extends GridMap

@export var ChunkWidth: int = 128
@export var ChunkHeight: int = 128
@export var WorldWidth: int = 1024
@export var WorldHeight: int = 1024

@onready var camera = $Camera3D

@onready var multimeshInstances = []

func _ready():
	setGridChunk(0, ChunkWidth, 0, ChunkHeight)
	
func generateGridChunk(cameraPos: Vector3) -> void:
	clear()
	for instance in multimeshInstances:
		remove_child(instance)
	multimeshInstances = []
	
	var chunkCenter = local_to_map(cameraPos)
	var rowStart: float = chunkCenter.z - (ChunkHeight / 2)
	var rowEnd: float = chunkCenter.z + (ChunkHeight / 2)
	var columnStart: float = chunkCenter.x - (ChunkWidth / 2)
	var columnEnd: float = chunkCenter.x + (ChunkWidth / 2)
	setGridChunk(columnStart, columnEnd, rowStart, rowEnd)
	setEntities(columnStart, columnEnd, rowStart, rowEnd)

func setGridChunk(columnStart: float, columnEnd: float, rowStart: float, rowEnd: float) -> void:
	if columnStart < 0 : 
		columnStart = 0
	if rowStart < 0 : 
		rowStart = 0
	if columnEnd > Global.world.width - 1 : 
		columnEnd =Global.world.width - 2
	if rowEnd > Global.world.height - 1 : 
		rowEnd = Global.world.height - 2

	for mz in range(rowStart, rowEnd):
		for mx in range(columnStart, columnEnd):
			var bloc = Global.world.get_bloc(Vector2(mx, mz))
			var my: float = bloc.y
			var meshID 
			var mesh_rotation 
			if bloc.type != 0:
				var neighbours = Global.world.get_neighbours_4_at_same_height(Vector2(mx, mz))
				if neighbours == Global.directions_4.RIGHT:
					meshID = Global.bloc_sides_id.SIDE_3
					mesh_rotation = Global.GRID_ROTATION[3]
				elif neighbours == Global.directions_4.LEFT:
					meshID = Global.bloc_sides_id.SIDE_3
					mesh_rotation = Global.GRID_ROTATION[1]
				elif neighbours == Global.directions_4.LEFT + Global.directions_4.RIGHT:
					meshID = Global.bloc_sides_id.SIDE_2_OPPOSITE
					mesh_rotation = Global.GRID_ROTATION[0]
				elif neighbours == Global.directions_4.BOTTOM:
					meshID = Global.bloc_sides_id.SIDE_3
					mesh_rotation = Global.GRID_ROTATION[0]
				elif neighbours == Global.directions_4.BOTTOM + Global.directions_4.RIGHT:
					meshID = Global.bloc_sides_id.SIDE_2_ANGLE
					mesh_rotation = Global.GRID_ROTATION[3]
				elif neighbours == Global.directions_4.BOTTOM + Global.directions_4.LEFT:
					meshID = Global.bloc_sides_id.SIDE_2_ANGLE
					mesh_rotation = Global.GRID_ROTATION[0]
				elif neighbours == Global.directions_4.BOTTOM + Global.directions_4.LEFT + Global.directions_4.RIGHT:
					meshID = Global.bloc_sides_id.SIDE_1
					mesh_rotation = Global.GRID_ROTATION[0]
				elif neighbours == Global.directions_4.TOP:
					meshID = Global.bloc_sides_id.SIDE_3
					mesh_rotation = Global.GRID_ROTATION[2]
				elif neighbours == Global.directions_4.TOP + Global.directions_4.RIGHT:
					meshID = Global.bloc_sides_id.SIDE_2_ANGLE
					mesh_rotation = Global.GRID_ROTATION[2]
				elif neighbours == Global.directions_4.TOP + Global.directions_4.LEFT:
					meshID = Global.bloc_sides_id.SIDE_2_ANGLE
					mesh_rotation = Global.GRID_ROTATION[1]
				elif neighbours == Global.directions_4.TOP + Global.directions_4.LEFT + Global.directions_4.RIGHT:
					meshID = Global.bloc_sides_id.SIDE_1
					mesh_rotation = Global.GRID_ROTATION[2]
				elif neighbours == Global.directions_4.TOP + Global.directions_4.BOTTOM:
					meshID = Global.bloc_sides_id.SIDE_2_OPPOSITE
					mesh_rotation = Global.GRID_ROTATION[1]
				elif neighbours == Global.directions_4.TOP + Global.directions_4.BOTTOM + Global.directions_4.RIGHT:
					meshID = Global.bloc_sides_id.SIDE_1
					mesh_rotation = Global.GRID_ROTATION[3]
				elif neighbours == Global.directions_4.TOP + Global.directions_4.BOTTOM + Global.directions_4.LEFT:
					meshID = Global.bloc_sides_id.SIDE_1
					mesh_rotation = Global.GRID_ROTATION[1]
				elif neighbours == Global.directions_4.TOP + Global.directions_4.BOTTOM + Global.directions_4.LEFT + Global.directions_4.RIGHT:
					meshID = Global.bloc_sides_id.SIDE_0
					mesh_rotation = Global.GRID_ROTATION[0]
				elif neighbours == 0:
					meshID = Global.bloc_sides_id.SIDE_4
					mesh_rotation = Global.GRID_ROTATION[0]

				set_cell_item( Vector3(mx, my, mz) , meshID, mesh_rotation)

func setEntities(columnStart: float, columnEnd: float, rowStart: float, rowEnd: float) -> void:
	if columnStart < 0 : 
		columnStart = 0
	if rowStart < 0 : 
		rowStart = 0
	if columnEnd > Global.world.width - 1 : 
		columnEnd =Global.world.width - 2
	if rowEnd > Global.world.height - 1 : 
		rowEnd = Global.world.height - 2
	var multimesh = MultiMesh.new()
	multimesh.mesh = CapsuleMesh.new()
	multimesh.transform_format = MultiMesh.TRANSFORM_3D
	var instances = []
	for mz in range(rowStart, rowEnd):
		for mx in range(columnStart, columnEnd):
			var bloc = Global.world.get_bloc(Vector2(mx, mz))
			if bloc.entity != -1:
				instances.append(map_to_local(Vector3(bloc.x, bloc.y, bloc.z)))
				
				
	multimesh.instance_count = instances.size()
	for instance_index in multimesh.instance_count:
		var transform := Transform3D()
		transform.origin = instances[instance_index]

		multimesh.set_instance_transform(instance_index, transform)

	if instances.size():
		var multimesh_instance = MultiMeshInstance3D.new()
		multimesh_instance.multimesh = multimesh
		multimeshInstances.append(multimesh_instance)
		add_child(multimeshInstances[multimeshInstances.size()-1])

func _on_map_update_timer_timeout():
	generateGridChunk(camera.global_transform.origin)