source for TRIGGER

local TRIGGER = {}
local triggers = {}

local chars = {
    "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o",
    "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z", "0", "1", "2", "3",
    "4", "5", "6", "7", "8", "9",
}

local function generate_id()
    local random = math.random
    local template = "xxxxxxx-xxxx-xxxx-yxxxx"
    return string.gsub(template, "[xy]", function(c)
        local v = (c == 'x') and random(0, 0xf) or random(8, 0xb)
        return string.format("%x", v)
    end)
end

--[[
    params {
        properties: 'table'
        _repeat:    'bool' -> true: touched event fires infinitely at the rate of the given cooldown ; false: touched event fires once
        callback:   'function' -> gets called when the trigger object gets touched
        part:       Instance of class 'BasePart' -> the part to turn into a trigger object
    }

    TRIGGER:new()        -> Creates trigger object from scratch with given properties
    *NOTICE* When using TRIGGER:new() you need to parent the part to workspace yourself.

    trigger:hook()       -> Hooks the trigger to the part
    trigger:unhook()     -> Unhooks the trigger from the part
    trigger:initialize() -> Initializes the trigger *fires when the trigger object gets called*
    trigger:destroy()    -> Destroys the part along with the trigger object
    trigger:reset()      -> Resets the trigger and leaves it unhooked

    <---------------------------->

    Example with part:
    local TRIGGER = require(PATH_TO_MODULE)

    local trigger = TRIGGER(PATH_TO_BASEPART, false, function()
        print("triggered")
    end)

    <---------------------------->

    Example without part:
    local TRIGGER = require(PATH_TO_MODULE)
    local properties = {
        Name = "New Trigger";
        Position = Vector3.new(0, 10, 0);
        Anchored = true;
        CanCollide = false;
        Size = Vector3.new(10, 10, 10);
        Parent = workspace;
    }

    TRIGGER:new(properties, false, function()
        print("new trigger")
    end)

    <---------------------------->
]]

function TRIGGER:new(properties, _repeat, callback)
    local trigger_part = Instance.new("Part")
    for property,value in pairs(properties) do
        trigger_part[property] = value
    end
    self(trigger_part, _repeat, callback)
end

function TRIGGER:getTriggers()
    return triggers
end

setmetatable(TRIGGER, {
    __call = function(self, part, _repeat, callback)
        callback = callback or function() end

        local trigger = {
            part = part;
            _repeat = _repeat;
            triggered = {};
            cooldowns = {};
            cooldown = 2;
            state = "unhooked";
            connection = nil;
            id = generate_id();

            hook = function(self)
                self.state = "hooked"
                if not self.connection then
                    self.connection = part.Touched:Connect(function(hit)
                        pcall(function()
                            local player = game:GetService("Players"):GetPlayerFromCharacter(hit.Parent)
                            if self._repeat then
                                while table.find(self.part:GetTouchingParts(), hit) do
                                    if os.time() - self.cooldowns[player] >= self.cooldown then
                                        self.cooldowns[player] = os.time()
                                        callback(player)
                                    end
                                    wait()
                                end
                            else
                                if not self.triggered[player] then
                                    self.triggered[player] = true
                                    for i,v in pairs(self.triggered) do print(i,v) end
                                    callback(player)
                                end
                            end
                        end)
                    end)
                end
            end;

            unhook = function(self)
                self.state = "unhooked";
                self.connection:Disconnect()
                self.connection = nil
            end;

            initialize = function(self)
                table.insert(triggers, self)
                for _,player in pairs(game:GetService("Players"):GetPlayers()) do
                    self.cooldowns[player] = os.time()
                end
                game:GetService("Players").PlayerAdded:Connect(function(player)
                    self.cooldowns[player] = os.time()
                end)
                self:hook()
            end;

            reset = function(self)
                if self.state == "hooked" then self.connection:Disconnect() end
                self.connection = nil
                self.state = "unhooked"
                self.triggered = {}
            end;

            destroy = function(self)
                local i = table.find(triggers, self)
                table.remove(triggers, i)
                self.part:Destroy()
            end;
        }

        trigger:initialize()

        return trigger
    end
});

return TRIGGER