--Author: MewMew. Liberally reinterpreted by grilledham

local Event = require "utils.event"

local function init()
	global.resource_cluster_truck = 0
end

Event.on_init(init)

local radius = 10
local radius_sq = radius * radius

return function(x, y, world)
	local entities = world.surface.find_entities_filtered {position = {world.x + 0.5, world.y + 0.5}, type = "resource"}
	for _, e in ipairs(entities) do
		e.destroy()
	end

	if not world.chunk then
		world.chunk = true

		global.resource_cluster_truck = global.resource_cluster_truck + 1

		world.ore_spawn = math.random(1, 6)

		if math.random(1, 12) == 1 then
			world.resource_amount = math.random(7000, 150000)
		else
			world.resource_amount = math.random(400, 7000)
		end

		world.oil_amount = math.random(10000, 150000)
	end

	if global.resource_cluster_truck % 2 == 0 then
		return nil
	end

	local x = world.x - world.top_x - 16
	local y = world.y - world.top_y - 16
	local d_sq = x * x + y * y

	if d_sq < radius_sq then
		local ore_spawn = world.ore_spawn
		local resource_amount = world.resource_amount

		local amount
		if ore_spawn == 6 then
			amount = world.oil_amount
		else
			amount = resource_amount
			if d_sq < radius_sq / 4 then
				amount = resource_amount * 1.5
			elseif d_sq < radius_sq / 9 then
				amount = resource_amount * 2
			end
		end

		if ore_spawn == 1 then
			return {name = "stone", amount = amount}
		end
		if ore_spawn == 2 then
			return {name = "iron-ore", amount = amount}
		end
		if ore_spawn == 3 then
			return {name = "coal", amount = amount}
		end
		if ore_spawn == 4 then
			return {name = "copper-ore", amount = amount}
		end
		if ore_spawn == 5 then
			return {name = "uranium-ore", amount = amount}
		end
		if ore_spawn == 6 then
			return {name = "crude-oil", amount = amount}
		end
	end
end