local Countdown = Class(function(self, inst)
    self.inst = inst
    self.counting = false

    self.countdown_max = 0
    self.countdown_current = 0

    self.rate = 1
    self.period = 1

    self.countdown_finish = nil
end)

function Countdown:Refresh()
        if self.countdown_current > 0 then
                self:DoDelta(-self.countdown_current)
        end
end

function Countdown:OnSave()
    if self.countdown_current ~= self.countdown_max then
        return {countdown = self.countdown_current}
    end
end

function Countdown:OnLoad(data)
    if data.countdown then
        self:StartCountdown(data.countdown_current)
    end
end

function Countdown:SetRefreshFn(fn)
    self.countdown_finish = fn
end

function Countdown:IsReady()
    return self.countdown_current <= 0
end

function Countdown:SetUpdateFn(fn)
    self.updatefn = fn
end

function Countdown:GetPercent()
    if self.countdown_max > 0 then
        return math.min(1, self.countdown_current / self.countdown_max)
    else
        return 0
    end
end

function Countdown:SetPercent(amount)
    local target = (self.countdown_max * amount)
    self:DoDelta(target - self.countdown_current)
end

 function Countdown:DoUpdate(dt)
    if self.counting then
        self:DoDelta(-dt*self.rate)
    end

    if self:IsReady() then
        self:Refresh()
    end

    if self.updatefn then
        self.updatefn(self.inst)
    end

end

function Countdown:StartCountdown()
    self.counting = true
    if self.task == nil then
        self.task = self.inst:DoPeriodicTask(self.period, function() self:DoUpdate(self.period) end)
    end
end

function Countdown:SetCountdown(amount)
    if self.countdown_max < amount then
        self.countdown_max = amount
    end
    self.countdown_current = amount
end

function Countdown:DoDelta(delta)
    self.countdown_current = math.max(0, math.min(self.countdown_max, self.countdown_current + delta) )
end



function Countdown:StopCounting()
    self.counting = false
    if self.task then
        self.task:Cancel()
        self.task = nil
    end
end

function Countdown:LongUpdate(dt)
        self:DoUpdate(dt)
end

return Countdown