isleward/src/server/components/mob.js

let abs = Math.abs.bind(Math);
let rnd = Math.random.bind(Math);
let max = Math.max.bind(Math);

const canPathHome = require('./mob/canPathHome');

const teleportHome = (physics, obj, mob) => {
	physics.removeObject(obj, obj.x, obj.y);
	obj.x = mob.originX;
	obj.y = mob.originY;
	const syncer = obj.syncer;
	syncer.o.x = obj.x;
	syncer.o.y = obj.y;
	physics.addObject(obj, obj.x, obj.y);
	obj.aggro.clearIgnoreList();
	obj.aggro.move();
};

module.exports = {
	type: 'mob',

	target: null,

	physics: null,

	originX: 0,
	originY: 0,

	walkDistance: 1,
	maxChaseDistance: 25,
	goHome: false,

	patrol: null,
	patrolTargetNode: 0,

	init: function (blueprint) {
		this.physics = this.obj.instance.physics;

		this.originX = this.obj.x;
		this.originY = this.obj.y;

		if (blueprint.patrol)
			this.patrol = blueprint.patrol;

		if (blueprint.maxChaseDistance)
			this.maxChaseDistance = blueprint.maxChaseDistance;
	},

	update: function () {
		let obj = this.obj;

		let target = null;
		if (obj.aggro)
			target = obj.aggro.getHighest();

		//Have we reached home?
		if (this.goHome) {
			let distanceFromHome = Math.max(abs(this.originX - obj.x), abs(this.originY - obj.y));
			if (!distanceFromHome)
				this.goHome = false;
		}

		//Are we too far from home?
		if ((!this.goHome) && (!obj.follower) && (target)) {
			if (!this.canChase(target)) {
				obj.clearQueue();
				obj.aggro.unAggro(target);
				target = obj.aggro.getHighest();
			}
		}

		if (!this.goHome) {
			if ((target) && (target !== obj) && ((!obj.follower) || (obj.follower.master !== target))) {
				//If we just started attacking, patrols need to know where home is
				if (!this.target && this.patrol) {
					this.originX = obj.x;
					this.originY = obj.y;
				}

				//Are we in fight mode?
				this.fight(target);
				return;
			} else if ((!target) && (this.target)) {
				//Is fight mode over?
				this.target = null;
				obj.clearQueue();

				if (canPathHome(this))
					this.goHome = true;
				else
					teleportHome(this.physics, obj, this);
			}
		}

		//If we're already going somewhere, don't calculate a new path
		if (obj.actionQueue.length > 0)
			return;

		//Unless we're going home, don't always move
		if (!this.goHome && rnd() < 0.85 && !this.patrol)
			return;

		//Don't move around if we're not allowed to, unless we're going home
		let walkDistance = this.walkDistance;
		if ((!this.goHome) && (walkDistance <= 0))
			return;

		let toX, toY;

		//Patrol mobs should not pick random locations unless they're going home
		if (this.goHome || !this.patrol) {
			toX = this.originX + ~~(rnd() * (walkDistance * 2)) - walkDistance;
			toY = this.originY + ~~(rnd() * (walkDistance * 2)) - walkDistance;
		} else if (this.patrol) {
			do {
				let toNode = this.patrol[this.patrolTargetNode];
				toX = toNode[0];
				toY = toNode[1];
				if ((toX - obj.x === 0) && (toY - obj.y === 0)) {
					this.patrolTargetNode++;
					if (this.patrolTargetNode >= this.patrol.length)
						this.patrolTargetNode = 0;
				} else
					break;
			} while (toX - obj.x !== 0 || toY - obj.y !== 0);
		}

		//We use goHome to force followers to follow us around but they should never stay in that state
		// since it messes with combat
		if (obj.follower)
			this.goHome = false;

		const dx = abs(obj.x - toX);
		const dy = abs(obj.y - toY);

		if (dx + dy === 0)
			return;
		else if (dx <= 1 && dy <= 1) {
			obj.queue({
				action: 'move',
				data: {
					x: toX,
					y: toY
				}
			});
		} else {
			let path = this.physics.getPath({
				x: obj.x,
				y: obj.y
			}, {
				x: toX,
				y: toY
			}, false);

			let pLen = path.length;
			for (let i = 0; i < pLen; i++) {
				let p = path[i];

				obj.queue({
					action: 'move',
					data: {
						x: p.x,
						y: p.y
					}
				});
			}
		}
	},

	fight: function (target) {
		let obj = this.obj;

		if (this.target !== target) {
			obj.clearQueue();
			this.target = target;
		}
		//If the target is true, it means we can't reach the target and should wait for a new one
		if (this.target === true)
			return;
		else if (obj.spellbook.isCasting())
			return;

		let x = obj.x;
		let y = obj.y;

		let tx = ~~target.x;
		let ty = ~~target.y;

		let distance = max(abs(x - tx), abs(y - ty));
		let furthestAttackRange = obj.spellbook.getFurthestRange(null, true);
		let furthestStayRange = obj.spellbook.getFurthestRange(null, false);

		let doesCollide = null;
		let hasLos = null;

		if (distance <= furthestAttackRange) {
			doesCollide = this.physics.mobsCollide(x, y, obj, target);
			if (!doesCollide) {
				hasLos = this.physics.hasLos(x, y, tx, ty);
				if (hasLos) {
					if (((obj.follower) && (obj.follower.master.player)) || (rnd() < 0.65)) {
						let spell = obj.spellbook.getRandomSpell(target);
						let success = obj.spellbook.cast({
							spell: spell,
							target: target
						});
						//null means we don't have LoS
						if (success !== null)
							return;
						hasLos = false;
					} else
						return;
				}
			}
		} else if (furthestAttackRange === 0) {
			if (distance <= obj.spellbook.closestRange && !this.physics.mobsCollide(x, y, obj, target))
				return;
		}

		let targetPos = this.physics.getClosestPos(x, y, tx, ty, target, obj);
		if (!targetPos) {
			//Find a new target
			obj.aggro.ignore(target);
			//TODO: Don't skip a turn
			return;
		}
		let newDistance = max(abs(targetPos.x - tx), abs(targetPos.y - ty));

		if (newDistance >= distance && newDistance > furthestStayRange) {
			obj.clearQueue();
			obj.aggro.ignore(target);
			if (!obj.aggro.getHighest()) {
				//Nobody left to attack so reset our aggro table
				obj.aggro.die();
				this.goHome = true;
			}

			return;
		}

		if (abs(x - targetPos.x) <= 1 && abs(y - targetPos.y) <= 1) {
			obj.queue({
				action: 'move',
				data: {
					x: targetPos.x,
					y: targetPos.y
				}
			});
		} else {
			let path = this.physics.getPath({
				x: x,
				y: y
			}, {
				x: targetPos.x,
				y: targetPos.y
			});
			if (path.length === 0) {
				obj.aggro.ignore(target);
				//TODO: Don't skip a turn
				return;
			}

			let p = path[0];
			obj.queue({
				action: 'move',
				data: {
					x: p.x,
					y: p.y
				}
			});
		}
	},

	canChase: function (obj) {
		//Patrol mobs can always chase if they don't have a target yet (since they don't have a home yet)
		if (this.patrol && !this.target && !this.goHome)
			return true;

		let distanceFromHome = Math.max(abs(this.originX - obj.x), abs(this.originY - obj.y));
		return ((!this.goHome) && (distanceFromHome <= this.maxChaseDistance));
	},

	events: {
		beforeTakeDamage: function (msg) {
			if (this.goHome)
				msg.failed = true;
		}
	}
};