class_name Block
extends Resource


const FACE_CORNERS = [
	Vector2(0, 0), Vector2(1, 0),
	Vector2(0, 1), Vector2(1, 1),
]

enum Face {
	FRONT,
	BACK,
	LEFT,
	RIGHT,
	TOP,
	BOTTOM,
}

const 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)],
	],
]

const 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)],
	],
]

const 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 Type {
	AIR,
	GRASS,
	DIRT,
	LEAVES,
	STONE,
}

const BLOCK_TYPES = {
	Type.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
		],
	},
	Type.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
		],
	},
	Type.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
		],
	},
	Type.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 position: Vector3
var type: Type


func add_face(surface_tool: SurfaceTool, face: Face):
	var uv2s = []
	uv2s.resize(3)
	uv2s.fill(BLOCK_TYPES[type].uv2s[face])
	
	var normals = []
	normals.resize(3)
	normals.fill(FACE_NORMALS[face])
	
	for idx in FACES[face].size():
		var triangle = FACES[face][idx]
		var triangle_positions = triangle.map(func(item):
			return item + position
		)
		
		var uvs = FACE_UVS[face][idx]
		
		surface_tool.add_triangle_fan(
			PackedVector3Array(triangle_positions),
			PackedVector2Array(uvs),
			PackedColorArray(),
			PackedVector2Array(uv2s),
			PackedVector3Array(normals)
		)