrite(10, LOW)))

const uint8_t smile[8] = {
        0b00000000,
        0b01100110,
        0b01100110,
        0b00011000,
        0b00011000,
        0b10000001,
        0b01000010,
        0b00111100};

const uint8_t sad[8] = {
        0b00000000,
        0b01100110,
        0b01100110,
        0b00011000,
        0b00011000,
        0b00000000,
        0b00111100,
        0b01000010
};


void spi_send(uint8_t data)
{
    uint8_t i;

    for (i = 0; i < 8; i++, data <<= 1)
    {
	Set_CLK(0);//CLK_HIGH();
	if (data & 0x80)
	    Set_DIN(1);//DATA_HIGH();
	else
	    Set_DIN(0);//DATA_LOW();
	Set_CLK(1);//CLK_HIGH();
    }
}

void max7219_writec(uint8_t high_byte, uint8_t low_byte)
{
    Set_CS(0);//CS_LOW();
    spi_send(high_byte);
    spi_send(low_byte);
    Set_CS(1);//CS_HIGH();
}

void max7219_clear(void)
{
    uint8_t i;
    for (i = 0; i < 8; i++)
    {
	max7219_writec(i+1, 0);
    }
}

void max7219_init(void)
{
    // Decode mode: none
    max7219_writec(0x09, 0);
    // Intensity: 3 (0-15)
    max7219_writec(0x0A, 1);
    // Scan limit: All "digits" (rows) on
    max7219_writec(0x0B, 7);
    // Shutdown register: Display on
    max7219_writec(0x0C, 1);
    // Display test: off
    max7219_writec(0x0F, 0);
    max7219_clear();
}

uint8_t display[8];

void update_display(void)
{
    uint8_t i;

    for (i = 0; i < 8; i++)
    {
	max7219_writec(i+1, display[i]);
    }
}

void image(const uint8_t im[8])
{
    uint8_t i;

    for (i = 0; i < 8; i++)
	display[i] = im[i];
}

void set_pixel(uint8_t r, uint8_t c, uint8_t value)
{
    switch (value)
    {
    case 0: // Clear bit
	display[r] &= (uint8_t) ~(0x80 >> c);
	break;
    case 1: // Set bit
	display[r] |= (0x80 >> c);
	break;
    default: // XOR bit
	display[r] ^= (0x80 >> c);
	break;
    }
}



int main (void)
{
  wiringPiSetup();
  pinMode(7, OUTPUT);
  pinMode(8, OUTPUT);
  pinMode(10, OUTPUT);

  uint8_t i;

  max7219_init();

  while(1)
  {
  image(sad);
  update_display();
  usleep(5000);
  image(smile);
  update_display();
  usleep(5000);

	// Invert display
  for (i = 0 ; i < 8*8; i++)
  {
    set_pixel(i / 8, i % 8, 2);
    update_display();
    usleep(5000);
  }
  usleep(5000);
  }

  return 0;
}