Fix weapon skills bug: prevent casting without weapon

[thefatcode]

Summary

Prevents weapon-based skills from being cast without a weapon equipped.

Problem

Players could exploit weapon skills (like Twisting Slash) by casting them without a weapon, potentially causing unexpected behavior.

Solution

Added a check in AreaSkillAttackAction.PerformAutomaticHitsAsync() that validates weapon presence for skills with MovesToTarget = true.

Changes

• Uses skill.MovesToTarget property instead of hardcoding skill number
• Uses GetRandomOffensiveItem() to check for any equipped weapon (handles left-hand, right-hand, and two-handed weapons)
• Covers all weapon-based melee skills (Twisting Slash, Death Stab, etc.)

[gemini-code-assist]

Summary of Changes

Hello @thefatcode, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request resolves an exploit allowing players to cast weapon-dependent skills without an equipped weapon, which could lead to unexpected game behavior. By introducing a robust validation mechanism, the change ensures that such skills can only be activated when an appropriate offensive item is present, thereby maintaining game balance and integrity.

Highlights

• Weapon Skill Validation: Implemented a check within AreaSkillAttackAction.PerformAutomaticHitsAsync() to prevent weapon-based skills from being cast if the player does not have an offensive weapon equipped. This addresses an exploit where skills like Twisting Slash or Death Stab could be used without a weapon.
• Dynamic Skill Requirement Check: The validation now dynamically checks the skill.MovesToTarget property, ensuring that any skill requiring movement to a target (and thus a weapon) is covered, rather than relying on hardcoded skill IDs.
• Comprehensive Weapon Detection: Utilizes player.Inventory?.GetRandomOffensiveItem() to accurately detect the presence of any equipped offensive weapon, covering various configurations (left-hand, right-hand, two-handed).

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[gemini-code-assist]

Code Review

This pull request aims to fix a bug where weapon-based skills could be cast without a weapon. The approach is to add a check for an equipped weapon for skills that move the player to the target.

The change in src/GameLogic/PlayerActions/Skills/AreaSkillAttackAction.cs correctly identifies the skills that need this check. However, the implementation of the check itself is flawed. It uses GetRandomOffensiveItem(), which can return a pendant, thus incorrectly allowing the skill to be cast without a weapon. I've suggested a more robust check that specifically verifies if a weapon is equipped in the hand slots.

The change in src/Web/AdminPanel/Pages/EditConfigGrid.razor.cs is correct and passes the necessary PersistenceContext to the creation modal.

Please address the issue in the weapon check to fully resolve the exploit.

[gemini-code-assist]

The current check using player.Inventory?.GetRandomOffensiveItem() is null is not sufficient to prevent casting weapon-based skills without a weapon. The GetRandomOffensiveItem method can return a pendant, which would allow the check to pass even if no weapon is equipped. This would allow the exploit to persist for players who have a pendant but no weapon.

The check should be more specific to only consider items in weapon slots that are actual weapons (not shields or ammunition).

You might need to add using MUnique.OpenMU.DataModel.Entities; for the Item type if it's not already available in the file's scope.

        if (skill.MovesToTarget)
        {
            var inventory = player.Inventory;
            var left = inventory?.GetItem(InventoryConstants.LeftHandSlot);
            var right = inventory?.GetItem(InventoryConstants.RightHandSlot);

            static bool IsWeapon(Item? item)
            {
                // A weapon is an item in a hand slot which is not a shield or ammunition.
                const byte ShieldItemGroup = 6;
                return item?.Definition is not null && !item.Definition.IsAmmunition && item.Definition.Group != ShieldItemGroup;
            }

            if (!IsWeapon(left) && !IsWeapon(right))
            {
                return;
            }
        }

[sven-n]

There is a more simple fix: Each weapon adds 1 to the Stats.EquippedWeaponCount, so just check if it's greater than 0, and it should work.

        if (skill.MovesToTarget && player.Attributes[Stats.EquippedWeaponCount] > 0)

[sven-n]

There is a more simple fix: Each weapon adds 1 to the Stats.EquippedWeaponCount, so just check if it's greater than 0, and it should work.

        if (skill.MovesToTarget && player.Attributes[Stats.EquippedWeaponCount] > 0)