From 13ae274106ebe8debcebdcea5de997197f867eb2 Mon Sep 17 00:00:00 2001
From: yuki <yvki@riseup.net>
Date: Fri, 14 Nov 2025 15:53:20 -0300
Subject: [PATCH] create abstract state machine class

---
 scenes/classes/state_machine.gd     | 48 +++++++++++++++++++++++++++++
 scenes/classes/state_machine.gd.uid |  1 +
 scenes/classes/state_machine.tscn   |  6 ++++
 3 files changed, 55 insertions(+)
 create mode 100644 scenes/classes/state_machine.gd
 create mode 100644 scenes/classes/state_machine.gd.uid
 create mode 100644 scenes/classes/state_machine.tscn

diff --git a/scenes/classes/state_machine.gd b/scenes/classes/state_machine.gd
new file mode 100644
index 0000000..7e0d627
--- /dev/null
+++ b/scenes/classes/state_machine.gd
@@ -0,0 +1,48 @@
+## Virtual base class for all nodes that deal directly with states.
+## Extend this class and override its methods to implement a state machine.
+@abstract class_name StateMachine extends Node
+
+## The initial state of the state machine. If not set, the first child node is used.
+@export var initial_state: State
+
+## The state machine's current loaded state
+@onready var state: State = _get_initial_state()
+
+
+func _ready() -> void:
+	for state_node: State in find_children("*", "State"):
+		state_node.finished.connect(_transition_to_next_state)
+		
+		await owner.ready
+		state.enter("")
+
+
+func _unhandled_input(event: InputEvent) -> void:
+	state.handle_input(event)
+
+
+func _process(delta: float) -> void:
+	state.update(delta)
+
+
+func _physics_process(delta: float) -> void:
+	state.physics_update(delta)
+
+
+## Called when initial state is not specified.
+## Returns the first child node by default.
+## Override if necessary, but don't call it directly.
+func _get_initial_state() -> State:
+	return initial_state if initial_state != null else get_child(0)
+
+
+## Transitions the active state out after receiving a finished signal.
+func _transition_to_next_state(target_state_path: String, data: Dictionary = {}) -> void:
+	if not has_node(target_state_path):
+		printerr(owner.name + ": Trying to transition to state " + target_state_path + " but it does not exist.")
+		return
+	
+	var previous_state_path: StringName = state.name
+	state.exit()
+	state = get_node(target_state_path)
+	state.enter(previous_state_path, data)
diff --git a/scenes/classes/state_machine.gd.uid b/scenes/classes/state_machine.gd.uid
new file mode 100644
index 0000000..01f45af
--- /dev/null
+++ b/scenes/classes/state_machine.gd.uid
@@ -0,0 +1 @@
+uid://dqjaxgmyxq3rx
diff --git a/scenes/classes/state_machine.tscn b/scenes/classes/state_machine.tscn
new file mode 100644
index 0000000..c42124a
--- /dev/null
+++ b/scenes/classes/state_machine.tscn
@@ -0,0 +1,6 @@
+[gd_scene load_steps=2 format=3 uid="uid://cy4h0xcy2kscg"]
+
+[ext_resource type="Script" uid="uid://dqjaxgmyxq3rx" path="res://scenes/classes/state_machine.gd" id="1_rnohx"]
+
+[node name="StateMachine" type="Node"]
+script = ExtResource("1_rnohx")