/*
 * 86Box	A hypervisor and IBM PC system emulator that specializes in
 *		running old operating systems and software designed for IBM
 *		PC systems and compatibles from 1981 through fairly recent
 *		system designs based on the PCI bus.
 *
 *		This file is part of the 86Box distribution.
 *
 *		Hercules emulation.
 *
 * Version:	@(#)vid_hercules.c	1.0.8	2017/11/14
 *
 * Authors:	Sarah Walker, <http://pcem-emulator.co.uk/>
 *		Miran Grca, <mgrca8@gmail.com>
 *
 *		Copyright 2008-2017 Sarah Walker.
 *		Copyright 2016,2017 Miran Grca.
 */
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <wchar.h>
#include "../86box.h"
#include "../mem.h"
#include "../rom.h"
#include "../io.h"
#include "../lpt.h"
#include "../pit.h"
#include "../timer.h"
#include "../device.h"
#include "video.h"
#include "vid_hercules.h"


typedef struct hercules_t
{
        mem_mapping_t mapping;
        
        uint8_t crtc[32];
        int crtcreg;

        uint8_t ctrl, ctrl2, stat;

        int64_t dispontime, dispofftime;
        int64_t vidtime;
        
        int firstline, lastline;

        int linepos, displine;
        int vc, sc;
        uint16_t ma, maback;
        int con, coff, cursoron;
        int dispon, blink;
        int64_t vsynctime;
	int vadj;

        uint8_t *vram;
} hercules_t;

static int mdacols[256][2][2];

void hercules_recalctimings(hercules_t *hercules);
void hercules_write(uint32_t addr, uint8_t val, void *p);
uint8_t hercules_read(uint32_t addr, void *p);


void hercules_out(uint16_t addr, uint8_t val, void *p)
{
        hercules_t *hercules = (hercules_t *)p;
//        pclog("Herc out %04X %02X\n",addr,val);
        switch (addr)
        {
                case 0x3b0: case 0x3b2: case 0x3b4: case 0x3b6:
                hercules->crtcreg = val & 31;
                return;
                case 0x3b1: case 0x3b3: case 0x3b5: case 0x3b7:
                hercules->crtc[hercules->crtcreg] = val;
                if (hercules->crtc[10] == 6 && hercules->crtc[11] == 7) /*Fix for Generic Turbo XT BIOS, which sets up cursor registers wrong*/
                {
                        hercules->crtc[10] = 0xb;
                        hercules->crtc[11] = 0xc;
                }
                hercules_recalctimings(hercules);
                return;
                case 0x3b8:
                hercules->ctrl = val;
                return;
                case 0x3bf:
                hercules->ctrl2 = val;
                if (val & 2)
                        mem_mapping_set_addr(&hercules->mapping, 0xb0000, 0x10000);
                else
                        mem_mapping_set_addr(&hercules->mapping, 0xb0000, 0x08000);
                return;
        }
}

uint8_t hercules_in(uint16_t addr, void *p)
{
        hercules_t *hercules = (hercules_t *)p;
 //       pclog("Herc in %04X %02X %04X:%04X %04X\n",addr,(hercules_stat & 0xF) | ((hercules_stat & 8) << 4),CS,pc,CX);
        switch (addr)
        {
                case 0x3b0: case 0x3b2: case 0x3b4: case 0x3b6:
                return hercules->crtcreg;
                case 0x3b1: case 0x3b3: case 0x3b5: case 0x3b7:
                return hercules->crtc[hercules->crtcreg];
                case 0x3ba:
                return (hercules->stat & 0xf) | ((hercules->stat & 8) << 4);
        }
        return 0xff;
}

void hercules_write(uint32_t addr, uint8_t val, void *p)
{
        hercules_t *hercules = (hercules_t *)p;
        egawrites++;
//        pclog("Herc write %08X %02X\n",addr,val);
        hercules->vram[addr & 0xffff] = val;
}

uint8_t hercules_read(uint32_t addr, void *p)
{
        hercules_t *hercules = (hercules_t *)p;
        egareads++;
        return hercules->vram[addr & 0xffff];
}

void hercules_recalctimings(hercules_t *hercules)
{
        double disptime;
	double _dispontime, _dispofftime;
        disptime = hercules->crtc[0] + 1;
        _dispontime  = hercules->crtc[1];
        _dispofftime = disptime - _dispontime;
        _dispontime  *= MDACONST;
        _dispofftime *= MDACONST;
	hercules->dispontime  = (int64_t)(_dispontime  * (1 << TIMER_SHIFT));
	hercules->dispofftime = (int64_t)(_dispofftime * (1 << TIMER_SHIFT));
}

void hercules_poll(void *p)
{
        hercules_t *hercules = (hercules_t *)p;
        uint16_t ca = (hercules->crtc[15] | (hercules->crtc[14] << 8)) & 0x3fff;
        int drawcursor;
        int x, c;
        int oldvc;
        uint8_t chr, attr;
        uint16_t dat;
        int oldsc;
        int blink;
        if (!hercules->linepos)
        {
                //pclog("Poll %i %i\n",vc,sc);
                hercules->vidtime += hercules->dispofftime;
                hercules->stat |= 1;
                hercules->linepos = 1;
                oldsc = hercules->sc;
                if ((hercules->crtc[8] & 3) == 3) 
                        hercules->sc = (hercules->sc << 1) & 7;
                if (hercules->dispon)
                {
                        if (hercules->displine < hercules->firstline)
                        {
                                hercules->firstline = hercules->displine;
                                video_wait_for_buffer();
                        }
                        hercules->lastline = hercules->displine;
                        if ((hercules->ctrl & 2) && (hercules->ctrl2 & 1))
                        {
                                ca = (hercules->sc & 3) * 0x2000;
                                if ((hercules->ctrl & 0x80) && (hercules->ctrl2 & 2)) 
                                        ca += 0x8000;
//                                printf("Draw herc %04X\n",ca);
                                for (x = 0; x < hercules->crtc[1]; x++)
                                {
                                        dat = (hercules->vram[((hercules->ma << 1) & 0x1fff) + ca] << 8) | hercules->vram[((hercules->ma << 1) & 0x1fff) + ca + 1];
                                        hercules->ma++;
                                        for (c = 0; c < 16; c++)
                                            buffer->line[hercules->displine][(x << 4) + c] = (dat & (32768 >> c)) ? 7 : 0;
                                }
                        }
                        else
                        {
                                for (x = 0; x < hercules->crtc[1]; x++)
                                {
                                        chr  = hercules->vram[(hercules->ma << 1) & 0xfff];
                                        attr = hercules->vram[((hercules->ma << 1) + 1) & 0xfff];
                                        drawcursor = ((hercules->ma == ca) && hercules->con && hercules->cursoron);
                                        blink = ((hercules->blink & 16) && (hercules->ctrl & 0x20) && (attr & 0x80) && !drawcursor);
                                        if (hercules->sc == 12 && ((attr & 7) == 1))
                                        {
                                                for (c = 0; c < 9; c++)
                                                    buffer->line[hercules->displine][(x * 9) + c] = mdacols[attr][blink][1];
                                        }
                                        else
                                        {
                                                for (c = 0; c < 8; c++)
                                                    buffer->line[hercules->displine][(x * 9) + c] = mdacols[attr][blink][(fontdatm[chr][hercules->sc] & (1 << (c ^ 7))) ? 1 : 0];
                                                if ((chr & ~0x1f) == 0xc0) buffer->line[hercules->displine][(x * 9) + 8] = mdacols[attr][blink][fontdatm[chr][hercules->sc] & 1];
                                                else                       buffer->line[hercules->displine][(x * 9) + 8] = mdacols[attr][blink][0];
                                        }
                                        hercules->ma++;
                                        if (drawcursor)
                                        {
                                                for (c = 0; c < 9; c++)
                                                    buffer->line[hercules->displine][(x * 9) + c] ^= mdacols[attr][0][1];
                                        }
                                }
                        }
                }
                hercules->sc = oldsc;
                if (hercules->vc == hercules->crtc[7] && !hercules->sc)
                {
                        hercules->stat |= 8;
//                        printf("VSYNC on %i %i\n",vc,sc);
                }
                hercules->displine++;
                if (hercules->displine >= 500) 
                        hercules->displine = 0;
        }
        else
        {
                hercules->vidtime += hercules->dispontime;
                if (hercules->dispon) 
                        hercules->stat &= ~1;
                hercules->linepos = 0;
                if (hercules->vsynctime)
                {
                        hercules->vsynctime--;
                        if (!hercules->vsynctime)
                        {
                                hercules->stat &= ~8;
//                                printf("VSYNC off %i %i\n",vc,sc);
                        }
                }
                if (hercules->sc == (hercules->crtc[11] & 31) || ((hercules->crtc[8] & 3) == 3 && hercules->sc == ((hercules->crtc[11] & 31) >> 1))) 
                { 
                        hercules->con = 0; 
                        hercules->coff = 1; 
                }
                if (hercules->vadj)
                {
                        hercules->sc++;
                        hercules->sc &= 31;
                        hercules->ma = hercules->maback;
                        hercules->vadj--;
                        if (!hercules->vadj)
                        {
                                hercules->dispon = 1;
                                hercules->ma = hercules->maback = (hercules->crtc[13] | (hercules->crtc[12] << 8)) & 0x3fff;
                                hercules->sc = 0;
                        }
                }
                else if (hercules->sc == hercules->crtc[9] || ((hercules->crtc[8] & 3) == 3 && hercules->sc == (hercules->crtc[9] >> 1)))
                {
                        hercules->maback = hercules->ma;
                        hercules->sc = 0;
                        oldvc = hercules->vc;
                        hercules->vc++;
                        hercules->vc &= 127;
                        if (hercules->vc == hercules->crtc[6]) 
                                hercules->dispon = 0;
                        if (oldvc == hercules->crtc[4])
                        {
//                                printf("Display over at %i\n",displine);
                                hercules->vc = 0;
                                hercules->vadj = hercules->crtc[5];
                                if (!hercules->vadj) hercules->dispon=1;
                                if (!hercules->vadj) hercules->ma = hercules->maback = (hercules->crtc[13] | (hercules->crtc[12] << 8)) & 0x3fff;
                                if ((hercules->crtc[10] & 0x60) == 0x20) hercules->cursoron = 0;
                                else                                     hercules->cursoron = hercules->blink & 16;
                        }
                        if (hercules->vc == hercules->crtc[7])
                        {
                                hercules->dispon = 0;
                                hercules->displine = 0;
                                hercules->vsynctime = 16;//(crtcm[3]>>4)+1;
                                if (hercules->crtc[7])
                                {
//                                        printf("Lastline %i Firstline %i  %i\n",lastline,firstline,lastline-firstline);
                                        if ((hercules->ctrl & 2) && (hercules->ctrl2 & 1)) x = hercules->crtc[1] << 4;
                                        else                                               x = hercules->crtc[1] * 9;
                                        hercules->lastline++;
                                        if ((x != xsize) || ((hercules->lastline - hercules->firstline) != ysize) || video_force_resize_get())
                                        {
                                                xsize = x;
                                                ysize = hercules->lastline - hercules->firstline;
//                                                printf("Resize to %i,%i - R1 %i\n",xsize,ysize,crtcm[1]);
                                                if (xsize < 64) xsize = 656;
                                                if (ysize < 32) ysize = 200;
                                                set_screen_size(xsize, ysize);

						if (video_force_resize_get())
							video_force_resize_set(0);
                                        }
                                        video_blit_memtoscreen_8(0, hercules->firstline, 0, ysize, xsize, ysize);
                                        frames++;
                                        if ((hercules->ctrl & 2) && (hercules->ctrl2 & 1))
                                        {
                                                video_res_x = hercules->crtc[1] * 16;
                                                video_res_y = hercules->crtc[6] * 4;
                                                video_bpp = 1;
                                        }
                                        else
                                        {
                                                video_res_x = hercules->crtc[1];
                                                video_res_y = hercules->crtc[6];
                                                video_bpp = 0;
                                        }
                                }
                                hercules->firstline = 1000;
                                hercules->lastline = 0;
                                hercules->blink++;
                        }
                }
                else
                {
                        hercules->sc++;
                        hercules->sc &= 31;
                        hercules->ma = hercules->maback;
                }
                if ((hercules->sc == (hercules->crtc[10] & 31) || ((hercules->crtc[8] & 3) == 3 && hercules->sc == ((hercules->crtc[10] & 31) >> 1))))
                {
                        hercules->con = 1;
//                        printf("Cursor on - %02X %02X %02X\n",crtcm[8],crtcm[10],crtcm[11]);
                }
        }
}


void *hercules_init(device_t *info)
{
        int c;
        hercules_t *hercules = malloc(sizeof(hercules_t));
        memset(hercules, 0, sizeof(hercules_t));

        hercules->vram = malloc(0x10000);

        timer_add(hercules_poll, &hercules->vidtime, TIMER_ALWAYS_ENABLED, hercules);
        mem_mapping_add(&hercules->mapping, 0xb0000, 0x08000, hercules_read, NULL, NULL, hercules_write, NULL, NULL,  NULL, MEM_MAPPING_EXTERNAL, hercules);
        io_sethandler(0x03b0, 0x0010, hercules_in, NULL, NULL, hercules_out, NULL, NULL, hercules);

        for (c = 0; c < 256; c++)
        {
                mdacols[c][0][0] = mdacols[c][1][0] = mdacols[c][1][1] = 16;
                if (c & 8) mdacols[c][0][1] = 15 + 16;
                else       mdacols[c][0][1] =  7 + 16;
        }
        mdacols[0x70][0][1] = 16;
        mdacols[0x70][0][0] = mdacols[0x70][1][0] = mdacols[0x70][1][1] = 16 + 15;
        mdacols[0xF0][0][1] = 16;
        mdacols[0xF0][0][0] = mdacols[0xF0][1][0] = mdacols[0xF0][1][1] = 16 + 15;
        mdacols[0x78][0][1] = 16 + 7;
        mdacols[0x78][0][0] = mdacols[0x78][1][0] = mdacols[0x78][1][1] = 16 + 15;
        mdacols[0xF8][0][1] = 16 + 7;
        mdacols[0xF8][0][0] = mdacols[0xF8][1][0] = mdacols[0xF8][1][1] = 16 + 15;
        mdacols[0x00][0][1] = mdacols[0x00][1][1] = 16;
        mdacols[0x08][0][1] = mdacols[0x08][1][1] = 16;
        mdacols[0x80][0][1] = mdacols[0x80][1][1] = 16;
        mdacols[0x88][0][1] = mdacols[0x88][1][1] = 16;

	overscan_x = overscan_y = 0;

        cga_palette = device_get_config_int("rgb_type") << 1;
	if (cga_palette > 6)
	{
		cga_palette = 0;
	}
	cgapal_rebuild();

	lpt3_init(0x3BC);

        return hercules;
}

void hercules_close(void *p)
{
        hercules_t *hercules = (hercules_t *)p;

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

void hercules_speed_changed(void *p)
{
        hercules_t *hercules = (hercules_t *)p;
        
        hercules_recalctimings(hercules);
}

static device_config_t hercules_config[] =
{
        {
                "rgb_type", "Display type", CONFIG_SELECTION, "", 0,
                {
                        {
                                "Default", 0
                        },
                        {
                                "Green", 1
                        },
                        {
                                "Amber", 2
                        },
                        {
                                "Gray", 3
                        },
                        {
                                ""
                        }
                }
        },
        {
                "", "", -1
        }
};


device_t hercules_device =
{
        "Hercules",
        DEVICE_ISA, 0,
        hercules_init, hercules_close, NULL,
        NULL,
        hercules_speed_changed,
        NULL,
	NULL,
	hercules_config
};