ForgottenWawiTech/Content/Projectiles/Protogen/ProtogenSentinelCore.cs

using Microsoft.Xna.Framework;
using Terraria;
using Terraria.Audio;
using Terraria.ID;
using Terraria.ModLoader;
using ForgottenWawiTech.Content.Players;
using ForgottenWawiTech.Content.GlobalProjectiles;

namespace ForgottenWawiTech.Content.Projectiles.Protogen
{
    public class ProtogenSentinelCore : ModProjectile
    {
        private const float HoverRadius = 70f;
        private const float HoverSpeed = 0.035f;
        private const int FireCooldown = 32;
        private const float TargetRange = 950f;
        private const float BeamVelocity = 18f;

        public override string Texture => "ForgottenWawiTech/Assets/PlaceholderProj";

        public override void SetStaticDefaults()
        {
            ProjectileID.Sets.MinionSacrificable[Type] = false;
            ProjectileID.Sets.MinionTargettingFeature[Type] = true;
        }

        public override void SetDefaults()
        {
            Projectile.width = 36;
            Projectile.height = 36;
            Projectile.friendly = false;
            Projectile.minion = true;
            Projectile.tileCollide = false;
            Projectile.ignoreWater = true;
            Projectile.penetrate = -1;
            Projectile.netImportant = true;
            Projectile.timeLeft = 2;
            Projectile.damage = 0;
            Projectile.minionSlots = 0f;
        }

        public override void AI()
        {
            Player owner = Main.player[Projectile.owner];
            ProtogenSentinelPlayer modPlayer = owner.GetModPlayer<ProtogenSentinelPlayer>();
            if (!owner.active || owner.dead || !modPlayer.SentinelCoreActive)
            {
                Projectile.Kill();
                return;
            }

            Projectile.timeLeft = 2;

            float rotation = ((float)Main.GameUpdateCount * HoverSpeed) % MathHelper.TwoPi;
            Vector2 desiredOffset = new Vector2(0f, -HoverRadius).RotatedBy(rotation);
            Vector2 desiredPosition = owner.Center + desiredOffset;
            Projectile.Center = Vector2.Lerp(Projectile.Center, desiredPosition, 0.2f);
            Projectile.velocity = owner.velocity;

            Lighting.AddLight(Projectile.Center, 0.2f, 0.6f, 0.9f);

            if (Projectile.owner == Main.myPlayer)
            {
                Projectile.localAI[0]++;
                if (Projectile.localAI[0] >= FireCooldown)
                {
                    Projectile.localAI[0] = 0f;
                    NPC target = AcquireTarget(owner, Projectile.Center, TargetRange);
                    if (target != null)
                    {
                        FireBeam(owner, target);
                    }
                }
            }
        }

        private void FireBeam(Player owner, NPC target)
        {
            Vector2 velocity = (target.Center - Projectile.Center).SafeNormalize(Vector2.UnitY) * BeamVelocity;
            int damage = ProtogenSentinelPlayer.GetCoreDamage(owner);
            var source = Projectile.GetSource_FromThis();
            Projectile beam = Projectile.NewProjectileDirect(
                source,
                Projectile.Center,
                velocity,
                ModContent.ProjectileType<ProtogenSentinelCoreBeam>(),
                damage,
                3f,
                owner.whoAmI);
            beam.GetGlobalProjectile<ProtogenSentinelGlobalProjectile>().DisableSentinelSplit = true;
            SoundEngine.PlaySound(SoundID.Item33 with { Volume = 0.7f, Pitch = 0.15f }, Projectile.Center);
        }

        private static NPC AcquireTarget(Player owner, Vector2 center, float range)
        {
            if (owner.HasMinionAttackTargetNPC)
            {
                NPC target = Main.npc[owner.MinionAttackTargetNPC];
                if (target.CanBeChasedBy())
                {
                    return target;
                }
            }

            NPC closest = null;
            float squaredRange = range * range;
            for (int i = 0; i < Main.maxNPCs; i++)
            {
                NPC npc = Main.npc[i];
                if (!npc.active || npc.friendly || npc.dontTakeDamage || npc.life <= 0)
                {
                    continue;
                }

                float distance = Vector2.DistanceSquared(npc.Center, center);
                if (distance <= squaredRange && Collision.CanHitLine(center, 0, 0, npc.Center, 0, 0))
                {
                    squaredRange = distance;
                    closest = npc;
                }
            }

            return closest;
        }
    }
}