local Hud = {}
local ESlateVisibility = import("ESlateVisibility")
local WidgetBlueprintLibrary = import("WidgetBlueprintLibrary")
local GameplayStatics = import("GameplayStatics")
local BusyActorManagerSubSystem = import("BusyActorManagerSubSystem")


local function ProcessSuspendShowRequests(hud)
    for _, request in pairs(hud.suspend_show_requests) do
        hud:CreateAndShowWidget(request[1], request[2])
    end
end



function Hud:ctor()
    self.layer = nil
    self.suspend_show_requests = {}
    self.widget_pool = {}
end

function Hud:ReceiveBeginPlay()
    print("Hud:ReceiveBeginPlay")

    if self.layer == nil then
        self.layer = self:GetOrCreateWidget("UILayer")
    end
    if self.layer ~= nil then
        self.layer:SetVisibility(ESlateVisibility.SelfHitTestInvisible)
        self.layer:AddToViewport(0)
        self:CreateAndShowWidget("MainUI", {})
        ProcessSuspendShowRequests(self)
    end
end

function Hud:ReceiveEndPlay()
    print("Hud:ReceiveEndPlay")
end


function Hud:GetOrCreateWidget(widget_name)
    local exist_widget = self.widget_pool[widget_name]
    if exist_widget ~= nil and exist_widget.bSingletonInstance then
        return exist_widget
    end
    local cls = self.UIClassMapping:Get(widget_name)
    local pc = GameplayStatics.GetPlayerController(self, 0)
    local widget = WidgetBlueprintLibrary.Create(self, cls, pc)
    self.widget_pool[widget_name] = widget
    return widget  -- TODO 这里如果非单例widget，会被覆盖
end

function Hud:GetFirstCachedWidget(widget_name)
    return self.widget_pool[widget_name]
end

function Hud:CreateAndShowWidget(widget_name, args)
    if not self.layer then
        table.insert(self.suspend_show_requests, {widget_name, args})
        return
    end
    local widget = self:GetOrCreateWidget(widget_name)
    if not widget then return end
    self.layer:ShowWidget(widget, args)
end

function Hud:CloseWidget(widget)
    self.layer:CloseWidget(widget)
end

function Hud:HideWidgetByName(widget_name)
    self.layer:HideWidget(self.widget_pool[widget_name])
end



return Class(nil, nil, Hud)