extends Node
## Device-independent gameplay input. Bindings remain in Godot's InputMap.

signal command_requested(action: StringName, command_context: int)
signal transient_input_cleared

## Gameplay input context enumeration.
## ON_FOOT: Player is on foot and can perform standard movement actions.
## VEHICLE: Player is controlling a vehicle and movement actions are mapped accordingly.
enum Context { ON_FOOT, VEHICLE }

## Current gameplay input context. 
var context: Context = Context.ON_FOOT
## Whether sprint is currently enabled.
var sprint_enabled: bool = false
## Controller turn speed for look input.
var controller_turn_speed: Vector2 = Vector2(2.5, 2.0)
## Whether the Y-axis of the controller look input is inverted.
var invert_controller_y: bool = false
## Deadzone for movement stick input.
var movement_deadzone: float = 0.2
## Deadzone for look stick input.
var look_deadzone: float = 0.2
## List of nodes that currently own the menu, blocking gameplay input.
var _menu_owners: Array[Node] = []
## Accumulated mouse displacement since the last frame.
var _mouse_displacement: Vector2 = Vector2.ZERO
## Whether a jump has been requested this frame.
var _jump_requested: bool = false
## Whether the input system is waiting for all controls to return to neutral.
var _awaiting_neutral: bool = false
## Whether the game window is currently focused.
var _window_focused: bool = true
## Dictionary tracking currently processed but not yet canceled: i.e. when you press the fire button and it has been handled but you have not yet released the button.
var _latched_commands: Dictionary = {}
## Outgoing/incoming controls monitored until an ownership handoff reaches neutral.
var _neutral_actions: Array[StringName] = []

## List of all trigger-based actions the player can perform.
const TRIGGER_ACTIONS: Array[StringName] = [
	&"interact", &"combat_reload", &"character_toggle_inventory", &"toggle_view",
	&"combat_toggle_weapon", &"character_toggle_mag_boots", &"character_sprint", &"character_jump", &"combat_fire",
	&"vehicle_toggle_gear", &"vehicle_toggle_crew_hatch", &"vehicle_toggle_dock_hatch",
	&"capsule_toggle_ladder", &"vehicle_activate_instruments", &"vehicle_toggle_cabin_lights",
]
## Explicit command membership; action prefixes are organizational only.
const CONTEXT_TRIGGER_ACTIONS: Dictionary = {
	Context.ON_FOOT: [
		&"interact", &"toggle_view", &"character_toggle_inventory", &"character_toggle_mag_boots",
		&"character_sprint", &"character_jump", &"combat_fire", &"combat_reload", &"combat_toggle_weapon",
	],
	Context.VEHICLE: [
		&"interact", &"toggle_view", &"vehicle_toggle_gear", &"vehicle_toggle_crew_hatch",
		&"vehicle_toggle_dock_hatch", &"capsule_toggle_ladder", &"vehicle_activate_instruments",
		&"vehicle_toggle_cabin_lights",
	],
}
## Commands requiring the controller auxiliary modifier, independent of their names.
const VEHICLE_AUXILIARY_ACTIONS: Array[StringName] = [
	&"vehicle_toggle_gear", &"vehicle_toggle_crew_hatch", &"vehicle_toggle_dock_hatch",
	&"capsule_toggle_ladder", &"vehicle_activate_instruments", &"vehicle_toggle_cabin_lights",
]
## List of all axis-based actions the player can perform.
const AXIS_ACTIONS: Array[StringName] = [
	&"character_move_left", &"character_move_right", &"character_move_forward", &"character_move_back",
	&"look_left", &"look_right", &"look_up", &"look_down",
	&"eva_roll_left", &"eva_roll_right", &"vehicle_pitch_up", &"vehicle_pitch_down",
	&"vehicle_yaw_left", &"vehicle_yaw_right", &"vehicle_roll_left", &"vehicle_roll_right",
]
## Look is shared; character/EVA and vehicle axes belong to distinct contexts.
const SHARED_AXIS_ACTIONS: Array[StringName] = [
	&"look_left", &"look_right", &"look_up", &"look_down",
]
const CONTEXT_AXIS_ACTIONS: Dictionary = {
	Context.ON_FOOT: [
		&"character_move_left", &"character_move_right", &"character_move_forward", &"character_move_back",
		&"eva_roll_left", &"eva_roll_right",
	],
	Context.VEHICLE: [
		&"vehicle_pitch_up", &"vehicle_pitch_down", &"vehicle_yaw_left", &"vehicle_yaw_right",
		&"vehicle_roll_left", &"vehicle_roll_right",
	],
}
## Held controls are polled, not dispatched through command_requested.
const CONTEXT_HELD_ACTIONS: Dictionary = {
	Context.ON_FOOT: [&"combat_aim", &"freelook", &"release_cursor"],
	Context.VEHICLE: [&"vehicle_thrust", &"vehicle_freelook", &"vehicle_auxiliary", &"vehicle_release_cursor"],
}

## Connects device/focus boundaries; project defaults are never reapplied on spawn.
func _ready() -> void:
	process_mode = Node.PROCESS_MODE_ALWAYS
	Input.joy_connection_changed.connect(_on_controller_connection_changed)
	get_tree().root.focus_entered.connect(_on_focus_entered)
	get_tree().root.focus_exited.connect(_on_focus_exited)


## Updates neutral gating and ends sprint when the movement stick is released.
func _process(_delta: float) -> void:
	for owner_index in range(_menu_owners.size() - 1, -1, -1):
		if not is_instance_valid(_menu_owners[owner_index]):
			_menu_owners.remove_at(owner_index)
	if _awaiting_neutral and _controls_are_neutral():
		_awaiting_neutral = false
		_neutral_actions.clear()
	if not gameplay_enabled() or read_movement().length_squared() < 0.0001:
		sprint_enabled = false


## UI receives events first. Only the current gameplay context gets commands.
func _unhandled_input(event: InputEvent) -> void:
	for action in _latched_commands.keys():
		if event.is_action_released(action):
			_latched_commands.erase(action)
	if not gameplay_enabled():
		return
	if event is InputEventMouseMotion:
		if Input.mouse_mode == Input.MOUSE_MODE_CAPTURED:
			record_mouse_displacement(event.relative)
		return
	for action in CONTEXT_TRIGGER_ACTIONS[context]:
		if event.is_action_pressed(action) and _command_is_available(action, event):
			if _latched_commands.has(action):
				return
			_latched_commands[action] = true
			get_viewport().set_input_as_handled()
			if action == &"character_sprint":
				sprint_enabled = not sprint_enabled
			elif action == &"character_jump":
				_jump_requested = true
			else:
				command_requested.emit(action, context)
			return


## Changes control ownership and discards commands from the previous owner.
func set_context(next_context: Context) -> void:
	_monitor_context_for_neutral(context)
	context = next_context
	clear_transient_input()


## Blocks gameplay while an owning menu is open; nested menus are supported.
func set_menu_open(owner_node: Node, is_open: bool) -> void:
	if is_open and not _menu_owners.has(owner_node):
		_menu_owners.append(owner_node)
	elif not is_open:
		_menu_owners.erase(owner_node)
	clear_transient_input()


## Clears held/queued state and requires neutral controls before gameplay resumes.
func clear_transient_input() -> void:
	_monitor_context_for_neutral(context)
	_mouse_displacement = Vector2.ZERO
	_jump_requested = false
	_latched_commands.clear()
	sprint_enabled = false
	_awaiting_neutral = true
	transient_input_cleared.emit()


## Polling must use this gate: UI event consumption does not block Input state.
## Returns true if the window is focused, the game is not paused, no menus are open, and we are not awaiting neutral input.
func gameplay_enabled() -> bool:
	return _window_focused and not get_tree().paused and _menu_owners.is_empty() and not _awaiting_neutral


## Checks explicit membership without relying on action naming prefixes.
func is_action_available(action: StringName) -> bool:
	return (
		CONTEXT_TRIGGER_ACTIONS[context].has(action)
		or SHARED_AXIS_ACTIONS.has(action)
		or CONTEXT_AXIS_ACTIONS[context].has(action)
		or CONTEXT_HELD_ACTIONS[context].has(action)
	)


## Returns body-relative movement, with forward on negative Y and magnitude <= 1.
func read_movement() -> Vector2:
	if not gameplay_enabled() or context != Context.ON_FOOT:
		return Vector2.ZERO
	return Input.get_vector("character_move_left", "character_move_right", "character_move_forward", "character_move_back", movement_deadzone)


## Returns signed analog strength without exposing device axes to gameplay.
func read_axis(negative_action: StringName, positive_action: StringName) -> float:
	if not gameplay_enabled() or not is_action_available(negative_action) or not is_action_available(positive_action):
		return 0.0
	return Input.get_axis(negative_action, positive_action)


## Returns an unsigned analog command strength in the range 0..1.
func read_strength(action: StringName) -> float:
	return Input.get_action_strength(action) if gameplay_enabled() and is_action_available(action) else 0.0


## Returns a held action; future automatic weapons can use this independently of presses.
func is_held(action: StringName) -> bool:
	return gameplay_enabled() and is_action_available(action) and Input.is_action_pressed(action)


## Consumes one UI-aware jump request during the next physics update.
func consume_jump_request() -> bool:
	var requested: bool = _jump_requested and gameplay_enabled()
	_jump_requested = false
	return requested


## Accumulates mouse pixels independently of the render/physics update rates.
func record_mouse_displacement(displacement: Vector2) -> void:
	if gameplay_enabled():
		_mouse_displacement += displacement


## Consumes mouse pixels, once per camera update, without time scaling.
func consume_mouse_displacement() -> Vector2:
	var displacement := _mouse_displacement if gameplay_enabled() else Vector2.ZERO
	_mouse_displacement = Vector2.ZERO
	return displacement


## Returns stick angular displacement in radians for this frame; positive Y looks down.
func read_controller_look(delta: float) -> Vector2:
	if not gameplay_enabled():
		return Vector2.ZERO
	var stick := Input.get_vector("look_left", "look_right", "look_up", "look_down", look_deadzone)
	if invert_controller_y:
		stick.y = -stick.y
	return stick * controller_turn_speed * delta


## Returns a current-device binding label, with a fallback for unmapped actions.
func binding_label(action: StringName) -> String:
	var helper := get_node_or_null("/root/InputHelper")
	if helper == null:
		return "Unbound"
	var binding: InputEvent = helper.get_keyboard_or_joypad_input_for_action(action)
	return helper.get_label_for_input(binding) if binding != null else "Unbound"


## Restricts contextual commands and routes modifier-layer controller buttons.
func _command_is_available(action: StringName, event: InputEvent) -> bool:
	if not CONTEXT_TRIGGER_ACTIONS[context].has(action):
		return false
	if context == Context.VEHICLE and event is InputEventJoypadButton:
		var auxiliary_layer := Input.is_action_pressed("vehicle_auxiliary")
		return auxiliary_layer if VEHICLE_AUXILIARY_ACTIONS.has(action) else not auxiliary_layer
	return true


## Adds only relevant controls to a handoff; unrelated future axes cannot block it.
func _monitor_context_for_neutral(monitored_context: Context) -> void:
	var actions: Array = CONTEXT_TRIGGER_ACTIONS[monitored_context] + SHARED_AXIS_ACTIONS
	actions.append_array(CONTEXT_AXIS_ACTIONS[monitored_context])
	actions.append_array(CONTEXT_HELD_ACTIONS[monitored_context])
	for action in actions:
		if not _neutral_actions.has(action):
			_neutral_actions.append(action)


## Waits for outgoing/incoming controls, including latched command releases.
func _controls_are_neutral() -> bool:
	for action in _neutral_actions:
		if not AXIS_ACTIONS.has(action) and Input.is_action_pressed(action):
			return false
		if Input.get_action_strength(action) > 0.2:
			return false
	return true


## Disconnects clear held commands; reconnects require neutral input too.
func _on_controller_connection_changed(_device: int, _connected: bool) -> void:
	clear_transient_input()


## Window focus loss must not leave firing, look, or sprint latched.
func _on_focus_exited() -> void:
	_window_focused = false
	clear_transient_input()


## Focus restoration requires a fresh press rather than replaying held controls.
func _on_focus_entered() -> void:
	_window_focused = true
	clear_transient_input()