onCollectibleSpawn

function Mod:onCollectibleSpawn(pickup)
	local player = Isaac.GetPlayer(0)
	local roomType = game:GetRoom():GetType()
	local hasEffect = player:GetEffects()

	-- check if the player plays the challenge
	if game.Challenge == Challenges.CHALLENGE_ONLY_TRINKETS then
		if pickup.Variant == PickupVariant.PICKUP_COLLECTIBLE then	-- look for items
			-- Isaac.ConsoleOutput("Yeahhh")
			local item = pickup
			-- check if a beggar spawned an item
			if waitForBeggar == true 	-- a beggar spawned an item
			and morphItem == false then	-- item hasn't morphed yet
				-- Isaac.ConsoleOutput("Wait!! ")
				if collectible.Beggar == true then
					-- get the beggar trinket "pool"
					local pool = {1,24,49,50,51,52,126}	-- mostly the penny trinkets
					local poolBackwards = {126,52,51,50,49,24,1}

					-- trinket pool stuff
					TrinketPools(item, pool, poolBackwards)

					collectible.Beggar = false
					Isaac.ConsoleOutput("Please? ")

				elseif collectible.DemonBeggar == true then
					-- get the devil beggar trinket "pool"
					local pool = {61,111}		-- Left Hand, Bloody Crown
					local poolBackwards = {111,61}

					-- trinket pool stuff
					TrinketPools(item, pool, poolBackwards)

					collectible.DemonBeggar = false

				elseif collectible.ShellGame == true then
					-- get the shell game trinket "pool"
					local pool = {2,93}		-- Petrified Poop, Used Diaper
					local poolBackwards = {93,2}

					-- trinket pool stuff
					TrinketPools(item, pool, poolBackwards)

					collectible.ShellGame = false

					-- Isaac.ConsoleOutput("Shell Game")

				elseif collectible.KeyBeggar == true then
					-- get the key master trinket "pool"
					local pool = {19,36,83,124}		-- key related trinkets
					local poolBackwards = {124,83,36,19}

					-- trinket pool stuff
					TrinketPools(item, pool, poolBackwards)

					collectible.KeyBeggar = false

				elseif collectible.BombBeggar == true then
					-- get the bomb beggar trinket "pool"
					local pool = {63,71,73}		-- Bob's Bladder / bomb related trinkets
					local poolBackwards = {73,71,63}

					-- trinket pool stuff
					TrinketPools(item, pool, poolBackwards)

					collectible.BombBeggar = false
					-- Isaac.ConsoleOutput("Kaboooom")
				end
				-- set waitForBeggar and morphItem
				waitForBeggar = false
				morphItem = true	-- the item is already morphed
			end

			if morphItem == true then
				-- break
				-- morphItem = false
			end

			-- Look for specific items via the CollectibleType
			if (item.SubType == CollectibleType.COLLECTIBLE_LUMP_OF_COAL		-- spawned from the Krampus fight
			or item.SubType == CollectibleType.COLLECTIBLE_KRAMPUS_HEAD) then
				-- possible needs room type?
				-- get krampu's trinket pool
				local pool = {35,95}
				local poolBackwards = {95,35}

				-- trinket pool stuff
				TrinketPools(item, pool, poolBackwards)

				morphItem = true	-- the item is already morphed

			elseif (item.SubType == CollectibleType.COLLECTIBLE_CUBE_OF_MEAT		-- spawned by the horesman fight
			or item.SubType == CollectibleType.COLLECTIBLE_BALL_OF_BANDAGES
			or item.SubType == CollectibleType.COLLECTIBLE_WHITE_PONY) then			-- spawned by Conquest
				-- get room data to see which horseman room it is
				if roomType == RoomType.ROOM_BOSS then		-- first check the room type
					if roomContains.Famine == true then
						-- morph the item into a locust. This will always happen regardless if the player has it or not
						item:ToPickup():Morph(EntityType.ENTITY_PICKUP, PickupVariant.PICKUP_TRINKET, TrinketType.TRINKET_LOCUST_OF_FAMINE, false)
						-- reset the roomContains
						roomContains.Famine = false

					elseif roomContains.Pestilence == true then
						-- morph the item into a locust. This will always happen regardless if the player has it or not
						item:ToPickup():Morph(EntityType.ENTITY_PICKUP, PickupVariant.PICKUP_TRINKET, TrinketType.TRINKET_LOCUST_OF_PESTILENCE, false)
						-- reset the roomContains
						roomContains.Pestilence = false

					elseif roomContains.Death == true then
						-- morph the item into a locust. This will always happen regardless if the player has it or not
						item:ToPickup():Morph(EntityType.ENTITY_PICKUP, PickupVariant.PICKUP_TRINKET, TrinketType.TRINKET_LOCUST_OF_DEATH, false)
						-- reset the roomContains
						roomContains.Death = false

					elseif roomContains.War == true then
						-- morph the item into a locust. This will always happen regardless if the player has it or not
						item:ToPickup():Morph(EntityType.ENTITY_PICKUP, PickupVariant.PICKUP_TRINKET, TrinketType.TRINKET_LOCUST_OF_WRATH, false)
						-- reset the roomContains
						roomContains.War = false

					elseif roomContains.Conquest == true then
						-- morph the item into a locust. This will always happen regardless if the player has it or not
						item:ToPickup():Morph(EntityType.ENTITY_PICKUP, PickupVariant.PICKUP_TRINKET, TrinketType.TRINKET_LOCUST_OF_CONQUEST, false)
						-- reset the roomContains
						roomContains.Conquest = false
					end
				end
				morphItem = true	-- the item is already morphed

			elseif (item.SubType == CollectibleType.COLLECTIBLE_POLAROID		-- spawned from the Krampus fight
			or item.SubType == CollectibleType.COLLECTIBLE_NEGATIVE) then
				-- get mom's "pool"
				-- local pool = {69}	-- Faded Polariod

				-- morph the item to the picked trinket
				item:ToPickup():Morph(EntityType.ENTITY_PICKUP, PickupVariant.PICKUP_TRINKET, TrinketType.TRINKET_FADED_POLAROID, false)

				morphItem = true	-- the item is already morphed

			elseif item.SubType == CollectibleType.COLLECTIBLE_SKATOLE then	-- shell game
				-- get the shell game trinket "pool"
				local pool = {2,93}		-- Petrified Poop, Used Diaper
				local poolBackwards = {93,2}

				-- trinket pool stuff
				TrinketPools(item, pool, poolBackwards)

				morphItem = true	-- the item is already morphed

			elseif item.SubType == CollectibleType.COLLECTIBLE_DOLLAR then	-- slot machine
				-- get the slot machine trinket "pool"
				-- local pool = 121
				-- morph the item to the picked trinket
				item:ToPickup():Morph(EntityType.ENTITY_PICKUP, PickupVariant.PICKUP_TRINKET, TrinketType.TRINKET_SILVER_DOLLAR, false)

				morphItem = true	-- the item is already morphed

			elseif item.SubType == CollectibleType.COLLECTIBLE_BLOOD_BAG	-- blood donation machine
			or item.SubType == CollectibleType.COLLECTIBLE_IV_BAG then
				-- get the blood donation trinket "pool"
				local pool = {34,40,87}
				local poolBackwards = {87,40,34}
				-- trinket pool stuff
				TrinketPools(item, pool, poolBackwards)

				morphItem = true	-- the item is already morphed

			elseif item.SubType == CollectibleType.COLLECTIBLE_CRYSTAL_BALL then	-- fortune teller
				-- get the fortune teller trinket "pool"
				-- local pool = 102		-- Fragmented Card
				-- morph the item to the picked trinket
				item:ToPickup():Morph(EntityType.ENTITY_PICKUP, PickupVariant.PICKUP_TRINKET, TrinketType.TRINKET_FRAGMENTED_CARD, false)

				morphItem = true	-- the item is already morphed

			elseif item.SubType == CollectibleType.COLLECTIBLE_PONY then
				-- get the headless trinket "pool"
				-- local pool = 54		-- Isaac's Head
				-- morph the item to the picked trinket
				item:ToPickup():Morph(EntityType.ENTITY_PICKUP, PickupVariant.PICKUP_TRINKET, TrinketType.TRINKET_ISAACS_HEAD, false)

				morphItem = true	-- the item is already morphed

			elseif item.SubType == CollectibleType.COLLECTIBLE_KEY_PIECE_1
			or item.SubType == CollectibleType.COLLECTIBLE_KEY_PIECE_2 then
				local droppedFeather = false	-- keeps track if the Filigree Feather is already in the room
				-- look for the feather
				for _, entity in pairs(Isaac.GetRoomEntities()) do
					if entity.Type == EntityType.ENTITY_PICKUP
					and entity.Variant == PickupVariant.PICKUP_TRINKET
					and entity.SubType == TrinketType.TRINKET_FILIGREE_FEATHERS then
						if droppedFeather == false then
							droppedFeather = true
							-- Isaac.ConsoleOutput("Kaboooom")
						end
					end
				end

				-- after searching decide in what the item is going to be morped
				if droppedFeather == true
				or player:HasTrinket(TrinketType.TRINKET_FILIGREE_FEATHERS)
				or hasEffect:HasTrinketEffect(TrinketType.TRINKET_FILIGREE_FEATHERS) then
					-- a random trinket from the angel trinket room pool
					-- get the angel room pool
					local pool = {7,18,38,85,87,92,100,110,121}
					local poolBackwards = {121,110,100,92,87,85,38,18,7}

					-- trinket pool stuff
					TrinketPools(item, pool, poolBackwards)
				else
					item:ToPickup():Morph(EntityType.ENTITY_PICKUP, PickupVariant.PICKUP_TRINKET, TrinketType.TRINKET_FILIGREE_FEATHERS, false)
				end

				morphItem = true	-- the item is already morphed
			end

			if morphItem == true then
				-- Isaac.ConsoleOutput("Kaboooom")
			end

			-- check the room pools
			if waitForBeggar == false	-- the item wasn't spawned by a beggar
			and morphItem == false then	-- item hasn't morphed yet

				-- go through the different room types
				if roomType == RoomType.ROOM_TREASURE
				or roomType == RoomType.ROOM_DUNGEON then
					-- get the treasure room pool
					local pool = {5,8,14,16,25,30,31,33,53,54,55,57,60,68,70,71,77,81,86,90,93,95,97,98,99,127}
					local poolBackwards = {127,99,98,97,95,93,90,86,81,77,71,70,68,60,57,55,54,53,33,31,30,25,16,14,8,5}

					-- trinket pool stuff
					TrinketPools(item, pool, poolBackwards)

				elseif roomType == RoomType.ROOM_SHOP
				or roomType == RoomType.ROOM_BLACK_MARKET then
					-- get the shop room pool
					local pool = {3,29,34,36,41,44,59,62,63,72,73,74,76,78,82,89,94,103,106,109,120,125}
					local poolBackwards = {125,120,109,106,103,94,89,82,78,76,74,73,72,63,62,59,44,41,36,34,29,3}

					-- trinket pool stuff
					TrinketPools(item, pool, poolBackwards)

					-- assign data to the entity to make it a shop item later down the line
					item:GetData().ShopTrinket = true
					item:GetData().NeedsNewPrize = true


				elseif roomType == RoomType.ROOM_LIBRARY then
					-- get the library room pool
					local pool = {9,10,11,12,21,23,26,27,45,48,64,65,66,96,102}
					local poolBackwards = {102,96,66,65,64,48,45,27,26,23,21,12,11,10,9}

					-- trinket pool stuff
					TrinketPools(item, pool, poolBackwards)

				elseif roomType == RoomType.ROOM_BOSS
				or roomType == RoomType.ROOM_MINIBOSS then
					if roomContains.Fallen == true then	-- the boss room contains the Fallen
						-- get the devil room pool
						local pool = {13,17,20,22,35,80,111,118}
						local poolBackwards = {118,111,80,35,22,20,17,13}

						-- trinket pool stuff
						TrinketPools(item, pool, poolBackwards)

						roomContains.Fallen = false
					else
						-- get the boss room pool
						local pool = {37,39,42,46,58,101,104,105,108,119}
						local poolBackwards = {119,108,105,104,101,58,46,42,39,37}

						-- trinket pool stuff
						TrinketPools(item, pool, poolBackwards)
					end

				elseif roomType == RoomType.ROOM_SECRET
				or roomType == RoomType.ROOM_SUPERSECRET then
					-- get the secret room pool
					local pool = {15,28,32,83,84,91}
					local poolBackwards = {91,84,83,32,28,15}

					-- trinket pool stuff
					TrinketPools(item, pool, poolBackwards)

				elseif roomType == RoomType.ROOM_DEVIL then
					-- get the secret room pool
					local pool = {13,17,20,22,35,80,111,118}
					local poolBackwards = {118,111,80,35,22,20,17,13}

					-- trinket pool stuff
					TrinketPools(item, pool, poolBackwards)

				elseif roomType == RoomType.ROOM_ANGEL
				or roomType == RoomType.ROOM_SACRIFICE then
					-- get the secret room pool
					local pool = {7,18,38,87,92,100,110,121}
					local poolBackwards = {121,110,100,92,87,38,18,7}

					-- trinket pool stuff
					TrinketPools(item, pool, poolBackwards)

				elseif roomType == RoomType.ROOM_CURSE then
					-- get the secret room pool
					local pool = {40,43,61,107,128}
					local poolBackwards = {128,107,61,43,40}

					-- trinket pool stuff
					TrinketPools(item, pool, poolBackwards)

				elseif roomType == RoomType.ROOM_ISAACS
				or roomType == RoomType.ROOM_BARREN then
					-- get the secret room pool
					local pool = {8,46,54,63,67,99}
					local poolBackwards = {99,67,63,54,46,8}

					-- trinket pool stuff
					TrinketPools(item, pool, poolBackwards)

				elseif roomType == RoomType.ROOM_CHALLENGE then
					-- get the secret room pool
					local pool = {6,40,58}
					local poolBackwards = {58,40,6}

					-- trinket pool stuff
					TrinketPools(item, pool, poolBackwards)

				elseif roomType == RoomType.ROOM_CHEST then
					-- get the secret room pool
					local pool = {29,54,55,56,57,58,59,60}
					local poolBackwards = {60,59,58,57,56,55,54,29}

					-- trinket pool stuff
					TrinketPools(item, pool, poolBackwards)

				elseif roomType == RoomType.ROOM_ARCADE then
					-- get the secret room pool
					local pool = {8,45,67,76,112}
					local poolBackwards = {112,76,67,45,8}

					-- trinket pool stuff
					TrinketPools(item, pool, poolBackwards)

				elseif roomType == RoomType.ROOM_ERROR then
					-- get the secret room pool
					local pool = {4,6,67,75,79,92}
					local poolBackwards = {92,79,75,67,6,4}

					-- trinket pool stuff
					TrinketPools(item, pool, poolBackwards)

				elseif roomType == RoomType.ROOM_BOSSRUSH
				or roomType == RoomType.ROOM_DEFAULT then
					-- Isaac.ConsoleOutput("s,rjzgqp")
					-- morph the item into a random trinket. This will always happen regardless if the player has it or not
					item:ToPickup():Morph(EntityType.ENTITY_PICKUP, PickupVariant.PICKUP_TRINKET, TrinketType.TRINKET_NULL, false)
				end
			end

			if morphItem == true then
				morphItem = false
			end
		end
	end

end
Mod:AddCallback(ModCallbacks.MC_POST_PICKUP_UPDATE, Mod.onCollectibleSpawn)