class_name Main
extends Node3D


var chunk_size := Vector3(16, 16, 16)

@onready var noise := FastNoiseLite.new()

var face_corners = [
	Vector2(0, 0), Vector2(1, 0),
	Vector2(0, 1), Vector2(1, 1),
]

enum BlockFace {
	FRONT,
	BACK,
	LEFT,
	RIGHT,
	TOP,
	BOTTOM,
}
var block_faces = [
	[ # FRONT
		[Vector3(-1.0, 1.0, 1.0), Vector3(1.0, -1.0, 1.0), Vector3(-1.0, -1.0, 1.0)],
		[Vector3(-1.0, 1.0, 1.0), Vector3(1.0, 1.0, 1.0), Vector3(1.0, -1.0, 1.0)],
	],
	[ # BACK
		[Vector3(1.0, 1.0, -1.0), Vector3(-1.0, -1.0, -1.0), Vector3(1.0, -1.0, -1.0)],
		[Vector3(1.0, 1.0, -1.0), Vector3(-1.0, 1.0, -1.0), Vector3(-1.0, -1.0, -1.0)],
	],
	[ # LEFT
		[Vector3(-1.0, 1.0, -1.0), Vector3(-1.0, -1.0, 1.0), Vector3(-1.0, -1.0, -1.0)],
		[Vector3(-1.0, 1.0, -1.0), Vector3(-1.0, 1.0, 1.0), Vector3(-1.0, -1.0, 1.0)],
	],
	[ # RIGHT
		[Vector3(1.0, 1.0, 1.0), Vector3(1.0, -1.0, -1.0), Vector3(1.0, -1.0, 1.0)],
		[Vector3(1.0, 1.0, 1.0), Vector3(1.0, 1.0, -1.0), Vector3(1.0, -1.0, -1.0)],
	],
	[ # TOP
		[Vector3(-1.0, 1.0, -1.0), Vector3(1.0, 1.0, 1.0), Vector3(-1.0, 1.0, 1.0)],
		[Vector3(-1.0, 1.0, -1.0), Vector3(1.0, 1.0, -1.0), Vector3(1.0, 1.0, 1.0)],
	],
	[ # BOTTOM
		[Vector3(-1.0, -1.0, 1.0), Vector3(1.0, -1.0, -1.0), Vector3(-1.0, -1.0, -1.0)],
		[Vector3(-1.0, -1.0, 1.0), Vector3(1.0, -1.0, 1.0), Vector3(1.0, -1.0, -1.0)],
	],
]
var block_face_uvs = [
	[ # FRONT
		[Vector2(0.0, 0.0), Vector2(1.0, 1.0), Vector2(0.0, 1.0)],
		[Vector2(0.0, 0.0), Vector2(1.0, 0.0), Vector2(1.0, 1.0)],
	],
	[ # BACK
		[Vector2(0.0, 0.0), Vector2(1.0, 1.0), Vector2(0.0, 1.0)],
		[Vector2(0.0, 0.0), Vector2(1.0, 0.0), Vector2(1.0, 1.0)],
	],
	[ # LEFT
		[Vector2(0.0, 0.0), Vector2(1.0, 1.0), Vector2(0.0, 1.0)],
		[Vector2(0.0, 0.0), Vector2(1.0, 0.0), Vector2(1.0, 1.0)],
	],
	[ # RIGHT
		[Vector2(0.0, 0.0), Vector2(1.0, 1.0), Vector2(0.0, 1.0)],
		[Vector2(0.0, 0.0), Vector2(1.0, 0.0), Vector2(1.0, 1.0)],
	],
	[ # TOP
		[Vector2(0.0, 1.0), Vector2(1.0, 2.0), Vector2(0.0, 2.0)],
		[Vector2(0.0, 1.0), Vector2(1.0, 1.0), Vector2(1.0, 2.0)],
	],
	[ # BOTTOM
		[Vector2(1.0, 0.0), Vector2(2.0, 1.0), Vector2(1.0, 1.0)],
		[Vector2(1.0, 0.0), Vector2(2.0, 0.0), Vector2(2.0, 1.0)],
	],
]
var block_face_normals = [
	Vector3(0, 0, 1), # FRONT
	Vector3(0, 0, -1), # BACK
	Vector3(-1, 0, 0), # LEFT
	Vector3(1, 0, 0), # RIGHT
	Vector3(0, 1, 0), # TOP
	Vector3(0, -1, 0), # BOTTOM
]

enum BlockType {
	AIR,
	GRASS,
	DIRT,
	LEAVES,
	STONE,
}
var block_types = {
	BlockType.GRASS: {
		"uv2s": [
			Vector2(0, 0), # FRONT
			Vector2(0, 0), # BACK
			Vector2(0, 0), # LEFT
			Vector2(0, 0), # RIGHT
			Vector2(0, 1), # TOP
			Vector2(1, 0), # BOTTOM
		],
	},
	BlockType.DIRT: {
		"uv2s": [
			Vector2(1, 0), # FRONT
			Vector2(1, 0), # BACK
			Vector2(1, 0), # LEFT
			Vector2(1, 0), # RIGHT
			Vector2(1, 0), # TOP
			Vector2(1, 0), # BOTTOM
		],
	},
	BlockType.LEAVES: {
		"uv2s": [
			Vector2(2, 2), # FRONT
			Vector2(2, 2), # BACK
			Vector2(2, 2), # LEFT
			Vector2(2, 2), # RIGHT
			Vector2(2, 2), # TOP
			Vector2(2, 2), # BOTTOM
		],
	},
	BlockType.STONE: {
		"uv2s": [
			Vector2(2, 0), # FRONT
			Vector2(2, 0), # BACK
			Vector2(2, 0), # LEFT
			Vector2(2, 0), # RIGHT
			Vector2(2, 0), # TOP
			Vector2(2, 0), # BOTTOM
		],
	},
}

var chunks := []


func _ready() -> void:
	brrr()


class OtherThread extends Thread:
	func _exit_tree():
		wait_to_finish()


func brrr():
	noise.seed = randi()
	
	var thread = OtherThread.new()
	var rrrb = func():
		for row in range(0, 8):
			chunks.append([])
			for column in range(0, 4):
				chunks[row].append([])
				for depth in range(0, 8):
					chunks[row][column].append([])
					generate_chunk(row, column, depth)
	
	thread.start(rrrb)
	#thread.wait_to_finish()


func generate_chunk(row, column, depth):
	#var material := StandardMaterial3D.new()
	#material.albedo_texture = preload("res://new_atlas_texture.tres")
	#material.vertex_color_use_as_albedo = true
	var material := preload("res://new_shader_material.tres")
	var st = SurfaceTool.new()
	st.begin(Mesh.PRIMITIVE_TRIANGLES)
	st.set_material(material)
	
	var blocks = []
	
	for x in chunk_size.x:
		#blocks[x] = []
		blocks.append([])
		for y in chunk_size.y:
			#blocks[x][y] = []
			blocks[x].append([])
			for z in chunk_size.z:
				var block_position = Vector3(
					row*chunk_size.x + x,
					column*chunk_size.y + y,
					depth*chunk_size.z + z
					#x,
					#y,
					#z
				) * 2
				var value = noise.get_noise_3d(block_position.x, block_position.y, block_position.z) * 100
				
				var type = BlockType.AIR
				if value > -15:
					type = BlockType.GRASS
				elif value > -20:
					type = BlockType.STONE
				
				var block = {
					"position": block_position,
					"type": type,
				}
				#blocks[x][y][z] = block_position
				blocks[x][y].append(block)
							
	for x in blocks.size():
		for y in blocks[x].size():
			for z in blocks[x][y].size():
				var block = blocks[x][y][z]
				var block_position = block.position
				
				if not block.type == BlockType.AIR:
					if block.type == BlockType.GRASS and blocks[x].size() > y + 1 and not blocks[x][y + 1][z].type == BlockType.AIR:
						block.type = BlockType.DIRT
					
					var rng = RandomNumberGenerator.new()
					rng.seed = randi()
					st.set_color(Color(rng.randf(), rng.randf(), rng.randf()))
					
					st.set_uv(Vector2(0, 0))
					
					if (blocks[x][y].size() > z+1 and blocks[x][y][z + 1].type == BlockType.AIR) or blocks[x][y].size() == z+1:
						add_face(st, BlockFace.FRONT, block)
					
					if (blocks.size() > x+1 and blocks[x + 1][y][z].type == BlockType.AIR) or blocks.size() == x+1:
						add_face(st, BlockFace.RIGHT, block)
					
					if blocks[x][y].size() > z-1 and (blocks[x][y][z - 1].type == BlockType.AIR or z == 0):
						add_face(st, BlockFace.BACK, block)
					
					if blocks.size() > x-1 and (blocks[x - 1][y][z].type == BlockType.AIR or x == 0):
						add_face(st, BlockFace.LEFT, block)
					
					if (blocks[x].size() > y+1 and blocks[x][y + 1][z].type == BlockType.AIR) or blocks[x].size() == y+1:
						add_face(st, BlockFace.TOP, block)
					
					if blocks[x].size() > y-1 and (blocks[x][y - 1][z].type == BlockType.AIR or y == 0):
						add_face(st, BlockFace.BOTTOM, block)
	
	chunks[row][column][depth] = blocks
	
	#st.generate_normals()
	var mesh = MeshInstance3D.new()
	mesh.mesh = st.commit()
	mesh.create_trimesh_collision()
	add_child.call_deferred(mesh)


# Called every frame. 'delta' is the elapsed time since the previous frame.
func _process(_delta: float) -> void:
	pass


func add_face(surface_tool: SurfaceTool, face: BlockFace, block: Dictionary):
	var block_position: Vector3 = block.position
	var type: BlockType = block.type
	
	var uv2s = []
	uv2s.resize(3)
	uv2s.fill(block_types[type].uv2s[face])
	
	var normals = []
	normals.resize(3)
	normals.fill(block_face_normals[face])
	
	for idx in block_faces[face].size():
		var triangle = block_faces[face][idx]
		var triangle_positions = triangle.map(func(item):
			return item + block_position
		)
		
		var uvs = block_face_uvs[face][idx]
		
		surface_tool.add_triangle_fan(
			PackedVector3Array(triangle_positions),
			PackedVector2Array(uvs),
			PackedColorArray(),
			PackedVector2Array(uv2s),
			PackedVector3Array(normals)
		)