isleward/src/server/config/spells/spellFireblast.js

const getTargetPos = (physics, obj, m, pushback) => {
	let targetPos = {
		x: m.x,
		y: m.y
	};

	let dx = m.x - obj.x;
	let dy = m.y - obj.y;

	while ((dx === 0) && (dy === 0)) {
		dx = ~~(Math.random() * 2) - 1;
		dy = ~~(Math.random() * 2) - 1;
	}

	dx = ~~(dx / Math.abs(dx));
	dy = ~~(dy / Math.abs(dy));
	for (let l = 0; l < pushback; l++) {
		if (physics.isTileBlocking(targetPos.x + dx, targetPos.y + dy)) {
			if (physics.isTileBlocking(targetPos.x + dx, targetPos.y)) {
				if (physics.isTileBlocking(targetPos.x, targetPos.y + dy)) 
					break;
				else {
					dx = 0;
					targetPos.y += dy;
				}
			} else {
				dy = 0;
				targetPos.x += dx;
			}
		} else {
			targetPos.x += dx;
			targetPos.y += dy;
		}
	}

	return targetPos;
};

module.exports = {
	type: 'fireblast',

	targetGround: true,
	targetPlayerPos: true,

	radius: 2,
	pushback: 4,

	damage: 1,

	cast: function (action) {
		const { obj, targetPlayerPos } = this;

		let { x, y, instance: { physics, syncer } } = obj;

		if (!targetPlayerPos) {
			x = action.target.x;
			y = action.target.y;
		}

		let radius = this.radius;

		const particleEvent = {
			source: this,
			particleConfig: extend({}, this.particles)
		};
		obj.fireEvent('beforeSpawnParticles', particleEvent);

		for (let i = x - radius; i <= x + radius; i++) {
			for (let j = y - radius; j <= y + radius; j++) {
				if (!physics.hasLos(~~x, ~~y, ~~i, ~~j))
					continue;

				let effect = {
					x: i,
					y: j,
					components: [{
						type: 'particles',
						ttl: 10,
						blueprint: particleEvent.particleConfig
					}]
				};

				if ((i !== x) || (j !== y))
					syncer.queue('onGetObject', effect, -1);

				let mobs = physics.getCell(i, j);
				let mLen = mobs.length;
				for (let k = 0; k < mLen; k++) {
					let m = mobs[k];

					//Maybe we killed something?
					if (!m) {
						mLen--;
						continue;
					} else if (!m.aggro || !m.effects)
						continue;
					else if (!obj.aggro.canAttack(m))
						continue;

					const targetPos = getTargetPos(physics, obj, m, this.pushback);

					let distance = Math.max(Math.abs(m.x - targetPos.x), Math.abs(m.y - targetPos.y));
					let ttl = distance * 125;

					m.clearQueue();

					let damage = this.getDamage(m);
					m.stats.takeDamage({
						damage,
						threatMult: 1,
						source: this.obj,
						target: m,
						spellName: 'fireblast',
						noEvents: this.noEvents
					});

					if (m.destroyed)
						continue;

					const eventMsg = {
						success: true,
						targetPos
					};
					m.fireEvent('beforePositionChange', eventMsg);

					if (!eventMsg.success)
						continue;

					const targetEffect = m.effects.addEffect({
						type: 'stunned',
						silent: true
					});

					//If targetEffect is undefined, it means that the target has become resistant
					if (!targetEffect)
						continue;

					this.sendAnimation({
						id: m.id,
						components: [{
							type: 'moveAnimation',
							targetX: targetPos.x,
							targetY: targetPos.y,
							ttl: ttl
						}]
					});

					this.queueCallback(
						this.endEffect.bind(this, m, targetPos, targetEffect),
						ttl,
						null,
						m
					);

					//To be called when the object is destroyed
					this.obj.spellbook.registerDestroyCallback(this.destroyEffectOnTarget.bind(this, m, targetEffect));
				}
			}
		}

		this.sendBump({
			x: x,
			y: y - 1
		});

		return true;
	},

	endEffect: function (target, targetPos, targetEffect) {
		const { instance: { physics }, syncer, effects } = target;
		const { x: xNew, y: yNew } = targetPos;

		const xOld = target.x;
		const yOld = target.y;

		effects.removeEffect(targetEffect.id);

		target.x = xNew;
		target.y = yNew;

		if (physics.addObject(target, xNew, yNew, xOld, yOld))
			physics.removeObject(target, xOld, yOld, xNew, yNew);
		else {
			target.x = xOld;
			target.y = yOld;

			return false;
		}

		//We can't use xNew and yNew because addObject could have changed the position (like entering a building interior with stairs)
		const { x: xFinal, y: yFinal } = target;

		syncer.o.x = xFinal;
		syncer.o.y = yFinal;

		const moveEvent = {
			oldPos: {
				x: xOld,
				y: yOld
			},
			newPos: {
				x: xFinal,
				y: yFinal
			},
			source: this.obj,
			target,
			spellName: 'fireblast',
			spell: this
		};
		target.fireEvent('afterPositionChange', moveEvent);
	},

	destroyEffectOnTarget: function (target, targetEffect) {
		if (targetEffect)
			target.effects.removeEffect(targetEffect.id);
	}
};