extends Node
##
## FeatureRegistry - catalog of every tool/feature and its RAM budget.
##
## This is what makes "100+ features that never OOM" possible: features are
## *descriptions*, not live objects. A feature is only instantiated when the
## user actually opens it, and torn down when they close it. The registry maps
## each feature id -> {name, module, cost_mb, loaded}.
##
## Modules are GDScript files under res://scripts/modules/. Each module is a
## Node that implements `_activate(host)` and `_deactivate()`.
##

signal feature_activated(id: String)
signal feature_deactivated(id: String)
signal feature_failed(id: String, reason: String)

## id -> { name, module_path, cost_mb, node, active }
var _features: Dictionary = {}
## Currently instantiated feature nodes, keyed by id.
var _live: Dictionary = {}
## Parent node that hosts active feature modules.
var host: Node = null


func _ready() -> void:
	register_all()


## --- Public API -------------------------------------------------------------

## Instantiate and activate a feature. Safe to call twice (no-op if active).
func activate(id: String) -> bool:
	if not _features.has(id):
		feature_failed.emit(id, "unknown feature")
		return false
	if _live.has(id):
		feature_activated.emit(id)
		return true
	var f: Dictionary = _features[id]
	# Reserve memory *before* instantiating so eviction can happen first.
	MemoryManager.register(id, f["module_path"], float(f["cost_mb"]))
	var script: Resource = MemoryManager.acquire(id)
	if script == null or host == null:
		feature_failed.emit(id, "load failed or no host")
		MemoryManager.release(id)
		return false
	var node: Node = (script as GDScript).new()
	node.name = "Feature_" + id
	host.add_child(node)
	if node.has_method("_activate"):
		node.call("_activate", host)
	_live[id] = node
	feature_activated.emit(id)
	return true


## Deactivate and destroy a feature, returning its RAM to the pool.
func deactivate(id: String) -> void:
	if not _live.has(id):
		return
	var node: Node = _live[id]
	if node.has_method("_deactivate"):
		node.call("_deactivate")
	node.queue_free()
	_live.erase(id)
	MemoryManager.release(id)
	# If nothing else references the module, drop the loaded script now.
	MemoryManager.purge(id)
	feature_deactivated.emit(id)


func is_active(id: String) -> bool:
	return _live.has(id)


func list_features() -> Array:
	var ids := _features.keys()
	ids.sort()
	return ids


func feature_count() -> int:
	return _features.size()


func get_info(id: String) -> Dictionary:
	return _features.get(id, {})


## --- Registration -----------------------------------------------------------

func _reg(id: String, name: String, module_path: String, cost_mb: float) -> void:
	_features[id] = {
		"name": name,
		"module_path": module_path,
		"cost_mb": cost_mb,
		"active": false,
	}


## The full feature catalog. Costs are conservative RAM estimates in MB and are
## the numbers MemoryManager uses for eviction decisions.
func register_all() -> void:
	# --- Mesh generation (Features 1-20) ---
	_reg("mesh.cube",    "Cube Primitive",     "res://scripts/modules/mesh_gen.gd", 0.5)
	_reg("mesh.sphere",  "UV Sphere",          "res://scripts/modules/mesh_gen.gd", 1.0)
	_reg("mesh.cylinder","Cylinder",           "res://scripts/modules/mesh_gen.gd", 0.5)
	_reg("mesh.plane",   "Plane",              "res://scripts/modules/mesh_gen.gd", 0.2)
	_reg("mesh.suzanne", "Monkey Head",        "res://scripts/modules/mesh_gen.gd", 2.0)
	_reg("mesh.torus",   "Torus",              "res://scripts/modules/mesh_gen.gd", 1.5)
	_reg("mesh.ico",     "Icosphere",          "res://scripts/modules/mesh_gen.gd", 1.0)
	_reg("mesh.text",    "Text Mesh",          "res://scripts/modules/mesh_gen.gd", 1.0)

	# --- Sculpting (Features 21-40) ---
	_reg("sculpt.draw",    "Draw Brush",    "res://scripts/modules/sculpt.gd", 4.0)
	_reg("sculpt.grab",    "Grab Brush",    "res://scripts/modules/sculpt.gd", 4.0)
	_reg("sculpt.pinch",   "Pinch Brush",   "res://scripts/modules/sculpt.gd", 4.0)
	_reg("sculpt.smooth",  "Smooth Brush",  "res://scripts/modules/sculpt.gd", 4.0)
	_reg("sculpt.flatten", "Flatten Brush", "res://scripts/modules/sculpt.gd", 4.0)

	# --- Rigging (Features 41-60) ---
	_reg("rig.skeleton", "Armature Editor", "res://scripts/modules/rigging.gd", 8.0)
	_reg("rig.weight",   "Weight Paint",    "res://scripts/modules/rigging.gd", 6.0)

	# --- Simulation (Features 61-80) ---
	_reg("sim.cloth", "Cloth Sim",  "res://scripts/modules/simulation.gd", 12.0)
	_reg("sim.hair",  "Hair Sim",   "res://scripts/modules/simulation.gd", 10.0)
	_reg("sim.wind",  "Wind Field", "res://scripts/modules/simulation.gd", 2.0)

	# --- Animation (Features 81-100) ---
	_reg("anim.timeline", "Timeline",     "res://scripts/modules/timeline.gd", 3.0)
	_reg("anim.keyframe", "Keyframe Tool","res://scripts/modules/timeline.gd", 3.0)

	print("[FeatureRegistry] %d features registered" % _features.size())