# Combat UI Unit Panel Implementation Plan

> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.

**Goal:** Replace the exit-button CombatUI with a bottom-left panel that shows the selected unit's name and HP.

**Architecture:** CombatUI listens to the `unit_selected_changed` signal from units in the `"units"` group. On selection, it populates a name label and HP progress bar and shows the panel. On deselection, it hides the panel.

**Tech Stack:** Godot 4.6, GDScript, `.tscn` scene files

---

## File Structure

| File | Action | Responsibility |
|------|--------|----------------|
| `prefabs/unit.tscn` | Modify | Add Unit node to `"units"` group |
| `scripts/combat_ui.gd` | Create | Script that connects to unit signals, shows/hides panel, populates data |
| `prefabs/combat_ui.tscn` | Modify | Remove exit button, add UnitPanel with NameLabel and HPBar, attach new script |

---

### Task 1: Add Unit to the "units" group

**Files:**
- Modify: `prefabs/unit.tscn`

- [ ] **Step 1: Add the group to the Unit scene**

In `prefabs/unit.tscn`, add a `groups` property to the root `Unit` node so every instantiated unit is automatically in the `"units"` group. Add this line to the root `[node name="Unit" ...]` block:

```
groups=["units"]
```

The full node line becomes:
```
[node name="Unit" type="Node2D" unique_id=1893234933 groups=["units"]]
```

- [ ] **Step 2: Verify in editor**

Open `scenes/combat_test.tscn` in Godot, run the scene (F5), and use the Remote scene tree to confirm the spawned unit node appears under the `"units"` group.

- [ ] **Step 3: Commit**

```bash
git add prefabs/unit.tscn
git commit -m "feat: add Unit to 'units' group for discovery"
```

---

### Task 2: Create combat_ui.gd script

**Files:**
- Create: `scripts/combat_ui.gd`

- [ ] **Step 1: Write the script**

Create `scripts/combat_ui.gd` with the following content:

```gdscript
class_name CombatUI extends CanvasLayer

@onready var unit_panel: PanelContainer = %UnitPanel
@onready var name_label: Label = %NameLabel
@onready var hp_bar: ProgressBar = %HPBar

func _ready() -> void:
	unit_panel.visible = false
	for unit: Unit in get_tree().get_nodes_in_group("units"):
		unit.unit_selected_changed.connect(_on_unit_selected_changed)

func _on_unit_selected_changed(unit: Unit, selected: bool) -> void:
	if selected:
		name_label.text = unit.current_info.name
		hp_bar.max_value = unit.current_stats.max_hp
		hp_bar.value = unit.current_stats.current_hp
		unit_panel.visible = true
	else:
		unit_panel.visible = false
```

- [ ] **Step 2: Commit**

```bash
git add scripts/combat_ui.gd
git commit -m "feat: add CombatUI script for unit info panel"
```

---

### Task 3: Rebuild combat_ui.tscn

**Files:**
- Modify: `prefabs/combat_ui.tscn`

- [ ] **Step 1: Replace the scene file contents**

Replace the entire contents of `prefabs/combat_ui.tscn` with:

```
[gd_scene format=3 uid="uid://cy7r0udfcsqbn"]

[ext_resource type="Theme" uid="uid://dx26d6py3n8xi" path="res://resources/main_ui_theme.tres" id="1_2ro41"]
[ext_resource type="Script" path="res://scripts/combat_ui.gd" id="2_ui_script"]

[node name="CombatUI" type="CanvasLayer" unique_id=1093388037]
script = ExtResource("2_ui_script")

[node name="UnitPanel" type="PanelContainer" parent="." unique_id=2000000001]
unique_name_in_owner = true
visible = false
anchors_preset = 2
anchor_top = 1.0
anchor_bottom = 1.0
offset_left = 8.0
offset_top = -78.0
offset_right = 208.0
offset_bottom = -8.0
grow_vertical = 0
theme = ExtResource("1_2ro41")

[node name="MarginContainer" type="MarginContainer" parent="UnitPanel"]
layout_mode = 2
theme_override_constants/margin_left = 8
theme_override_constants/margin_top = 8
theme_override_constants/margin_right = 8
theme_override_constants/margin_bottom = 8

[node name="VBoxContainer" type="VBoxContainer" parent="UnitPanel/MarginContainer"]
layout_mode = 2

[node name="NameLabel" type="Label" parent="UnitPanel/MarginContainer/VBoxContainer" unique_id=2000000002]
unique_name_in_owner = true
layout_mode = 2
text = "Unit"

[node name="HPBar" type="ProgressBar" parent="UnitPanel/MarginContainer/VBoxContainer" unique_id=2000000003]
unique_name_in_owner = true
layout_mode = 2
max_value = 100.0
value = 100.0
show_percentage = false
```

Key changes from the old file:
- Removed the exit button, its inline GDScript, the VBoxContainer, and the `[connection]` block.
- Added the `combat_ui.gd` script as an ext_resource and attached it to the root node.
- Added `UnitPanel` (PanelContainer) anchored to bottom-left with 8px margin from edges, 200px wide, ~70px tall.
- `NameLabel` and `HPBar` are marked with `unique_name_in_owner = true` so the script can reference them via `%NameLabel` and `%HPBar`.
- `UnitPanel` is also unique-named for `%UnitPanel` access.
- `show_percentage = false` on HPBar since we just want the bar visual.

- [ ] **Step 2: Open in Godot and verify scene tree**

Open `prefabs/combat_ui.tscn` in the Godot editor. Confirm:
1. No errors in the Scene dock.
2. The node tree shows: `CombatUI > UnitPanel > MarginContainer > VBoxContainer > NameLabel + HPBar`.
3. The UnitPanel is positioned at the bottom-left of the viewport.

- [ ] **Step 3: Commit**

```bash
git add prefabs/combat_ui.tscn
git commit -m "feat: replace exit button with unit info panel in CombatUI"
```

---

### Task 4: Integration test — verify end-to-end behavior

**Files:**
- None (manual verification)

- [ ] **Step 1: Run the combat test scene**

Run `scenes/combat_test.tscn` (F5 or F6 from the scene). The test map generator spawns a unit named "Putit" with 50 HP.

- [ ] **Step 2: Verify panel is hidden on start**

Confirm the bottom-left corner is empty — no panel visible.

- [ ] **Step 3: Click the unit to select it**

Click the "Putit" unit on the map. Confirm:
1. The panel appears in the bottom-left corner.
2. The name label shows "Putit".
3. The HP bar is full (50/50).

- [ ] **Step 4: Click an empty tile to deselect**

Click an empty floor tile (this moves the unit, but the unit stays selected). Currently, clicking a different unit would deselect the first — since there's only one test unit, verify that selecting the same unit again keeps the panel visible and data correct.

- [ ] **Step 5: Verify exit button is gone**

Confirm there is no "Exit" button anywhere in the UI.

- [ ] **Step 6: Commit (if any tweaks were needed)**

```bash
git add -A
git commit -m "fix: adjustments from integration testing"
```