/******************************************************************************

Video Technology Laser 110-310 computers:

    Video Technology Laser 110
      Sanyo Laser 110
    Video Technology Laser 200
      Salora Fellow
      Texet TX-8000
      Video Technology VZ-200
    Video Technology Laser 210
      Dick Smith Electronics VZ-200
      Sanyo Laser 210
    Video Technology Laser 310
      Dick Smith Electronics VZ-300

Machine driver:

    Juergen Buchmueller <pullmoll@t-online.de>, Dec 1999
      - everything

    Dirk Best <duke@redump.de>, May 2004
      - clean up
      - fixed mode 1 display (graphic mode)
      - fixed loading of the DOS ROM
      - preliminary printer emulation

    Dirk Best <duke@redump.de>, March 2006
      - 64K bank switched memory implemented
      - better printer emulation
      - cartridge support

Thanks go to:

    - Guy Thomason
    - Jason Oakley
    - Bushy Maunder
    - and anybody else on the vzemu list :)
    - Davide Moretti for the detailed description of the colors.

Todo:

    - Lightpen
    - RS232 serial

****************************************************************************/


#include "driver.h"
#include "video/generic.h"
#include "video/m6847.h"
#include "includes/vtech1.h"
#include "devices/cassette.h"
#include "devices/printer.h"
#include "cpu/z80/z80.h"
#include "sound/speaker.h"
#include "image.h"

#define LOG_VTECH1_LATCH 0
#define LOG_VTECH1_FDC   0

int vtech1_latch = -1;

#define TRKSIZE_VZ	0x9a0	/* arbitrary (actually from analyzing format) */
#define TRKSIZE_FM	3172	/* size of a standard FM mode track */

static UINT8 vtech1_track_x2[2] = {80, 80};
static UINT8 vtech1_fdc_wrprot[2] = {0x80, 0x80};
static UINT8 vtech1_fdc_status = 0;
static UINT8 vtech1_fdc_data[TRKSIZE_FM];

static int vtech1_data;

static int vtech1_fdc_edge = 0;
static int vtech1_fdc_bits = 8;
static int vtech1_drive = -1;
static int vtech1_fdc_start = 0;
static int vtech1_fdc_write = 0;
static int vtech1_fdc_offs = 0;
static int vtech1_fdc_latch = 0;

/******************************************************************************
 Machine Initialisation
******************************************************************************/

static void common_init_machine(int base)
{
	/* internal ram */
	memory_configure_bank(1, 0, 1, mess_ram, 0);
	memory_set_bank(1, 0);

	/* expansion memory configuration */
	switch (mess_ram_size) {
		case 18 * 1024:
		case 22 * 1024:
		case 32 * 1024:
			/* install 16KB memory expansion */
			memory_install_read8_handler (0, ADDRESS_SPACE_PROGRAM, base, base + 0x3fff, 0, 0, MRA8_BANK2);
			memory_install_write8_handler(0, ADDRESS_SPACE_PROGRAM, base, base + 0x3fff, 0, 0, MWA8_BANK2);
			memory_configure_bank(2, 0, 1, mess_ram + base - 0x7800, 0);
			memory_set_bank(2, 0);

			memory_install_read8_handler (0, ADDRESS_SPACE_PROGRAM, base + 0x4000, 0xffff, 0, 0, MRA8_NOP);
			memory_install_write8_handler(0, ADDRESS_SPACE_PROGRAM, base + 0x4000, 0xffff, 0, 0, MWA8_NOP);
			break;

		case 66 * 1024:
		case 4098 * 1024:
			/* 64KB/4MB memory expansion */

			/* install fixed first bank */
			memory_install_read8_handler (0, ADDRESS_SPACE_PROGRAM, 0x8000, 0xbfff, 0, 0, MRA8_BANK2);
			memory_install_write8_handler(0, ADDRESS_SPACE_PROGRAM, 0x8000, 0xbfff, 0, 0, MWA8_BANK2);
			memory_configure_bank(2, 0, 1, mess_ram + 0x800, 0);
			memory_set_bank(2, 0);

			/* install the others, dynamically banked in */
			memory_install_read8_handler (0, ADDRESS_SPACE_PROGRAM, 0xc000, 0xffff, 0, 0, MRA8_BANK3);
			memory_install_write8_handler(0, ADDRESS_SPACE_PROGRAM, 0xc000, 0xffff, 0, 0, MWA8_BANK3);
			memory_configure_bank(3, 0, (mess_ram_size - 0x4800) / 0x4000, mess_ram + 0x4800, 0x4000);
			memory_set_bank(3, 0);
			break;

		default:
			/* no memory expansion */
			memory_install_read8_handler (0, ADDRESS_SPACE_PROGRAM, base, 0xffff, 0, 0, MRA8_NOP);
			memory_install_write8_handler(0, ADDRESS_SPACE_PROGRAM, base, 0xffff, 0, 0, MWA8_NOP);
			break;
	}
}

MACHINE_START(laser110)
{
	common_init_machine(0x8000);
}

MACHINE_START(laser210)
{
	common_init_machine(0x9000);
}

MACHINE_START(laser310)
{
	common_init_machine(0xb800);
}


/******************************************************************************
 Memory Bank Handling

 TODO: What happens when an invalid bank is selected?
       Currently, we just ignore it and keep the current bank.
******************************************************************************/

WRITE8_HANDLER (vtech1_memory_bank_w)
{
	logerror("vtech1_memory_bank_w $%02X\n", data);

	if (data >= 1)
		if ((data <= 3 && (mess_ram_size == (66 * 1024))) || (mess_ram_size == (4098 * 1024)))
			memory_set_bank(3, data - 1);
}


/******************************************************************************
 Cassette Handling
******************************************************************************/

static mess_image *cassette_device_image(void)
{
	return image_from_devtype_and_index(IO_CASSETTE, 0);
}


/******************************************************************************
 Snapshot Handling
******************************************************************************/

SNAPSHOT_LOAD(vtech1)
{
	UINT8 header[24];
	UINT16 start, end;

	/* get the header */
	image_fread(image, &header, sizeof(header));

	/* get start and end addresses */
	start = pick_integer_le(header, 22, 2);
	end = start + snapshot_size - sizeof(header);

	/* check if we have enough ram */
	if (mess_ram_size < end - start)
		return INIT_FAIL;

	/* write it to ram */
	image_fread(image, &mess_ram[start - 0x7800], end - start);

	/* patch variables depending on snapshot type */
	switch (header[21])
	{
	case VZ_BASIC:
		program_write_byte_8(0x78a4, start % 256); /* start of basic program */
		program_write_byte_8(0x78a5, start / 256);
		program_write_byte_8(0x78f9, end % 256); /* end of basic program */
		program_write_byte_8(0x78fa, end / 256);
		program_write_byte_8(0x78fb, end % 256); /* start variable table */
		program_write_byte_8(0x78fc, end / 256);
		program_write_byte_8(0x78fd, end % 256); /* start free mem, end variable table */
		program_write_byte_8(0x78fe, end / 256);
		break;

	case VZ_MCODE:
		program_write_byte_8(0x788e, start % 256); /* usr subroutine address */
		program_write_byte_8(0x788f, start / 256);
		break;

	default:
		image_seterror(image, IMAGE_ERROR_UNSUPPORTED, "Snapshot format not supported.");
		return INIT_FAIL;
		break;
	}

	return INIT_PASS;
}


/******************************************************************************
 Floppy Handling
******************************************************************************/

static mess_image *vtech1_file(void)
{
	if (vtech1_drive < 0)
		return NULL;

	return image_from_devtype_and_index(IO_FLOPPY, vtech1_drive);
}

/*
int vtech1_floppy_id(int id)
{
    mame_file *file;
    UINT8 buff[32];

    file = image_fopen(IO_FLOPPY, id, FILETYPE_IMAGE, OSD_FOPEN_READ);
    if (file)
    {
        mame_fread(file, buff, sizeof(buff));
        mame_fclose(file);
        if( memcmp(buff, "\x80\x80\x80\x80\x80\x80\x00\xfe\0xe7\0x18\0xc3\x00\x00\x00\x80\x80", 16) == 0 )
            return 1;
    }
    return 0;
}
*/

DEVICE_LOAD(vtech1_floppy)
{
	int id = image_index_in_device(image);

	if (image_is_writable(image))
		vtech1_fdc_wrprot[id] = 0x00;
	else
		vtech1_fdc_wrprot[id] = 0x80;

	return INIT_PASS;
}

static void vtech1_get_track(void)
{
    /* drive selected or and image file ok? */
	if (vtech1_drive >= 0 && image_exists(vtech1_file()))
	{
		int size, offs;
		size = TRKSIZE_VZ;
		offs = TRKSIZE_VZ * vtech1_track_x2[vtech1_drive]/2;
		image_fseek(vtech1_file(), offs, SEEK_SET);
		size = image_fread(vtech1_file(), vtech1_fdc_data, size);
		if (LOG_VTECH1_FDC)
			logerror("get track @$%05x $%04x bytes\n", offs, size);
    }
	vtech1_fdc_offs = 0;
	vtech1_fdc_write = 0;
}

static void vtech1_put_track(void)
{
    /* drive selected and image file ok? */
	if (vtech1_drive >= 0 && vtech1_file() != NULL)
	{
		int size, offs;
		offs = TRKSIZE_VZ * vtech1_track_x2[vtech1_drive]/2;
		image_fseek(vtech1_file(), offs + vtech1_fdc_start, SEEK_SET);
		size = image_fwrite(vtech1_file(), &vtech1_fdc_data[vtech1_fdc_start], vtech1_fdc_write);
		if (LOG_VTECH1_FDC)
			logerror("put track @$%05X+$%X $%04X/$%04X bytes\n", offs, vtech1_fdc_start, size, vtech1_fdc_write);
    }
}

#define PHI0(n) (((n)>>0)&1)
#define PHI1(n) (((n)>>1)&1)
#define PHI2(n) (((n)>>2)&1)
#define PHI3(n) (((n)>>3)&1)

READ8_HANDLER(vtech1_fdc_r)
{
    int data = 0xff;
    switch (offset)
    {
    case 1: /* data (read-only) */
		if (vtech1_fdc_bits > 0)
        {
			if( vtech1_fdc_status & 0x80 )
				vtech1_fdc_bits--;
			data = (vtech1_data >> vtech1_fdc_bits) & 0xff;
			if (LOG_VTECH1_FDC) {
				logerror("vtech1_fdc_r bits %d%d%d%d%d%d%d%d\n",
	                (data>>7)&1,(data>>6)&1,(data>>5)&1,(data>>4)&1,
	                (data>>3)&1,(data>>2)&1,(data>>1)&1,(data>>0)&1 );
			}
        }
		if (vtech1_fdc_bits == 0)
        {
			vtech1_data = vtech1_fdc_data[vtech1_fdc_offs];
			if (LOG_VTECH1_FDC)
				logerror("vtech1_fdc_r %d : data ($%04X) $%02X\n", offset, vtech1_fdc_offs, vtech1_data);
			if(vtech1_fdc_status & 0x80)
            {
				vtech1_fdc_bits = 8;
				vtech1_fdc_offs = (vtech1_fdc_offs + 1) % TRKSIZE_FM;
            }
			vtech1_fdc_status &= ~0x80;
        }
        break;
    case 2: /* polling (read-only) */
        /* fake */
		if (vtech1_drive >= 0)
			vtech1_fdc_status |= 0x80;
		data = vtech1_fdc_status;
        break;
    case 3: /* write protect status (read-only) */
		if (vtech1_drive >= 0)
			data = vtech1_fdc_wrprot[vtech1_drive];
		if (LOG_VTECH1_FDC)
			logerror("vtech1_fdc_r %d : write_protect $%02X\n", offset, data);
        break;
    }
    return data;
}

WRITE8_HANDLER(vtech1_fdc_w)
{
	int drive;

    switch (offset)
	{
	case 0: /* latch (write-only) */
		drive = (data & 0x10) ? 0 : (data & 0x80) ? 1 : -1;
		if (drive != vtech1_drive)
		{
			vtech1_drive = drive;
			if (vtech1_drive >= 0)
				vtech1_get_track();
        }
		if (vtech1_drive >= 0)
        {
			if ((PHI0(data) && !(PHI1(data) || PHI2(data) || PHI3(data)) && PHI1(vtech1_fdc_latch)) ||
				(PHI1(data) && !(PHI0(data) || PHI2(data) || PHI3(data)) && PHI2(vtech1_fdc_latch)) ||
				(PHI2(data) && !(PHI0(data) || PHI1(data) || PHI3(data)) && PHI3(vtech1_fdc_latch)) ||
				(PHI3(data) && !(PHI0(data) || PHI1(data) || PHI2(data)) && PHI0(vtech1_fdc_latch)))
            {
				if (vtech1_track_x2[vtech1_drive] > 0)
					vtech1_track_x2[vtech1_drive]--;
				if (LOG_VTECH1_FDC)
					logerror("vtech1_fdc_w(%d) $%02X drive %d: stepout track #%2d.%d\n", offset, data, vtech1_drive, vtech1_track_x2[vtech1_drive]/2,5*(vtech1_track_x2[vtech1_drive]&1));
				if ((vtech1_track_x2[vtech1_drive] & 1) == 0)
					vtech1_get_track();
            }
            else
			if ((PHI0(data) && !(PHI1(data) || PHI2(data) || PHI3(data)) && PHI3(vtech1_fdc_latch)) ||
				(PHI1(data) && !(PHI0(data) || PHI2(data) || PHI3(data)) && PHI0(vtech1_fdc_latch)) ||
				(PHI2(data) && !(PHI0(data) || PHI1(data) || PHI3(data)) && PHI1(vtech1_fdc_latch)) ||
				(PHI3(data) && !(PHI0(data) || PHI1(data) || PHI2(data)) && PHI2(vtech1_fdc_latch)))
            {
				if (vtech1_track_x2[vtech1_drive] < 2*40)
					vtech1_track_x2[vtech1_drive]++;
				if (LOG_VTECH1_FDC)
					logerror("vtech1_fdc_w(%d) $%02X drive %d: stepin track #%2d.%d\n", offset, data, vtech1_drive, vtech1_track_x2[vtech1_drive]/2,5*(vtech1_track_x2[vtech1_drive]&1));
				if ((vtech1_track_x2[vtech1_drive] & 1) == 0)
					vtech1_get_track();
            }
            if ((data & 0x40) == 0)
			{
				vtech1_data <<= 1;
				if ((vtech1_fdc_latch ^ data) & 0x20)
					vtech1_data |= 1;
				if ((vtech1_fdc_edge ^= 1) == 0)
                {
					if (--vtech1_fdc_bits == 0)
					{
						UINT8 value = 0;
						vtech1_data &= 0xffff;
						if (vtech1_data & 0x4000 ) value |= 0x80;
						if (vtech1_data & 0x1000 ) value |= 0x40;
						if (vtech1_data & 0x0400 ) value |= 0x20;
						if (vtech1_data & 0x0100 ) value |= 0x10;
						if (vtech1_data & 0x0040 ) value |= 0x08;
						if (vtech1_data & 0x0010 ) value |= 0x04;
						if (vtech1_data & 0x0004 ) value |= 0x02;
						if (vtech1_data & 0x0001 ) value |= 0x01;
						if (LOG_VTECH1_FDC)
							logerror("vtech1_fdc_w(%d) data($%04X) $%02X <- $%02X ($%04X)\n", offset, vtech1_fdc_offs, vtech1_fdc_data[vtech1_fdc_offs], value, vtech1_data);
						vtech1_fdc_data[vtech1_fdc_offs] = value;
						vtech1_fdc_offs = (vtech1_fdc_offs + 1) % TRKSIZE_FM;
						vtech1_fdc_write++;
						vtech1_fdc_bits = 8;
					}
                }
            }
			/* change of write signal? */
			if ((vtech1_fdc_latch ^ data) & 0x40)
            {
                /* falling edge? */
				if (vtech1_fdc_latch & 0x40)
                {
					vtech1_fdc_start = vtech1_fdc_offs;
					vtech1_fdc_edge = 0;
                }
                else
                {
                    /* data written to track before? */
					if (vtech1_fdc_write)
						vtech1_put_track();
                }
				vtech1_fdc_bits = 8;
				vtech1_fdc_write = 0;
            }
        }
		vtech1_fdc_latch = data;
		break;
    }
}


/******************************************************************************
 Input Handling
******************************************************************************/

READ8_HANDLER(vtech1_lightpen_r)
{
	logerror("vtech1_lightpen_r(%d)\n", offset);
	return 0xff;
}

READ8_HANDLER(vtech1_joystick_r)
{
    int data = 0xff;

	if (!(offset & 1))
		data &= readinputportbytag("joystick_0");
	if (!(offset & 2))
		data &= readinputportbytag("joystick_0_arm");
	if (!(offset & 4))
		data &= readinputportbytag("joystick_1");
	if (!(offset & 8))
		data &= readinputportbytag("joystick_1_arm");

    return data;
}

READ8_HANDLER(vtech1_keyboard_r)
{
	static int cassette_bit = 0;
	int row, data = 0xff;
	char portname[11];
	double level;

	/* scan keyboard rows */
	for (row = 0; row < 8; row++) {
		sprintf(portname, "keyboard_%d", row);
		if (!(offset & (1 << row)))
			data &= readinputportbytag(portname);
	}

	if (video_screen_get_vblank(0))
        data &= ~0x80;

	/* cassette input is bit 5 (0x40) */
	level = cassette_input(cassette_device_image());
	if (level < -0.008)
		cassette_bit = 0x00;
	if (level > +0.008)
		cassette_bit = 0x40;

	data &= ~cassette_bit;

    return data;
}

/*************************************************
 * bit  function
 * 7    not assigned
 * 6    not assigned
 * 5    speaker B
 * 4    VDC background 0 green, 1 orange
 * 3    VDC display mode 0 text, 1 graphics
 * 2    cassette out (MSB)
 * 1    cassette out (LSB)
 * 0    speaker A
 ************************************************/
WRITE8_HANDLER(vtech1_latch_w)
{
	if (LOG_VTECH1_LATCH)
		logerror("vtech1_latch_w $%02X\n", data);

	/* cassette data bits toggle? */
	if ((vtech1_latch ^ data ) & 0x06)
	{
		static double amp[4] = { +1.0, +0.5, -0.5, -1.0 };
		cassette_output(cassette_device_image(), amp[(data >> 1) & 3]);
	}

	/* speaker data bits toggle? */
	if ((vtech1_latch ^ data ) & 0x41)
		speaker_level_w(0, (data & 1) | ((data >> 5) & 2));

	vtech1_latch = data;
}


/******************************************************************************
 Printer Handling
******************************************************************************/

/*
The VZ200/300 printer interface uses I/O port address OE Hex for the ASCII
character code data and strobe output, and address OOH for the busy/ready-bar
status input (bit 0).
*/

READ8_HANDLER(vtech1_printer_r)
{
	int data = 0xff;

	if (printer_status(image_from_devtype_and_index(IO_PRINTER, 0), 0))
		data &= ~0x01;

	return data;
}

WRITE8_HANDLER(vtech1_printer_w)
{
	static int prn_data;

	switch (offset) {
		case 0x0d:	/* strobe data to printer */
			printer_output(image_from_devtype_and_index(IO_PRINTER, 0), prn_data);
			break;
		case 0x0e:	/* load output latch */
			prn_data = data;
			break;
		default:
			logerror("vtech1_printer_w $%02x, unknown offset %02x\n", data, offset);
	}
}


/******************************************************************************
 Serial RS232 Handling
******************************************************************************/

READ8_HANDLER(vtech1_serial_r)
{
	int data = 0xff;
	logerror("vtech1_serial_r offset $%02x\n", offset);
	return data;
}

WRITE8_HANDLER(vtech1_serial_w)
{
	logerror("vtech1_serial_w $%02x, offset %02x\n", data, offset);
}