extends Spatial

signal world_loaded

export(int) var width = 2000
export(int) var height = 2000
export(int) var spacing = 20
export(int, 1, 9) var octaves = 5
export(int, 1, 30) var wavelength = 8
export(int) var border_width = 200
export(int) var terraces = 24
export(int) var terrace_height = 5
export(float) var mountain_height = 6.0 / 24.0
export(int) var river_proba = 100

var rng = RandomNumberGenerator.new()
var noise = OpenSimplexNoise.new()

var terrain

func _ready():
	rng.randomize()
	noise.seed = rng.randi()
	noise.octaves = octaves
	terrain = Terrain.new(width,height,spacing,true)
	init_data()
	emit_signal("world_loaded", terrain)

func init_data():
	for point in terrain.get_points():
		point.set_elevation(point_find_elevation(point.point2d()))
		point.set_data("water", point_is_water(point))
		point.set_data("mountain", point_is_mountain(point))
		point.set_data("river", point_is_river(point))

	fill_oceans()
	
	for point in terrain.get_points():
		if point.get_data("water") and not point.get_data("ocean"):
			point.set_elevation(0.1)
		point.set_data("coast", point_is_coast(point))
		if point.get_data("river"):
			set_river_path(point)
	for triangle in terrain.get_triangles():
		triangle.set_data("elevation", triangle_find_elevation(triangle))
		triangle.set_data("water", triangle_is_water(triangle))
		triangle.set_data("ocean", false)
		# TODO #1 : Get triangles around point
		for point in triangle.points():
			if point.get_data("ocean"):
				triangle.set_data("ocean", true)
	for edge in terrain.get_edges():
		edge.set_data("coast", edge_is_coast(edge))
		edge.set_data("river", edge_is_river(edge))

func fill_oceans():
	var stack = []
	for point in terrain.get_points():
		if point.point2d().x < 10 and point.get_data("water") and not point.get_data("ocean"):
			stack.append(point.get_index())
			while stack.size():
				var current_point_id = stack.pop_back()
				terrain.get_point(current_point_id).set_data("ocean", true)
				for neighbour in terrain.get_point(current_point_id).points_around():
					if neighbour.get_data("water") and not neighbour.get_data("ocean"):
						stack.append(neighbour.get_index())
			break

func set_river_path(point):
	#TODO #2 fix rivers
	var start_elevation = point.get_elevation()
	var waypoints = []
	var stack = []
	stack.append(point.get_index())
	var came_from = {}
	
	while stack.size():
		var current_point_id = stack.pop_front()
		if terrain.get_point(current_point_id).get_elevation() < start_elevation:
			waypoints.append(current_point_id)
			start_elevation = terrain.get_point(current_point_id).get_elevation()
			stack = []
		if terrain.get_point(current_point_id).get_data("ocean"):
			break
		for neighbour in terrain.get_point(current_point_id).points_around():
			if not came_from.has(neighbour.get_index()):
				stack.append(neighbour.get_index())
				came_from[neighbour.get_index()] = current_point_id
				
	var path = []
	for waypoint in waypoints:
		var current = waypoint
		while current != point.get_index(): 
			if not path.has(current):
				path.append(current)
			current = came_from[current]
	
	path.append(point.get_index())
	for index in path:
		terrain.get_point(index).set_data("river", true)

# Point

func point_find_elevation(point):
	var border = border_width + rng.randf_range(-20.0, 20.0)
	var elevation = noise.get_noise_2d(point.x / wavelength, point.y / wavelength)
	
	if point.x < border:
		elevation -= ((border - point.x) / border) / 2.0
	if point.y < border:
		elevation -= (border - point.y) / border
	if point.x > width - border:
		elevation -= (border - (width - point.x)) / border
	if point.y > height - border:
		elevation -= (border - (height - point.y)) / border
		
	elevation = max(elevation, -1)
			
	if elevation > 0.1:
		elevation = max(pow((elevation) * 1.2, 1.5), 0.1)
		
	elevation = min(elevation, 1)
		
	# elevation = elevation * terraces
	return elevation
	
func point_is_water(point):
	if (point.get_elevation() <= 0):
		return true
	return false

func point_is_mountain(point):
	if (point.get_elevation() >= mountain_height):
		return true
	return false

func point_is_coast(point):
	if not point.get_data("water"):
		for neighbour in point.points_around():
			if neighbour.get_data("ocean"):
				return true
	return false

func point_is_river(point):
	if point.get_data("mountain") and not point.get_data("river"):
		var random = rng.randi_range(1, river_proba)
		if random == 1:
			return true
	return false

# Triangle

func triangle_find_elevation(triangle):
	var elevation = 0
	for point in triangle.points():
		elevation += point.get_elevation()
	elevation /= 3.0
	return elevation

func triangle_is_water(triangle):
	if triangle.get_data("elevation") <= 0:
		return true
	return false

# Edge

func edge_is_coast(edge):
	if edge.start().get_data("coast") and edge.end().get_data("coast") and edge.triangle().get_data("ocean"):
		return true
	return false

func edge_is_river(edge):
	if edge.start().get_data("river") and edge.end().get_data("river"):
		return true
	return false