// license:LGPL-2.1+
// copyright-holders:Angelo Salese
/*******************************************************************************************************************

Nichibutsu 1414M4 device emulation

Written by Angelo Salese, based on researches by Tomasz Slanina with Legion

This is some fancy blitter DMA or MCU or even a discrete structure that copies text strings to a 8-bit text layer in
various Nihon Bussan games;

TODO:
- Identify what exactly this "device" is;
- The overlying text layer should actually be a base device for this (and used where not applicable like galivan,
  armedf and bigfightr);
- Command triggering condition not understood (and diverges between galivan.cpp and armedf.cpp);
- where is the condition that makes "insert coin" text to properly blink?
- first byte meaning is completely unknown;
- Ninja Emaki triggers unknown commands 0x8000 & 0xff20;

Notes:
- Just before any string in the "MCU" rom, there's a control byte, this meaning is as follows:
  0?-- ---- ---- ---- interpret as data?
  10-- ---- ---- ---- single string transfer
  11-- ---- ---- ---- src -> dst copy, if destination != 0 fixed src, otherwise do a src -> dst
  --xx xxxx xxxx xxxx destination offset in the VRAM tilemap

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

#include "emu.h"
#include "machine/nb1414m4.h"
#include "screen.h"

DEFINE_DEVICE_TYPE(NB1414M4, nb1414m4_device, "nb1414m4", "NB1414M4 Mahjong Custom")

nb1414m4_device::nb1414m4_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
	: device_t(mconfig, NB1414M4, tag, owner, clock)
	, device_video_interface(mconfig, *this)
	, m_data(*this, DEVICE_SELF)
{
}


//-------------------------------------------------
//  device_start - device-specific startup
//-------------------------------------------------

void nb1414m4_device::device_start()
{
	m_previous_0200_command = 0xffff;
	m_previous_0200_command_frame = 0;
	m_in_game = false;
	save_item(NAME(m_previous_0200_command));
	save_item(NAME(m_previous_0200_command_frame));
	save_item(NAME(m_in_game));
}

//-------------------------------------------------
//  device_reset - device-specific startup
//-------------------------------------------------

void nb1414m4_device::device_reset()
{
	m_previous_0200_command = 0xffff;
	m_previous_0200_command_frame = 0;
	m_in_game = false;
}

/*****************************************************************************
    DEVICE HANDLERS
*****************************************************************************/

void nb1414m4_device::dma(uint16_t src, uint16_t dst, uint16_t size, uint8_t condition, uint8_t *vram)
{
	int i;

	for(i=0;i<size;i++)
	{
		if(i+dst+0x000 < 18) //avoid param overwrite
			continue;

		vram[i+dst+0x000] = (condition) ? (m_data[i+(0)+src] & 0xff) : 0x20;

		vram[i+dst+0x400] = (condition) ? (m_data[i+(size)+src] & 0xff) : m_data[0x13];
	}
}

void nb1414m4_device::fill(uint16_t dst, uint8_t tile, uint8_t pal, uint8_t *vram)
{
	int i;

	for(i=0;i<0x400;i++)
	{
		if(i+dst+0x000 < 18) //avoid param overwrite
			continue;

		vram[i+dst+0x000] = tile;
		vram[i+dst+0x400] = pal;
	}
}

void nb1414m4_device::insert_coin_msg(uint8_t *vram)
{
	if (m_in_game)
		return;

	int credit_count = (vram[0xf] & 0xff);
	uint8_t fl_cond = screen().frame_number() & 0x10; /* for insert coin "flickering" */
	uint16_t dst;

	if(credit_count == 0)
	{
		dst = (m_data[0x01]<<8|m_data[0x02]) & 0x3fff;

		dma(0x0003,dst,0x10,fl_cond,vram);
	}
	else
	{
		dst = (m_data[0x49]<<8|m_data[0x4a]) & 0x3fff;

		dma(0x004b,dst,0x18,1,vram);
	}
}

void nb1414m4_device::credit_msg(uint8_t *vram)
{
	int credit_count = (vram[0xf] & 0xff);
	uint8_t fl_cond = screen().frame_number() & 0x10; /* for insert coin "flickering" */
	uint16_t dst;

	dst = ((m_data[0x023]<<8)|(m_data[0x024]&0xff)) & 0x3fff;
	dma(0x0025,dst,0x10,1,vram); /* credit */

	/* credit num */
	dst = ((m_data[0x045]<<8)|(m_data[0x046]&0xff)) & 0x3fff;
	vram[dst+0x000] = (credit_count & 0xf0) ? (((credit_count & 0xf0)>>4) + 0x30) : 0x20;
	vram[dst+0x400] = (m_data[0x47]);
	vram[dst+0x001] = ((credit_count & 0x0f) + 0x30);
	vram[dst+0x401] = (m_data[0x48]);

	if (m_in_game)
		return;

	if(credit_count == 1) /* ONE PLAYER ONLY */
	{
		dst = ((m_data[0x07b]<<8)|(m_data[0x07c]&0xff)) & 0x3fff;
		dma(0x007d,dst,0x18,fl_cond,vram);
	}
	else if(credit_count > 1) /* ONE OR TWO PLAYERS */
	{
		dst = ((m_data[0x0ad]<<8)|(m_data[0x0ae]&0xff)) & 0x3fff;
		dma(0x00af,dst,0x18,fl_cond,vram);
	}
}

void nb1414m4_device::kozure_score_msg(uint16_t dst, uint8_t src_base, uint8_t *vram)
{
	int i;
	uint8_t first_digit;
	uint8_t res;

	first_digit = 0;

	for(i=0;i<6;i++)
	{
		res = ((vram[(i/2)+5+src_base*3] >> (!(i & 1) * 4)) & 0xf);

		if(first_digit || res)
		{
			vram[i+dst+0x0000] = res + 0x30;
			first_digit = 1;
		}
		else
			vram[i+dst+0x0000] = 0x20;

		vram[i+dst+0x0400] = m_data[0x10f+(src_base*0x1c)+i];
	}

	vram[6+dst+0x0000] = vram[5+dst+0x0000] == 0x20 ? 0x20 : 0x30;
	vram[6+dst+0x0400] = m_data[0x10f+(src_base*0x1c)+6];
	vram[7+dst+0x0000] = 0x30;
	vram[7+dst+0x0400] = m_data[0x10f+(src_base*0x1c)+7];

}

void nb1414m4_device::_0200(uint16_t mcu_cmd, uint8_t *vram)
{
	uint16_t dst;

	// In any game, this bit is set when now playing.
	// If it is set, "INSERT COIN" etc. are not displayed.
	m_in_game = (mcu_cmd & 0x80) != 0;

	// If the same command in an extremely short cycle (1 frame or less), ignored it.
	// This is required to displaying continue screen of ninjaemak.
	// ninjaemak calls this command to clear the screen, draw the continuation screen, and then immediately call the same command.
	// This second command must be ignored in order not to corrupt the continue screen.
	if (m_previous_0200_command == mcu_cmd && (screen().frame_number() - m_previous_0200_command_frame) <= 1)
		return;

	dst = (m_data[0x330+((mcu_cmd & 0xf)*2)]<<8)|(m_data[0x331+((mcu_cmd & 0xf)*2)]&0xff);

	dst &= 0x3fff;

	if(dst & 0x7ff) // fill
		fill(0x0000,m_data[dst],m_data[dst+1],vram);
	else // src -> dst
		dma(dst,0x0000,0x400,1,vram);

	m_previous_0200_command = mcu_cmd;
	m_previous_0200_command_frame = screen().frame_number();
}

/*
[0x02] & 0x01 p1 up
[0x02] & 0x02 p1 down
[0x02] & 0x04 p1 left
[0x02] & 0x08 p1 right
[0x02] & 0x10 p1 button 1
[0x02] & 0x20 p1 button 2
[0x02] & 0x40 p1 button 3
[0x03] & 0x01 p2 up
[0x03] & 0x02 p2 down
[0x03] & 0x04 p2 left
[0x03] & 0x08 p2 right
[0x03] & 0x10 p2 button 1
[0x03] & 0x20 p2 button 2
[0x03] & 0x40 p2 button 3
[0x04] & 0x10 service
[0x04] & 0x04 coin A
[0x04] & 0x08 coin B
[0x04] & 0x01 start 1
[0x04] & 0x02 start 2
[0x05] DSW1
[0x06] DSW2
[0x07] & 0x40 demo sounds ON / OFF
[0x07] & 0x7 lives setting
[0x07] & 0x80 cabinet (upright / table)
[0x07] & 0x30 difficulty (easy / normal / hard / hardest)
[0x0f] coinage A
[0x10] coinage B
[0x11] sound test num
*/
void nb1414m4_device::_0600(uint8_t is2p, uint8_t *vram)
{
	uint16_t dst;
	int i;

	dst = ((m_data[0x1f5]<<8)|(m_data[0x1f6]&0xff)) & 0x3fff;
	vram[dst] = (vram[7] & 0x7) + 0x30;//m_data[0x1f7];

	dst = ((m_data[0x1f8]<<8)|(m_data[0x1f9]&0xff)) & 0x3fff;
	dma(0x1fa + (((vram[7] & 0x30) >> 4) * 0x18),dst,12,1,vram);

	// 0x25a - 0x261 unknown meaning

	dst = ((m_data[0x262]<<8)|(m_data[0x263]&0xff)) & 0x3fff;
	dma(0x264 + (((vram[7] & 0x80) >> 7) * 0x18),dst,12,1,vram);

	dst = ((m_data[0x294]<<8)|(m_data[0x295]&0xff)) & 0x3fff;
	dma(0x296 + (((vram[7] & 0x40) >> 6) * 0x18),dst,12,1,vram);

	dst = ((m_data[0x2c6]<<8)|(m_data[0x2c7]&0xff)) & 0x3fff;
	vram[dst] = ((vram[0xf] & 0xf0) >> 4) + 0x30;//m_data[0x2c8];

	dst = ((m_data[0x2c9]<<8)|(m_data[0x2ca]&0xff)) & 0x3fff;
	vram[dst] = ((vram[0xf] & 0x0f) >> 0) + 0x30;//m_data[0x2cb];

	dst = ((m_data[0x2cc]<<8)|(m_data[0x2cd]&0xff)) & 0x3fff;
	vram[dst] = ((vram[0x10] & 0xf0) >> 4) + 0x30;//m_data[0x2ce];

	dst = ((m_data[0x2cf]<<8)|(m_data[0x2d0]&0xff)) & 0x3fff;
	vram[dst] = ((vram[0x10] & 0x0f) >> 0) + 0x30;//m_data[0x2d1];

	dst = ((m_data[0x2d2]<<8)|(m_data[0x2d3]&0xff)) & 0x3fff;
	vram[dst+0] = ((vram[0x11] & 0xf0) >> 4) + 0x30;//m_data[0x2d4];
	vram[dst+1] = (vram[0x11] & 0x0f) + 0x30;//m_data[0x2d5];

	dst = ((m_data[0x2d6]<<8)|(m_data[0x2d7]&0xff)) & 0x3fff;
	dma(0x2d8 + (is2p * 0x18),dst,12,1,vram); // 1p / 2p string

	dst = ((m_data[0x308]<<8)|(m_data[0x309]&0xff)) & 0x3fff;
	for(i=0;i<5;i++) /* system inputs */
		dma(0x310 + (((vram[0x04] >> (4-i)) & 1) * 6),dst + (i * 0x20),0x3,1,vram);

	dst = ((m_data[0x30a]<<8)|(m_data[0x30b]&0xff)) & 0x3fff;
	for(i=0;i<7;i++) /* 1p / 2p inputs */
		dma(0x310 + (((vram[0x02 + is2p] >> (6-i)) & 1) * 6),dst + (i * 0x20),0x3,1,vram);

	dst = ((m_data[0x30c]<<8)|(m_data[0x30d]&0xff)) & 0x3fff;
	for(i=0;i<8;i++) /* dips */
		dma(0x310 + (((vram[0x05] >> (7-i)) & 1) * 6),dst + (i * 0x20),0x3,1,vram);

	dst = ((m_data[0x30e]<<8)|(m_data[0x30f]&0xff)) & 0x3fff;
	for(i=0;i<8;i++) /* dips */
		dma(0x310 + (((vram[0x06] >> (7-i)) & 1) * 6),dst + (i * 0x20),0x3,1,vram);
}

void nb1414m4_device::_0e00(uint16_t mcu_cmd, uint8_t *vram)
{
	uint16_t dst;

	dst = ((m_data[0xdf]<<8)|(m_data[0xe0]&0xff)) & 0x3fff;
	dma(0x00e1,dst,8,1,vram); /* hi-score */

	dst = ((m_data[0xfb]<<8)|(m_data[0xfc]&0xff)) & 0x3fff;
	dma(0x00fd,dst,8,!(mcu_cmd & 1),vram); /* 1p-msg */
	dst = ((m_data[0x10d]<<8)|(m_data[0x10e]&0xff)) & 0x3fff;
	kozure_score_msg(dst,0,vram); /* 1p score */

	if(mcu_cmd & 0x80)
	{
		dst = ((m_data[0x117]<<8)|(m_data[0x118]&0xff)) & 0x3fff;
		dma(0x0119,dst,8,!(mcu_cmd & 2),vram); /* 2p-msg */
		dst = ((m_data[0x129]<<8)|(m_data[0x12a]&0xff)) & 0x3fff;
		kozure_score_msg(dst,1,vram); /* 2p score */
	}

	if((mcu_cmd & 0x04) == 0)
	{
		dst = ((m_data[0x133]<<8)|(m_data[0x134]&0xff)) & 0x3fff;
		dma(0x0135,dst,0x10,1,vram); /* game over */
		insert_coin_msg(vram);
		if((mcu_cmd & 0x18) == 0) // TODO: either one of these two disables credit display
			credit_msg(vram);
	}
}

/*****************************************************************************
    DEVICE SETTERS
*****************************************************************************/

void nb1414m4_device::vblank_trigger()
{
	// TODO: use this for frame number synchronization instead of screen().frame_number()
	//  real HW references definitely syncs insert coin blinking after POST so whatever is the host actually
	//  have an interest over vblank signal.
}

void nb1414m4_device::exec(uint16_t mcu_cmd, uint8_t *vram, uint16_t &scrollx, uint16_t &scrolly, tilemap_t *tilemap)
{
	/* latch fg scroll values */
	scrollx = (vram[0x0d] & 0xff) | ((vram[0x0e] & 0xff) << 8);
	scrolly = (vram[0x0b] & 0xff) | ((vram[0x0c] & 0xff) << 8);

	/* process the command */
	switch(mcu_cmd & 0xff00)
	{
		/* title screen / continue screens */
		case 0x0000: insert_coin_msg(vram); credit_msg(vram); break;

		/* direct DMA'ing / fill */
		case 0x0200: _0200(mcu_cmd & 0x87,vram); break;

		/* service mode */
		case 0x0600: _0600(mcu_cmd & 1,vram); break;

		/* gameplay */
		case 0x0e00: _0e00(mcu_cmd & 0xff,vram); break;

		case 0x8000: break; //Ninja Emaki, attract mode
		case 0xff00: break; //Ninja Emaki POST, presumably invalid
		default:
			popmessage("NB 1414M4 executes %04x command, contact MAMEdev",mcu_cmd);
			break;
	}

	/* mark tiles dirty */
	tilemap->mark_all_dirty();
}
