ForgottenWawiTech/Content/NPCs/OriginalLyyka/Lyyka.cs

using Terraria;
using Terraria.ID;
using Terraria.ModLoader;
using Microsoft.Xna.Framework;
using Terraria.Chat;
using Terraria.Localization;

namespace ForgottenWawiTech.Content.NPCs.OriginalLyyka
{
    [AutoloadBossHead]
    public class Lyyka : ModNPC
    {
        public override void SetStaticDefaults()
        {
            // DisplayName.SetDefault("Original Lyyka");
            Main.npcFrameCount[NPC.type] = 1;
        }

        public override void SetDefaults()
        {
            NPC.width = 40;
            NPC.height = 40;
            NPC.damage = 1786;
            NPC.defense = 290;
            NPC.lifeMax = 1000000;
            NPC.HitSound = SoundID.NPCHit1;
            NPC.DeathSound = SoundID.NPCDeath1;
            NPC.knockBackResist = 0f;
            NPC.boss = true;
            NPC.aiStyle = -1;
            NPC.value = Item.buyPrice(0, 1, 0, 0);
        }

        public override void AI()
        {
            // Phased boss AI for Lyyka:
            // - At 50% HP, spawn Terra. Lyyka becomes invulnerable and waits until Terra is defeated -> Phase 2
            // - At 30% HP (after Terra phase), spawn Clara. Lyyka becomes invulnerable and waits until Clara is defeated -> Phase 3

            NPC.TargetClosest(false);
            Player target = Main.player[NPC.target];
            if (!target.active || target.dead)
            {
                NPC.timeLeft = 300;
                return;
            }

            int phase = (int)NPC.ai[0]; // 0 = initial, 1 = waiting Terra, 2 = after Terra, 3 = waiting Clara, 4 = final
            int flags = (int)NPC.ai[1]; // bit0 = Terra spawned, bit1 = Clara spawned

            // Phase 0: before Terra summoned
            if (phase == 0)
            {
                if (NPC.life <= NPC.lifeMax / 2 && (flags & 1) == 0)
                {
                    flags |= 1;
                    NPC.ai[1] = flags;

                    // Make invulnerable and wait for Terra
                    NPC.dontTakeDamage = true;
                    NPC.ai[0] = 1;
                    NPC.netUpdate = true;

                }

                // basic approach movement
                if (NPC.ai[0] == 0)
                {
                    Vector2 dir = (target.Center - NPC.Center);
                    if (dir.Length() > 8f)
                    {
                        dir.Normalize();
                        NPC.velocity = Vector2.Lerp(NPC.velocity, dir * 3.5f, 0.02f);
                    }
                }
            }
            // Phase 1: waiting for Terra
            else if (phase == 1)
            {
                bool terraAlive = false;
                int terraType = ModContent.NPCType<Terra>();
                for (int i = 0; i < Main.maxNPCs; i++)
                {
                    NPC check = Main.npc[i];
                    if (check.active && check.type == terraType)
                    {
                        terraAlive = true;
                        break;
                    }
                }

                if (!terraAlive)
                {
                    NPC.dontTakeDamage = false;
                    NPC.ai[0] = 2; // enter Phase 2
                    NPC.netUpdate = true;
                }
                else
                {
                    NPC.velocity *= 0.98f; // idle while waiting
                }
            }
            // Phase 2: after Terra defeated, before Clara
            else if (phase == 2)
            {
                // When at or below 30% HP, spawn Clara (if not already spawned)
                if (NPC.life <= (int)(NPC.lifeMax * 0.3f) && (flags & 2) == 0)
                {
                    flags |= 2;
                    NPC.ai[1] = flags;

                    NPC.dontTakeDamage = true;
                    NPC.ai[0] = 3; // waiting for Clara
                    NPC.netUpdate = true;

                    string announceClara = "Clara descends from the sky!";
                }

                // basic movement in Phase 2
                Vector2 dir2 = (target.Center - NPC.Center);
                if (dir2.Length() > 8f)
                {
                    dir2.Normalize();
                    NPC.velocity = Vector2.Lerp(NPC.velocity, dir2 * 4f, 0.02f);
                }
            }
            // Phase 3: waiting for Clara
            else if (phase == 3)
            {
                bool claraAlive = false;
                int claraType = ModContent.NPCType<Clara>();
                for (int i = 0; i < Main.maxNPCs; i++)
                {
                    NPC check = Main.npc[i];
                    if (check.active && check.type == claraType)
                    {
                        claraAlive = true;
                        break;
                    }
                }

                if (!claraAlive)
                {
                    NPC.dontTakeDamage = false;
                    NPC.ai[0] = 4; // final phase
                    NPC.netUpdate = true;
                }
                else
                {
                    NPC.velocity *= 0.98f;
                }
            }
            // Phase 4+: final behaviour
            else
            {
                Vector2 dir3 = (target.Center - NPC.Center);
                if (dir3.Length() > 8f)
                {
                    dir3.Normalize();
                    NPC.velocity = Vector2.Lerp(NPC.velocity, dir3 * 4.5f, 0.02f);
                }
            }
        }

        public override void OnKill()
        {
/*             // Spawn LyykaNPC when killed
            if (Main.netMode != NetmodeID.MultiplayerClient)
            {
                NPC.NewNPC(NPC.GetSource_Death(), (int)NPC.Center.X, (int)NPC.Center.Y, ModContent.NPCType<LyykaNPC>());
            }
            else
            {
                NetMessage.SendData(MessageID.SpawnNPC, number: ModContent.NPCType<LyykaNPC>(), number2: NPC.whoAmI);
            } */
            // Set a world flag or similar to indicate Lyyka has been defeated
            WorldDefeatedBosses.Lyyka = true;
            // Immediate sync of world flags
            WorldDefeatedBosses.Sync(ModContent.GetInstance<ForgottenWawiTech>());
        }
    }
}