Player Tracker - Ziffixture

-- Services
local RunService = game:GetService("RunService")

local Players = game:GetService("Players")


-- Variables
local PlayerTracker = {}
local PlayerTrackerData = {}

local PlayerTrackerPrototype = {}
local PlayerTrackerMeta = {

    __index = PlayerTrackerPrototype,
    __newindex = function() end,

    __metatable = "This metatable is locked."

}


-- Functions
local function AnalyzePartsForPlayers(BaseParts)
    local PlayersFound = {}

    for _, BasePart in ipairs(BaseParts) do
        local Character = BasePart.Parent
        local Humanoid = Character:FindFirstChildWhichIsA("Humanoid")
        if (Humanoid and Humanoid.Health > 0) then

            local Player = Players:GetPlayerFromCharacter(Character)
            if (Player) then
                PlayersFound[Player] = true
            end

        end
    end

    return PlayersFound
end

local function UpdatePlayerMap(PlayerTracker, BaseParts)
    local TrackerData = PlayerTrackerData[PlayerTracker]

    local MaximumPlayers = TrackerData.MaximumPlayers
    local CurrentPopulation = TrackerData.Population
    local CurrentPlayers = TrackerData.Players

    local NewPlayers = AnalyzePartsForPlayers(BaseParts)

    for Player in pairs(NewPlayers) do
        if (MaximumPlayers and TrackerData.Population >= MaximumPlayers) then
            break
        end

        if (CurrentPlayers[Player] == nil) then
            CurrentPlayers[Player] = true

            TrackerData.Population += 1
            TrackerData.PlayerEnteredBindable:Fire(Player)
        end
    end

    for Player in pairs(CurrentPlayers) do
        if (NewPlayers[Player] == nil) then
            CurrentPlayers[Player] = nil

            TrackerData.Population -= 1
            TrackerData.PlayerLeftBindable:Fire(Player)
        end
    end
end


-- Constructors
function PlayerTracker.new(TrackingSpace : BasePart, MaximumPlayers : number)
    local PlayerLeftBindable = Instance.new("BindableEvent")
    local PlayerEnteredBindable = Instance.new("BindableEvent")

    local Tracker = setmetatable(
        {
            PlayerLeft = PlayerLeftBindable.Event,
            PlayerEntered = PlayerEnteredBindable.Event
        },
        PlayerTrackerMeta
    )

    local TrackerData = {

        IsTracking = false,
        TrackingSpace = TrackingSpace,
        SpaceTrackingConnection = nil,

        MaximumPlayers = MaximumPlayers,
        Population = 0,

        Players = {},

        PlayerLeftBindable = PlayerLeftBindable,
        PlayerEnteredBindable = PlayerEnteredBindable,

    }

    PlayerTrackerData[Tracker] = TrackerData

    return Tracker
end


-- Methods
function PlayerTrackerPrototype:StartTracking()
    local TrackerData = PlayerTrackerData[self]
    if (TrackerData.IsTracking == false) then
        TrackerData.IsTracking = true

        local TrackingSpace = TrackerData.TrackingSpace

        TrackerData.SpaceTrackingConnection = RunService.Heartbeat:Connect(function()
            UpdatePlayerMap(
                self,
                workspace:GetPartBoundsInBox(TrackingSpace.CFrame, TrackingSpace.Size)
            )
        end)
    end
end

function PlayerTrackerPrototype:StopTracking()
    local TrackerData = PlayerTrackerData[self]

    TrackerData.SpaceTrackingConnection:Disconnect()
    TrackerData.IsTracking = false
end

function PlayerTrackerPrototype:Destroy()
    if (PlayerTrackerData[self] ~= nil) then
        self:StopTracking()

        PlayerTrackerData[self] = nil
    end
end


function PlayerTrackerPrototype:GetPlayers()
    local Players = {}

    for Player in pairs(PlayerTrackerData[self].Players) do
        table.insert(Players, Player)
    end

    return Players
end

function PlayerTrackerPrototype:GetPopulation()
    return PlayerTrackerData[self].Population
end


-- Setup
return PlayerTracker