ClientSideInventorySystem

-- keeps track of the clients inventory

-- some references
local invRemotes = game:GetService("ReplicatedStorage"):WaitForChild("Shared"):WaitForChild("Remotes"):WaitForChild("Inventory")
local invRemoteEvent = invRemotes:WaitForChild("Event")
local invRemoteFunction = invRemotes:WaitForChild("Function")

--- the table
local it = {}
it.Inventory = {} -- the main items inventory
it.InventorySize = 0

-- client listening functions --
it.connections = {
    newSlot = {};
    updateSlot = {};
    emptySlot = {};
    sizeChange = {};
}
-- the utility event functions
function it:fireConnection(eventname,...)
    local t = self.connections[eventname]
    if not t then
        error("unrecognized event id")
        return
    end
    for i,f in pairs(t) do
        if typeof(f) == "function" then
            local c = coroutine.create(function(...)
                f(...)
            end)
            coroutine.resume(c,...)
        end
    end
end
-- the binding functions
function it:bindTo(eventName,id,f)
    local t = self.connections[eventName]
    if not t then
        error("unrecognized event id")
        return
    end
    if t[id] then
        error("can't overwrite binding with same id (already function with that bind in index)")
        return
    else
        print(id .. "   " .. tostring(f))
        t[id] = f
    end
end

function it:unbindFrom(eventName,id)
    local t = self.connections[eventName]
    if not t then
        error("unrecognized event id")
        return
    end
    t[id] = nil
end


-- update functions --
function it:newSlot(i,id,amt)
    --print("slot @" .. i .. "; id : " .. id .. "; amt : " .. amt .. ";")
    self.Inventory[id] = {id = id; amt = amt}
    self:fireConnection("newSlot",i,id,amt)
end

function it:emptySlot(i)
    --print("empty slot @" .. i)
    self.Inventory[i] = nil
    self:fireConnection("emptySlot",i)
end

function it:updateSlot(i,id,amt)
    --print("slot @" .. i .. "; id : " .. id .. "; amt : " .. amt .. ";")
    local oldSlot = self.Inventory[id]
    local newSlot =  {id = id; amt = amt}
    self.Inventory[id] = newSlot
    if not oldSlot or not (oldSlot.id == newSlot.id) then
        self:fireConnection("newSlot",i,id,amt)
    else
        self:fireConnection("updateSlot",i,id,amt)
    end
end
function it:incoming(t,...)
    if t == "NEWSLOT" then
        self:newSlot(...)
    elseif t == "EMPTYSLOT" then
        self:emptySlot(...)
    elseif t == "UPDATESLOT" then
        self:updateSlot(...)
    end
end
-- init function
function it:Init() -- setups so it can start tracking immediately
    -- get current table
    local contents,size = invRemoteFunction:InvokeServer("REQINFO")
    if contents and size then
        self.Inventory = contents
        self.InventorySize = size
    end
    invRemoteEvent.OnClientEvent:Connect(function(...)
        self:incoming(...)
    end)
end

return it