#include "hal.h"
#include <string.h>
#include "bitmap.h"

#define DIN A_0
#define CLK A_1
#define CS A_2
#define HW_DELAY() for(volatile uint8_t d=0; d<2; d++)


// display buffer is called static buffer
volatile uint8_t static_buffer[64]={0};

void setup() {
  max7219_init();
  load_static_buffer("ETAL1234");
  refresh_display();
}


void loop() {
  // put your main code here, to run repeatedly:

}

void cs_active()
{
  pin_drive_out(CS, 0);
}

void cs_idle()
{
  pin_drive_out(CS, 1);
}

void clk_low()
{
  pin_drive_out(CLK, 0);
}

void clk_high()
{
  pin_drive_out(CLK, 1);
}

void write_byte(volatile uint8_t u_byte)
{
  for (uint8_t i = 0; i < 8; i++)
  {
    (u_byte & 0x80) ? (pin_drive_out(DIN, 1)) : (pin_drive_out(DIN, 0));
    HW_DELAY();
    u_byte <<= 1;
    clk_high();
    HW_DELAY();
    clk_low();
  }
}

void send(uint8_t matrix_addr, uint8_t matrix_data)
{
  cs_active();
  for(uint8_t i=0;i<8;i++)
  {
    write_byte(matrix_addr);
    write_byte(matrix_data);
  }
  cs_idle();
}

void max7219_init() {
  init_pin(CLK, output);
  init_pin(DIN, output);
  init_pin(CS, output);

  clk_low();//make clk low while initialization
  cs_idle();//make CS idle while initialization

  send(0x09, 0x00); // Decode Mode: No decode (Matrix mode)
  send(0x0A, 0x03); // Intensity: 3/15 brightness
  send(0x0B, 0x07); // Scan Limit: Display all 8 rows (0-7)
  send(0x0C, 0x01); // Shutdown: 0x01 = Normal Operation
  send(0x0F, 0x00); // Display Test: 0x00 = Off

  // Clear the matrix initially
  for (uint8_t i = 1; i <= 8; i++) {
    send(i, 0x00);
  }
}

void load_static_buffer(volatile uint8_t* str)
{
    for(uint8_t m = 0; m < 8; m++)
    {
      volatile uint8_t *curr_char=fetch_char_data(str[m]);
      volatile uint8_t matrix_off=m*8;
      for (uint8_t i = 0; i < 8; i++)
      {
        static_buffer[matrix_off+i] = curr_char[i];
      }
    }
}

void refresh_display()
{
  for (uint8_t row = 1; row < 9; row++)
  {
    cs_active();
    for (uint8_t m = 0; m < 8; m++)
    {
      write_byte(row);
      write_byte(static_buffer[(m * 8) + (row - 1)]);
    }
    cs_idle();
  }
}