#include "driver.h"
#include "eeprom.h"
#include "savegame.h"
#include <stdarg.h>
#include <stdio.h>
#include <string.h>

#define VERBOSE 0

#define SERIAL_BUFFER_LENGTH 40
#define MEMORY_SIZE 1024

static struct EEPROM_interface *intf;

static int serial_count;
static char serial_buffer[SERIAL_BUFFER_LENGTH];
static unsigned char eeprom_data[MEMORY_SIZE];
static int eeprom_data_bits;
static int eeprom_read_address;
static int eeprom_clock_count;
static int latch,reset_line,clock_line,sending;
static int locked;
static int reset_delay;

/*
	EEPROM_command_match:

	Try to match the first (len) digits in the EEPROM serial buffer
	string (*buf) with	an EEPROM command string (*cmd).
	Return non zero if a match was found.

	The serial buffer only contains '0' or '1' (e.g. "1001").
	The command can contain: '0' or '1' or these wildcards:

	'x' :	match both '0' and '1'
	"*1":	match "1", "01", "001", "0001" etc.
	"*0":	match "0", "10", "110", "1110" etc.

	Note: (cmd) may be NULL. Return 0 (no match) in this case.
*/

void logerror(const char *text, ...)
{
#ifdef VERBOSE
  va_list arg;

  va_start(arg, text);
  vfprintf(stderr, text, arg);
  va_end(arg);
#endif
}

static int EEPROM_command_match(const char *buf, const char *cmd, int len)
{
  if ( cmd == 0 )	return 0;
  if ( len == 0 )	return 0;

  for (;len>0;)
    {
      char b = *buf;
      char c = *cmd;

      if ((b==0) || (c==0))
	return (b==c);

      switch ( c )
	{
	case '0':
	case '1':
	  if (b != c)	return 0;
	case 'X':
	case 'x':
	  buf++;
	  len--;
	  cmd++;
	  break;

	case '*':
	  c = cmd[1];
	  switch( c )
	    {
	    case '0':
	    case '1':
	      if (b == c)	{	cmd++;			}
	      else		{	buf++;	len--;	}
	      break;
	    default:	return 0;
	    }
	}
    }
  return (*cmd==0);
}

void EEPROM_init(struct EEPROM_interface *interface)
{
  int size = (1 << interface->address_bits) * interface->data_bits / 8;
  intf = interface;


  if (size > MEMORY_SIZE)
    {
      //		usrintf_showmessage("EEPROM larger than eeprom.c allows");
      return;
    }

  memset(eeprom_data,0xff,size);
  serial_count = 0;
  latch = 0;
  reset_line = ASSERT_LINE;
  clock_line = ASSERT_LINE;
  sending = 0;
  if (intf->cmd_unlock) locked = 1;
  else locked = 0;
  // The following line should include this as a normal eeprom... Hope.
  add_eeprom(eeprom_data,size,1);
}

static void EEPROM_write(int bit)
{
#if VERBOSE
logerror("EEPROM write bit %d\n",bit);
#endif

	if (serial_count >= SERIAL_BUFFER_LENGTH-1)
	{
logerror("error: EEPROM serial buffer overflow\n");
		return;
	}

	serial_buffer[serial_count++] = (bit ? '1' : '0');
	serial_buffer[serial_count] = 0;	/* nul terminate so we can treat it as a string */

	if ( (serial_count > intf->address_bits) &&
	      EEPROM_command_match((char*)serial_buffer,intf->cmd_read,strlen((char*)serial_buffer)-intf->address_bits) )
	{
		int i,address;

		address = 0;
		for (i = serial_count-intf->address_bits;i < serial_count;i++)
		{
			address <<= 1;
			if (serial_buffer[i] == '1') address |= 1;
		}
		if (intf->data_bits == 16)
			eeprom_data_bits = (eeprom_data[2*address+0] << 8) + eeprom_data[2*address+1];
		else
			eeprom_data_bits = eeprom_data[address];
		eeprom_read_address = address;
		eeprom_clock_count = 0;
		sending = 1;
		serial_count = 0;
		//logerror("EEPROM read %04x from address %02x\n",eeprom_data_bits,address);
	}
	else if ( (serial_count > intf->address_bits) &&
	           EEPROM_command_match((char*)serial_buffer,intf->cmd_erase,strlen((char*)serial_buffer)-intf->address_bits) )
	{
		int i,address;

		address = 0;
		for (i = serial_count-intf->address_bits;i < serial_count;i++)
		{
			address <<= 1;
			if (serial_buffer[i] == '1') address |= 1;
		}
		//logerror("EEPROM erase address %02x\n",address);
		if (locked == 0)
		{
			if (intf->data_bits == 16)
			{
				eeprom_data[2*address+0] = 0x00;
				eeprom_data[2*address+1] = 0x00;
			}
			else
				eeprom_data[address] = 0x00;
		}
		else
		  //logerror("Error: EEPROM is locked\n");
		serial_count = 0;
	}
	else if ( (serial_count > (intf->address_bits + intf->data_bits)) &&
	           EEPROM_command_match((char*)serial_buffer,intf->cmd_write,strlen((char*)serial_buffer)-(intf->address_bits + intf->data_bits)) )
	{
		int i,address,data;

		address = 0;
		for (i = serial_count-intf->data_bits-intf->address_bits;i < (serial_count-intf->data_bits);i++)
		{
			address <<= 1;
			if (serial_buffer[i] == '1') address |= 1;
		}
		data = 0;
		for (i = serial_count-intf->data_bits;i < serial_count;i++)
		{
			data <<= 1;
			if (serial_buffer[i] == '1') data |= 1;
		}
		//logerror("EEPROM write %04x to address %02x\n",data,address);
		if (locked == 0)
		{
			if (intf->data_bits == 16)
			{
				eeprom_data[2*address+0] = data >> 8;
				eeprom_data[2*address+1] = data & 0xff;
			}
			else
				eeprom_data[address] = data;
		}
		else
		  //logerror("Error: EEPROM is locked\n");
		serial_count = 0;
	}
	else if ( EEPROM_command_match((char*)serial_buffer,intf->cmd_lock,strlen((char*)serial_buffer)) )
	{
	  //logerror("EEPROM lock\n");
		locked = 1;
		serial_count = 0;
	}
	else if ( EEPROM_command_match((char*)serial_buffer,intf->cmd_unlock,strlen((char*)serial_buffer)) )
	{
	  //logerror("EEPROM unlock\n");
		locked = 0;
		serial_count = 0;
	}
}

static void EEPROM_reset(void)
{
if (serial_count)
  //logerror("EEPROM reset, buffer = %s\n",serial_buffer);

	serial_count = 0;
	sending = 0;
	reset_delay = 5;	/* delay a little before returning setting data to 1 (needed by wbeachvl) */
}


void EEPROM_write_bit(int bit)
{
#if VERBOSE
  //logerror("write bit %d\n",bit);
#endif
	latch = bit;
}

int EEPROM_read_bit(void)
{
	int res;

	if (sending)
		res = (eeprom_data_bits >> intf->data_bits) & 1;
	else
	{
		if (reset_delay > 0)
		{
			/* this is needed by wbeachvl */
			reset_delay--;
			res = 0;
		}
		else
			res = 1;
	}

#if VERBOSE
	//logerror("read bit %d\n",res);
#endif

	return res;
}

void EEPROM_set_cs_line(int state)
{
#if VERBOSE
  //logerror("set reset line %d\n",state);
#endif
	reset_line = state;

	if (reset_line != CLEAR_LINE)
		EEPROM_reset();
}

void EEPROM_set_clock_line(int state)
{
#if VERBOSE
  //logerror("set clock line %d\n",state);
#endif
	if (state == PULSE_LINE || (clock_line == CLEAR_LINE && state != CLEAR_LINE))
	{
		if (reset_line == CLEAR_LINE)
		{
			if (sending)
			{
				if (eeprom_clock_count == intf->data_bits && intf->enable_multi_read)
				{
					eeprom_read_address = (eeprom_read_address + 1) & ((1 << intf->address_bits) - 1);
					if (intf->data_bits == 16)
						eeprom_data_bits = (eeprom_data[2*eeprom_read_address+0] << 8) + eeprom_data[2*eeprom_read_address+1];
					else
						eeprom_data_bits = eeprom_data[eeprom_read_address];
					eeprom_clock_count = 0;
					//logerror("EEPROM read %04x from address %02x\n",eeprom_data_bits,eeprom_read_address);
				}
				eeprom_data_bits = (eeprom_data_bits << 1) | 1;
				eeprom_clock_count++;
			}
			else
				EEPROM_write(latch);
		}
	}

	clock_line = state;
}

UINT8 * EEPROM_get_data_pointer(int * length)
{
	if(length)
		*length = MEMORY_SIZE;

	return eeprom_data;
}
