/*
 * ----------------------------------------------------------------------------
 * "THE BEER-WARE LICENSE" (Revision 42):
 * <struppi@struppi.name> wrote this file. As long as you retain this notice you
 * can do whatever you want with this stuff. If we meet some day, and you think
 * this stuff is worth it, you can buy me a beer in return.
 * (c) 2014 Stefan Rupp
 * ----------------------------------------------------------------------------
 */


#include "ledcontroller.h"
#include <string.h>


#define NUM_LED1642GW_ICs (3)
#define NUM_LED1642GW_CHANNELS (16)
#define NUM_CHANNELS (NUM_LED1642GW_CHANNELS*NUM_LED1642GW_ICs)

static uint16_t ledbuffer[NUM_CHANNELS];

static int8_t get_channel_from_lednum(uint8_t lednum, uint8_t *channel_r, uint8_t *channel_g, uint8_t *channel_b)
{
  uint8_t ret;

  if (lednum < 15) {
    *channel_r = 3*lednum;
    *channel_g = 3*lednum+1;
    *channel_b = 3*lednum+2;
    if ( lednum >= 10 ) {
      *channel_r += 2;
      *channel_g += 2;
      *channel_b += 2;
    }
    else if ( lednum >= 5 ) {
      *channel_r += 1;
      *channel_g += 1;
      *channel_b += 1;
    }
    ret = 1;
  }
  else {
    ret = 0;
  }

  return ret;
}

static void write_data(uint16_t data, uint8_t le_clocks)
{
  PORTC &= ~(1<<PC3);
  PORTC &= ~(1<<PC2);
  uint16_t mask = 0x8000;
  int8_t bit;
  for (bit=15; bit>=le_clocks; bit--) {
    if(data&mask) { PORTC |= (1<<PC4); }
    else { PORTC &= ~(1<<PC4); }
    PORTC |= (1<<PC3);
    PORTC &= ~(1<<PC3);
    mask >>= 1;
  }
  PORTC |= (1<<PC2);
  for (/*noting to initialize*/; bit>=0; bit--) {
    if(data&mask) { PORTC |= (1<<PC4); }
    else { PORTC &= ~(1<<PC4); }
    PORTC |= (1<<PC3);
    PORTC &= ~(1<<PC3);
    mask >>= 1;
  }
}

static void write_data_latch(uint16_t data)
{
  write_data(data, 4);
}

static void write_global_latch(uint16_t data)
{
  write_data(data, 6);
}


void ledcontroller_init(void)
{

  DDRC |= (1<<PC3); // SCK
  DDRC |= (1<<PC4); // DATA
  DDRC |= (1<<PC2); // LE
  PORTC |= (1<<PC3); // SCK
  PORTC |= (1<<PC4); // DATA
  PORTC |= (1<<PC2); // LE
  memset(ledbuffer, 0x00, sizeof(ledbuffer));
  led_flush();
}


void led_set(uint8_t lednum, uint16_t red, uint16_t green, uint16_t blue)
{
  uint8_t c_r, c_g, c_b;
  
  if ( get_channel_from_lednum(lednum, &c_r, &c_g, &c_b) > 0 ) {
    ledbuffer[c_r] = red;
    ledbuffer[c_g] = green;
    ledbuffer[c_b] = blue;
  }
}


void led_flush(void)
{
  for (uint8_t i=0; i<NUM_CHANNELS-1; i++) {
    write_data_latch(ledbuffer[i]);
  }
  write_global_latch(ledbuffer[NUM_CHANNELS-1]);
}