--!native
--!optimize 2

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

local Replica = require(ReplicatedStorage.Packages.replica)

local ClientStateService = {}

local HOTBAR_SIZE = 10

local token = Replica.Token("ClientState")

local blockCatalog = {}
local playerReplicas = {} :: {[Player]: any}
local blocksFolder: Folder? = nil
local readyConnections = {} :: {[Player]: RBXScriptConnection}

local function sortBlocks()
	table.sort(blockCatalog, function(a, b)
		local na = tonumber(a.id)
		local nb = tonumber(b.id)
		if na and nb then
			return na < nb
		end
		if na then
			return true
		end
		if nb then
			return false
		end
		return a.id < b.id
	end)
end

local function rebuildBlockCatalog()
	table.clear(blockCatalog)
	if not blocksFolder then
		return
	end

	for _, block in ipairs(blocksFolder:GetChildren()) do
		local id = block:GetAttribute("n")
		if id ~= nil then
			local displayName = block:GetAttribute("name") or block:GetAttribute("displayName") or block:GetAttribute("dn") or block.Name
			table.insert(blockCatalog, {
				id = tostring(id),
				name = displayName,
			})
		end
	end
	sortBlocks()
end

local function makeBaseState()
	local inventory = {}
	local hotbar = {}

	for _, entry in ipairs(blockCatalog) do
		inventory[entry.id] = {
			name = entry.name,
			count = 999999,
		}
		if #hotbar < HOTBAR_SIZE then
			table.insert(hotbar, entry.id)
		end
	end

	return {
		inventory = inventory,
		hotbar = hotbar,
		selectedSlot = #hotbar > 0 and 1 or 0,
	}
end

local function sanitizeSelection(hotbar, selectedSlot)
	if type(selectedSlot) ~= "number" then
		return (#hotbar > 0) and 1 or 0
	end
	if selectedSlot < 1 or selectedSlot > HOTBAR_SIZE then
		return (#hotbar > 0) and 1 or 0
	end
	return selectedSlot
end

local function refreshReplica(replica)
	local state = makeBaseState()
	replica:Set({"inventory"}, state.inventory)
	replica:Set({"hotbar"}, state.hotbar)
	replica:Set({"selectedSlot"}, sanitizeSelection(state.hotbar, replica.Data.selectedSlot))
end

function ClientStateService:SetBlocksFolder(folder: Folder?)
	blocksFolder = folder
	rebuildBlockCatalog()
	for _, replica in pairs(playerReplicas) do
		refreshReplica(replica)
	end
end

function ClientStateService:GetReplica(player: Player)
	return playerReplicas[player]
end

function ClientStateService:GetSelectedBlockId(player: Player)
	local replica = playerReplicas[player]
	if not replica then
		return nil
	end
	local data = replica.Data
	local hotbar = data.hotbar or {}
	local selectedSlot = sanitizeSelection(hotbar, data.selectedSlot)
	return hotbar[selectedSlot]
end

function ClientStateService:HasInInventory(player: Player, blockId: any): boolean
	local replica = playerReplicas[player]
	if not replica or not blockId then
		return false
	end
	local inv = replica.Data.inventory
	return inv and inv[tostring(blockId)] ~= nil or false
end

local function handleReplicaEvents(player: Player, replica)
	replica.OnServerEvent:Connect(function(plr, action, payload)
		if plr ~= player then
			return
		end

		if action == "SelectHotbarSlot" then
			local slot = tonumber(payload)
			local hotbar = replica.Data.hotbar
			if not hotbar then
				return
			end
			if slot and slot >= 1 and slot <= HOTBAR_SIZE then
				replica:Set({"selectedSlot"}, slot)
			end
		end
	end)
end

local function onPlayerAdded(player: Player)
	local replica = Replica.New({
		Token = token,
		Tags = {
			UserId = player.UserId,
			Player = player,
		},
		Data = makeBaseState(),
	})

	if Replica.ReadyPlayers[player] then
		replica:Subscribe(player)
	else
		readyConnections[player] = Replica.NewReadyPlayer:Connect(function(newPlayer)
			if newPlayer ~= player then
				return
			end
			if readyConnections[player] then
				readyConnections[player]:Disconnect()
				readyConnections[player] = nil
			end
			replica:Subscribe(player)
		end)
	end

	handleReplicaEvents(player, replica)
	playerReplicas[player] = replica
end

local function onPlayerRemoving(player: Player)
	local replica = playerReplicas[player]
	if replica then
		replica:Destroy()
		playerReplicas[player] = nil
	end
	if readyConnections[player] then
		readyConnections[player]:Disconnect()
		readyConnections[player] = nil
	end
end

function ClientStateService:Init()
	rebuildBlockCatalog()

	for _, player in ipairs(Players:GetPlayers()) do
		onPlayerAdded(player)
	end
	Players.PlayerAdded:Connect(onPlayerAdded)
	Players.PlayerRemoving:Connect(onPlayerRemoving)
end

return ClientStateService