feat: Adds Feature Flag System (#2328)
## Feature Flag System
A runtime feature flag system for dynamically enabling/disabling game systems and blocking specific game elements
without server restarts.
### Overview
Two types of controls:
1. Feature Flags - Named boolean flags that gate entire systems (trading, PvP, vendors, housing, etc.)
2. Dynamic Blocks - Block specific gumps, items, skills, or spells by type
All changes are persisted to JSON, broadcast to online staff, and bypass-able by administrators.
### Predefined Flags
```
┌─────────────────┬──────────┬─────────────────────────────────────┐
│ Flag │ Category │ Description │
├─────────────────┼──────────┼─────────────────────────────────────┤
│ player_trading │ Economy │ Allow secure trades between players │
├─────────────────┼──────────┼─────────────────────────────────────┤
│ vendor_purchase │ Economy │ Allow purchasing from NPC vendors │
├─────────────────┼──────────┼─────────────────────────────────────┤
│ vendor_sell │ Economy │ Allow selling to NPC vendors │
├─────────────────┼──────────┼─────────────────────────────────────┤
│ player_vendors │ Economy │ Allow player vendor interactions │
├─────────────────┼──────────┼─────────────────────────────────────┤
│ bank_access │ Economy │ Allow bank box access │
├─────────────────┼──────────┼─────────────────────────────────────┤
│ house_placement │ Housing │ Allow new house placements │
├─────────────────┼──────────┼─────────────────────────────────────┤
│ boat_placement │ Housing │ Allow new boat placements │
├─────────────────┼──────────┼─────────────────────────────────────┤
│ bulk_orders │ Crafting │ Allow bulk order deeds │
├─────────────────┼──────────┼─────────────────────────────────────┤
│ pvp_combat │ Combat │ Allow player vs player combat │
└─────────────────┴──────────┴─────────────────────────────────────┘
```
### Commands
#### Feature Flags
```
┌────────────────────────────────────────────────────┬───────────────────────┐
│ Command │ Description │
├────────────────────────────────────────────────────┼───────────────────────┤
│ [FeatureFlag <key> on|off|toggle|info │ Manage a feature flag │
├────────────────────────────────────────────────────┼───────────────────────┤
│ [FF <key> on|off │ Shorthand alias │
├────────────────────────────────────────────────────┼───────────────────────┤
│ [FeatureFlag <key> create <category> <desc> │ Create a custom flag │
├────────────────────────────────────────────────────┼───────────────────────┤
│ [FeatureFlag <key> delete │ Delete a custom flag │
├────────────────────────────────────────────────────┼───────────────────────┤
│ [FeatureList [flags|gumps|items|skills|spells|all] │ List all flags/blocks │
├────────────────────────────────────────────────────┼───────────────────────┤
│ [FeatureAdmin │ Open the admin gump │
└────────────────────────────────────────────────────┴───────────────────────┘
```
#### Gump Blocks
```
┌────────────────────────────────┬──────────────────────────────────────────────────────┐
│ Command │ Description │
├────────────────────────────────┼──────────────────────────────────────────────────────┤
│ [BlockGump <typeName> [reason] │ Block a gump type from displaying │
├────────────────────────────────┼──────────────────────────────────────────────────────┤
│ [UnblockGump <typeName> │ Remove a gump block │
├────────────────────────────────┼──────────────────────────────────────────────────────┤
│ [ListGumps [self] │ List open gumps on a player (for finding type names) │
└────────────────────────────────┴──────────────────────────────────────────────────────┘
```
#### Item Blocks
```
┌────────────────────────────────────────────────┬───────────────────────────────┐
│ Command │ Description │
├────────────────────────────────────────────────┼───────────────────────────────┤
│ [BlockItemUse <typeName|target> [reason] │ Block item use │
├────────────────────────────────────────────────┼───────────────────────────────┤
│ [BlockItemEquip <typeName|target> [reason] │ Block item equipping │
├────────────────────────────────────────────────┼───────────────────────────────┤
│ [BlockItemContainer <typeName|target> [reason] │ Block container access │
├────────────────────────────────────────────────┼───────────────────────────────┤
│ [UnblockItemUse <typeName> │ Remove use block │
├────────────────────────────────────────────────┼───────────────────────────────┤
│ [UnblockItemEquip <typeName> │ Remove equip block │
├────────────────────────────────────────────────┼───────────────────────────────┤
│ [UnblockItemContainer <typeName> │ Remove container access block │
└────────────────────────────────────────────────┴───────────────────────────────┘
```
Item block commands create an entry if one doesn't exist, or flip the relevant flag on an existing entry. Unblock
commands only clear their specific flag -- the entry is removed when all flags (use/equip/container) are off.
#### Skill & Spell Blocks
```
┌──────────────────────────────────────┬──────────────────────┐
│ Command │ Description │
├──────────────────────────────────────┼──────────────────────┤
│ [BlockSkill <SkillName> [reason] │ Block a skill │
├──────────────────────────────────────┼──────────────────────┤
│ [UnblockSkill <SkillName> │ Remove a skill block │
├──────────────────────────────────────┼──────────────────────┤
│ [BlockSpell <SpellTypeName> [reason] │ Block a spell │
├──────────────────────────────────────┼──────────────────────┤
│ [UnblockSpell <SpellTypeName> │ Remove a spell block │
└──────────────────────────────────────┴──────────────────────┘
```
### Architecture
- Static bool classes for hot-path checks (no dictionary lookups): ServerFeatureFlags (Server project) and
ContentFeatureFlags (UOContent)
- Synced automatically by FeatureFlagManager.SyncStaticFlag() when flags change
- Predefined flags loaded from Distribution/Configuration/FeatureFlags/default-flags.json
- Runtime state persisted to Configuration/FeatureFlags/*.json (flags, gump-blocks, item-blocks, skill-blocks,
spell-blocks)
- Admin gump with tabbed UI for managing all block types, per-entry PropertiesGump editing, and pagination
- All staff at AccessLevel.GameMaster+ bypass dynamic blocks; AccessLevel.Administrator+ bypass feature flags
### Hook Points
Hook: Player trading
Location: Mobile.OpenTrade
Mechanism: ServerFeatureFlags.PlayerTrading
────────────────────────────────────────
Hook: PvP combat
Location: Mobile.CanBeHarmful
Mechanism: ServerFeatureFlags.PvPCombat
────────────────────────────────────────
Hook: Bank access
Location: BankBox.Open()
Mechanism: ServerFeatureFlags.BankAccess
────────────────────────────────────────
Hook: Vendor buy/sell
Location: BaseVendor
Mechanism: ContentFeatureFlags.VendorPurchase/Sell
────────────────────────────────────────
Hook: Player vendors
Location: PlayerVendor
Mechanism: ContentFeatureFlags.PlayerVendors
────────────────────────────────────────
Hook: House placement
Location: HousePlacement.Check()
Mechanism: ContentFeatureFlags.HousePlacement (returns BadRegionTemp)
────────────────────────────────────────
Hook: Boat placement
Location: BaseBoatDeed.OnDoubleClick/OnPlacement
Mechanism: ContentFeatureFlags.BoatPlacement
────────────────────────────────────────
Hook: Bulk orders
Location: SmallBOD/LargeBOD
Mechanism: ContentFeatureFlags.BulkOrders
────────────────────────────────────────
Hook: Gump display
Location: GumpSystem.SendGump
Mechanism: FeatureFlagManager.IsGumpBlocked
────────────────────────────────────────
Hook: Item use
Location: PlayerMobile.AllowItemUse
Mechanism: FeatureFlagManager.IsItemUseBlocked
────────────────────────────────────────
Hook: Item equip
Location: PlayerMobile.CheckEquip
Mechanism: FeatureFlagManager.IsItemEquipBlocked
────────────────────────────────────────
Hook: Container access
Location: BaseContainer.DisplayTo
Mechanism: FeatureFlagManager.IsContainerAccessBlocked
────────────────────────────────────────
Hook: Skill use
Location: PlayerMobile.AllowSkillUse
Mechanism: FeatureFlagManager.IsSkillBlocked
────────────────────────────────────────
Hook: Spell casting
Location: Spell.Cast / Spellbook.CastSpellRequest
Mechanism: FeatureFlagManager.IsSpellBlocked
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