class_name UnitModel
extends Node3D

var skeleton : Skeleton3D = null
var anim_player : AnimationPlayer = null
var anim_lib : AnimationLibrary = null
var sub_units : Array[UnitModel]
var meshes : Array[MeshInstance3D]

# COLOUR VARIABLES
@export_group("Colors")
@export var primary_colour : Color:
	set(col_in):
		primary_colour = col_in
		_set_shader_parameter(&"colour_primary", primary_colour)
		for unit : UnitModel in sub_units:
			unit.primary_colour = col_in

@export var secondary_colour: Color:
	set(col_in):
		secondary_colour = col_in
		_set_shader_parameter(&"colour_secondary", secondary_colour)
		for unit : UnitModel in sub_units:
			unit.secondary_colour = col_in

@export var tertiary_colour : Color:
	set(col_in):
		tertiary_colour = col_in
		_set_shader_parameter(&"colour_tertiary", tertiary_colour)
		for unit : UnitModel in sub_units:
			unit.tertiary_colour = col_in

# ANIMATION VARIABLES
@export_group("Animation")
@export var idle_anim : Animation:
	set(anim_in):
		load_animation("idle", anim_in)
		idle_anim = anim_in

@export var move_anim : Animation:
	set(anim_in):
		load_animation("move", anim_in)
		move_anim = anim_in

@export var attack_anim : Animation:
	set(anim_in):
		load_animation("attack", anim_in)
		attack_anim = anim_in

enum Anim { NONE, IDLE, MOVE, ATTACK }

const ANIMATION_LIBRARY : StringName = &"default_lib"
const ANIMATION_IDLE : String = ANIMATION_LIBRARY + "/idle"
const ANIMATION_MOVE : String = ANIMATION_LIBRARY + "/move"
const ANIMATION_ATTACK : String = ANIMATION_LIBRARY + "/attack"

@export var current_anim : Anim:
	set(anim_in):
		for unit : UnitModel in sub_units:
			unit.current_anim = anim_in

		if anim_player:
			match anim_in:
				Anim.IDLE:
					if idle_anim:
						anim_player.set_current_animation(ANIMATION_IDLE)
						_set_tex_scroll(scroll_speed_idle)
						current_anim = Anim.IDLE
						return
				Anim.MOVE:
					if move_anim:
						anim_player.set_current_animation(ANIMATION_MOVE)
						_set_tex_scroll(scroll_speed_move)
						current_anim = Anim.MOVE
						return
				Anim.ATTACK:
					if attack_anim:
						anim_player.set_current_animation(ANIMATION_ATTACK)
						_set_tex_scroll(scroll_speed_attack)
						current_anim = Anim.ATTACK
						return
				_: #None
					pass

			anim_player.stop()

		_set_tex_scroll(0.0)
		current_anim = Anim.NONE

# TEXTURE SCROLL SPEEDS (TANKS TRACKS AND SMOKE)
@export_subgroup("Texture_Scroll")
@export var scroll_speed_idle : float:
	set(speed_in):
		scroll_speed_idle = speed_in
		for unit : UnitModel in sub_units:
			unit.scroll_speed_idle = speed_in

@export var scroll_speed_move : float:
	set(speed_in):
		scroll_speed_move = speed_in
		for unit : UnitModel in sub_units:
			unit.scroll_speed_move = speed_in

@export var scroll_speed_attack : float:
	set(speed_in):
		scroll_speed_attack = speed_in
		for unit : UnitModel in sub_units:
			unit.scroll_speed_attack = speed_in

func unit_init() -> void:
	for child : Node in get_children():
		if child is MeshInstance3D:
			meshes.append(child)
		elif child is Skeleton3D:
			skeleton = child

func add_anim_player() -> void:
	anim_player = AnimationPlayer.new()
	anim_player.name = "anim_player"

	anim_lib = AnimationLibrary.new()
	anim_lib.resource_name = ANIMATION_LIBRARY
	anim_player.add_animation_library(ANIMATION_LIBRARY, anim_lib)

	add_child(anim_player)

func has_bone(bone_name : String) -> bool:
	return skeleton and skeleton.find_bone(bone_name) > -1

func attach_model(bone_name : String, model : Node3D) -> Error:
	if not model:
		push_error("Cannot attach null model to bone \"", bone_name, "\" of UnitModel ", get_name())
		return FAILED

	if not skeleton:
		push_error("Cannot attach model \"", model.get_name(), "\" to bone \"", bone_name, "\" of UnitModel ", get_name(), " - has no skeleton!")
		return FAILED

	var bone_idx : int = skeleton.find_bone(bone_name)
	if bone_idx < 0 or bone_idx >= skeleton.get_bone_count():
		push_error("Invalid bone \"", bone_name, "\" (index ", bone_idx, ") for attachment \"", model.get_name(), "\" to UnitModel \"", get_name(), "\"")
		return FAILED

	var bone_attachment := BoneAttachment3D.new()
	bone_attachment.name = bone_name
	bone_attachment.bone_idx = bone_idx
	bone_attachment.add_child(model)
	skeleton.add_child(bone_attachment)

	if model is UnitModel:
		sub_units.push_back(model)
		model.current_anim = current_anim
		model.primary_colour = primary_colour
		model.secondary_colour = secondary_colour
		model.tertiary_colour = tertiary_colour

	return OK

func _set_shader_parameter(param_name : StringName, param_val : Variant) -> void:
	for mesh : MeshInstance3D in meshes:
		mesh.set_instance_shader_parameter(param_name, param_val)

func _set_tex_scroll(speed : float) -> void:
	_set_shader_parameter(&"scroll_speed", speed)

func set_flag_index(index : int) -> void:
	_set_shader_parameter(&"flag_index", index)

func load_animation(prop_name : String, animIn : Animation) -> void:
	if not animIn:
		return
	if not anim_player:
		add_anim_player()
	anim_lib.add_animation(prop_name,animIn)