--Set up WeaponTypes lookup table
do
	local function onNewWeaponType(weaponTypeModule)
		if not weaponTypeModule:IsA("ModuleScript") then
			return
		end
		local weaponTypeName = weaponTypeModule.Name
		xpcall(function()
			coroutine.wrap(function()
				local weaponType = require(weaponTypeModule)
				assert(typeof(weaponType) == "table", string.format("WeaponType \"%s\" did not return a valid table", weaponTypeModule:GetFullName()))
				WEAPON_TYPES_LOOKUP[weaponTypeName] = weaponType
			end)()
		end, function(errMsg)
			warn(string.format("Error while loading %s: %s", weaponTypeModule:GetFullName(), errMsg))
			warn(debug.traceback())
		end)
	end
	for _, child in pairs(WeaponTypes:GetChildren()) do
		onNewWeaponType(child)
	end
	WeaponTypes.ChildAdded:Connect(onNewWeaponType)
end

local WeaponsSystem = {}
WeaponsSystem.didSetup = false
WeaponsSystem.knownWeapons = {}
WeaponsSystem.connections = {}
WeaponsSystem.networkFolder = nil
WeaponsSystem.remoteEvents = {}
WeaponsSystem.remoteFunctions = {}
WeaponsSystem.currentWeapon = nil
WeaponsSystem.aimRayCallback = nil

WeaponsSystem.CurrentWeaponChanged = Instance.new("BindableEvent")

local NetworkingCallbacks = require(WeaponsSystemFolder:WaitForChild("NetworkingCallbacks"))
NetworkingCallbacks.WeaponsSystem = WeaponsSystem

local _damageCallback = nil
local _getTeamCallback = nil

function WeaponsSystem.setDamageCallback(cb)
	_damageCallback = cb
end

function WeaponsSystem.setGetTeamCallback(cb)
	_getTeamCallback = cb
end

function WeaponsSystem.setup()
	if WeaponsSystem.didSetup then
		warn("Warning: trying to run WeaponsSystem setup twice on the same module.")
		return
	end
	print(script.Parent:GetFullName(), "is now active.")

	WeaponsSystem.doingSetup = true

	--Setup network routing
	if IsServer then
		local networkFolder = Instance.new("Folder")
		networkFolder.Name = "Network"

		for _, remoteEventName in pairs(REMOTE_EVENT_NAMES) do
			local remoteEvent = Instance.new("RemoteEvent")
			remoteEvent.Name = remoteEventName
			remoteEvent.Parent = networkFolder

			local callback = NetworkingCallbacks[remoteEventName]
			if not callback then
				--Connect a no-op function to ensure the queue doesn't pile up.
				warn("There is no server callback implemented for the WeaponsSystem RemoteEvent \"%s\"!")
				warn("A default no-op function will be implemented so that the queue cannot be abused.")
				callback = function() end
			end
			WeaponsSystem.connections[remoteEventName .. "Remote"] = remoteEvent.OnServerEvent:Connect(function(...)
				callback(...)
			end)
			WeaponsSystem.remoteEvents[remoteEventName] = remoteEvent
		end
		for _, remoteFuncName in pairs(REMOTE_FUNCTION_NAMES) do
			local remoteFunc = Instance.new("RemoteEvent")
			remoteFunc.Name = remoteFuncName
			remoteFunc.Parent = networkFolder

			local callback = NetworkingCallbacks[remoteFuncName]
			if not callback then
				--Connect a no-op function to ensure the queue doesn't pile up.
				warn("There is no server callback implemented for the WeaponsSystem RemoteFunction \"%s\"!")
				warn("A default no-op function will be implemented so that the queue cannot be abused.")
				callback = function() end
			end
			remoteFunc.OnServerInvoke = function(...)
				return callback(...)
			end
			WeaponsSystem.remoteFunctions[remoteFuncName] = remoteFunc
		end

		networkFolder.Parent = WeaponsSystemFolder
		WeaponsSystem.networkFolder = networkFolder
	else
		WeaponsSystem.StarterGui = game:GetService("StarterGui")

		WeaponsSystem.camera = ShoulderCamera.new(WeaponsSystem)
		WeaponsSystem.gui = WeaponsGui.new(WeaponsSystem)

		if ConfigurationValues.SprintEnabled.Value then
			WeaponsSystem.camera:setSprintEnabled(ConfigurationValues.SprintEnabled.Value)
		end
		
		if ConfigurationValues.SlowZoomWalkEnabled.Value then
			WeaponsSystem.camera:setSlowZoomWalkEnabled(ConfigurationValues.SlowZoomWalkEnabled.Value)
		end

		local networkFolder = WeaponsSystemFolder:WaitForChild("Network", math.huge)

		for _, remoteEventName in pairs(REMOTE_EVENT_NAMES) do
			coroutine.wrap(function()
				local remoteEvent = networkFolder:WaitForChild(remoteEventName, math.huge)
				local callback = NetworkingCallbacks[remoteEventName]
				if callback then
					WeaponsSystem.connections[remoteEventName .. "Remote"] = remoteEvent.OnClientEvent:Connect(function(...)
						callback(...)
					end)
				end
				WeaponsSystem.remoteEvents[remoteEventName] = remoteEvent
			end)()
		end
		for _, remoteFuncName in pairs(REMOTE_FUNCTION_NAMES) do
			coroutine.wrap(function()
				local remoteFunc = networkFolder:WaitForChild(remoteFuncName, math.huge)
				local callback = NetworkingCallbacks[remoteFuncName]
				if callback then
					remoteFunc.OnClientInvoke = function(...)
						return callback(...)
					end
				end
				WeaponsSystem.remoteFunctions[remoteFuncName] = remoteFunc
			end)()
		end

		Players.LocalPlayer.CharacterAdded:Connect(WeaponsSystem.onCharacterAdded)
		if Players.LocalPlayer.Character then
			WeaponsSystem.onCharacterAdded(Players.LocalPlayer.Character)
		end

		WeaponsSystem.networkFolder = networkFolder
		
		-- Enable over-the-shoulder camera for internal initializations. Keep this disabled till the character holds a weapon (see BaseWeapon module script).
		WeaponsSystem.camera:setEnabled(true)
		WeaponsSystem.camera:setEnabled(false)	
	end

	--Setup weapon tools and listening
	WeaponsSystem.connections.weaponAdded = CollectionService:GetInstanceAddedSignal(WEAPON_TAG):Connect(WeaponsSystem.onWeaponAdded)
	WeaponsSystem.connections.weaponRemoved = CollectionService:GetInstanceRemovedSignal(WEAPON_TAG):Connect(WeaponsSystem.onWeaponRemoved)

	for _, instance in pairs(CollectionService:GetTagged(WEAPON_TAG)) do
		WeaponsSystem.onWeaponAdded(instance)
	end

	WeaponsSystem.doingSetup = false
	WeaponsSystem.didSetup = true
end

function WeaponsSystem.onCharacterAdded(character)
	-- Make it so players unequip weapons while seated, then reequip weapons when they become unseated
	local humanoid = character:WaitForChild("Humanoid")
	WeaponsSystem.connections.seated = humanoid.Seated:Connect(function(isSeated)
		if isSeated then
			WeaponsSystem.seatedWeapon = character:FindFirstChildOfClass("Tool")
			humanoid:UnequipTools()
			WeaponsSystem.StarterGui:SetCoreGuiEnabled(Enum.CoreGuiType.Backpack, false)
		else
			WeaponsSystem.StarterGui:SetCoreGuiEnabled(Enum.CoreGuiType.Backpack, true)
			humanoid:EquipTool(WeaponsSystem.seatedWeapon)
		end
	end)
end

function WeaponsSystem.shutdown()
	if not WeaponsSystem.didSetup then
		return
	end

	for _, weapon in pairs(WeaponsSystem.knownWeapons) do
		weapon:onDestroyed()
	end
	WeaponsSystem.knownWeapons = {}

	if IsServer and WeaponsSystem.networkFolder then
		WeaponsSystem.networkFolder:Destroy()
	end
	WeaponsSystem.networkFolder = nil
	WeaponsSystem.remoteEvents = {}
	WeaponsSystem.remoteFunctions = {}

	for _, connection in pairs(WeaponsSystem.connections) do
		if typeof(connection) == "RBXScriptConnection" then
			connection:Disconnect()
		end
	end
	WeaponsSystem.connections = {}
end

function WeaponsSystem.getWeaponTypeFromTags(instance)
	for _, tag in pairs(CollectionService:GetTags(instance)) do
		local weaponTypeFound = WEAPON_TYPES_LOOKUP[tag]
		if weaponTypeFound then
			return weaponTypeFound
		end
	end

	return nil
end

function WeaponsSystem.createWeaponForInstance(weaponInstance)
	coroutine.wrap(function()
		local weaponType = WeaponsSystem.getWeaponTypeFromTags(weaponInstance)
		if not weaponType then
			local weaponTypeObj = weaponInstance:WaitForChild("WeaponType")

			if weaponTypeObj and weaponTypeObj:IsA("StringValue") then
				local weaponTypeName = weaponTypeObj.Value
				local weaponTypeFound = WEAPON_TYPES_LOOKUP[weaponTypeName]
				if not weaponTypeFound then
					warn(string.format("Cannot find the weapon type \"%s\" for the instance %s!", weaponTypeName, weaponInstance:GetFullName()))
					return
				end

				weaponType = weaponTypeFound
			else
				warn("Could not find a WeaponType tag or StringValue for the instance ", weaponInstance:GetFullName())
				return
			end
		end

		-- Since we might have yielded while trying to get the WeaponType, we need to make sure not to continue
		-- making a new weapon if something else beat this iteration.
		if WeaponsSystem.getWeaponForInstance(weaponInstance) then
			warn("Already got ", weaponInstance:GetFullName())
			warn(debug.traceback())
			return
		end

		-- We should be pretty sure we got a valid weaponType by now
		assert(weaponType, "Got invalid weaponType")

		local weapon = weaponType.new(WeaponsSystem, weaponInstance)
		WeaponsSystem.knownWeapons[weaponInstance] = weapon
	end)()
end

function WeaponsSystem.getWeaponForInstance(weaponInstance)
	if not typeof(weaponInstance) == "Instance" then
		warn("WeaponsSystem.getWeaponForInstance(weaponInstance): 'weaponInstance' was not an instance.")
		return nil
	end

	return WeaponsSystem.knownWeapons[weaponInstance]
end