vm_lighting_wand/core/power.lua

local vMod = vm_lighting_wand
local max_power = 0

-- Set the max power (set from levels)
vMod.set_max_power = function(amount)
	max_power = amount or max_power
end

vMod.get_max_power = function()
	return max_power
end

-- Sets players power to the given amount or max_power
vMod.set_power = function(player, amount)
	if not player or not amount or amount < 0 then
		return
	end
	local meta = player:get_meta()
	amount = vMod.round(amount)
	amount = amount >= 0 and amount or 0
	amount = amount <= max_power and amount or max_power
	meta:set_int(vMod.modname .. "_power", amount)
end

-- Get a players power
vMod.get_power = function(player)
	if not player then
		return 0
	end
	local power = player:get_meta():get_int(vMod.modname .. "_power") or 0
	if power > max_power then
		power = max_power
		vMod.set_power(player, power)
	end
	return power
end

-- Add an amount to a player power
vMod.add_power = function(player, amount)
	if not player or not amount or amount <= 0 then
		return
	end
	local power = vMod.get_power(player)
	local sum = power + amount
	vMod.set_power(player, sum)
end

-- Remove an amount from a players power
vMod.remove_power = function(player, amount)
	if not player or not amount or amount <= 0 then
		return
	end
	local power = vMod.get_power(player)
	local sum = power - amount
	vMod.set_power(player, sum)
end

-- Test if the player has enough power for the given amount
vMod.can_output_power = function(player, amount)
	if not player or not amount or amount < 0 then
		return false
	end

	if vMod.is_creative_mode(player) then
		return true
	end

	if vMod.get_power(player) >= amount then
		return true
	end

	return false
end

-- Test if the player can store the given amount
vMod.can_input_power = function(player, amount)
	if not player or not amount or amount <= 0 then
		return 0
	end
	local free = max_power - vMod.get_power(player)
	if free <= 0 then
		free = 0
	end
	if free >= amount then
		return amount
	end
	return free
end

-- Works out the cost of placing a node
vMod.get_power_cost = function(player, to_pos, removal)
	if not player or not to_pos then
		return false
	end
	if vMod.is_creative_mode(player) then
		return 0
	end

	removal = removal or false
	local cost = player:get_pos()
	local level = vMod.get_level(player)
	for key, value in pairs(cost) do
		value = to_pos[key] - vMod.round(value)
		cost[key] = value < 0 and value * -1 or value
	end
	local sum = (cost.x + cost.z + cost.y) * level.cost_per_node
	if not removal then
		return vMod.round(sum + level.cost_per_use)
	else
		return vMod.round((sum / level.removal_reduction) + level.cost_per_use)
	end
end

-- Will apply a charge to the players power if it can - returns true/false
vMod.do_power_cost = function(player, to_pos, removal)
	-- skip everything if the player is in creative mode
	if vMod.is_creative_mode(player) then
		return true
	end
	local cost = vMod.get_power_cost(player, to_pos, removal)
	if cost == false then
		return false
	end

	-- if the player doesnt have enough power
	if not vMod.can_output_power(player, cost) then
		return false
	end

	-- charge the player
	vMod.remove_power(player, cost)
	return true
end