// license:GPL-2.0+
// copyright-holders:Kevin Thacker, Robbbert
/******************************************************************************

  Exidy Sorcerer machine functions

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

#include "emu.h"
#include "includes/sorcerer.h"
#include "machine/z80bin.h"

// ************ TIMERS **************
/* timer for sorcerer serial chip transmit and receive */

TIMER_CALLBACK_MEMBER(sorcerer_state::serial_tc)
{
	/* if rs232 is enabled, uart is connected to clock defined by bit6 of port fe.
	Transmit and receive clocks are connected to the same clock. */

	/* if rs232 is disabled, receive clock is linked to cassette hardware */
	if (BIT(m_portfe, 7))
	{
		/* connect to rs232 */
		m_rs232->write_txd(m_uart->so_r());
		m_uart->write_si(m_rs232->rxd_r());
	}
}


void sorcerer_state::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
{
	switch (id)
	{
	case TIMER_SERIAL:
		serial_tc(ptr, param);
		break;
	case TIMER_CASSETTE:
		cassette_tc(ptr, param);
		break;
	default:
		throw emu_fatalerror("Unknown id in sorcerer_state::device_timer");
	}
}


/* timer to read cassette waveforms */

TIMER_CALLBACK_MEMBER(sorcerer_state::cassette_tc)
{
	u8 cass_ws = 0;
	switch (m_portfe & 0xc0)        /*/ bit 7 low indicates cassette */
	{
		case 0x00:              /* Cassette 300 baud */

			/* loading a tape - this is basically the same as the super80.
			               We convert the 1200/2400 Hz signal to a 0 or 1, and send it to the uart. */

			m_cass_data.input.length++;

			cass_ws = ((((m_portfe & 0x20) ? m_cassette2 : m_cassette1))->input() > +0.02) ? 1 : 0;

			if (cass_ws != m_cass_data.input.level)
			{
				m_cass_data.input.level = cass_ws;
				m_cass_data.input.bit = ((m_cass_data.input.length < 0x6) || (m_cass_data.input.length > 0x20)) ? 1 : 0;
				m_cass_data.input.length = 0;
				m_uart->write_si(m_cass_data.input.bit);
			}

			/* saving a tape - convert the serial stream from the uart, into 1200 and 2400 Hz frequencies.
			               Synchronisation of the frequency pulses to the uart is extremely important. */

			m_cass_data.output.length++;
			if (!(m_cass_data.output.length & 0x1f))
			{
				cass_ws = m_uart->so_r();
				if (cass_ws != m_cass_data.output.bit)
				{
					m_cass_data.output.bit = cass_ws;
					m_cass_data.output.length = 0;
				}
			}

			if (!(m_cass_data.output.length & 3))
			{
				if (!((m_cass_data.output.bit == 0) && (m_cass_data.output.length & 4)))
				{
					m_cass_data.output.level ^= 1;          // toggle output this, except on 2nd half of low bit
					((m_portfe & 0x20) ? m_cassette2 : m_cassette1)->output(m_cass_data.output.level ? -1.0 : +1.0);
				}
			}
			return;

		case 0x40:          /* Cassette 1200 baud */
			/* loading a tape */
			m_cass_data.input.length++;

			cass_ws = ((((m_portfe & 0x20) ? m_cassette2 : m_cassette1))->input() > +0.02) ? 1 : 0;

			if (cass_ws != m_cass_data.input.level || m_cass_data.input.length == 10)
			{
				m_cass_data.input.bit = ((m_cass_data.input.length < 10) || (m_cass_data.input.length > 0x20)) ? 1 : 0;
				if ( cass_ws != m_cass_data.input.level )
				{
					m_cass_data.input.length = 0;
					m_cass_data.input.level = cass_ws;
				}
				m_uart->write_si(m_cass_data.input.bit);
			}

			/* saving a tape - convert the serial stream from the uart, into 600 and 1200 Hz frequencies. */

			m_cass_data.output.length++;
			if (!(m_cass_data.output.length & 7))
			{
				cass_ws = m_uart->so_r();
				if (cass_ws != m_cass_data.output.bit)
				{
					m_cass_data.output.bit = cass_ws;
					m_cass_data.output.length = 0;
				}
			}

			if (!(m_cass_data.output.length & 7))
			{
				if (!((m_cass_data.output.bit == 0) && (m_cass_data.output.length & 8)))
				{
					m_cass_data.output.level ^= 1;          // toggle output this, except on 2nd half of low bit
					((m_portfe & 0x20) ? m_cassette2 : m_cassette1)->output(m_cass_data.output.level ? -1.0 : +1.0);
				}
			}
			return;
	}
}


// ************ EXIDY VIDEO UNIT FDC **************
// The floppy sector has been read. Enable CPU.
void sorcererd_state::intrq2_w(bool state)
{
	m_intrq_off = state ? false : true;
	if (state)
	{
		m_maincpu->set_input_line(Z80_INPUT_LINE_WAIT, CLEAR_LINE);
		m_wait = false;
	}
	else
	if (BIT(m_port2c, 0) && m_drq_off && !m_wait)
	{
		m_maincpu->set_input_line(Z80_INPUT_LINE_WAIT, ASSERT_LINE);
		m_wait = true;
	}
}

// The next byte from floppy is available. Enable CPU so it can get the byte.
void sorcererd_state::drq2_w(bool state)
{
	m_drq_off = state ? false : true;
	if (state)
	{
		m_maincpu->set_input_line(Z80_INPUT_LINE_WAIT, CLEAR_LINE);
		m_wait = false;
	}
	else
	if (BIT(m_port2c, 0) && m_intrq_off && !m_wait)
	{
		m_maincpu->set_input_line(Z80_INPUT_LINE_WAIT, ASSERT_LINE);
		m_wait = true;
	}
}

// Port 2C control signals for the video/disk unit's floppy disks
// Signals are unknown so guess
// It outputs 24 or 25 when booting, so suppose that
// bit 0 = enable wait generator, bit 2 = drive 0 select, bit 5 = ??
void sorcererd_state::port2c_w(u8 data)
{
	m_port2c = data;

	if (BIT(data, 0))
	{
		if (!m_wait && m_drq_off && m_intrq_off)
		{
			m_maincpu->set_input_line(Z80_INPUT_LINE_WAIT, ASSERT_LINE);
			m_wait = true;
		}
	}

	floppy_image_device *floppy = nullptr;

	if (BIT(data, 2)) floppy = m_floppy20->get_device();
	if (BIT(data, 3)) floppy = m_floppy21->get_device();

	m_fdc2->set_floppy(floppy);

	if (floppy)
	{
		floppy->mon_w(0);
		floppy->ss_w(0);     // assume side 0 ? // BIT(data, 4));
	}

	m_fdc2->dden_w(0);   // assume double density ? //!BIT(data, 0));
}

// ************ DREAMDISK FDC **************
// Dreamdisk interrupts
void sorcerer_state::intrq4_w(bool state)
{
	if (state && m_halt)
		m_maincpu->set_input_line(INPUT_LINE_NMI, ASSERT_LINE);
	else
		m_maincpu->set_input_line(INPUT_LINE_NMI, CLEAR_LINE);
}

u8 sorcerer_state::port48_r()
{
	return m_port48;
}

void sorcerer_state::port48_w(u8 data)
{
	m_port48 = data;
	data ^= 0x1f;
	floppy_image_device *floppy = nullptr;

	if (BIT(data, 0)) floppy = m_floppy40->get_device();
	if (BIT(data, 1)) floppy = m_floppy41->get_device();
	if (BIT(data, 2)) floppy = m_floppy42->get_device();
	if (BIT(data, 3)) floppy = m_floppy43->get_device();

	m_fdc4->set_floppy(floppy);

	if (floppy)
	{
		floppy->mon_w(0);
		floppy->ss_w(BIT(data, 4));
	}

	m_fdc4->dden_w(BIT(data, 5));
	m_fdc4->enmf_w(BIT(data, 6));  // also connected to unsupported 5/8 pin.
}

// ************ DIGITRIO FDC **************
u8 sorcerer_state::port34_r()
{
	u8 data = m_port34;
	data |= m_fdc3->intrq_r() ? 0x80 : 0;
	//data |= m_floppy->twosid_r() ? 0 : 0x20; // for 20cm disks only, 0=indicates the disk has 2 sides (drive has 2 heads?)
	return data;
}

void sorcerer_state::port34_w(u8 data)
{
	m_port34 = data & 0x5f;
	floppy_image_device *floppy = nullptr;

	if (BIT(data, 0)) floppy = m_floppy30->get_device();
	if (BIT(data, 1)) floppy = m_floppy31->get_device();
	if (BIT(data, 2)) floppy = m_floppy32->get_device();
	if (BIT(data, 3)) floppy = m_floppy33->get_device();

	m_fdc3->set_floppy(floppy);

	if (floppy)
	{
		floppy->mon_w(0);
		floppy->ss_w(BIT(data, 5));
	}

	m_fdc3->dden_w(BIT(data, 6));
	m_fdc3->set_unscaled_clock (BIT(data, 4) ? 2'000'000 : 1'000'000);
}

// ************ DIGITRIO DMA **************
void sorcerer_state::busreq_w(bool state)
{
// since our Z80 has no support for BUSACK, we assume it is granted immediately
	m_maincpu->set_input_line(Z80_INPUT_LINE_BUSRQ, state);
	m_maincpu->set_input_line(INPUT_LINE_HALT, state);
	m_dma->bai_w(state); // tell dma that bus has been granted
}

u8 sorcerer_state::memory_read_byte(offs_t offset)
{
	address_space& prog_space = m_maincpu->space(AS_PROGRAM);
	return prog_space.read_byte(offset);
}

void sorcerer_state::memory_write_byte(offs_t offset, u8 data)
{
	address_space& prog_space = m_maincpu->space(AS_PROGRAM);
	prog_space.write_byte(offset, data);
}

u8 sorcerer_state::io_read_byte(offs_t offset)
{
	address_space& prog_space = m_maincpu->space(AS_IO);
	return prog_space.read_byte(offset);
}

void sorcerer_state::io_write_byte(offs_t offset, u8 data)
{
	address_space& prog_space = m_maincpu->space(AS_IO);
	prog_space.write_byte(offset, data);
}

// ************ INBUILT PORTS **************
void sorcerer_state::portfd_w(u8 data)
{
	/* Translate data to control signals */

	m_uart->write_cs(0);
	m_uart->write_nb1(BIT(data, 0));
	m_uart->write_nb2(BIT(data, 1));
	m_uart->write_tsb(BIT(data, 2));
	m_uart->write_eps(BIT(data, 3));
	m_uart->write_np(BIT(data, 4));
	m_uart->write_cs(1);
}

void sorcerer_state::portfe_w(u8 data)
{
	u8 changed_bits = (m_portfe ^ data) & 0xf0;
	m_portfe = data;

	/* bits 0..3 */
	m_keyboard_line = data & 0x0f;

	if (!changed_bits) return;

	/* bits 4..5 */
	/* does user want to hear the sound? */

	if (!BIT(data, 7)) // cassette operations
	{
		m_serial_timer->adjust(attotime::zero);

		bool sound = BIT(m_iop_config->read(), 3);

		m_cassette1->change_state(
			(BIT(data,4) && sound) ? CASSETTE_SPEAKER_ENABLED : CASSETTE_SPEAKER_MUTED, CASSETTE_MASK_SPEAKER);

		m_cassette2->change_state(
			(BIT(data,5) && sound) ? CASSETTE_SPEAKER_ENABLED : CASSETTE_SPEAKER_MUTED, CASSETTE_MASK_SPEAKER);

		/* cassette 1 motor */
		m_cassette1->change_state(
			(BIT(data,4)) ? CASSETTE_MOTOR_ENABLED : CASSETTE_MOTOR_DISABLED, CASSETTE_MASK_MOTOR);

		/* cassette 2 motor */
		m_cassette2->change_state(
			(BIT(data,5)) ? CASSETTE_MOTOR_ENABLED : CASSETTE_MOTOR_DISABLED, CASSETTE_MASK_MOTOR);

		if (data & 0x30)
			m_cassette_timer->adjust(attotime::zero, 0, attotime::from_hz(ES_UART_CLOCK*4));
		else
			m_cassette_timer->adjust(attotime::zero);
	}
	else
	{
		m_serial_timer->adjust(attotime::zero, 0, attotime::from_hz(ES_UART_CLOCK*4));
		m_cassette_timer->adjust(attotime::zero);
	}

	// bit 6 baud rate */
	if (BIT(changed_bits, 6))
	{
		m_uart_clock->set_unscaled_clock(BIT(data, 6) ? ES_UART_CLOCK*4 : ES_UART_CLOCK);
	}
}

void sorcerer_state::portff_w(u8 data)
{
	/// TODO: create a sorcerer parallel slot with a 7 bit and 8 bit centronics adapter as two of the options
	/// TODO: figure out what role FE plays http://www.trailingedge.com/exidy/exidych7.html
	m_centronics->write_data0(BIT(data, 0));
	m_centronics->write_data1(BIT(data, 1));
	m_centronics->write_data2(BIT(data, 2));
	m_centronics->write_data3(BIT(data, 3));
	m_centronics->write_data4(BIT(data, 4));
	m_centronics->write_data5(BIT(data, 5));
	m_centronics->write_data6(BIT(data, 6));

	/* reading the config switch */
	switch (m_iop_config->read() & 0x02)
	{
	case 0: /* 7-bit port */
		/* bit 7 = strobe, bit 6..0 = data */
		m_centronics->write_data7(0);
		m_centronics->write_strobe(BIT(data, 7));
		break;

	case 2: /* 8-bit port */
		/* hardware strobe driven from port select, bit 7..0 = data */
		m_centronics->write_data7(BIT(data, 7));
		m_centronics->write_strobe(0);
		m_centronics->write_strobe(1);
		break;
	}
}

u8 sorcerer_state::portfd_r()
{
	/* set unused bits high */
	u8 data = 0xe0;

	m_uart->write_swe(0);
	data |= m_uart->tbmt_r() ? 0x01 : 0;
	data |= m_uart->dav_r( ) ? 0x02 : 0;
	data |= m_uart->or_r(  ) ? 0x04 : 0;
	data |= m_uart->fe_r(  ) ? 0x08 : 0;
	data |= m_uart->pe_r(  ) ? 0x10 : 0;
	m_uart->write_swe(1);

	return data;
}

u8 sorcerer_state::portfe_r()
{
	/* bits 6..7
	 - hardware handshakes from user port
	 - not emulated
	 - tied high, allowing PARIN and PAROUT bios routines to run */

	u8 data = 0xc0;

	/* bit 5 - vsync */
	data |= m_iop_vs->read();

	/* bits 4..0 - keyboard data */
	data |= m_iop_x[m_keyboard_line]->read();

	return data;
}

// ************ MACHINE **************
void sorcerer_state::machine_start_common(offs_t endmem)
{
	m_cassette_timer = timer_alloc(TIMER_CASSETTE);
	m_serial_timer = timer_alloc(TIMER_SERIAL);

	m_halt = false;

	// register for savestates
	save_item(NAME(m_portfe));
	save_item(NAME(m_keyboard_line));

	address_space &space = m_maincpu->space(AS_PROGRAM);
	/* configure RAM */
	switch (m_ram->size())
	{
	case 8*1024:
		space.unmap_readwrite(0x2000, endmem);
		break;

	case 16*1024:
		space.unmap_readwrite(0x4000, endmem);
		break;

	case 32*1024:
		space.unmap_readwrite(0x8000, endmem);
		break;
	}

	if (m_cart && m_cart->exists())
		space.install_read_handler(0xc000, 0xdfff, read8sm_delegate(*m_cart, FUNC(generic_slot_device::read_rom)));
}

void sorcerer_state::machine_start()
{
	machine_start_common(0xbfff);
	save_item(NAME(m_port48));
	save_item(NAME(m_port34));
	save_item(NAME(m_halt));
}

void sorcererd_state::machine_start()
{
	machine_start_common(0xbbff);
	save_item(NAME(m_port2c));
	save_item(NAME(m_wait));
	save_item(NAME(m_drq_off));
	save_item(NAME(m_intrq_off));
}

void sorcerer_state::machine_reset_common()
{
	address_space &space = m_maincpu->space(AS_PROGRAM);

	/* Initialize cassette interface */
	m_cass_data.output.length = 0;
	m_cass_data.output.level = 1;
	m_cass_data.input.length = 0;
	m_cass_data.input.bit = 1;

	m_portfe = 0xff;
	portfe_w(0);

	space.install_rom(0x0000, 0x0fff, m_rom);   // do it here for F3
	m_rom_shadow_tap = space.install_read_tap(0xe000, 0xefff, "rom_shadow_r",[this](offs_t offset, u8 &data, u8 mem_mask)
	{
		if (!machine().side_effects_disabled())
		{
			// delete this tap
			m_rom_shadow_tap->remove();

			// reinstall ram over the rom shadow
			m_maincpu->space(AS_PROGRAM).install_ram(0x0000, 0x0fff, m_ram->pointer());
		}

		// return the original data
		return data;
	});
}

void sorcerer_state::machine_reset()
{
	machine_reset_common();
}

void sorcererd_state::machine_reset()
{
	m_drq_off = true;
	m_intrq_off = true;
	m_wait = false;
	m_port2c = 0;
	machine_reset_common();
}


/*-------------------------------------------------
    QUICKLOAD_LOAD_MEMBER( sorcerer_state, sorcerer )
    Handles BIN and SNP extensions.
-------------------------------------------------*/

QUICKLOAD_LOAD_MEMBER(sorcerer_state::quickload_cb)
{
	// get autorun setting
	bool autorun = BIT(m_iop_config->read(), 0);
	address_space &space = m_maincpu->space(AS_PROGRAM);

	if (image.is_filetype("bin"))
	{
		u16 execute_address, start_address, end_address;

		// load the binary into memory
		if (z80bin_load_file(image, space, execute_address, start_address, end_address) != image_init_result::PASS)
			return image_init_result::FAIL;

		// is this file executable?
		if (execute_address != 0xffff)
		{

			if ((execute_address >= 0xc000) && (execute_address <= 0xdfff) && (space.read_byte(0xdffa) != 0xc3))
				return image_init_result::FAIL;     // can't run a program if the cartridge isn't in

			/* Since Exidy Basic is by Microsoft, it needs some preprocessing before it can be run.
			1. A start address of 01D5 indicates a basic program which needs its pointers fixed up.
			2. If autorunning, jump to C689 (command processor), else jump to C3DD (READY prompt).
			Important addresses:
			    01D5 = start (load) address of a conventional basic program
			    C858 = an autorun basic program will have this exec address on the tape
			    C3DD = part of basic that displays READY and lets user enter input */

			if (((start_address == 0x1d5) || (execute_address == 0xc858)) && (space.read_byte(0xdffa) == 0xc3))
			{
				static const u8 data[]={
					0xcd, 0x26, 0xc4,   // CALL C426    ;set up other pointers
					0x21, 0xd4, 1,      // LD HL,01D4   ;start of program address (used by C689)
					0x36, 0,            // LD (HL),00   ;make sure dummy end-of-line is there
					0xc3, 0x89, 0xc6    // JP C689  ;run program
				};

				for (u8 i = 0; i < std::size(data); i++)
					space.write_byte(0xf01f + i, data[i]);

				if (!autorun)
					space.write_word(0xf028,0xc3dd);

				/* tell BASIC where program ends */
				space.write_byte(0x1b7, end_address & 0xff);
				space.write_byte(0x1b8, (end_address >> 8) & 0xff);

				if ((execute_address != 0xc858) && autorun)
					space.write_word(0xf028, execute_address);

				m_maincpu->set_pc(0xf01f);
			}
			else
			{
				if (autorun)
					m_maincpu->set_pc(execute_address);
			}
		}
	}
	else
	{
		// SNP extension
		// check size
		if (image.length() != 0x1001c)
		{
			image.seterror(IMAGE_ERROR_INVALIDIMAGE, "Snapshot must be 65564 bytes");
			image.message("Snapshot must be 65564 bytes");
			return image_init_result::FAIL;
		}

		/* get the header */
		u8 header[28];
		image.fread( &header, sizeof(header));

		logerror("SNP PC register = 0x%04x\n", header[26] | (header[27] << 8));

		// write it to ram, and skip roms
		unsigned char s_byte;
		for (int i = 0; i < 0xe000; i++)
		{
			image.fread( &s_byte, 1);
			space.write_byte(i, s_byte);  // ram
		}

		for (int i = 0xe000; i < 0xf000; i++)
			image.fread( &s_byte, 1);

		for (int i = 0xf000; i < 0xf800; i++)
		{
			image.fread( &s_byte, 1);
			space.write_byte(i, s_byte);  // screen
		}

		for (int i = 0xf800; i < 0xfc00; i++)
			image.fread( &s_byte, 1);

		for (int i = 0xfc00; i < 0x10000; i++)
		{
			image.fread( &s_byte, 1);
			space.write_byte(i, s_byte);  //pcg
		}

		// it's assumed if autorun was off that you wished to examine the image rather than to play it
		if (autorun)
		{
			// patch CPU registers
			m_maincpu->set_state_int(Z80_I, header[0]);
			m_maincpu->set_state_int(Z80_HL2, header[1] | (header[2] << 8));
			m_maincpu->set_state_int(Z80_DE2, header[3] | (header[4] << 8));
			m_maincpu->set_state_int(Z80_BC2, header[5] | (header[6] << 8));
			m_maincpu->set_state_int(Z80_AF2, header[7] | (header[8] << 8));
			m_maincpu->set_state_int(Z80_HL, header[9] | (header[10] << 8));
			m_maincpu->set_state_int(Z80_DE, header[11] | (header[12] << 8));
			m_maincpu->set_state_int(Z80_BC, header[13] | (header[14] << 8));
			m_maincpu->set_state_int(Z80_IY, header[15] | (header[16] << 8));
			m_maincpu->set_state_int(Z80_IX, header[17] | (header[18] << 8));
			m_maincpu->set_state_int(Z80_IFF1, header[19]&2 ? 1 : 0);
			m_maincpu->set_state_int(Z80_IFF2, header[19]&4 ? 1 : 0);
			m_maincpu->set_state_int(Z80_R, header[20]);
			m_maincpu->set_state_int(Z80_AF, header[21] | (header[22] << 8));
			m_maincpu->set_state_int(STATE_GENSP, header[23] | (header[24] << 8));
			m_maincpu->set_state_int(Z80_IM, header[25]);
			m_maincpu->set_pc(header[26] | (header[27] << 8));
		}
		else
			m_maincpu->set_pc(0xe000);  // SNP destroys workspace, so do cold start.
	}

	return image_init_result::PASS;
}

