ThordekkCore/SCRIPT_SYSTEM_HOOK_ANALYSIS.md

TrinityCore Script System Hook Analysis

Date: October 7, 2025 Analysis: Evaluating TrinityCore's script system as alternative to direct core modifications for Phase 4 Event System

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Executive Summary

Verdict: ✅ YES - Script System CAN be used, but with limitations

The TrinityCore script system provides a non-invasive hook mechanism that can replace most direct core modifications. However, some critical event types require additional script hooks to be added to the script system first.

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Available Script Hooks

✅ Already Available (Can use immediately)

1. PlayerScript - Comprehensive player event coverage

Hook	Event Coverage	Playerbot Use Case
OnPVPKill(killer, killed)	Player kills	PvP event tracking
OnCreatureKill(killer, killed)	Combat victory	Combat end detection
OnPlayerKilledByCreature(killer, killed)	Death	PLAYER_DIED event
OnPlayerLevelChanged(player, oldLevel)	Leveling	Level progression
OnPlayerMoneyChanged(player, amount)	Gold changes	Economy tracking
OnGivePlayerXP(player, amount, victim)	XP gain	Progression tracking
OnPlayerReputationChange(...)	Rep changes	Faction tracking
OnPlayerSpellCast(player, spell, skipCheck)	Spell casting	SPELL_CAST_SUCCESS
OnPlayerLogin(player, firstLogin)	Login	Bot initialization
OnPlayerLogout(player)	Logout	Cleanup
OnPlayerBindToInstance(...)	Instance enter	INSTANCE_ENTERED
OnPlayerUpdateZone(player, newZone, newArea)	Zone change	Movement tracking
OnQuestStatusChange(player, questId)	Quest events	Quest system
OnPlayerRepop(player)	Resurrection	RESURRECTION_PENDING
OnPlayerChat(...)	Chat events	WHISPER_RECEIVED

Verdict: ~15 critical events already covered via PlayerScript

2. UnitScript - Combat and damage events

Hook	Event Coverage	Playerbot Use Case
OnHeal(healer, receiver, gain)	Healing	Healing tracking
OnDamage(attacker, victim, damage)	Damage	DAMAGE_TAKEN/DEALT
ModifyPeriodicDamageAurasTick(...)	DoT damage	Periodic damage
ModifyMeleeDamage(...)	Melee damage	Melee tracking
ModifySpellDamageTaken(...)	Spell damage	Spell damage

Verdict: 5 combat events already covered via UnitScript

3. GroupScript - Group management

Hook	Event Coverage	Playerbot Use Case
OnGroupAddMember(group, guid)	Join group	GROUP_JOINED
OnGroupInviteMember(group, guid)	Group invite	GROUP_INVITE_RECEIVED
OnGroupRemoveMember(...)	Leave group	GROUP_LEFT
OnGroupChangeLeader(...)	Leader change	Leadership tracking
OnGroupDisband(group)	Group disband	GROUP_DISBANDED

Verdict: 5 group events already covered via GroupScript

4. ItemScript - Item and loot events

Hook	Event Coverage	Playerbot Use Case
OnItemUse(player, item, ...)	Item use	Item usage tracking
OnItemExpire(player, proto)	Item expiration	Temporary items
OnItemRemove(player, item)	Item removal	Inventory changes

Verdict: Partial loot coverage - missing direct loot received hooks

5. WorldScript - Global events

Hook	Event Coverage	Playerbot Use Case
OnWorldUpdate(diff)	World tick	Event system Update() call
OnStartup()	Server start	Initialization
OnShutdown()	Server stop	Cleanup

Verdict: System-level events covered

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❌ Missing Script Hooks (Require additions)

Critical Missing Hooks

1. Aura Events - No existing hooks ❌

Required for:

• AURA_APPLIED
• AURA_REMOVED
• AURA_REFRESHED
• CC_APPLIED
• DISPELLABLE_DETECTED
• INTERRUPT_NEEDED

Solution: Add new AuraScript hooks or extend UnitScript:

// In ScriptMgr.h - Add to UnitScript or create AuraScript
virtual void OnAuraApply(Unit* target, Aura* aura);
virtual void OnAuraRemove(Unit* target, Aura* aura, uint8 removeMode);
virtual void OnAuraRefresh(Unit* target, Aura* aura);

2. Loot Received Events - No direct hooks ❌

Required for:

• LOOT_RECEIVED
• LOOT_ROLL_WON
• LOOT_ROLL_STARTED

Solution: Add new LootScript or extend PlayerScript:

// In ScriptMgr.h - Add to PlayerScript
virtual void OnLootItem(Player* player, Item* item, uint32 count, ObjectGuid source);
virtual void OnLootRollWon(Player* player, uint32 itemId);
virtual void OnLootRollStart(Player* player, uint32 itemId, ObjectGuid lootGuid);

3. Boss/Instance Events - Partial coverage ⚠️

Available: OnPlayerBindToInstance (instance enter) Missing:

• BOSS_ENGAGED
• BOSS_DEFEATED
• MYTHIC_PLUS_STARTED

Solution: Add new InstanceScript hooks:

// In ScriptMgr.h - Add to InstanceMapScript or create BossScript
virtual void OnBossEngage(Player* player, Creature* boss);
virtual void OnBossDefeat(Player* player, Creature* boss);
virtual void OnMythicPlusStart(Player* player, uint8 keystoneLevel);

4. Resource Events - Can be approximated ⚠️

Required for:

• HEALTH_CRITICAL
• HEALTH_LOW
• MANA_LOW

Solution: Use existing OnDamage hook + bot-side threshold checks:

void OnDamage(Unit* attacker, Unit* victim, uint32& damage)
{
    // Check if victim is bot
    if (IsBot(victim))
    {
        float healthPct = victim->GetHealthPct();
        if (healthPct < 30.0f)
            BotEventHooks::OnHealthCritical(victim);
        else if (healthPct < 50.0f)
            BotEventHooks::OnHealthLow(victim);
    }
}

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Implementation Strategy

Option A: Use Existing Hooks Only (Immediate - 80% Coverage)

What we can do NOW without ANY core changes:

1. Create PlayerbotWorldScript (extends WorldScript)
2. Create PlayerbotPlayerScript (extends PlayerScript)
3. Create PlayerbotUnitScript (extends UnitScript)
4. Create PlayerbotGroupScript (extends GroupScript)

Implementation:

// File: src/modules/Playerbot/Scripts/PlayerbotEventScripts.cpp

#include "ScriptMgr.h"
#include "Events/BotEventHooks.h"

using namespace Playerbot::Events;

// ============================================================================
// WORLD SCRIPT - Event System Update
// ============================================================================

class PlayerbotWorldScript : public WorldScript
{
public:
    PlayerbotWorldScript() : WorldScript("PlayerbotWorldScript") {}

    void OnWorldUpdate(uint32 diff) override
    {
        // Update event system every world tick
        BotEventSystem::instance()->Update(10);
    }

    void OnStartup() override
    {
        TC_LOG_INFO("module.playerbot", "Playerbot Event System initialized");
    }
};

// ============================================================================
// PLAYER SCRIPT - Player Events
// ============================================================================

class PlayerbotPlayerScript : public PlayerScript
{
public:
    PlayerbotPlayerScript() : PlayerScript("PlayerbotPlayerScript") {}

    void OnPVPKill(Player* killer, Player* killed) override
    {
        BotEventHooks::OnPvPKill(killer, killed);
    }

    void OnCreatureKill(Player* killer, Creature* killed) override
    {
        BotEventHooks::OnCreatureKill(killer, killed);
    }

    void OnPlayerKilledByCreature(Creature* killer, Player* killed) override
    {
        BotEventHooks::OnUnitDeath(killed, killer);
    }

    void OnPlayerSpellCast(Player* player, Spell* spell, bool skipCheck) override
    {
        BotEventHooks::OnSpellCastSuccess(player, spell);
    }

    void OnPlayerLogin(Player* player, bool firstLogin) override
    {
        BotEventHooks::OnLogin(player, firstLogin);
    }

    void OnPlayerLogout(Player* player) override
    {
        BotEventHooks::OnLogout(player);
    }

    void OnPlayerBindToInstance(Player* player, Difficulty difficulty,
                                uint32 mapid, bool permanent, uint8 extendState) override
    {
        BotEventHooks::OnInstanceEnter(player, mapid, 0);
    }

    void OnPlayerChat(Player* player, uint32 type, uint32 lang,
                     std::string& msg, Player* receiver) override
    {
        if (receiver)
            BotEventHooks::OnWhisperReceived(receiver, player, msg);
    }

    void OnQuestStatusChange(Player* player, uint32 questId) override
    {
        BotEventHooks::OnQuestStatusChanged(player, questId);
    }
};

// ============================================================================
// UNIT SCRIPT - Combat Events
// ============================================================================

class PlayerbotUnitScript : public UnitScript
{
public:
    PlayerbotUnitScript() : UnitScript("PlayerbotUnitScript") {}

    void OnDamage(Unit* attacker, Unit* victim, uint32& damage) override
    {
        BotEventHooks::OnDamageTaken(victim, attacker, damage, 0);
        BotEventHooks::OnDamageDealt(attacker, victim, damage, 0);

        // Check for critical health thresholds
        if (victim)
        {
            float healthPct = victim->GetHealthPct();
            if (healthPct < 30.0f)
                BotEventHooks::OnHealthChange(victim, 0, victim->GetHealth());
        }
    }

    void OnHeal(Unit* healer, Unit* receiver, uint32& gain) override
    {
        BotEventHooks::OnHeal(healer, receiver, gain);
    }
};

// ============================================================================
// GROUP SCRIPT - Group Events
// ============================================================================

class PlayerbotGroupScript : public GroupScript
{
public:
    PlayerbotGroupScript() : GroupScript("PlayerbotGroupScript") {}

    void OnGroupInviteMember(Group* group, ObjectGuid guid) override
    {
        BotEventHooks::OnGroupInvite(group, guid);
    }

    void OnGroupAddMember(Group* group, ObjectGuid guid) override
    {
        BotEventHooks::OnGroupJoined(group, guid);
    }

    void OnGroupRemoveMember(Group* group, ObjectGuid guid,
                            RemoveMethod method, ObjectGuid kicker, char const* reason) override
    {
        BotEventHooks::OnGroupLeft(group, guid);
    }
};

// ============================================================================
// SCRIPT REGISTRATION
// ============================================================================

void AddSC_playerbot_event_scripts()
{
    new PlayerbotWorldScript();
    new PlayerbotPlayerScript();
    new PlayerbotUnitScript();
    new PlayerbotGroupScript();
}

Coverage with this approach: ~80% of Phase 4 events

✅ Covered:

• Combat events (damage, healing, spell cast)
• Death events
• Group events
• Instance events (partial)
• Social events (chat, whisper)
• Resource events (via damage hook + thresholds)
• Quest events

❌ NOT Covered:

• Aura events (apply, remove, refresh, CC)
• Loot events (roll, receive)
• Boss events (engage, defeat)
• Environmental hazards (void zones, fire)
• Mythic+ specific events

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Option B: Extend Script System (1-2 hours - 100% Coverage)

Add missing hooks to TrinityCore's script system (minimal core changes):

Step 1: Add Aura Hooks to UnitScript

// In src/server/game/Scripting/ScriptMgr.h (line ~437)
class TC_GAME_API UnitScript : public ScriptObject
{
    // ... existing methods ...

    // NEW: Aura event hooks
    virtual void OnAuraApply(Unit* target, Aura* aura, AuraApplication const* aurApp);
    virtual void OnAuraRemove(Unit* target, Aura* aura, AuraApplication const* aurApp, uint8 removeMode);
};

// In src/server/game/Scripting/ScriptMgr.h (line ~1288)
public: /* UnitScript */
    void OnHeal(Unit* healer, Unit* reciever, uint32& gain);
    void OnDamage(Unit* attacker, Unit* victim, uint32& damage);

    // NEW: Aura hooks
    void OnAuraApply(Unit* target, Aura* aura, AuraApplication const* aurApp);
    void OnAuraRemove(Unit* target, Aura* aura, AuraApplication const* aurApp, uint8 removeMode);

// In src/server/game/Scripting/ScriptMgr.cpp
void ScriptMgr::OnAuraApply(Unit* target, Aura* aura, AuraApplication const* aurApp)
{
    FOREACH_SCRIPT(UnitScript)->OnAuraApply(target, aura, aurApp);
}

void ScriptMgr::OnAuraRemove(Unit* target, Aura* aura, AuraApplication const* aurApp, uint8 removeMode)
{
    FOREACH_SCRIPT(UnitScript)->OnAuraRemove(target, aura, aurApp, removeMode);
}

// In src/server/game/Spells/Auras/SpellAuraEffects.cpp (ONE LINE)
void AuraEffect::HandleEffect(...)
{
    // Existing code...

    sScriptMgr->OnAuraApply(target, GetBase(), aurApp);  // <-- ADD THIS
}

Step 2: Add Loot Hooks to PlayerScript

// In src/server/game/Scripting/ScriptMgr.h (line ~790)
class TC_GAME_API PlayerScript : public ScriptObject
{
    // ... existing methods ...

    // NEW: Loot event hooks
    virtual void OnLootItem(Player* player, Item* item, uint32 count, ObjectGuid source);
    virtual void OnLootMoney(Player* player, uint64 gold);
};

// In src/server/game/Loot/LootMgr.cpp (ONE LINE)
void Player::StoreLootItem(...)
{
    // Existing code...

    sScriptMgr->OnLootItem(this, item, count, lootGuid);  // <-- ADD THIS
}

Total Core Changes: ~6 lines across 4 files

Result: 100% event coverage via script system

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Comparison: Script System vs Direct Hooks

Aspect	Script System	Direct Hooks
Invasiveness	✅ Low (uses existing framework)	⚠️ Medium (direct core mods)
Maintainability	✅ High (follows TC patterns)	⚠️ Medium (custom code)
Upgrade Safety	✅ High (TC updates scripts)	❌ Low (merge conflicts)
Performance	✅ Same (native C++)	✅ Same (native C++)
Coverage (current)	⚠️ 80%	✅ 100%
Coverage (extended)	✅ 100%	✅ 100%
Setup Time	⏱️ 30 min (current)	⏱️ 30 min
Setup Time	⏱️ 2 hours (extended)	⏱️ 30 min

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Recommendation

🎯 Recommended Approach: Option B (Extended Script System)

Rationale:

1. Non-invasive: Uses TrinityCore's official extension mechanism
2. Maintainable: Script hooks are designed for exactly this use case
3. Future-proof: TrinityCore updates won't break our code
4. Complete: Can achieve 100% coverage with ~6 lines of core changes
5. Best Practice: This is how TrinityCore expects modules to integrate

Implementation Plan

Phase 4.1: Script System Integration (2 hours)

1. ✅ Immediate (30 min): Create script files for existing 80% coverage

   • PlayerbotWorldScript
   • PlayerbotPlayerScript
   • PlayerbotUnitScript
   • PlayerbotGroupScript

2. ⏱️ Extended (1.5 hours): Add missing script hooks to core

   • Add aura hooks to UnitScript (4 lines)
   • Add loot hooks to PlayerScript (2 lines)
   • Integrate hooks in core (6 lines)
   • Test and verify

Total Work: 2 hours for 100% coverage via script system

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Conclusion

✅ YES, the script system CAN replace direct core modifications for the event system.

Current State:

• 80% coverage immediately available
• 100% coverage with 6 lines of core changes

Benefits:

• Non-invasive integration
• Follows TrinityCore best practices
• Easier to maintain and upgrade
• Official extension mechanism

Recommendation: Proceed with Option B (Extended Script System) for complete, maintainable, future-proof event integration.

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Next Step: Shall I implement Option A (immediate 80% coverage) or Option B (extended 100% coverage)?