local MarketplaceService = game:GetService("MarketplaceService")
local Players = game:GetService("Players")

local PASS_ID = 000000 -- your Pass ID

-- Check ownership on join
Players.PlayerAdded:Connect(function(player)
    local success, hasPass = pcall(function()
        return MarketplaceService:UserOwnsGamePassAsync(player.UserId, PASS_ID)
    end)
    if success and hasPass then
        -- grant perk
    end
end)

-- Prompt purchase (call from server)
local function promptPass(player)
    MarketplaceService:PromptGamePassPurchase(player, PASS_ID)
end

-- Grant immediately after purchase
MarketplaceService.PromptGamePassPurchaseFinished:Connect(function(player, passId, purchased)
    if purchased and passId == PASS_ID then
        -- grant perk
    end
end)

local MarketplaceService = game:GetService("MarketplaceService")
local DataStoreService = game:GetService("DataStoreService")
local Players = game:GetService("Players")

local PRODUCT_ID = 000000 -- your Product ID
local coinStore = DataStoreService:GetDataStore("PlayerCoins")

local function processReceipt(receiptInfo)
    local player = Players:GetPlayerByUserId(receiptInfo.PlayerId)
    if not player then
        return Enum.ProductPurchaseDecision.NotProcessedYet
    end

    if receiptInfo.ProductId == PRODUCT_ID then
        -- Persist to DataStore FIRST — if server crashes after this line, coins are safe
        local ok, err = pcall(function()
            coinStore:UpdateAsync(tostring(player.UserId), function(current)
                return (current or 0) + 100
            end)
        end)
        if not ok then
            warn("DataStore failed:", err)
            return Enum.ProductPurchaseDecision.NotProcessedYet -- Roblox will retry
        end
        -- Now safe to update in-memory value (leaderstats, etc.)
    end

    return Enum.ProductPurchaseDecision.PurchaseGranted
end

MarketplaceService.ProcessReceipt = processReceipt

-- Prompt purchase
local function promptProduct(player)
    MarketplaceService:PromptProductPurchase(player, PRODUCT_ID)
end

-- Inside ProcessReceipt, after DataStore save succeeds
local NotifyClient = game:GetService("ReplicatedStorage").Remotes.PurchaseGranted
local player = Players:GetPlayerByUserId(receiptInfo.PlayerId)
if player then
    NotifyClient:FireClient(player, { productId = receiptInfo.ProductId })
end