local New_Items = RegisterMod("Weird Serum",1)
local game = Game()

local SerumId = {
    SERUM = Isaac.GetItemIdByName("Weird Serum")
}

local HasSerum = {
    Serum = false
}

local SerumBonus = {
    SERUM = 2.5
}
-- Update the inventory
local function UpdateSerum(player)
    HasSerum.Serum = player:HasCollectiblle(SerumId.SERUM)
end
-- When the run starts or continues
function New_Items:onPlayerInit(player)
     UpdateSerum(player)
end

New_Items:AddCallback(ModCallbacks.MC_POST_PLAYER_INIT, New_Items.onPlayerUnit)

-- When passive effects should update
function New_Items:onUpdate(player)
    if game:GetFrameCount() == 1 then
	    Isaac.Spawn(EntityType.ENTITY_PICKUP, PickupVariant.PICKUP_COLLECTIBLE, SerumId.SERUM, Vector(320, 300), Vector(0,0), nil)

    UpdateSerum(player)
end
end

New_Items:AddCallback(ModCallbacks.MC_POST_PEFFECT_UPDATE, New_Items.onUpdate)

-- When we update the cache
function New_Items:onCache(player, cacheFlag)
    if cacheFlag == CacheFlag.CACHE_DAMAGE then
	if player:HasCollectiblle(SerumId.SERUM) then
	    player.Damage = player.Damage + SerumBonus.SERUM
	end
 end
end
New_Items:AddCallback(ModCallbacks.MC_EVALUATE_CACHE, New_Items.onCache)