basic_powerplant logic

function ENT:Think()
    self.Entity:NextThink(CurTime()+1)
    local EmptySlots = 0

    --Invalidate entities that don't exist and count up the empty slots
    for i=1, self.PowerSlots, 1 do
        if not IsValid(self.PoweredEntities[i]) then
            self.PoweredEntities[i] = nil
            EmptySlots = EmptySlots + 1
        end
    end
    self.SlotsUsed = self.PowerSlots - EmptySlots

    --Move existing entities to the end of the PoweredEntities table
    i=self.PowerSlots
    TempTable = {}
    for key, value in pairs(self.PoweredEntities) do
        TempTable[i] = value
        i = i - 1
    end
    self.PoweredEntities = {}
    for key, value in pairs(TempTable) do
        self.PoweredEntities[key] = value
    end

    --Insert new entities into the PoweredEntities table
    if self.SlotsUsed < self.PowerSlots then
        i = 1
        local NewEntityList = ents.FindInSphere(self:GetPos(), self.PowerDist)
        for key, value in pairs(NewEntityList) do
            if value.PowerUsage != nil and self.SlotsUsed + value.PowerUsage <= self.PowerSlots and not value:IsPowered() then
                for j=1, value.PowerUsage, 1 do
                    self.PoweredEntities[i] = value
                    self.SlotsUsed = self.SlotsUsed + 1
                    i = i + 1
                end
            end
        end
    end

    --Power the entities in the PoweredEntities table
    for key, value in pairs(self.PoweredEntities) do
        value:Power()
    end
end