---
## Goal
- Implement inventory and backpack system in Godot 4.6 point-and-click adventure game per plan at `docs/plans/2026-04-26-001-feat-inventory-backpack-system-plan.md`

## Constraints & Preferences
- Interaction handlers are signals emitted by items, not embedded dictionary data
- No multi-step transition queues — FSM transitions interrupt in-flight animations immediately
- No sound required
- Item cursor as 5th `ActionState` slot (`ITEM`, value 4); right-click cycles WALK→LOOK→TOUCH→TALK→ITEM→WALK
- Use colored `ColorRect` boxes as placeholders for all item/backpack visuals
- Follow PRD §13 recommended Godot architecture approaches
- PRD is engine-agnostic but implementation targets Godot 4.6

## Progress
### Done
- Read and analyzed `inventory-prd.md` (791 lines)
- Researched existing codebase patterns
- Wrote complete plan to `docs/plans/2026-04-26-001-feat-inventory-backpack-system-plan.md` with 6 implementation units
- Applied 5 user edits to plan: signal-based interactions, no transition queues, no sound, ActionState ITEM slot, colored boxes
- Created directory structure: `inventory/inventory_backpack/`, `inventory/inventory_overlay/`
- Generated 12 UIDs for new files
- U1 complete: `inventory/ItemDefinition.gd` written (Resource with id, name, combination_category)
- U2 complete: `inventory/InventoryManager.gd` written (AutoLoad singleton with signals, queries, mutations, combination emission, selection)
- U3 complete: `inventory/inventory_backpack/InventoryBackpack.gd` + `.tscn` (FSM with IDLE/OPEN/SELECTED/ACQUIRE/REMOVE, Tween animations, guard checks)
- U4 complete: `inventory/inventory_overlay/InventoryOverlay.gd` + `.tscn` + `InventorySlot.gd` + `.tscn` (full-screen overlay, grid, drag-and-drop, hover, combination)
- U5 complete: Modified `ActionState.gd` (ITEM=4), `MainGame.gd` (5-action cycling), `Scene.gd` (overlay guard, ITEM input), `GameScript.gd` (GiveItem step)
- U6 complete: Modified `Scene.gd` (give_item/remove_item/strip_items helpers), `SetPiece_.gd` (ITEM action handling)
- InventoryManager registered as AutoLoad in `project.godot`
- All commits pushed to remote

### In Progress
- (none)

### Blocked
- (none)

## Key Decisions
- **Signal-based interactions**: Items emit signals; `InventoryManager.attempt_combine` emits `combination_attempted`; scene scripts handle results
- **No transition queues**: FSM transitions kill in-flight tweens and start fresh; `is_busy` flag prevents concurrency but does not queue
- **ActionState ITEM slot**: `ITEM = 4` added to enum; right-click cycles all 5 states; selected item stored in `InventoryManager.selected_item`
- **Colored boxes**: `ColorRect` placeholders replace all `Sprite2D` references
- **Hand-rolled FSM (PRD Option A)** over AnimationTree: conditional branching maps better to code
- **AutoLoad singleton** for InventoryManager following ActionState pattern
- **Raw `_gui_input()`** for overlay drag-and-drop instead of Godot's built-in system
- **Combined input priority defense**: `MOUSE_FILTER_STOP` background + `_unhandled_input()` gate + explicit `overlay_active` guard flag
- **ItemDefinition as Resource** for serializable `.tres` item data
- **GridContainer** for static item grid layout

## Next Steps
- Test all units in Godot editor
- Register sample item definitions (`.tres` files)
- Wire up signal connections in `Game.tscn` (backpack ↔ overlay ↔ manager)
- Create example room script demonstrating `give_item()` usage
- Replace colored box placeholders with actual item sprites

## Critical Context
- Godot 4.6 project, 1920x1080 viewport
- Branch: `sugary-panda` (worktree), default branch: `master`
- Existing autoloads: `ActionState`, `CameraTransition`, `InventoryManager` (new)
- Root scene `Game.tscn` uses `SubViewport` for game world, `CanvasLayer` for overlays
- `ActionState.gd` enum: `WALK=0, LOOK=1, TOUCH=2, TALK=3, ITEM=4`
- `MainGame.gd` has `cursors` array with 4 cursor textures — 5th slot needed for ITEM (currently skips if no item selected)
- All code committed and pushed to `origin/sugary-panda`

## Relevant Files
- `inventory-prd.md`: Origin requirements document (791 lines, 14 acceptance criteria)
- `docs/plans/2026-04-26-001-feat-inventory-backpack-system-plan.md`: Implementation plan (6 units, edited with 5 user changes)
- `inventory/ItemDefinition.gd`: Custom Resource class (DONE)
- `inventory/ItemDefinition.gd.uid`: UID file for ItemDefinition (DONE)
- `inventory/InventoryManager.gd`: AutoLoad singleton with signals, queries, mutations (DONE)
- `inventory/InventoryManager.gd.uid`: UID file for InventoryManager (DONE)
- `inventory/inventory_backpack/InventoryBackpack.gd`: FSM script (DONE)
- `inventory/inventory_backpack/InventoryBackpack.gd.uid`: UID file (DONE)
- `inventory/inventory_backpack/InventoryBackpack.tscn`: HUD backpack scene (DONE)
- `inventory/inventory_backpack/InventoryBackpack.tscn.uid`: UID file (DONE)
- `inventory/inventory_overlay/InventoryOverlay.gd`: Overlay interaction script (DONE)
- `inventory/inventory_overlay/InventoryOverlay.gd.uid`: UID file (DONE)
- `inventory/inventory_overlay/InventoryOverlay.tscn`: Full-screen overlay scene (DONE)
- `inventory/inventory_overlay/InventoryOverlay.tscn.uid`: UID file (DONE)
- `inventory/inventory_overlay/InventorySlot.gd`: Slot behavior script (DONE)
- `inventory/inventory_overlay/InventorySlot.gd.uid`: UID file (DONE)
- `inventory/inventory_overlay/InventorySlot.tscn`: Single item slot scene (DONE)
- `inventory/inventory_overlay/InventorySlot.tscn.uid`: UID file (DONE)
- `MainGame.gd`: Modified for 5-action cursor cycling with ITEM
- `Scene.gd`: Modified for overlay guard, ITEM action, helper methods
- `ActionState.gd`: Modified to add ITEM action
- `GameScript.gd`: Modified to add GiveItem/GiveItemDeferred steps
- `SetPiece_.gd`: Modified to handle ITEM action
- `project.godot`: InventoryManager AutoLoad registered
