class_name ChunkHandler
extends Node2D

# one tilemap is one chunk
# map consists of many chunks
# chunks are loaded to view when needed
# chunks are deleted after they are no longer needed (in view)

# This is done to speed up game loading and avoiding setting one large tilemap in one go
# which is extremely slow in godot 4.0, 4096x4096 takes minutes to fill with set_cell() commands

var chunks:Dictionary = {}
var unready_chunks:Dictionary = {}
var chunk_amount = 16
var window_width = DisplayServer.window_get_size(0).x
var distance = abs((window_width/(Globals.CHUNK_SIZE.x*Globals.TILE_SIZE_X)) / 2 +1 )

func _init() -> void:
	self.name = "ChunkHandler"
	
func _process(_delta):
	update_chunks()
	clean_up_chunks()
	reset_chunks()

func _ready():
	#thread = Thread.new()
	

	#print(distance)
	pass

func add_chunk(x:int, y:int) -> void:
	var key = str(y) + "," + str(x)
	if chunks.has(key):
		return
		
	load_chunk(x, y, key)
	
func clean_up_chunks():
	for key in chunks:
		var chunk = chunks[key]
		if chunk.should_remove:
			chunk.queue_free()
			chunks.erase(key)
	
func clear_chunk(pos:Vector2i) -> void:
	self.chunks[pos.y][pos.x].clear()

func get_chunk(x:int, y:int):
	var key = str(y) + "," + str(x)
	if self.chunks.has(key):
		return chunks.get(key)
		
	return null

func load_chunk(x:int, y:int, key:String):
	var chunk = Chunk.new(x,y)
	self.add_child(chunk)
	chunks[key] = chunk	
	
	Globals.chunks_loaded += 1

	
func reset_chunks():
	for key in chunks:
		chunks[key].should_remove = true
	
func update_chunks():		 
	var p_x = int(Globals.CAMERA_POSITION.x- Globals.CHUNK_SIZE.x) / Globals.TILE_SIZE_X / Globals.CHUNK_SIZE.x
	var p_y = int(Globals.CAMERA_POSITION.y- Globals.CHUNK_SIZE.y) / Globals.TILE_SIZE_Y / Globals.CHUNK_SIZE.y

	for y in Globals.map_size/Globals.CHUNK_SIZE.y:
		for x in Globals.map_size/Globals.CHUNK_SIZE.x:
			if (abs(x - p_x) <= distance && abs(y - p_y) <= distance):
				add_chunk(x, y)
				
				var chunk = get_chunk(x,y) 
				if chunk != null:
					chunk.should_remove = false