// monster.cpp: implements AI for single player monsters, currently client only

#include "cube.h"

dvector monsters;
int nextmonster, spawnremain, numkilled, monstertotal, mtimestart;

VARF(skill, 1, 3, 10, conoutf(@"skill is now %d", skill));

dvector &
getmonsters()
{
	return monsters;
};
void
restoremonsterstate()
{
	loopv(monsters) if (monsters[i]->state == CS_DEAD) numkilled++;
}; // for savegames

#define TOTMFREQ 13
#define NUMMONSTERTYPES 8

struct monstertype // see docs for how these values modify behaviour
{
	short gun, speed, health, freq, lag, rate, pain, loyalty, mscale,
	    bscale;
	short painsound, diesound;
	OFConstantString *name, *mdlname;
}

monstertypes[NUMMONSTERTYPES] = {
    {GUN_FIREBALL, 15, 100, 3, 0, 100, 800, 1, 10, 10, S_PAINO, S_DIE1,
        @"an ogre", @"monster/ogro"},
    {GUN_CG, 18, 70, 2, 70, 10, 400, 2, 8, 9, S_PAINR, S_DEATHR, @"a rhino",
        @"monster/rhino"},
    {GUN_SG, 14, 120, 1, 100, 300, 400, 4, 14, 14, S_PAINE, S_DEATHE,
        @"ratamahatta", @"monster/rat"},
    {GUN_RIFLE, 15, 200, 1, 80, 300, 300, 4, 18, 18, S_PAINS, S_DEATHS,
        @"a slith", @"monster/slith"},
    {GUN_RL, 13, 500, 1, 0, 100, 200, 6, 24, 24, S_PAINB, S_DEATHB, @"bauul",
        @"monster/bauul"},
    {GUN_BITE, 22, 50, 3, 0, 100, 400, 1, 12, 15, S_PAINP, S_PIGGR2,
        @"a hellpig", @"monster/hellpig"},
    {GUN_ICEBALL, 12, 250, 1, 0, 10, 400, 6, 18, 18, S_PAINH, S_DEATHH,
        @"a knight", @"monster/knight"},
    {GUN_SLIMEBALL, 15, 100, 1, 0, 200, 400, 2, 13, 10, S_PAIND, S_DEATHD,
        @"a goblin", @"monster/goblin"},
};

dynent *
basicmonster(int type, int yaw, int state, int trigger, int move)
{
	if (type >= NUMMONSTERTYPES) {
		conoutf(@"warning: unknown monster in spawn: %d", type);
		type = 0;
	}
	dynent *m = newdynent();
	monstertype *t = &monstertypes[m->mtype = type];
	m->eyeheight = 2.0f;
	m->aboveeye = 1.9f;
	m->radius *= t->bscale / 10.0f;
	m->eyeheight *= t->bscale / 10.0f;
	m->aboveeye *= t->bscale / 10.0f;
	m->monsterstate = state;
	if (state != M_SLEEP)
		spawnplayer(m);
	m->trigger = lastmillis + trigger;
	m->targetyaw = m->yaw = (float)yaw;
	m->move = move;
	m->enemy = player1;
	m->gunselect = t->gun;
	m->maxspeed = (float)t->speed;
	m->health = t->health;
	m->armour = 0;
	loopi(NUMGUNS) m->ammo[i] = 10000;
	m->pitch = 0;
	m->roll = 0;
	m->state = CS_ALIVE;
	m->anger = 0;
	@autoreleasepool {
		strcpy_s(m->name, t->name.UTF8String);
	}
	monsters.add(m);
	return m;
};

void
spawnmonster() // spawn a random monster according to freq distribution in DMSP
{
	int n = rnd(TOTMFREQ), type;
	for (int i = 0;; i++)
		if ((n -= monstertypes[i].freq) < 0) {
			type = i;
			break;
		};
	basicmonster(type, rnd(360), M_SEARCH, 1000, 1);
};

void
monsterclear() // called after map start of when toggling edit mode to
               // reset/spawn all monsters to initial state
{
	loopv(monsters) gp()->dealloc(monsters[i], sizeof(dynent));
	monsters.setsize(0);
	numkilled = 0;
	monstertotal = 0;
	spawnremain = 0;
	if (m_dmsp) {
		nextmonster = mtimestart = lastmillis + 10000;
		monstertotal = spawnremain = gamemode < 0 ? skill * 10 : 0;
	} else if (m_classicsp) {
		mtimestart = lastmillis;
		loopv(ents) if (ents[i].type == MONSTER)
		{
			dynent *m = basicmonster(
			    ents[i].attr2, ents[i].attr1, M_SLEEP, 100, 0);
			m->o.x = ents[i].x;
			m->o.y = ents[i].y;
			m->o.z = ents[i].z;
			entinmap(m);
			monstertotal++;
		};
	};
};

bool
los(float lx, float ly, float lz, float bx, float by, float bz,
    OFVector3D &v) // height-correct line of sight for monster shooting/seeing
{
	if (OUTBORD((int)lx, (int)ly) || OUTBORD((int)bx, (int)by))
		return false;
	float dx = bx - lx;
	float dy = by - ly;
	int steps = (int)(sqrt(dx * dx + dy * dy) / 0.9);
	if (!steps)
		return false;
	float x = lx;
	float y = ly;
	int i = 0;
	for (;;) {
		sqr *s = S(fast_f2nat(x), fast_f2nat(y));
		if (SOLID(s))
			break;
		float floor = s->floor;
		if (s->type == FHF)
			floor -= s->vdelta / 4.0f;
		float ceil = s->ceil;
		if (s->type == CHF)
			ceil += s->vdelta / 4.0f;
		float rz = lz - ((lz - bz) * (i / (float)steps));
		if (rz < floor || rz > ceil)
			break;
		v.x = x;
		v.y = y;
		v.z = rz;
		x += dx / (float)steps;
		y += dy / (float)steps;
		i++;
	};
	return i >= steps;
};

bool
enemylos(dynent *m, OFVector3D &v)
{
	v = m->o;
	return los(m->o.x, m->o.y, m->o.z, m->enemy->o.x, m->enemy->o.y,
	    m->enemy->o.z, v);
};

// monster AI is sequenced using transitions: they are in a particular state
// where they execute a particular behaviour until the trigger time is hit, and
// then they reevaluate their situation based on the current state, the
// environment etc., and transition to the next state. Transition timeframes are
// parametrized by difficulty level (skill), faster transitions means quicker
// decision making means tougher AI.

void
transition(dynent *m, int state, int moving, int n,
    int r) // n = at skill 0, n/2 = at skill 10, r = added random factor
{
	m->monsterstate = state;
	m->move = moving;
	n = n * 130 / 100;
	m->trigger = lastmillis + n - skill * (n / 16) + rnd(r + 1);
};

void
normalise(dynent *m, float angle)
{
	while (m->yaw < angle - 180.0f)
		m->yaw += 360.0f;
	while (m->yaw > angle + 180.0f)
		m->yaw -= 360.0f;
};

void
monsteraction(
    dynent *m) // main AI thinking routine, called every frame for every monster
{
	if (m->enemy->state == CS_DEAD) {
		m->enemy = player1;
		m->anger = 0;
	};
	normalise(m, m->targetyaw);
	if (m->targetyaw > m->yaw) // slowly turn monster towards his target
	{
		m->yaw += curtime * 0.5f;
		if (m->targetyaw < m->yaw)
			m->yaw = m->targetyaw;
	} else {
		m->yaw -= curtime * 0.5f;
		if (m->targetyaw > m->yaw)
			m->yaw = m->targetyaw;
	};

	vdist(disttoenemy, vectoenemy, m->o, m->enemy->o);
	m->pitch = atan2(m->enemy->o.z - m->o.z, disttoenemy) * 180 / PI;

	if (m->blocked) // special case: if we run into scenery
	{
		m->blocked = false;
		if (!rnd(20000 /
		         monstertypes[m->mtype]
		             .speed)) // try to jump over obstackle (rare)
		{
			m->jumpnext = true;
		} else if (m->trigger < lastmillis &&
		           (m->monsterstate != M_HOME ||
		               !rnd(5))) // search for a way around (common)
		{
			m->targetyaw +=
			    180 + rnd(180); // patented "random walk" AI
			                    // pathfinding (tm) ;)
			transition(m, M_SEARCH, 1, 400, 1000);
		};
	};

	float enemyyaw =
	    -(float)atan2(m->enemy->o.x - m->o.x, m->enemy->o.y - m->o.y) / PI *
	        180 +
	    180;

	switch (m->monsterstate) {
	case M_PAIN:
	case M_ATTACKING:
	case M_SEARCH:
		if (m->trigger < lastmillis)
			transition(m, M_HOME, 1, 100, 200);
		break;

	case M_SLEEP: // state classic sp monster start in, wait for visual
	              // contact
	{
		OFVector3D target;
		if (editmode || !enemylos(m, target))
			return; // skip running physics
		normalise(m, enemyyaw);
		float angle = (float)fabs(enemyyaw - m->yaw);
		if (disttoenemy < 8 // the better the angle to the player, the
		                    // further the monster can see/hear
		    || (disttoenemy < 16 && angle < 135) ||
		    (disttoenemy < 32 && angle < 90) ||
		    (disttoenemy < 64 && angle < 45) || angle < 10) {
			transition(m, M_HOME, 1, 500, 200);
			playsound(S_GRUNT1 + rnd(2), &m->o);
		};
		break;
	};

	case M_AIMING: // this state is the delay between wanting to shoot and
	               // actually firing
		if (m->trigger < lastmillis) {
			m->lastaction = 0;
			m->attacking = true;
			shoot(m, m->attacktarget);
			transition(m, M_ATTACKING, 0, 600, 0);
		};
		break;

	case M_HOME: // monster has visual contact, heads straight for player
	             // and may want to shoot at any time
		m->targetyaw = enemyyaw;
		if (m->trigger < lastmillis) {
			OFVector3D target;
			if (!enemylos(
			        m, target)) // no visual contact anymore, let
			                    // monster get as close as possible
			                    // then search for player
			{
				transition(m, M_HOME, 1, 800, 500);
			} else // the closer the monster is the more likely he
			       // wants to shoot
			{
				if (!rnd((int)disttoenemy / 3 + 1) &&
				    m->enemy->state ==
				        CS_ALIVE) // get ready to fire
				{
					m->attacktarget = target;
					transition(m, M_AIMING, 0,
					    monstertypes[m->mtype].lag, 10);
				} else // track player some more
				{
					transition(m, M_HOME, 1,
					    monstertypes[m->mtype].rate, 0);
				};
			};
		};
		break;
	};

	moveplayer(m, 1, false); // use physics to move monster
};

void
monsterpain(dynent *m, int damage, dynent *d)
{
	if (d->monsterstate) // a monster hit us
	{
		if (m != d) // guard for RL guys shooting themselves :)
		{
			m->anger++; // don't attack straight away, first get
			            // angry
			int anger =
			    m->mtype == d->mtype ? m->anger / 2 : m->anger;
			if (anger >= monstertypes[m->mtype].loyalty)
				m->enemy = d; // monster infight if very angry
		};
	} else // player hit us
	{
		m->anger = 0;
		m->enemy = d;
	};
	transition(m, M_PAIN, 0, monstertypes[m->mtype].pain,
	    200); // in this state monster won't attack
	if ((m->health -= damage) <= 0) {
		m->state = CS_DEAD;
		m->lastaction = lastmillis;
		numkilled++;
		player1->frags = numkilled;
		playsound(monstertypes[m->mtype].diesound, &m->o);
		int remain = monstertotal - numkilled;
		if (remain > 0 && remain <= 5)
			conoutf(@"only %d monster(s) remaining", remain);
	} else {
		playsound(monstertypes[m->mtype].painsound, &m->o);
	};
};

void
endsp(bool allkilled)
{
	conoutf(allkilled ? @"you have cleared the map!"
	                  : @"you reached the exit!");
	conoutf(@"score: %d kills in %d seconds", numkilled,
	    (lastmillis - mtimestart) / 1000);
	monstertotal = 0;
	startintermission();
};

void
monsterthink()
{
	if (m_dmsp && spawnremain && lastmillis > nextmonster) {
		if (spawnremain-- == monstertotal)
			conoutf(@"The invasion has begun!");
		nextmonster = lastmillis + 1000;
		spawnmonster();
	};

	if (monstertotal && !spawnremain && numkilled == monstertotal)
		endsp(true);

	loopv(ents) // equivalent of player entity touch, but only teleports are
	            // used
	{
		entity &e = ents[i];
		if (e.type != TELEPORT)
			continue;
		if (OUTBORD(e.x, e.y))
			continue;
		OFVector3D v =
		    OFMakeVector3D(e.x, e.y, (float)S(e.x, e.y)->floor);
		loopv(monsters) if (monsters[i]->state == CS_DEAD)
		{
			if (lastmillis - monsters[i]->lastaction < 2000) {
				monsters[i]->move = 0;
				moveplayer(monsters[i], 1, false);
			};
		}
		else
		{
			v.z += monsters[i]->eyeheight;
			vdist(dist, t, monsters[i]->o, v);
			v.z -= monsters[i]->eyeheight;
			if (dist < 4)
				teleport((int)(&e - &ents[0]), monsters[i]);
		};
	};

	loopv(monsters) if (monsters[i]->state == CS_ALIVE)
	    monsteraction(monsters[i]);
};

void
monsterrender()
{
	loopv(monsters) renderclient(monsters[i], false,
	    monstertypes[monsters[i]->mtype].mdlname, monsters[i]->mtype == 5,
	    monstertypes[monsters[i]->mtype].mscale / 10.0f);
}
