class_name SyncController
extends Area3D

@export var shape: CollisionShape3D

var peer_id: int
var module: copyMultiplayer
var model_controller: ModelController

var nickname: String

var version: int = -1
var bone_lookup: Array[String]
var blendshape_lookup: Array[NodePath]

var model_name  : String
var model       : Node
var skeleton    : Skeleton3D
var anim_player : AnimationPlayer
var anim_root   : Node
var settings    : PlayerSettings

var is_dragging := false
var drag_current: Vector3

# Reusable buffer to write data for synchronizing models.
static var write_stream: StreamBuffer = StreamBuffer.with_capacity(2048)

func _ready() -> void:
	peer_id = name.to_int()
	module = get_parent()
	model_controller = ModelController.new()
	model_controller.name = "ModelController"
	add_child(model_controller)

func _process(_delta: float) -> void:
	update_collision_shape_position()
	handle_dragging()

func _exit_tree() -> void:
	if settings: settings.queue_free()

func get_display_name() -> String:
	if nickname: return "Player '%s' (%d)" % [ nickname, peer_id ]
	else:        return "Player (%d)" % peer_id

func change_nickname(new_nickname: String) -> void:
	new_nickname = new_nickname.strip_edges()
	if new_nickname == "": return # Ignore empty nicknames.
	if new_nickname == nickname: return # Ignore unchanged nicknames.
	module.print_log("%s is now known as '%s'" % [ get_display_name(), new_nickname ])
	nickname = new_nickname

	if !settings:
		settings = module.new_player_settings()
		settings.on_transform_changed(transform)
		settings.value_changed.connect(func(value): transform = value)
	settings.set_nickname(nickname)

## Attempts to change the model of this player.
func change_model(
	new_version: int,
	new_bone_lookup: Array[String],
	new_blendshape_lookup: Array[NodePath],
	filename: String,
) -> void:
	# These should be safe to update even if the model doesn't load.
	# We just need to stay in sync with the lookup tables.
	version           = new_version
	bone_lookup       = new_bone_lookup
	blendshape_lookup = new_blendshape_lookup

	if not filename.is_valid_filename():
		module.print_log("ERROR: '%s' is not a valid file name!" % filename)
		return
	var full_path := module.cache.path_join(filename)
	if not FileAccess.file_exists(full_path):
		module.print_log("%s wanted to switch to '%s', but it doesn't exist, skipping" % [ get_display_name(), filename ])
		return
	if not model_controller.load_vrm(full_path):
		module.print_log("ERROR: Model '%s' could not be loaded!" % filename)
		return

	model_name  = filename
	model       = model_controller.get_node_or_null("Model")
	skeleton    = model_controller._get_model_skeleton()
	anim_player = model.find_child("AnimationPlayer", false, false)
	anim_root   = anim_player.get_node(anim_player.root_node)

	recalculate_collision_shape()

	module.print_log("%s switched to '%s'" % [ get_display_name(), filename ])

func sync_model_animation(
	current_version: int,
	uncompressed_length: int,
	buffer: PackedByteArray,
) -> void:
	if version != current_version: return
	if (not model) or (not skeleton) or (not anim_root): return

	var uncompressed_buffer := buffer.decompress(uncompressed_length, FileAccess.COMPRESSION_ZSTD);
	var stream := StreamBuffer.from_buffer(uncompressed_buffer)

	model.transform = stream.read_transform16()

	var all_bones: Array[Dictionary] = []
	var all_blendshapes: Array[Dictionary] = []

	# We filter out bones at rest and blendshapes at zero, so this
	# is initializing all_bones/blendshapes to the default values.
	for bone_name in bone_lookup:
		var bone_idx  := skeleton.find_bone(bone_name)
		var bone_rest := skeleton.get_bone_rest(bone_idx)
		all_bones.append({ name = bone_name, idx = bone_idx, pose = bone_rest })
	for anim_path in blendshape_lookup:
		all_blendshapes.append({ path = anim_path, value = 0.0 })

	# 256 bones (and blendshapes) should be enough, right?
	for i in stream.read_uint8():
		var lookup := stream.read_uint8()
		all_bones[lookup].pose = stream.read_bone_pose(all_bones[lookup].pose)
	for i in stream.read_uint8():
		var lookup := stream.read_uint8()
		all_blendshapes[lookup].value = stream.read_range16()

	# Apply all the values to bones / blendshapes.
	for bone in all_bones:
		if bone.idx == -1: continue # Different model might not have this bone.
		skeleton.set_bone_pose(bone.idx, bone.pose)
	for blendshape in all_blendshapes:
		var anim_node := anim_root.get_node_or_null(blendshape.path)
		if not anim_node: continue # Different model might not have this node.
		anim_node.set("blend_shapes/" + blendshape.path.get_subname(0), blendshape.value)

@warning_ignore("shadowed_variable")
static func send_model_animation(module: copyMultiplayer) -> void:
	# Check if there's other players we're connected to.
	if module.multiplayer.get_peers().size() == 0: return

	var model       := module.get_model()
	var skeleton    := module.get_skeleton()
	var anim_player := model.find_child("AnimationPlayer", false, false)
	var anim_root   := anim_player.get_node_or_null(anim_player.root_node)
	if (not model) or (not skeleton) or (not anim_root): return

	write_stream.write_transform16(model.transform)

	# Pre-filter any bones that are at rest / blendshapes that are at zero.
	# Unless most bones / blendshapes are active, this should reduce packet size.
	var restless_bones     := []
	var active_blendshapes := []

	for i in module.bone_lookup.size():
		var bone_name := module.bone_lookup[i]
		var bone_idx  := skeleton.find_bone(bone_name)
		var bone_pose := skeleton.get_bone_pose(bone_idx)
		var bone_rest := skeleton.get_bone_rest(bone_idx)
		if not bone_pose.is_equal_approx(bone_rest):
			restless_bones.append({ lookup = i, pose = bone_pose, rest = bone_rest })

	for i in module.blendshape_lookup.size():
		var anim_path := module.blendshape_lookup[i]
		var anim_node := anim_root.get_node_or_null(anim_path)
		var value: float = anim_node.get("blend_shapes/" + anim_path.get_subname(0))
		if not is_zero_approx(value):
			active_blendshapes.append({ lookup = i, value = value })

	write_stream.write_uint8(restless_bones.size())
	for bone in restless_bones:
		write_stream.write_uint8(bone.lookup)
		write_stream.write_bone_pose(bone.pose, bone.rest)

	write_stream.write_uint8(active_blendshapes.size())
	for blendshape in active_blendshapes:
		write_stream.write_uint8(blendshape.lookup)
		write_stream.write_range16(blendshape.value)

	# The compression still helps, so we'll keep it for now.
	var compressed_buffer := write_stream.slice().compress(FileAccess.COMPRESSION_ZSTD);
	# Uncomment this to see packet size. Can we hit < 256 bytes?
	# module.set_status("Packet size: %d bytes (%d uncompressed)" % [ compressed_buffer.size(), write_stream.size ])
	module.sync_model_animation.rpc(module.version, write_stream.size, compressed_buffer)
	write_stream.clear()


# Updates the collision shapes used for allowing the player model to be
# repositioned based on the current model's skeleton. This functionality
# is only enabled when the "Players" tab is selected.
func recalculate_collision_shape() -> void:
	var head_y       := _get_bone_position("Head").y
	var left_foot_y  := _get_bone_position("LeftFoot").y
	var right_foot_y := _get_bone_position("RightFoot").y
	var avg_foot_y   := (left_foot_y + right_foot_y) / 2
	var shoulder_x   := _get_bone_position("LeftUpperArm").x

	var capsule := CapsuleShape3D.new()
	capsule.height = (head_y - avg_foot_y) * 1.5
	capsule.radius = shoulder_x            * 1.75
	shape.shape = capsule

func update_collision_shape_position() -> void:
	if not skeleton: return
	var head       := _get_bone_position("Head")
	var left_foot  := _get_bone_position("LeftFoot")
	var right_foot := _get_bone_position("RightFoot")
	var avg_foot   := (left_foot + right_foot) / 2
	shape.global_position = skeleton.global_position + (head + avg_foot) / 2
	# FIXME: This doesn't consider rotation or scale.

func _get_bone_position(bone_name: String) -> Vector3:
	var idx  := skeleton.find_bone(bone_name)
	var pose := skeleton.get_bone_global_pose(idx)
	return pose.origin


func _input_event(_camera: Node, event: InputEvent,
                  pos: Vector3, _normal: Vector3, _idx: int) -> void:
	if (module.can_move_players
			&& event is InputEventMouseButton
			&& event.button_index == MOUSE_BUTTON_LEFT
			&& event.pressed):
		is_dragging  = true
		drag_current = pos

func _unhandled_input(event: InputEvent) -> void:
	if (is_dragging
			&& event is InputEventMouseButton
			&& event.button_index == MOUSE_BUTTON_LEFT
			&& not event.pressed):
		is_dragging = false
		get_viewport().set_input_as_handled()

func handle_dragging() -> void:
	if not is_dragging: return

	var camera := get_viewport().get_camera_3d()
	var mouse  := get_viewport().get_mouse_position()
	var origin := camera.project_ray_origin(mouse)
	var dir    := camera.project_ray_normal(mouse)

	if dir.z == 0: return
	var distance := (drag_current.z - origin.z) / dir.z
	var target   := origin + dir * distance

	position += target - drag_current
	drag_current = target

	sortof_face_the_camera()
	settings.on_transform_changed(transform)

# FIXME: Kind of a hack, find a better way.
## Rotates the model a little bit towards the camera
## so it doesn't appear to be staring into nowhere.
func sortof_face_the_camera() -> void:
	var camera  := get_viewport().get_camera_3d()
	var from_2d := Vector2(global_position.x, global_position.z)
	var to_2d   := Vector2(camera.global_position.x, camera.global_position.z)
	rotation.y = -from_2d.angle_to_point(to_2d) + TAU/4