class_name P91AnimationAdapter
extends RefCounted

var library: Dictionary = {}

func load_specs(specs: Dictionary) -> void:
	library.clear()
	for character in specs:
		var loaded_states := {}
		for state in specs[character]:
			var spec: Dictionary = specs[character][state]
			var frames: Array[Texture2D] = []
			for index in range(int(spec["frames"])):
				var path := "res://assets/animations/%s/frame-%d.png" % [spec["root"], index]
				var texture := load(path) as Texture2D
				assert(texture != null, "Missing animation texture: %s" % path)
				frames.append(texture)
			loaded_states[state] = {"frames": frames, "fps": float(spec["fps"]), "loop": bool(spec["loop"])}
		library[character] = loaded_states

func frame_index(character: String, state: String, elapsed: float) -> int:
	if not library.has(character):
		return 0
	var resolved := state if library[character].has(state) else "idle"
	var spec: Dictionary = library[character][resolved]
	var count: int = spec["frames"].size()
	var raw := int(floor(maxf(0.0, elapsed) * float(spec["fps"])))
	return raw % count if spec["loop"] else mini(raw, count - 1)

func texture(character: String, state: String, elapsed: float) -> Texture2D:
	if not library.has(character):
		return null
	var resolved := state if library[character].has(state) else "idle"
	return library[character][resolved]["frames"][frame_index(character, resolved, elapsed)]