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

#include "cube.h"

#import "DynamicEntity.h"
#import "Entity.h"

static OFMutableArray<DynamicEntity *> *monsters;
static int nextmonster, spawnremain, numkilled, monstertotal, mtimestart;

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

OFArray<DynamicEntity *> *
getmonsters()
{
	return monsters;
}

// for savegames
void
restoremonsterstate()
{
	for (DynamicEntity *monster in monsters)
		if (monster.state == CS_DEAD)
			numkilled++;
}

#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" },
};

DynamicEntity *
basicmonster(int type, int yaw, int state, int trigger, int move)
{
	if (type >= NUMMONSTERTYPES) {
		conoutf(@"warning: unknown monster in spawn: %d", type);
		type = 0;
	}
	DynamicEntity *m = [DynamicEntity entity];
	struct monstertype *t = &monstertypes[(m.monsterType = 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;
	m.name = t->name;

	if (monsters == nil)
		monsters = [[OFMutableArray alloc] init];

	[monsters addObject: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);
}

// called after map start of when toggling edit mode to reset/spawn all
// monsters to initial state
void
monsterclear()
{
	[monsters removeAllObjects];
	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;

		for (Entity *e in ents) {
			if (e.type != MONSTER)
				continue;

			DynamicEntity *m =
			    basicmonster(e.attr2, e.attr1, M_SLEEP, 100, 0);
			m.origin = OFMakeVector3D(e.x, e.y, e.z);
			entinmap(m);
			monstertotal++;
		}
	}
}

// height-correct line of sight for monster shooting/seeing
bool
los(float lx, float ly, float lz, float bx, float by, float bz, OFVector3D *v)
{
	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 (;;) {
		struct 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(DynamicEntity *m, OFVector3D *v)
{
	*v = m.origin;
	return los(m.origin.x, m.origin.y, m.origin.z, m.enemy.origin.x,
	    m.enemy.origin.y, m.enemy.origin.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.

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

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

// main AI thinking routine, called every frame for every monster
void
monsteraction(DynamicEntity *m)
{
	if (m.enemy.state == CS_DEAD) {
		m.enemy = player1;
		m.anger = 0;
	}
	normalise(m, m.targetYaw);
	// slowly turn monster towards his target
	if (m.targetYaw > m.yaw) {
		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.origin, m.enemy.origin);
	m.pitch = atan2(m.enemy.origin.z - m.origin.z, disttoenemy) * 180 / PI;

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

	float enemyYaw = -(float)atan2(m.enemy.origin.x - m.origin.x,
	                     m.enemy.origin.y - m.origin.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);
			OFVector3D loc = m.origin;
			playsound(S_GRUNT1 + rnd(2), &loc);
		}
		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;
			OFVector3D attackTarget = m.attackTarget;
			shoot(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.monsterType].lag,
					    10);
				} else
					// track player some more
					transition(m, M_HOME, 1,
					    monstertypes[m.monsterType].rate,
					    0);
			}
		}
		break;
	}

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

void
monsterpain(DynamicEntity *m, int damage, DynamicEntity *d)
{
	// a monster hit us
	if (d.monsterState) {
		// guard for RL guys shooting themselves :)
		if (m != d) {
			// don't attack straight away, first get angry
			m.anger++;
			int anger = m.monsterType == d.monsterType ? m.anger / 2
			                                           : m.anger;
			if (anger >= monstertypes[m.monsterType].loyalty)
				// monster infight if very angry
				m.enemy = d;
		}
	} else {
		// player hit us
		m.anger = 0;
		m.enemy = d;
	}
	// in this state monster won't attack
	transition(m, M_PAIN, 0, monstertypes[m.monsterType].pain, 200);
	if ((m.health -= damage) <= 0) {
		m.state = CS_DEAD;
		m.lastAction = lastmillis;
		numkilled++;
		player1.frags = numkilled;
		OFVector3D loc = m.origin;
		playsound(monstertypes[m.monsterType].diesound, &loc);
		int remain = monstertotal - numkilled;
		if (remain > 0 && remain <= 5)
			conoutf(@"only %d monster(s) remaining", remain);
	} else {
		OFVector3D loc = m.origin;
		playsound(monstertypes[m.monsterType].painsound, &loc);
	}
}

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);

	// equivalent of player entity touch, but only teleports are used
	[ents enumerateObjectsUsingBlock:^(Entity *e, size_t i, bool *stop) {
		if (e.type != TELEPORT)
			return;

		if (OUTBORD(e.x, e.y))
			return;

		OFVector3D v =
		    OFMakeVector3D(e.x, e.y, (float)S(e.x, e.y)->floor);
		for (DynamicEntity *monster in monsters) {
			if (monster.state == CS_DEAD) {
				if (lastmillis - monster.lastAction < 2000) {
					monster.move = 0;
					moveplayer(monster, 1, false);
				}
			} else {
				v.z += monster.eyeHeight;
				vdist(dist, t, monster.origin, v);
				v.z -= monster.eyeHeight;

				if (dist < 4)
					teleport(i, monster);
			}
		}
	}];

	for (DynamicEntity *monster in monsters)
		if (monster.state == CS_ALIVE)
			monsteraction(monster);
}

void
monsterrender()
{
	for (DynamicEntity *monster in monsters)
		renderclient(monster, false,
		    monstertypes[monster.monsterType].mdlname,
		    monster.monsterType == 5,
		    monstertypes[monster.monsterType].mscale / 10.0f);
}