/*MDA emulation*/
#include <stdlib.h>
#include "ibm.h"
#include "device.h"
#include "io.h"
#include "mem.h"
#include "timer.h"
#include "video.h"
#include "vid_mda.h"

static uint32_t mdacols[256][2][2];

void mda_recalctimings(mda_t *mda);

void mda_out(uint16_t addr, uint8_t val, void *p) {
	mda_t *mda = (mda_t *)p;
	switch (addr) {
	case 0x3b0:
	case 0x3b2:
	case 0x3b4:
	case 0x3b6:mda->crtcreg = val & 31;
		return;
	case 0x3b1:
	case 0x3b3:
	case 0x3b5:
	case 0x3b7:mda->crtc[mda->crtcreg] = val;
		if (mda->crtc[10] == 6 && mda->crtc[11] == 7) /*Fix for Generic Turbo XT BIOS, which sets up cursor registers wrong*/
		{
			mda->crtc[10] = 0xb;
			mda->crtc[11] = 0xc;
		}
		mda_recalctimings(mda);
		return;
	case 0x3b8:mda->ctrl = val;
		return;
	}
}

uint8_t mda_in(uint16_t addr, void *p) {
	mda_t *mda = (mda_t *)p;
	switch (addr) {
	case 0x3b0:
	case 0x3b2:
	case 0x3b4:
	case 0x3b6:return mda->crtcreg;
	case 0x3b1:
	case 0x3b3:
	case 0x3b5:
	case 0x3b7:return mda->crtc[mda->crtcreg];
	case 0x3ba:return mda->stat | 0xF0;
	}
	return 0xff;
}

void mda_write(uint32_t addr, uint8_t val, void *p) {
	mda_t *mda = (mda_t *)p;
	egawrites++;
	mda->vram[addr & 0xfff] = val;
}

uint8_t mda_read(uint32_t addr, void *p) {
	mda_t *mda = (mda_t *)p;
	egareads++;
	return mda->vram[addr & 0xfff];
}

void mda_recalctimings(mda_t *mda) {
	double _dispontime, _dispofftime, disptime;
	disptime = mda->crtc[0] + 1;
	_dispontime = mda->crtc[1];
	_dispofftime = disptime - _dispontime;
	_dispontime *= MDACONST;
	_dispofftime *= MDACONST;
	mda->dispontime = (uint64_t)_dispontime;
	mda->dispofftime = (uint64_t)_dispofftime;
}

void mda_poll(void *p) {
	mda_t *mda = (mda_t *)p;
	uint16_t ca = (mda->crtc[15] | (mda->crtc[14] << 8)) & 0x3fff;
	int drawcursor;
	int x, c;
	int oldvc;
	uint8_t chr, attr;
	int oldsc;
	int blink;
	if (!mda->linepos) {
		timer_advance_u64(&mda->timer, mda->dispofftime);
		mda->stat |= 1;
		mda->linepos = 1;
		oldsc = mda->sc;
		if ((mda->crtc[8] & 3) == 3)
			mda->sc = (mda->sc << 1) & 7;
		if (mda->dispon) {
			if (mda->displine < mda->firstline) {
				mda->firstline = mda->displine;
				video_wait_for_buffer();
			}
			mda->lastline = mda->displine;
			for (x = 0; x < mda->crtc[1]; x++) {
				chr = mda->vram[(mda->ma << 1) & 0xfff];
				attr = mda->vram[((mda->ma << 1) + 1) & 0xfff];
				drawcursor = ((mda->ma == ca) && mda->con && mda->cursoron);
				blink = ((mda->blink & 16) && (mda->ctrl & 0x20) && (attr & 0x80) && !drawcursor);
				if (mda->sc == 12 && ((attr & 7) == 1)) {
					for (c = 0; c < 9; c++)
						((uint32_t *)buffer32->line[mda->displine])[(x * 9) + c] = mdacols[attr][blink][1];
				} else {
					for (c = 0; c < 8; c++)
						((uint32_t *)buffer32->line[mda->displine])[(x * 9) + c] = mdacols[attr][blink][(fontdatm[chr][mda->sc] & (1 << (c ^ 7))) ? 1 : 0];
					if ((chr & ~0x1f) == 0xc0)
						((uint32_t *)buffer32->line[mda->displine])[(x * 9) + 8] = mdacols[attr][blink][fontdatm[chr][mda->sc] & 1];
					else
						((uint32_t *)buffer32->line[mda->displine])[(x * 9) + 8] = mdacols[attr][blink][0];
				}
				mda->ma++;
				if (drawcursor) {
					for (c = 0; c < 9; c++)
						((uint32_t *)buffer32->line[mda->displine])[(x * 9) + c] ^= mdacols[attr][0][1];
				}
			}
		}
		mda->sc = oldsc;
		if (mda->vc == mda->crtc[7] && !mda->sc) {
			mda->stat |= 8;
//                        printf("VSYNC on %i %i\n",vc,sc);
		}
		mda->displine++;
		if (mda->displine >= 500)
			mda->displine = 0;
	} else {
		timer_advance_u64(&mda->timer, mda->dispontime);
		if (mda->dispon)
			mda->stat &= ~1;
		mda->linepos = 0;
		if (mda->vsynctime) {
			mda->vsynctime--;
			if (!mda->vsynctime) {
				mda->stat &= ~8;
//                                printf("VSYNC off %i %i\n",vc,sc);
			}
		}
		if (mda->sc == (mda->crtc[11] & 31) || ((mda->crtc[8] & 3) == 3 && mda->sc == ((mda->crtc[11] & 31) >> 1))) {
			mda->con = 0;
			mda->coff = 1;
		}
		if (mda->vadj) {
			mda->sc++;
			mda->sc &= 31;
			mda->ma = mda->maback;
			mda->vadj--;
			if (!mda->vadj) {
				mda->dispon = 1;
				mda->ma = mda->maback = (mda->crtc[13] | (mda->crtc[12] << 8)) & 0x3fff;
				mda->sc = 0;
			}
		} else if (mda->sc == mda->crtc[9] || ((mda->crtc[8] & 3) == 3 && mda->sc == (mda->crtc[9] >> 1))) {
			mda->maback = mda->ma;
			mda->sc = 0;
			oldvc = mda->vc;
			mda->vc++;
			mda->vc &= 127;
			if (mda->vc == mda->crtc[6])
				mda->dispon = 0;
			if (oldvc == mda->crtc[4]) {
//                                printf("Display over at %i\n",displine);
				mda->vc = 0;
				mda->vadj = mda->crtc[5];
				if (!mda->vadj)
					mda->dispon = 1;
				if (!mda->vadj)
					mda->ma = mda->maback = (mda->crtc[13] | (mda->crtc[12] << 8)) & 0x3fff;
				if ((mda->crtc[10] & 0x60) == 0x20)
					mda->cursoron = 0;
				else
					mda->cursoron = mda->blink & 16;
			}
			if (mda->vc == mda->crtc[7]) {
				mda->dispon = 0;
				mda->displine = 0;
				mda->vsynctime = 16;
				if (mda->crtc[7]) {
//                                        printf("Lastline %i Firstline %i  %i\n",lastline,firstline,lastline-firstline);
					x = mda->crtc[1] * 9;
					mda->lastline++;
					if (x != xsize || (mda->lastline - mda->firstline) != ysize) {
						xsize = x;
						ysize = mda->lastline - mda->firstline;
//                                                printf("Resize to %i,%i - R1 %i\n",xsize,ysize,crtcm[1]);
						if (xsize < 64)
							xsize = 656;
						if (ysize < 32)
							ysize = 200;
						updatewindowsize(xsize, ysize);
					}

					video_blit_memtoscreen(0, mda->firstline, 0, ysize, xsize, ysize);

					frames++;
					video_res_x = mda->crtc[1];
					video_res_y = mda->crtc[6];
					video_bpp = 0;
				}
				mda->firstline = 1000;
				mda->lastline = 0;
				mda->blink++;
			}
		} else {
			mda->sc++;
			mda->sc &= 31;
			mda->ma = mda->maback;
		}
		if ((mda->sc == (mda->crtc[10] & 31) || ((mda->crtc[8] & 3) == 3 && mda->sc == ((mda->crtc[10] & 31) >> 1)))) {
			mda->con = 1;
//                        printf("Cursor on - %02X %02X %02X\n",crtcm[8],crtcm[10],crtcm[11]);
		}
	}
}

void *mda_standalone_init() {
	mda_t *mda = malloc(sizeof(mda_t));

	memset(mda, 0, sizeof(mda_t));
	mda_init(mda);

	mda->vram = malloc(0x1000);
	mem_mapping_add(&mda->mapping, 0xb0000, 0x08000, mda_read, NULL, NULL, mda_write, NULL, NULL, NULL, MEM_MAPPING_EXTERNAL, mda);
	io_sethandler(0x03b0, 0x0010, mda_in, NULL, NULL, mda_out, NULL, NULL, mda);

	return mda;
}

void mda_init(mda_t *mda) {
	int display_type;
	int c;

	display_type = device_get_config_int("display_type");
	cgapal_rebuild(display_type, 0);

	for (c = 0; c < 256; c++) {
		mdacols[c][0][0] = mdacols[c][1][0] = mdacols[c][1][1] = cgapal[0];
		if (c & 8)
			mdacols[c][0][1] = cgapal[0xf];
		else
			mdacols[c][0][1] = cgapal[0x7];
	}
	mdacols[0x70][0][1] = cgapal[0];
	mdacols[0x70][0][0] = mdacols[0x70][1][0] = mdacols[0x70][1][1] = cgapal[0xf];
	mdacols[0xF0][0][1] = cgapal[0];
	mdacols[0xF0][0][0] = mdacols[0xF0][1][0] = mdacols[0xF0][1][1] = cgapal[0xf];
	mdacols[0x78][0][1] = cgapal[0x7];
	mdacols[0x78][0][0] = mdacols[0x78][1][0] = mdacols[0x78][1][1] = cgapal[0xf];
	mdacols[0xF8][0][1] = cgapal[0x7];
	mdacols[0xF8][0][0] = mdacols[0xF8][1][0] = mdacols[0xF8][1][1] = cgapal[0xf];
	mdacols[0x00][0][1] = mdacols[0x00][1][1] = cgapal[0];
	mdacols[0x08][0][1] = mdacols[0x08][1][1] = cgapal[0];
	mdacols[0x80][0][1] = mdacols[0x80][1][1] = cgapal[0];
	mdacols[0x88][0][1] = mdacols[0x88][1][1] = cgapal[0];

	timer_add(&mda->timer, mda_poll, mda, 1);
}

void mda_setcol(int chr, int blink, int fg, uint8_t cga_ink) {
	mdacols[chr][blink][fg] = cgapal[cga_ink];
}

void mda_close(void *p) {
	mda_t *mda = (mda_t *)p;

	free(mda->vram);
	free(mda);
}

void mda_speed_changed(void *p) {
	mda_t *mda = (mda_t *)p;

	mda_recalctimings(mda);
}

static device_config_t mda_config[] =
	{
		{
			.name = "display_type",
			.description = "Display type",
			.type = CONFIG_SELECTION,
			.selection =
				{
					{
						.description = "Green",
						.value = DISPLAY_GREEN
					},
					{
						.description = "Amber",
						.value = DISPLAY_AMBER
					},
					{
						.description = "White",
						.value = DISPLAY_WHITE
					},
					{
						.description = ""
					}
				},
			.default_int = DISPLAY_WHITE
		},
		{
			.type = -1
		}
	};

device_t mda_device =
	{
		"MDA",
		0,
		mda_standalone_init,
		mda_close,
		NULL,
		mda_speed_changed,
		NULL,
		NULL,
		mda_config
	};
