//-------------------------------------------------------------------------
/*
Copyright (C) 2010-2019 EDuke32 developers and contributors
Copyright (C) 2019 Nuke.YKT

This file is part of NBlood.

NBlood is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License version 2
as published by the Free Software Foundation.

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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/
//-------------------------------------------------------------------------
#include "ns.h"	// Must come before everything else!

#include <stdlib.h>
#include <string.h>

#include "build.h"
#include "v_font.h"

#include "blood.h"
#include "choke.h"
#include "zstring.h"
#include "razemenu.h"
#include "gstrings.h"
#include "v_2ddrawer.h"
#include "v_video.h"
#include "v_font.h"

BEGIN_BLD_NS

void fakePlayerProcess(PLAYER* pPlayer, InputPacket* pInput);
void fakeActProcessSprites(void);

bool gPrediction = true;
VIEW predict, predictOld;
static VIEW predictFifo[256];

void viewInitializePrediction(void)
{
	predict.angle = gMe->angle.ang;
	predict.horiz = gMe->horizon.horiz;
	predict.horizoff = gMe->horizon.horizoff;
	predict.at2c = gMe->slope;
	predict.at6f = gMe->cantJump;
	predict.at70 = gMe->isRunning;
	predict.at72 = gMe->isUnderwater;
    predict.at71 = !!(gMe->input.actions & SB_JUMP);
	predict.x = gMe->pSprite->x;
	predict.y = gMe->pSprite->y;
	predict.z = gMe->pSprite->z;
	predict.sectnum = gMe->pSprite->sectnum;
	predict.at73 = gMe->pSprite->flags;
	predict.xvel = gMe->actor->xvel;
	predict.yvel = gMe->actor->yvel;
	predict.zvel = gMe->actor->zvel;
	predict.floordist = gMe->pXSprite->height;
	predict.at48 = gMe->posture;
	predict.spin = gMe->angle.spin;
	predict.at6e = !!(gMe->input.actions & SB_CENTERVIEW);
	predict.at75 = gMe->actor->hit;
	predict.bobPhase = gMe->bobPhase;
	predict.Kills = gMe->bobAmp;
	predict.bobHeight = gMe->bobHeight;
	predict.bobWidth = gMe->bobWidth;
	predict.at10 = gMe->swayPhase;
	predict.at14 = gMe->swayAmp;
	predict.shakeBobY = gMe->swayHeight;
	predict.shakeBobX = gMe->swayWidth;
	predict.weaponZ = gMe->zWeapon-gMe->zView-(12<<8);
	predict.viewz = gMe->zView;
	predict.at3c = gMe->zViewVel;
	predict.at40 = gMe->zWeapon;
	predict.at44 = gMe->zWeaponVel;
    predictOld = predict;
}

void viewUpdatePrediction(InputPacket *pInput)
{
    predictOld = predict;
	auto bakCstat = gMe->pSprite->cstat;
    gMe->pSprite->cstat = 0;
    fakePlayerProcess(gMe, pInput);
    fakeActProcessSprites();
    gMe->pSprite->cstat = bakCstat;
    //predictFifo[gPredictTail&255] = predict;
    //gPredictTail++;
}

static void sub_158B4(PLAYER *pPlayer)
{
    predict.viewz = predict.z - pPlayer->pPosture[pPlayer->lifeMode][predict.at48].eyeAboveZ;
    predict.at40 = predict.z - pPlayer->pPosture[pPlayer->lifeMode][predict.at48].weaponAboveZ;
}

static void fakeProcessInput(PLAYER *pPlayer, InputPacket *pInput)
{
    POSTURE *pPosture = &pPlayer->pPosture[pPlayer->lifeMode][predict.at48];

    predict.at70 = !!(gMe->input.actions & SB_RUN);
    predict.at71 = !!(gMe->input.actions & SB_JUMP);
    if (predict.at48 == 1)
    {
        int x = Cos(predict.angle.asbuild());
        int y = Sin(predict.angle.asbuild());
        if (pInput->fvel)
        {
            int forward = pInput->fvel;
            if (forward > 0)
                forward = MulScale(pPosture->frontAccel, forward, 8);
            else
                forward = MulScale(pPosture->backAccel, forward, 8);
            predict.xvel += MulScale(forward, x, 30);
            predict.yvel += MulScale(forward, y, 30);
        }
        if (pInput->svel)
        {
            int strafe = pInput->svel;
            strafe = MulScale(pPosture->sideAccel, strafe, 8);
            predict.xvel += MulScale(strafe, y, 30);
            predict.yvel -= MulScale(strafe, x, 30);
        }
    }
    else if (predict.floordist < 0x100)
    {
        int speed = 0x10000;
        if (predict.floordist > 0)
            speed -= DivScale(predict.floordist, 0x100, 16);
        int x = Cos(predict.angle.asbuild());
        int y = Sin(predict.angle.asbuild());
        if (pInput->fvel)
        {
            int forward = pInput->fvel;
            if (forward > 0)
                forward = MulScale(pPosture->frontAccel, forward, 8);
            else
                forward = MulScale(pPosture->backAccel, forward, 8);
            if (predict.floordist)
                forward = MulScale(forward, speed, 16);
            predict.xvel += MulScale(forward, x, 30);
            predict.yvel += MulScale(forward, y, 30);
        }
        if (pInput->svel)
        {
            int strafe = pInput->svel;
            strafe = MulScale(pPosture->sideAccel, strafe, 8);
            if (predict.floordist)
                strafe = MulScale(strafe, speed, 16);
            predict.xvel += MulScale(strafe, y, 30);
            predict.yvel -= MulScale(strafe, x, 30);
        }
    }
    if (pInput->avel)
        predict.angle = degang(pInput->avel);
    if (pInput->actions & SB_TURNAROUND)
        if (!predict.spin)
            predict.spin = -1024;
    if (predict.spin < 0)
    {
        int speed;
        if (predict.at48 == 1)
            speed = 64;
        else
            speed = 128;

        predict.spin = min(int(predict.spin) + speed, 0);
        predict.angle += buildang(speed);
    }

    if (!predict.at71)
        predict.at6f = 0;

    switch (predict.at48)
    {
    case 1:
        if (predict.at71)
            predict.zvel -= pPosture->normalJumpZ;//0x5b05;
        if (pInput->actions & SB_CROUCH)
            predict.zvel += pPosture->normalJumpZ;//0x5b05;
        break;
    case 2:
        if (!(pInput->actions & SB_CROUCH))
            predict.at48 = 0;
        break;
    default:
        if (!predict.at6f && predict.at71 && predict.floordist == 0) {
            if (packItemActive(pPlayer, 4)) predict.zvel = pPosture->pwupJumpZ;//-0x175555;
            else predict.zvel = pPosture->normalJumpZ;//-0xbaaaa;
            predict.at6f = 1;
        }
        if (pInput->actions & SB_CROUCH)
            predict.at48 = 2;
        break;
    }

#if 0
    if (predict.at6e && !(pInput->actions & (SB_LOOK_UP | SB_LOOK_DOWN)))
    {
        if (predict.at20 < 0)
            predict.at20 = min(predict.at20+IntToFixed(4), 0);
        if (predict.at20 > 0)
            predict.at20 = max(predict.at20-IntToFixed(4), 0);
        if (predict.at20 == 0)
            predict.at6e = 0;
    }
    else
    {
        if (pInput->actions & SB_LOOK_UP)
            predict.at20 = min(predict.at20+IntToFixed(4), IntToFixed(60));
        if (pInput->actions & SB_LOOK_DOWN)
            predict.at20 = max(predict.at20-IntToFixed(4), IntToFixed(-60));
    }
    predict.at20 = clamp(predict.at20+pInput->horz, IntToFixed(-60), IntToFixed(60));

    if (predict.at20 > 0)
        predict.at24 = FloatToFixed(MulScaleF(120., bsinf(FixedToFloat(predict.at20) * 8., 16)), 30);
    else if (predict.at20 < 0)
        predict.at24 = FloatToFixed(MulScaleF(180., bsinf(FixedToFloat(predict.at20) * 8., 16)), 30);
    else
        predict.at24 = 0;
#endif

    int nSector = predict.sectnum;
    int florhit = predict.at75.florhit.type;
	bool va = (predict.floordist < 16 && (florhit == kHitSector || florhit == 0));

    if (va && (sector[nSector].floorstat&2) != 0)
    {
        int z1 = getflorzofslope(nSector, predict.x, predict.y);
        int x2 = predict.x+MulScale(64, Cos(predict.angle.asbuild()), 30);
        int y2 = predict.y+MulScale(64, Sin(predict.angle.asbuild()), 30);
        int nSector2 = nSector;
        updatesector(x2, y2, &nSector2);
        if (nSector2 == nSector)
        {
            int z2 = getflorzofslope(nSector2, x2, y2);
            predict.horizoff = interpolatedhorizon(predict.horizoff, q16horiz((z1 - z2) << 13), 0x4000);
        }
    }
    else
    {
        predict.horizoff = interpolatedhorizon(predict.horizoff, q16horiz(0), 0x4000);
        if (abs(predict.horizoff.asq16()) < 4)
            predict.horizoff = q16horiz(0);
    }
    predict.at2c = -predict.horiz.asq16() >> 9;
}

void fakePlayerProcess(PLAYER *pPlayer, InputPacket *pInput)
{
    spritetype *pSprite = pPlayer->pSprite;
    XSPRITE *pXSprite = pPlayer->pXSprite;
    POSTURE* pPosture = &pPlayer->pPosture[pPlayer->lifeMode][predict.at48];

    int top, bottom;
    GetSpriteExtents(pSprite, &top, &bottom);

    top += predict.z-pSprite->z;
    bottom += predict.z-pSprite->z;

    int dzb = (bottom-predict.z)/4;
    int dzt = (predict.z-top)/4;

    int dw = pSprite->clipdist<<2;
    int nSector = predict.sectnum;
    if (!gNoClip)
    {
        pushmove(&predict.pos, &predict.sectnum, dw, dzt, dzb, CLIPMASK0);
        if (predict.sectnum == -1)
            predict.sectnum = nSector;
    }
    fakeProcessInput(pPlayer, pInput);

    int nSpeed = approxDist(predict.xvel, predict.yvel);

    predict.at3c = interpolatedvalue(predict.at3c, predict.zvel, 0x7000);
    int dz = predict.z-pPosture->eyeAboveZ-predict.viewz;
    if (dz > 0)
        predict.at3c += MulScale(dz<<8, 0xa000, 16);
    else
        predict.at3c += MulScale(dz<<8, 0x1800, 16);
    predict.viewz += predict.at3c>>8;

    predict.at44 = interpolatedvalue(predict.at44, predict.zvel, 0x5000);
    dz = predict.z-pPosture->weaponAboveZ-predict.at40;
    if (dz > 0)
        predict.at44 += MulScale(dz<<8, 0x8000, 16);
    else
        predict.at44 += MulScale(dz<<8, 0xc00, 16);
    predict.at40 += predict.at44>>8;

    predict.weaponZ = predict.at40 - predict.viewz - (12<<8);

    predict.bobPhase = ClipLow(predict.bobPhase-4, 0);

    nSpeed >>= FRACBITS;
	if (predict.at48 == 1)
	{
		predict.Kills = (predict.Kills+17)&2047;
		predict.at14 = (predict.at14+17)&2047;
		predict.bobHeight = MulScale(10*pPosture->bobV,Sin(predict.Kills*2), 30);
		predict.bobWidth = MulScale(predict.bobPhase*pPosture->bobH,Sin(predict.Kills-256), 30);
		predict.shakeBobY = MulScale(predict.bobPhase*pPosture->swayV,Sin(predict.at14*2), 30);
		predict.shakeBobX = MulScale(predict.bobPhase*pPosture->swayH,Sin(predict.at14-0x155), 30);
	}
	else
	{
		if (pXSprite->height < 256)
		{
			predict.Kills = (predict.Kills+(pPosture->pace[predict.at70]*4))&2047;
			predict.at14 = (predict.at14+(pPosture->pace[predict.at70]*4)/2)&2047;
			if (predict.at70)
			{
				if (predict.bobPhase < 60)
                    predict.bobPhase = ClipHigh(predict.bobPhase + nSpeed, 60);
			}
			else
			{
				if (predict.bobPhase < 30)
                    predict.bobPhase = ClipHigh(predict.bobPhase + nSpeed, 30);
			}
		}
		predict.bobHeight = MulScale(predict.bobPhase*pPosture->bobV,Sin(predict.Kills*2), 30);
		predict.bobWidth = MulScale(predict.bobPhase*pPosture->bobH,Sin(predict.Kills-256), 30);
		predict.shakeBobY = MulScale(predict.bobPhase*pPosture->swayV,Sin(predict.at14*2), 30);
		predict.shakeBobX = MulScale(predict.bobPhase*pPosture->swayH,Sin(predict.at14-0x155), 30);
	}
	if (!pXSprite->health)
        return;
	predict.at72 = 0;
	if (predict.at48 == 1)
	{
		predict.at72 = 1;
        int nSector = predict.sectnum;
        auto nLink = getLowerLink(nSector);
		if (nLink && (nLink->s().type == kMarkerLowGoo || nLink->s().type == kMarkerLowWater))
		{
			if (getceilzofslope(nSector, predict.x, predict.y) > predict.viewz)
				predict.at72 = 0;
		}
	}
}

static void fakeMoveDude(spritetype *pSprite)
{
#if 0 // not needed for single player, temporarily disabled due to icompatibilities with the refactored API.
    PLAYER *pPlayer = NULL;
    int bottom, top;
    if (IsPlayerSprite(pSprite))
        pPlayer = &gPlayer[pSprite->type-kDudePlayer1];
    assert(pSprite->type >= kDudeBase && pSprite->type < kDudeMax);
    GetSpriteExtents(pSprite, &top, &bottom);
	top += predict.z - pSprite->z;
	bottom += predict.z - pSprite->z;
    int bz = (bottom-predict.z)/4;
    int tz = (predict.z-top)/4;
    int wd = pSprite->clipdist*4;
    int nSector = predict.sectnum;
    assert(validSectorIndex(nSector));
    if (predict.xvel || predict.yvel)
    {
        if (pPlayer && gNoClip)
        {
            predict.x += predict.xvel>>12;
            predict.y += predict.yvel>>12;
            if (!FindSector(predict.x, predict.y, &nSector))
                nSector = predict.sectnum;
        }
        else
        {
            auto bakCstat = pSprite->cstat;
            pSprite->cstat &= ~257;
            predict.at75.hit = ClipMove(&predict.pos, &nSector, predict.xvel >> 12, predict.yvel >> 12, wd, tz, bz, CLIPMASK0);
            if (nSector == -1)
                nSector = predict.sectnum;
                    
            if (sector[nSector].type >= kSectorPath && sector[nSector].type <= kSectorRotate)
            {
                int nSector2 = nSector;
                pushmove(&predict.pos, &nSector2, wd, tz, bz, CLIPMASK0);
                if (nSector2 != -1)
                    nSector = nSector2;
            }

            assert(nSector >= 0);

            pSprite->cstat = bakCstat;
        }
        switch (predict.at75.hit.type)
        {
        case kHitSprite:
        {
            int nHitWall = predict.at75.hit.index;
            walltype *pHitWall = &wall[nHitWall];
            if (pHitWall->nextsector != -1)
            {
                sectortype *pHitSector = &sector[pHitWall->nextsector];
                if (top < pHitSector->ceilingz || bottom > pHitSector->floorz)
                {
                    // ???
                }
            }
            actWallBounceVector(&predict.xvel, &predict.yvel, nHitWall, 0);
            break;
        }
        }
    }
    if (predict.sectnum != nSector)
    {
        assert(validSectorIndex(nSector));
        predict.sectnum = nSector;
    }
    bool bUnderwater = 0;
    bool bDepth = 0;
    if (sector[sectnum].hasX())
    {
        XSECTOR *pXSector = &sector[sectnum].xs();
        if (pXSector->Underwater)
            bUnderwater = 1;
        if (pXSector->Depth)
            bDepth = 1;
    }
    auto nUpperLink = getUpperLink(nSector);
    auto nLowerLink = getLowerLink(nSector);
    if (nUpperLink >= 0 && (nUpperLink->s().type == kMarkerUpWater || nUpperLink->s().type == kMarkerUpGoo))
        bDepth = 1;
    if (nLowerLink >= 0 && (nLowerLink->s().type == kMarkerLowWater || nLowerLink->s().type == kMarkerLowGoo))
        bDepth = 1;
    if (pPlayer)
        wd += 16;

    if (predict.zvel)
        predict.z += predict.zvel >> 8;

    static_assert(sizeof(tspritetype) == sizeof(spritetype));
    tspritetype pSpriteBak; memcpy(&pSpriteBak, pSprite, sizeof(pSpriteBak)); // how dare you??? (Use a tspritetype here so that if the sprite storage gets refactored, this line gets flagged.)
    spritetype *pTempSprite = pSprite;
    pTempSprite->x = predict.x;
    pTempSprite->y = predict.y;
    pTempSprite->z = predict.z;
    pTempSprite->sectnum = predict.sectnum;
    int ceilZ, floorZ;
    Collision ceilColl, floorColl;
    GetZRange(pTempSprite, &ceilZ, &ceilColl, &floorZ, &floorColl, wd, CLIPMASK0);
    GetSpriteExtents(pTempSprite, &top, &bottom);
    if (predict.at73 & 2)
    {
        int vc = 58254;
        if (bDepth)
        {
            if (bUnderwater)
            {
                int cz = getceilzofslope(nSector, predict.x, predict.y);
                if (cz > top)
                    vc += ((bottom-cz)*-80099) / (bottom-top);
                else
                    vc = 0;
            }
            else
            {
                int fz = getflorzofslope(nSector, predict.x, predict.y);
                if (fz < bottom)
                    vc += ((bottom-fz)*-80099) / (bottom-top);
            }
        }
        else
        {
            if (bUnderwater)
                vc = 0;
            else if (bottom >= floorZ)
                vc = 0;
        }
        if (vc)
        {
            predict.z += ((vc*4)/2)>>8;
            predict.zvel += vc;
        }
    }
    GetSpriteExtents(pTempSprite, &top, &bottom);
    if (bottom >= floorZ)
    {
        int floorZ2 = floorZ;
        auto floorHit2 = floorColl;
        GetZRange(pTempSprite, &ceilZ, &ceilColl, &floorZ, &floorColl, pSprite->clipdist<<2, CLIPMASK0, PARALLAXCLIP_CEILING|PARALLAXCLIP_FLOOR);
        if (bottom <= floorZ && predict.z-floorZ2 < bz)
        {
            floorZ = floorZ2;
            floorColl = floorHit2;
        }
    }
    if (floorZ <= bottom)
    {
        predict.at75.florhit = floorColl;
        predict.z += floorZ-bottom;
        int var44 = predict.zvel-predict.sector()->velFloor;
        if (var44 > 0)
        {
            actFloorBounceVector(&predict.xvel, &predict.yvel, &var44, predict.sectnum, 0);
            predict.zvel = var44;
            if (abs(predict.zvel) < 0x10000)
            {
                predict.zvel = predict.sector()->velFloor;
                predict.at73 &= ~4;
            }
            else
                predict.at73 |= 4;
        }
        else if (predict.zvel == 0)
            predict.at73 &= ~4;
    }
    else
    {
        predict.at75.florhit.setNone();
        if (predict.at73 & 2)
            predict.at73 |= 4;
    }
    if (top <= ceilZ)
    {
        predict.at75.ceilhit = ceilColl;
        predict.z += ClipLow(ceilZ-top, 0);
        if (predict.zvel <= 0 && (predict.at73&4))
            predict.zvel = MulScale(-predict.zvel, 0x2000, 16);
    }
    else
        predict.at75.ceilhit = 0;

    GetSpriteExtents(pTempSprite, &top, &bottom);
    memcpy(pSprite, &pSpriteBak, sizeof(pSpriteBak));
    predict.floordist = ClipLow(floorZ-bottom, 0)>>8;
    if (predict.xvel || predict.yvel)
    {
        if (floorColl.type == kHitSprite)
        {
            auto hitactor = floorColl.actor;
            if ((hitactor->s().cstat & 0x30) == 0)
            {
                predict.xvel += MulScale(4, predict.x - hitactor->s().x, 2);
                predict.yvel += MulScale(4, predict.y - hitactor->s().y, 2);
                return;
            }
        }
        if (pSprite->sector()->hasX() && pSprite->sector()->xs().Underwater)
            return;
        if (predict.floordist >= 0x100)
            return;
        int nDrag = gDudeDrag;
        if (predict.floordist > 0)
            nDrag -= scale(gDudeDrag, predict.floordist, 0x100);
        predict.xvel -= mulscale16r(predict.xvel, nDrag);
        predict.yvel -= mulscale16r(predict.yvel, nDrag);
        if (approxDist(predict.xvel, predict.yvel) < 0x1000)
            predict.xvel = predict.yvel = 0;
    }
#endif
}

static void fakeActAirDrag(spritetype *, int num)
{
#if 0
    int xvec = 0;
    int yvec = 0;
    assert(validSectorIndex(predict.sectnum));
    sectortype *pSector = &sector[predict.sectnum];
    if (pSector->hasX())
    {
        XSECTOR *pXSector = &pSector->xs();
        if (pXSector->windVel && (pXSector->windAlways || pXSector->busy))
        {
            int vel = pXSector->windVel<<12;
            if (!pXSector->windAlways && pXSector->busy)
                vel = MulScale(vel, pXSector->busy, 16);
            xvec = MulScale(vel, Cos(pXSector->windAng), 30);
            yvec = MulScale(vel, Sin(pXSector->windAng), 30);
        }
    }
    predict.xvel += MulScale(xvec-predict.xvel, num, 16);
    predict.yvel += MulScale(yvec-predict.yvel, num, 16);
    predict.zvel -= MulScale(predict.zvel, num, 16);
#endif
}

void fakeActProcessSprites(void)
{
#if 0
	spritetype *pSprite = gMe->pSprite;
	if (pSprite->statnum == kStatDude)
	{
		int nSector = predict.sectnum;
        auto pSector = &sector[predict.sectnum];
		auto pXSector = pSector->hasX()? &pSector->xs() : nullptr;
		if (pXSector)
		{
            int top, bottom;
            GetSpriteExtents(pSprite, &top, &bottom);
			top += predict.z - pSprite->z;
			bottom += predict.z - pSprite->z;
			if (getflorzofslope(nSector, predict.x, predict.y) < bottom)
			{
				int angle = pXSector->panAngle;
                int speed = 0;
				if (pXSector->panAlways || pXSector->state || pXSector->busy)
				{
					speed = pXSector->panVel << 9;
					if (!pXSector->panAlways && pXSector->busy)
						speed = MulScale(speed, pXSector->busy, 16);
				}
				if (pSector->floorstat&64)
					angle = (GetWallAngle(pSector->wallptr)+512)&2047;
				predict.xvel += MulScale(speed,Cos(angle), 30);
				predict.yvel += MulScale(speed,Sin(angle), 30);
			}
		}
        if (pXSector && pXSector->Underwater)
            fakeActAirDrag(pSprite, 5376);
        else
            fakeActAirDrag(pSprite, 128);

        if ((predict.at73 & 4) != 0 || predict.xvel != 0 || predict.yvel != 0 || predict.zvel != 0 || predict.sector()->velFloor != 0 || predict.sector()->velCeil != 0)
        {
            fakeMoveDude(pSprite);
        }
	}
#endif
}

void viewCorrectPrediction(void)
{
#if 0
    spritetype *pSprite = gMe->pSprite;
    VIEW *pView = &predictFifo[(gNetFifoTail-1)&255];
    if (gMe->angle.ang != pView->at30 || pView->at24 != gMe->horizon.horiz || pView->at50 != pSprite->x || pView->at54 != pSprite->y || pView->at58 != pSprite->z)
    {
        viewInitializePrediction();
        predictOld = gPrevView[myconnectindex];
        gPredictTail = gNetFifoTail;
        while (gPredictTail < gNetFifoHead[myconnectindex])
        {
            viewUpdatePrediction(&gFifoInput[gPredictTail&255][myconnectindex]);
        }
    }
#endif
}

END_BLD_NS