/*
 *  Copyright (C) 2002-2015  The DOSBox Team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */


#include <time.h>
#include <math.h>

#include "dosbox.h"
#include "timer.h"
#include "cpu.h"
#include "pic.h"
#include "inout.h"
#include "mem.h"
#include "bios_disk.h"
#include "setup.h"
#include "cross.h" //fmod on certain platforms
#include "control.h"
bool date_host_forced=false;
#if defined (WIN32)
#include "sys/timeb.h"
#else
#include "sys/time.h"
#endif

// sigh... Windows doesn't know gettimeofday
#if defined (WIN32)
typedef Bitu suseconds_t;

struct timeval {
	time_t tv_sec;
	suseconds_t tv_usec;
};

static void gettimeofday (timeval* ptime, void* pdummy) {
	struct _timeb thetime;
	_ftime(&thetime);

	ptime->tv_sec = thetime.time;
	ptime->tv_usec = (Bitu)thetime.millitm;
}

#endif

static struct {
	Bit8u regs[0x40];
	bool nmi;
	bool bcd;
	bool ampm;					// am/pm mode (false = 24h mode)
	bool lock;					// lock bit set (no updates)
	Bit8u reg;
	struct {
		bool enabled;
		Bit8u div;
		float delay;
		bool acknowledged;
	} timer;
	struct {
		double timer;
		double ended;
		double alarm;
	} last;
	bool update_ended;
	time_t time_diff;			// difference between real UTC and DOSbox UTC
	struct timeval locktime;	// UTC time of setting lock bit
	struct timeval safetime;	// UTC time of last safe time
} cmos;

static void cmos_timerevent(Bitu val) {
	if (cmos.timer.acknowledged) {
		cmos.timer.acknowledged=false;
		PIC_ActivateIRQ(8);
	}
	if (cmos.timer.enabled) {
		PIC_AddEvent(cmos_timerevent,cmos.timer.delay);
		cmos.regs[0xc] = 0xC0;//Contraption Zack (music)
	}
}

static void cmos_checktimer(void) {
	PIC_RemoveEvents(cmos_timerevent);	
	if (cmos.timer.div<=2) cmos.timer.div+=7;
	cmos.timer.delay=(1000.0f/(32768.0f / (1 << (cmos.timer.div - 1))));
	if (!cmos.timer.div || !cmos.timer.enabled) return;
	LOG(LOG_PIT,LOG_NORMAL)("RTC Timer at %.2f hz",1000.0/cmos.timer.delay);
//	PIC_AddEvent(cmos_timerevent,cmos.timer.delay);
	/* A rtc is always running */
	double remd=fmod(PIC_FullIndex(),(double)cmos.timer.delay);
	PIC_AddEvent(cmos_timerevent,(float)((double)cmos.timer.delay-remd)); //Should be more like a real pc. Check
//	status reg A reading with this (and with other delays actually)
}

void cmos_selreg(Bitu port,Bitu val,Bitu iolen) {
	if (machine != MCH_PCJR) {
		/* bit 7 also controls NMI masking, if set, NMI is disabled */
		CPU_NMI_gate = (val&0x80) ? false : true;
	}

	cmos.reg=val & 0x3f;
	cmos.nmi=(val & 0x80)>0;
}

static void cmos_writereg(Bitu port,Bitu val,Bitu iolen) {
	if (date_host_forced && (cmos.reg <= 0x09 || cmos.reg == 0x32)) {	// date/time related registers
		if (cmos.bcd)			// values supplied are BCD, convert to binary values
		{
			if ((val & 0xf0) > 0x90 || (val & 0x0f) > 0x09) return;		// invalid BCD value
			// other checks for valid values are done in case-switch

			// convert pm hours differently (bcd 81-92 corresponds to hex 81-8c)
			if (cmos.reg == 0x04 && val >= 0x80)
			{
				val = (val < 90) ? 0x80 : 0x8a + (val & 0x0f);
			}
			else
			{
				val = ((val >> 4) * 10) + (val & 0x0f);
			}
		}

		struct tm *loctime;			// local dosbox time (based on dosbox UTC)

		if (cmos.lock)				// if locked, use locktime instead of current time
		{
			loctime = localtime(&cmos.locktime.tv_sec);
		}
		else						// not locked, use current time
		{
			struct timeval curtime;
			gettimeofday(&curtime, NULL);
			curtime.tv_sec += cmos.time_diff;
			loctime = localtime (&curtime.tv_sec);
		}

		switch (cmos.reg)
		{
		case 0x00:		/* Seconds */
			if (val > 59) return;		// invalid seconds value
			loctime->tm_sec = val;
			break;

		case 0x02:		/* Minutes */
			if (val > 59) return;		// invalid minutes value
			loctime->tm_min = val;
			break;

		case 0x04:		/* Hours */
			if (cmos.ampm)				// 12h am/pm mode
			{
				if ((val > 12 && val < 0x81) || val > 0x8c) return;	// invalid hour value
				if (val > 12) val -= (0x80-12);			// convert pm to 24h
			}
			else						// 24h mode
			{
				if (val > 23) return;								// invalid hour value
			}

			loctime->tm_hour = val;			
			break;

		case 0x06:		/* Day of week */
			// seems silly to set this, as it is calculated? ignore for now
			break;

		case 0x07:		/* Date of month */
			if (val > 31) return;				// invalid date value (mktime() should catch the rest)
			loctime->tm_mday = val;
			break;

		case 0x08:		/* Month */
			if (val > 12) return;				// invalid month value
			loctime->tm_mon = val;
			break;

		case 0x09:		/* Year */
			loctime->tm_year = val;
			break;

		case 0x32:		/* Century */
			if (val < 19) return;				// invalid century value?
			loctime->tm_year += (val * 100) - 1900;
			break;

		case 0x01:		/* Seconds Alarm */
		case 0x03:		/* Minutes Alarm */
		case 0x05:		/* Hours Alarm */
			LOG(LOG_BIOS,LOG_NORMAL)("CMOS:Trying to set alarm");
			cmos.regs[cmos.reg] = val;
			return;		// done
		}

		time_t newtime = mktime(loctime);		// convert new local time back to dosbox UTC

		if (newtime != (time_t)-1)
		{
			if (!cmos.lock)			// no lock, takes immediate effect
			{
				cmos.time_diff = newtime - time(NULL);	// calculate new diff
			}
			else
			{
				cmos.locktime.tv_sec = newtime;			// store for later use
				// no need to set usec, we don't use it
			}
		}

		return;
	}

	switch (cmos.reg) {
	case 0x00:		/* Seconds */
	case 0x02:		/* Minutes */
	case 0x04:		/* Hours */
	case 0x06:		/* Day of week */
	case 0x07:		/* Date of month */
	case 0x08:		/* Month */
	case 0x09:		/* Year */
	case 0x32:              /* Century */
		/* Ignore writes to change alarm */
		if(!date_host_forced) break;
	case 0x01:		/* Seconds Alarm */
	case 0x03:		/* Minutes Alarm */
	case 0x05:		/* Hours Alarm */
		if(!date_host_forced) {
			LOG(LOG_BIOS,LOG_NORMAL)("CMOS:Trying to set alarm");
			cmos.regs[cmos.reg]=val;
			break;
		}
	case 0x0a:		/* Status reg A */
		cmos.regs[cmos.reg]=val & 0x7f;
		if ((val & 0x70)!=0x20) LOG(LOG_BIOS,LOG_ERROR)("CMOS Illegal 22 stage divider value");
		cmos.timer.div=(val & 0xf);
		cmos_checktimer();
		break;
	case 0x0b:		/* Status reg B */
		if(date_host_forced) {
			bool waslocked = cmos.lock;

			cmos.ampm = !(val & 0x02);
			cmos.bcd = !(val & 0x04);
			if ((val & 0x10) != 0) LOG(LOG_BIOS,LOG_ERROR)("CMOS:Updated ended interrupt not supported yet");
			cmos.timer.enabled = (val & 0x40) > 0;
			cmos.lock = (val & 0x80) != 0;

			if (cmos.lock)				// if locked, set locktime for later use
			{
				if (!waslocked)			// if already locked, no further action
				{
					// locked for the first time, calculate dosbox UTC
					gettimeofday(&cmos.locktime, NULL);
					cmos.locktime.tv_sec += cmos.time_diff;
				}
			}
			else if (waslocked)			// time was locked, now unlock
			{
				// calculate new diff between real UTC and dosbox UTC
				cmos.time_diff = cmos.locktime.tv_sec - time(NULL);
			}

			cmos.regs[cmos.reg] = val;
			cmos_checktimer();
		} else {
			cmos.bcd=!(val & 0x4);
			cmos.regs[cmos.reg]=val & 0x7f;
			cmos.timer.enabled=(val & 0x40)>0;
			if (val&0x10) LOG(LOG_BIOS,LOG_ERROR)("CMOS:Updated ended interrupt not supported yet");
			cmos_checktimer();
		}
		break;
	case 0x0c:
		if(date_host_forced) break;
	case 0x0d:/* Status reg D */
		if(!date_host_forced) {
			cmos.regs[cmos.reg]=val & 0x80;	/*Bit 7=1:RTC Pown on*/
		}
		break;
	case 0x0f:		/* Shutdown status byte */
		cmos.regs[cmos.reg]=val & 0x7f;
		break;
	default:
		cmos.regs[cmos.reg]=val & 0x7f;
		LOG(LOG_BIOS,LOG_ERROR)("CMOS:WRite to unhandled register %x",cmos.reg);
	}
}

unsigned char CMOS_GetShutdownByte() {
	return cmos.regs[0x0F];
}

#define MAKE_RETURN(_VAL) (cmos.bcd ? ((((_VAL) / 10) << 4) | ((_VAL) % 10)) : (_VAL));

static Bitu cmos_readreg(Bitu port,Bitu iolen) {
	if (cmos.reg>0x3f) {
		LOG(LOG_BIOS,LOG_ERROR)("CMOS:Read from illegal register %x",cmos.reg);
		return 0xff;
	}

	// JAL_20060817 - rewrote most of the date/time part
	if (date_host_forced && (cmos.reg <= 0x09 || cmos.reg == 0x32)) {		// date/time related registers
		struct tm* loctime;

		if (cmos.lock)				// if locked, use locktime instead of current time
		{
			loctime = localtime(&cmos.locktime.tv_sec);
		}
		else						// not locked, get current time
		{
			struct timeval curtime;
			gettimeofday(&curtime, NULL);
	
			// allow a little more leeway (1 sec) than the .244 sec officially given
			if (curtime.tv_sec - cmos.safetime.tv_sec == 1 &&
				curtime.tv_usec < cmos.safetime.tv_usec)
			{
				curtime = cmos.safetime;		// within safe range, use safetime instead of current time
			}

			curtime.tv_sec += cmos.time_diff;
			loctime = localtime (&curtime.tv_sec);
		}

		switch (cmos.reg)
		{
		case 0x00:		// seconds
			return MAKE_RETURN(loctime->tm_sec);
		case 0x02:		// minutes
			return MAKE_RETURN(loctime->tm_min);
		case 0x04:		// hours
			if (cmos.ampm && loctime->tm_hour > 12)		// time pm, convert
			{
				loctime->tm_hour -= 12;
				loctime->tm_hour += (cmos.bcd) ? 80 : 0x80;
			}
			return MAKE_RETURN(loctime->tm_hour);
		case 0x06:		/* Day of week */
			return MAKE_RETURN(loctime->tm_wday + 1);
		case 0x07:		/* Date of month */
			return MAKE_RETURN(loctime->tm_mday);
		case 0x08:		/* Month */
			return MAKE_RETURN(loctime->tm_mon + 1);
		case 0x09:		/* Year */
			return MAKE_RETURN(loctime->tm_year % 100);
		case 0x32:		/* Century */
			return MAKE_RETURN(loctime->tm_year / 100 + 19);

		case 0x01:		/* Seconds Alarm */
		case 0x03:		/* Minutes Alarm */
		case 0x05:		/* Hours Alarm */
			return MAKE_RETURN(cmos.regs[cmos.reg]);
		}
	}

	Bitu drive_a, drive_b;
	Bit8u hdparm;
	time_t curtime;
	struct tm *loctime;
	/* Get the current time. */
	curtime = time (NULL);

	/* Convert it to local time representation. */
	loctime = localtime (&curtime);

	switch (cmos.reg) {
	case 0x00:		/* Seconds */
		if(!date_host_forced) return 	MAKE_RETURN(loctime->tm_sec);
	case 0x02:		/* Minutes */
		if(!date_host_forced) return 	MAKE_RETURN(loctime->tm_min);
	case 0x04:		/* Hours */
		if(!date_host_forced) return 	MAKE_RETURN(loctime->tm_hour);
	case 0x06:		/* Day of week */
		if(!date_host_forced) return 	MAKE_RETURN(loctime->tm_wday + 1);
	case 0x07:		/* Date of month */
		if(!date_host_forced) return 	MAKE_RETURN(loctime->tm_mday);
	case 0x08:		/* Month */
		if(!date_host_forced) return 	MAKE_RETURN(loctime->tm_mon + 1);
	case 0x09:		/* Year */
		if(!date_host_forced) return 	MAKE_RETURN(loctime->tm_year % 100);
	case 0x32:		/* Century */
		if(!date_host_forced) return 	MAKE_RETURN(loctime->tm_year / 100 + 19);
	case 0x01:		/* Seconds Alarm */
	case 0x03:		/* Minutes Alarm */
	case 0x05:		/* Hours Alarm */
		if(!date_host_forced) return cmos.regs[cmos.reg];
	case 0x0a:		/* Status register A */
		if(date_host_forced) {
			// take bit 7 of reg b into account (if set, never updates)
			gettimeofday (&cmos.safetime, NULL);		// get current UTC time
			if (cmos.lock ||							// if lock then never updated, so reading safe
				cmos.safetime.tv_usec < (1000-244)) {	// if 0, at least 244 usec should be available
				return cmos.regs[0x0a];					// reading safe
			} else {
				return cmos.regs[0x0a] | 0x80;			// reading not safe!
			}
		} else {
			if (PIC_TickIndex()<0.002) {
				return (cmos.regs[0x0a]&0x7f) | 0x80;
			} else {
				return (cmos.regs[0x0a]&0x7f);
			}
		}
	case 0x0c:		/* Status register C */
		cmos.timer.acknowledged=true;
		if (cmos.timer.enabled) {
			/* In periodic interrupt mode only care for those flags */
			Bit8u val=cmos.regs[0xc];
			cmos.regs[0xc]=0;
			return val;
		} else {
			/* Give correct values at certain times */
			Bit8u val=0;
			double index=PIC_FullIndex();
			if (index>=(cmos.last.timer+cmos.timer.delay)) {
				cmos.last.timer=index;
				val|=0x40;
			} 
			if (index>=(cmos.last.ended+1000)) {
				cmos.last.ended=index;
				val|=0x10;
			}
			if(date_host_forced) cmos.regs[0xc] = 0;		// JAL_20060817 - reset here too!
			return val;
		}
	case 0x10:		/* Floppy size */
		drive_a = 0;
		drive_b = 0;
		if(imageDiskList[0] != NULL) drive_a = imageDiskList[0]->GetBiosType();
		if(imageDiskList[1] != NULL) drive_b = imageDiskList[1]->GetBiosType();
		return ((drive_a << 4) | (drive_b));
	/* First harddrive info */
	case 0x12:
		/* NTS: DOSBox 0.74 mainline has these backwards: the upper nibble is the first hard disk,
		   the lower nibble is the second hard disk. It makes a big difference to stupid OS's like
		   Windows 95. */
		hdparm = 0;
		if(imageDiskList[3] != NULL) hdparm |= 0xf;
		if(imageDiskList[2] != NULL) hdparm |= 0xf0;
//		hdparm = 0;
		return hdparm;
	case 0x19:
		if(imageDiskList[2] != NULL) return 47; /* User defined type */
		return 0;
	case 0x1b:
		if(imageDiskList[2] != NULL) return (imageDiskList[2]->cylinders & 0xff);
		return 0;
	case 0x1c:
		if(imageDiskList[2] != NULL) return ((imageDiskList[2]->cylinders & 0xff00)>>8);
		return 0;
	case 0x1d:
		if(imageDiskList[2] != NULL) return (imageDiskList[2]->heads);
		return 0;
	case 0x1e:
		if(imageDiskList[2] != NULL) return 0xff;
		return 0;
	case 0x1f:
		if(imageDiskList[2] != NULL) return 0xff;
		return 0;
	case 0x20:
		if(imageDiskList[2] != NULL) return (0xc0 | (((imageDiskList[2]->heads) > 8) << 3));
		return 0;
	case 0x21:
		if(imageDiskList[2] != NULL) return (imageDiskList[2]->cylinders & 0xff);
		return 0;
	case 0x22:
		if(imageDiskList[2] != NULL) return ((imageDiskList[2]->cylinders & 0xff00)>>8);
		return 0;
	case 0x23:
		if(imageDiskList[2] != NULL) return (imageDiskList[2]->sectors);
		return 0;
	/* Second harddrive info */
	case 0x1a:
		if(imageDiskList[3] != NULL) return 47; /* User defined type */
		return 0;
	case 0x24:
		if(imageDiskList[3] != NULL) return (imageDiskList[3]->cylinders & 0xff);
		return 0;
	case 0x25:
		if(imageDiskList[3] != NULL) return ((imageDiskList[3]->cylinders & 0xff00)>>8);
		return 0;
	case 0x26:
		if(imageDiskList[3] != NULL) return (imageDiskList[3]->heads);
		return 0;
	case 0x27:
		if(imageDiskList[3] != NULL) return 0xff;
		return 0;
	case 0x28:
		if(imageDiskList[3] != NULL) return 0xff;
		return 0;
	case 0x29:
		if(imageDiskList[3] != NULL) return (0xc0 | (((imageDiskList[3]->heads) > 8) << 3));
		return 0;
	case 0x2a:
		if(imageDiskList[3] != NULL) return (imageDiskList[3]->cylinders & 0xff);
		return 0;
	case 0x2b:
		if(imageDiskList[3] != NULL) return ((imageDiskList[3]->cylinders & 0xff00)>>8);
		return 0;
	case 0x2c:
		if(imageDiskList[3] != NULL) return (imageDiskList[3]->sectors);
		return 0;
	case 0x39:
		return 0;
	case 0x3a:
		return 0;


	case 0x0b:		/* Status register B */
	case 0x0d:		/* Status register D */
	case 0x0f:		/* Shutdown status byte */
	case 0x14:		/* Equipment */
	case 0x15:		/* Base Memory KB Low Byte */
	case 0x16:		/* Base Memory KB High Byte */
	case 0x17:		/* Extended memory in KB Low Byte */
	case 0x18:		/* Extended memory in KB High Byte */
	case 0x30:		/* Extended memory in KB Low Byte */
	case 0x31:		/* Extended memory in KB High Byte */
//		LOG(LOG_BIOS,LOG_NORMAL)("CMOS:Read from reg %X : %04X",cmos.reg,cmos.regs[cmos.reg]);
		return cmos.regs[cmos.reg];
	case 0x2F:
		extern bool PS1AudioCard;
		if( PS1AudioCard )
			return 0xFF;
	default:
		LOG(LOG_BIOS,LOG_NORMAL)("CMOS:Read from reg %X",cmos.reg);
		return cmos.regs[cmos.reg];
	}
}

void CMOS_SetRegister(Bitu regNr, Bit8u val) {
	cmos.regs[regNr] = val;
}


static IO_ReadHandleObject ReadHandler[2];
static IO_WriteHandleObject WriteHandler[2];	

void CMOS_Destroy(Section* sec) {
}

void CMOS_Reset(Section* sec) {
	LOG(LOG_MISC,LOG_DEBUG)("CMOS_Reset(): reinitializing CMOS/RTC controller");

	WriteHandler[0].Uninstall();
	WriteHandler[1].Uninstall();
	ReadHandler[0].Uninstall();
	ReadHandler[1].Uninstall();

	WriteHandler[0].Install(0x70,cmos_selreg,IO_MB);
	WriteHandler[1].Install(0x71,cmos_writereg,IO_MB);
	ReadHandler[0].Install(0x71,cmos_readreg,IO_MB);
	cmos.timer.enabled=false;
	cmos.timer.acknowledged=true;
	cmos.reg=0xa;
	cmos_writereg(0x71,0x26,1);
	cmos.reg=0xb;
	cmos_writereg(0x71,0x2,1);	//Struct tm *loctime is of 24 hour format,
	if(date_host_forced) {
		cmos.regs[0x0d]=(Bit8u)0x80;
	} else {
		cmos.reg=0xd;
		cmos_writereg(0x71,0x80,1); /* RTC power on */
	}
	// Equipment is updated from bios.cpp and bios_disk.cpp
	/* Fill in base memory size, it is 640K always */
	cmos.regs[0x15]=(Bit8u)0x80;
	cmos.regs[0x16]=(Bit8u)0x02;
	/* Fill in extended memory size */
	Bitu exsize=MEM_TotalPages()*4;
	if (exsize >= 1024) exsize -= 1024;
	else exsize = 0;
	if (exsize > 65535) exsize = 65535; /* cap at 64MB. this value is returned as-is by INT 15H AH=0x88 in a 16-bit register */
	cmos.regs[0x17]=(Bit8u)exsize;
	cmos.regs[0x18]=(Bit8u)(exsize >> 8);
	cmos.regs[0x30]=(Bit8u)exsize;
	cmos.regs[0x31]=(Bit8u)(exsize >> 8);
	if (date_host_forced) {
		cmos.time_diff = 0;
		cmos.locktime.tv_sec = 0;
	}
}

void CMOS_Init() {
	LOG(LOG_MISC,LOG_DEBUG)("Initializing CMOS/RTC");

	if (control->opt_date_host_forced) {
		LOG_MSG("Synchronize date with host: Forced");
		date_host_forced=true;
	}

	AddExitFunction(AddExitFunctionFuncPair(CMOS_Destroy),true);
	AddVMEventFunction(VM_EVENT_RESET,AddVMEventFunctionFuncPair(CMOS_Reset));
}

