MainModule

local API = {}

local id = nil
local remoteEvent = script.ReportGoogleAnalyticsEvent
local helper = script.GoogleAnalyticsHelper
local category = "PlaceId: " .. tostring(game.PlaceId) .. " Version: " .. tostring(game.PlaceVersion)
local googleUserTrackingId = game:GetService("HttpService"):GenerateGUID()
local lastTimeGeneratedGoogleUserId = os.time()

local playerJoinTimes = {} -- key : UserId , value : JoinTime

function convertNewlinesToVertLine(stack)
    local rebuiltStack = ""
    local first = true
    for line in stack:gmatch("[^\r\n]+") do
        if first then
            rebuiltStack = line
            first = false
        else
            rebuiltStack = rebuiltStack .. " | " .. line
        end
    end
    return rebuiltStack
end

function removePlayerNameFromStack(stack)
    stack = string.gsub(stack, "Players%.[^.]+%.", "Players.<Player>.")
    return stack
end

function setupScriptErrorTracking()
    game:GetService("ScriptContext").Error:connect(function (message, stack)
        API.ReportEvent(category,
            removePlayerNameFromStack(message) .. " | " ..
            removePlayerNameFromStack(stack), "Server Error", 1)
    end)
    -- add tracking for clients
    helper.Parent = game.StarterGui
    -- add to any players that are already in game
    for i, c in ipairs(game.Players:GetChildren()) do
        helper:Clone().Parent = (c:WaitForChild("PlayerGui"))
    end
end

function printEventInsteadOfActuallySendingIt(category, action, label, value)
    print("GA EVENT: " ..
        "Category: [" .. tostring(category) .. "] " ..
        "Action: [" .. tostring(action) .. "] " ..
        "Label: [" .. tostring(label) .. "] " ..
        "Value: [" .. tostring(value) .. "]")
end

function API.ReportEvent(category, action, label, value)
    if game:FindFirstChild("NetworkServer") ~= nil then
        if id == nil then
            print("WARNING: not reporting event because Init() has not been called")
            return
        end

        -- Try to detect studio start server + player
        if game.CreatorId <= 0 then
            printEventInsteadOfActuallySendingIt(category, action, label, value)
            return
        end

        if os.time() - lastTimeGeneratedGoogleUserId > 7200 then
            googleUserTrackingId = game:GetService("HttpService"):GenerateGUID()
            lastTimeGeneratedGoogleUserId = os.time()
        end

        hs = game:GetService("HttpService")
        hs:PostAsync(
            "http://www.google-analytics.com/collect",
            "v=1&t=event&sc=start" ..
            "&tid=" .. id ..
            "&cid=" .. googleUserTrackingId ..
            "&ec=" .. hs:UrlEncode(category) ..
            "&ea=" .. hs:UrlEncode(action) ..
            "&el=" .. hs:UrlEncode(label) ..
            "&ev=" .. hs:UrlEncode(value),
            Enum.HttpContentType.ApplicationUrlEncoded)

        --printEventInsteadOfActuallySendingIt(category, action, label, value)
    elseif game:FindFirstChild("NetworkClient") ~= nil then
        game:GetService("ReplicatedStorage").ReportGoogleAnalyticsEvent:FireServer(category, action, label, value)
    else
        printEventInsteadOfActuallySendingIt(category, action, label, value)
    end
end

function API.Init(userId, config)
    if game:FindFirstChild("NetworkServer") == nil then
        error("Init() can only be called from game server")
    end
    if id == nil then
        if userId == nil then
            error("Cannot Init with nil Analytics ID")
        end

        id = userId
        remoteEvent.Parent = game:GetService("ReplicatedStorage")
        remoteEvent.OnServerEvent:connect(
            function (client, ...) API.ReportEvent(category, ...) end)

        if config == nil or not config["DoNotReportScriptErrors"] then
            setupScriptErrorTracking()
        end

        if config == nil or not config["DoNotTrackServerStart"] then
            API.ReportEvent(category, "Server Startup", "General Statistics", 0)
        end

        if config == nil or not config["DoNotTrackVisits"] then
            game.Players.ChildAdded:connect(function( newPlayer )
                if newPlayer:IsA("Player") then
                    API.ReportEvent(category, "Visit", "General Statistics", 1)
                    table.insert(playerJoinTimes, newPlayer.userId, os.time() )
                end
            end)
        end

        if config == nil or not config["DoNotTackVisitTimes"] then
            game.Players.ChildRemoved:connect(function( oldPlayer )
                if oldPlayer:IsA("Player") and playerJoinTimes[oldPlayer.userId] then
                    local timeValue = ( os.time() - playerJoinTimes[oldPlayer.userId] ) / 60 --Time in Minutes
                    timeValue = ( timeValue < 15 and timeValue ) or math.floor(timeValue/5 + .5)*5
                    API.ReportEvent(category, tostring(math.floor(timeValue + .5)) .. " Minutes", "Play Time Statistics", 1)
                    table.remove(playerJoinTimes, oldPlayer.userId)
                end
            end)
        end
    else
        error("Cannot re-initalize Analytics Module")
    end
end

return API