#include "project.h"

#ifndef SLIM

#define FOO do { printf("lcd:%x\r\n",__LINE__); usart1_drain(); } while (0)

#define PCF8574_I2C_ADDRESS 0x27

#define LINE_RS		0x1
#define LINE_RnW	0x2
#define LINE_EN		0x4
#define LINE_BACKLIGHT	0x8

#define LCD_CLEAR	0x1
#define LCD_HOME	0x2

#define LCD_DISP 	0x8
#define LCD_DISP_ON 	0x4
#define LCD_DISP_CURSOR 0x2
#define LCD_DISP_CURSOR_BLINK 0x1

#define LCD_FUNC        0x20
#define LCD_FUNC_8BIT   0x10
#define LCD_FUNC_4BIT	0x00
#define LCD_FUNC_2ROWS	0x08
#define LCD_FUNC_1ROW 	0x00
#define LCD_FUNC_5x10 	0x04
#define LCD_FUNC_5X7	0x00

#define LCD_SET_DDRAM_ADDR 0x80

#define LCD_H_SHIFT 5
#define LCD_RS (1 << LCD_H_SHIFT)
#define LCD_W 16
#define LCD_W_MASK (LCD_RS -1 )
#define LCD_H 2
#define LCD_SZ (LCD_H << LCD_H_SHIFT)
#define LCD_POS(c,r) (((r) << LCD_H_SHIFT ) +(c))

#define BYTES_PER_BYTE 6

#define DMA_BUF_SZ (BYTES_PER_BYTE * ( (1 + LCD_W) *LCD_H  + 1))


static int backlight;
uint8_t fb[LCD_H][LCD_W];
uint8_t shadow[LCD_H][LCD_W];

static int pos;


static void
clock_nibble (uint8_t n)
{
  if (backlight)
    n |= LINE_BACKLIGHT;
  i2c_bb_send_data (n);
  i2c_bb_send_data (LINE_EN | n);
  i2c_bb_send_data (n);
}


static void
write_reg (uint8_t c, int r)
{
  uint8_t b;

  b = c & 0xf0;
  if (r)
    b |= LINE_RS;

  clock_nibble (b);

  b = (c & 0xf) << 4;
  if (r)
    b |= LINE_RS;

  clock_nibble (b);
}

static void
send_data (uint8_t c)
{
  write_reg (c, 1);
}


static void
send_command (uint8_t c)
{
  write_reg (c, 0);
}

static void
send_one_command (uint8_t cmd, int delay)
{
  i2c_bb_start_transaction (PCF8574_I2C_ADDRESS, I2C_WRITE);
  send_command (cmd);
  i2c_bb_stop ();
  if (delay)
    delay_ms (delay);
}



static void
cls (void)
{
  send_one_command (LCD_CLEAR, 2);
}

#if 0
static void
home (void)
{
  send_one_command (LCD_HOME, 2);
}
#endif

static void
on (void)
{
  send_one_command (LCD_DISP | LCD_DISP_ON /* | LCD_DISP_CURSOR */ , 4);
}

static void
off (void)
{
  send_one_command (LCD_DISP, 4);
}

static int
lcd_addr (int x, int y)
{
  return x + ((y & 1) << 6) + ((y & 2) ? 20 : 0);
}


#if 0
static void
move (uint8_t c, uint8_t r)
{
  send_one_command (LCD_SET_DDRAM_ADDR | lcd_addr (c, r), 2);
}
#endif


void
lcd_refresh (void)
{
  int c, r;
  int addr;


  i2c_bb_start_transaction (PCF8574_I2C_ADDRESS, I2C_WRITE);


  for (r = 0; r < LCD_H; ++r)
    {
      for (c = 0; c < LCD_W; ++c)
        {

          if (shadow[r][c] != fb[r][c])
            {

              addr = lcd_addr (c, r);

              if (addr != pos)
                {
                  send_command (LCD_SET_DDRAM_ADDR | addr);
                  pos = addr;
                }

              send_data (shadow[r][c]);
              fb[r][c] = shadow[r][c];

              pos++;
            }

        }
    }

  i2c_bb_stop ();
}

void
lcd_tick (void)
{
  static int u;

  u++;

  if (u < 100)
    return;

  u = 0;

  if (!memcmp (shadow, fb, sizeof (fb)))
    return;

  lcd_refresh ();
}






void
lcd_write_char (uint8_t c, int x, int y)
{
  shadow[y][x] = c;
}


void
lcd_erase (int x, int y, int w)
{
  uint8_t *ptr = &shadow[y][x];
  while (w--)
    *ptr = ' ';
}

void
lcd_erase_line (int w, int y)
{
  lcd_erase (0, y, w);
}

void
lcd_erase_all (void)
{
  int y;
  for (y = 0; y < LCD_H; ++y)
    {
      lcd_erase (0, 0, LCD_W);
    }
}

void
lcd_write (char *c, int x, int y)
{
  while (*c)
    {
      lcd_write_char (*(c++), x++, y);
      if (x == LCD_W)
        break;
    }
}

#if 0
static void
lcd_scroll (uint8_t * p)
{
  int i;
  for (i = 0; i < 3; ++i)
    {
      memcpy (p, p + LCD_RS, LCD_W);
      p += LCD_RS;
    }
  memset (p, ' ', LCD_W);
}

void
lcd_putc (uint8_t c)
{

  switch (c)
    {
    case '\r':
      pos &= ~LCD_W_MASK;
      break;
    case '\n':
      pos &= ~LCD_W_MASK;
      pos += LCD_RS;
      break;
    default:
      buf[pos] = c;
      pos++;
    }


  if ((pos & LCD_W_MASK) == LCD_W)
    {
      pos &= ~LCD_W_MASK;
      pos += LCD_RS;
    }

  if (pos == LCD_SZ)
    {
      lcd_scroll (buf);
      pos -= LCD_RS;
    }


}
#endif

void
lcd_backlight (int i)
{
  backlight = i;

  i2c_bb_start_transaction (PCF8574_I2C_ADDRESS, I2C_WRITE);
  i2c_bb_send_data (backlight ? LINE_BACKLIGHT : 0);
  i2c_bb_stop ();
}






void
lcd_reset (void)
{
  i2c_bb_start_transaction (PCF8574_I2C_ADDRESS, I2C_WRITE);
  clock_nibble (0x30);
  delay_ms (5);
  clock_nibble (0x30);
  delay_us (64);
  clock_nibble (0x30);
  delay_us (64);
  clock_nibble (0x20);

  send_command (LCD_FUNC | LCD_FUNC_4BIT | LCD_FUNC_2ROWS | LCD_FUNC_5X7);
  i2c_bb_stop ();
  on ();
  cls ();
}

void
lcd_init (void)
{
  lcd_backlight (0);
  lcd_reset ();
  lcd_backlight (1);

}

void
lcd_shutdown (void)
{
  lcd_backlight (0);
  off ();
}
#endif