Main.lua

local json = require("json")

local mod = RegisterMod("Random Start Item Plus", 1)

local config = {
    ["NumberOfItems"] = 1,
    ["TreasurePool"] = true,
    ["ShopPool"] = false,
    ["BossPool"] = false,
    ["DevilPool"] = false,
    ["AngelPool"] = false,
    ["SecretPool"] = false,
    ["LibraryPool"] = false,
    ["UltraSecretPool"] = false,
    ["PlanetariumPool"] = false,
}

function getItemPool()
    local itemPools = {}

    if config["TreasurePool"] then
        itemPools[#itemPools+1] = ItemPoolType.POOL_TREASURE
    end

    if config["ShopPool"] then
        itemPools[#itemPools+1] = ItemPoolType.POOL_SHOP
    end

    if config["BossPool"] then
        itemPools[#itemPools+1] = ItemPoolType.POOL_BOSS
    end

    if config["DevilPool"] then
        itemPools[#itemPools+1] = ItemPoolType.POOL_DEVIL
    end

    if config["AngelPool"] then
        itemPools[#itemPools+1] = ItemPoolType.POOL_ANGEL
    end

    if config["SecretPool"] then
        itemPools[#itemPools+1] = ItemPoolType.POOL_SECRET
    end

    if config["LibraryPool"] then
        itemPools[#itemPools+1] = ItemPoolType.POOL_LIBRARY
    end

    if config["UltraSecretPool"] then
        itemPools[#itemPools+1] = ItemPoolType.POOL_ULTRA_SECRET
    end

    if config["PlanetariumPool"] then
        itemPools[#itemPools+1] = ItemPoolType.POOL_PLANETARIUM
    end

    if #itemPools == 0 then
        itemPools[#itemPools+1] = ItemPoolType.POOL_TREASURE
    end

    local itemPool = itemPools[math.random(#itemPools)]

    return itemPool
end

function mod:spawnItem()
    if Game():GetFrameCount() == 1 then 

        local spawnLocations = {
            { Vector(320, 300) },
            { Vector(280, 300), Vector(360, 300) },
            { Vector(260, 300), Vector(320, 300), Vector(380, 300) },
        }

        for i = 1, config["NumberOfItems"], 1 do

            local spawnLocation = (spawnLocations[config["NumberOfItems"]])[i]

            Isaac.Spawn(EntityType.ENTITY_PICKUP, 
                PickupVariant.PICKUP_COLLECTIBLE, 
                Game():GetItemPool():GetCollectible(getItemPool()),
                spawnLocation, Vector(0,0), nil)
        end
    end
end

mod:AddCallback(ModCallbacks.MC_POST_UPDATE , mod.spawnItem)

local isGameStarted = false

function mod.onGameStart()
    if mod:HasData() then
		config = json.decode(Isaac.LoadModData(mod))
	end
end

mod:AddCallback(ModCallbacks.MC_POST_GAME_STARTED, mod.onGameStart)

--Saving Moddata--
function mod:SaveGame()
    mod.SaveData(mod, json.encode(config))
end

mod:AddCallback(ModCallbacks.MC_PRE_GAME_EXIT, mod.SaveGame)

if ModConfigMenu then

    function AnIndexOf(t,val)
        for k,v in ipairs(t) do 
            if v == val then return k end
        end

        return 1
    end

    local sizes = {1, 2, 3}
    ModConfigMenu.AddSetting("Random Start Item Plus", "General", {
        Type = ModConfigMenu.OptionType.NUMBER,
        CurrentSetting = function()
            return AnIndexOf(sizes, config["NumberOfItems"])
        end,
        Minimum = 1,
        Maximum = #sizes,
        Display = function()
            return "# of Items to Spawn: " .. config["NumberOfItems"]
        end,
        OnChange = function(currentNum)
            config["NumberOfItems"] = sizes[currentNum]
        end,
    })

    ModConfigMenu.AddSetting("Random Start Item Plus","Item Pools", {
        Type = ModConfigMenu.OptionType.BOOLEAN,
        CurrentSetting = function()
            return config["TreasurePool"]
        end,
        Display = function()
            local onOff = "False"

            if config["TreasurePool"] then
                onOff = "True"
            end
            return "Use Treasure Pool: " .. onOff
        end,
        OnChange = function(currentBool)
            config["TreasurePool"] = currentBool
        end,
    })

    ModConfigMenu.AddSetting("Random Start Item Plus","Item Pools", {
        Type = ModConfigMenu.OptionType.BOOLEAN,
        CurrentSetting = function()
            return config["ShopPool"]
        end,
        Display = function()
            local onOff = "False"

            if config["ShopPool"] then
                onOff = "True"
            end
            return "Use Shop Pool: " .. onOff
        end,
        OnChange = function(currentBool)
            config["ShopPool"] = currentBool
        end,
    })

    ModConfigMenu.AddSetting("Random Start Item Plus","Item Pools", {
        Type = ModConfigMenu.OptionType.BOOLEAN,
        CurrentSetting = function()
            return config["BossPool"]
        end,
        Display = function()
            local onOff = "False"

            if config["BossPool"] then
                onOff = "True"
            end
            return "Use Boss Pool: " .. onOff
        end,
        OnChange = function(currentBool)
            config["BossPool"] = currentBool
        end,
    })

    ModConfigMenu.AddSetting("Random Start Item Plus","Item Pools", {
        Type = ModConfigMenu.OptionType.BOOLEAN,
        CurrentSetting = function()
            return config["DevilPool"]
        end,
        Display = function()
            local onOff = "False"

            if config["DevilPool"] then
                onOff = "True"
            end
            return "Use Devil Pool: " .. onOff
        end,
        OnChange = function(currentBool)
            config["DevilPool"] = currentBool
        end,
    })

    ModConfigMenu.AddSetting("Random Start Item Plus","Item Pools", {
        Type = ModConfigMenu.OptionType.BOOLEAN,
        CurrentSetting = function()
            return config["AngelPool"]
        end,
        Display = function()
            local onOff = "False"

            if config["AngelPool"] then
                onOff = "True"
            end
            return "Use Angel Pool: " .. onOff
        end,
        OnChange = function(currentBool)
            config["AngelPool"] = currentBool
        end,
    })

    ModConfigMenu.AddSetting("Random Start Item Plus","Item Pools", {
        Type = ModConfigMenu.OptionType.BOOLEAN,
        CurrentSetting = function()
            return config["SecretPool"]
        end,
        Display = function()
            local onOff = "False"

            if config["SecretPool"] then
                onOff = "True"
            end
            return "Use Secret Pool: " .. onOff
        end,
        OnChange = function(currentBool)
            config["SecretPool"] = currentBool
        end,
    })

    ModConfigMenu.AddSetting("Random Start Item Plus","Item Pools", {
        Type = ModConfigMenu.OptionType.BOOLEAN,
        CurrentSetting = function()
            return config["LibraryPool"]
        end,
        Display = function()
            local onOff = "False"

            if config["LibraryPool"] then
                onOff = "True"
            end
            return "Use Library Pool: " .. onOff
        end,
        OnChange = function(currentBool)
            config["LibraryPool"] = currentBool
        end,
    })

    ModConfigMenu.AddSetting("Random Start Item Plus","Item Pools", {
        Type = ModConfigMenu.OptionType.BOOLEAN,
        CurrentSetting = function()
            return config["UltraSecretPool"]
        end,
        Display = function()
            local onOff = "False"

            if config["UltraSecretPool"] then
                onOff = "True"
            end
            return "Use Ultra Secret Pool: " .. onOff
        end,
        OnChange = function(currentBool)
            config["UltraSecretPool"] = currentBool
        end,
    })

    ModConfigMenu.AddSetting("Random Start Item Plus","Item Pools", {
        Type = ModConfigMenu.OptionType.BOOLEAN,
        CurrentSetting = function()
            return config["PlanetariumPool"]
        end,
        Display = function()
            local onOff = "False"

            if config["PlanetariumPool"] then
                onOff = "True"
            end
            return "Use Planetarium Pool: " .. onOff
        end,
        OnChange = function(currentBool)
            config["PlanetariumPool"] = currentBool
        end,
    })
end