--[[ The Module ]]
--
local BaseCamera = {}
BaseCamera.__index = BaseCamera

function BaseCamera.new()
	local self = setmetatable({}, BaseCamera)

	-- So that derived classes have access to this
	self.FIRST_PERSON_DISTANCE_THRESHOLD = FIRST_PERSON_DISTANCE_THRESHOLD

	self.cameraType = nil
	self.cameraMovementMode = nil

	self.lastCameraTransform = nil
	self.lastUserPanCamera = tick()

	self.humanoidRootPart = nil
	self.humanoidCache = {}

	-- Subject and position on last update call
	self.lastSubject = nil
	self.lastSubjectPosition = Vector3.new(0, 5, 0)
	self.lastSubjectCFrame = CFrame.new(self.lastSubjectPosition)

	-- These subject distance members refer to the nominal camera-to-subject follow distance that the camera
	-- is trying to maintain, not the actual measured value.
	-- The default is updated when screen orientation or the min/max distances change,
	-- to be sure the default is always in range and appropriate for the orientation.
	self.defaultSubjectDistance = math.clamp(DEFAULT_DISTANCE, player.CameraMinZoomDistance, player.CameraMaxZoomDistance)
	self.currentSubjectDistance = math.clamp(DEFAULT_DISTANCE, player.CameraMinZoomDistance, player.CameraMaxZoomDistance)

	self.inFirstPerson = false
	self.inMouseLockedMode = false
	self.portraitMode = false
	self.isSmallTouchScreen = false

	-- Used by modules which want to reset the camera angle on respawn.
	self.resetCameraAngle = true

	self.enabled = false

	-- Input Event Connections

	self.PlayerGui = nil

	self.cameraChangedConn = nil
	self.viewportSizeChangedConn = nil

	-- VR Support
	self.shouldUseVRRotation = false
	self.VRRotationIntensityAvailable = false
	self.lastVRRotationIntensityCheckTime = 0
	self.lastVRRotationTime = 0
	self.vrRotateKeyCooldown = {}
	self.cameraTranslationConstraints = Vector3.new(1, 1, 1)
	self.humanoidJumpOrigin = nil
	self.trackingHumanoid = nil
	self.cameraFrozen = false
	self.subjectStateChangedConn = nil

	self.gamepadZoomPressConnection = nil

	-- Mouse locked formerly known as shift lock mode
	self.mouseLockOffset = ZERO_VECTOR3

	-- Initialization things used to always execute at game load time, but now these camera modules are instantiated
	-- when needed, so the code here may run well after the start of the game

	if player.Character then
		self:OnCharacterAdded(player.Character)
	end

	player.CharacterAdded:Connect(function(char)
		self:OnCharacterAdded(char)
	end)

	if self.cameraChangedConn then self.cameraChangedConn:Disconnect() end
	self.cameraChangedConn = workspace:GetPropertyChangedSignal("CurrentCamera"):Connect(function()
		self:OnCurrentCameraChanged()
	end)
	self:OnCurrentCameraChanged()

	if self.playerCameraModeChangeConn then self.playerCameraModeChangeConn:Disconnect() end
	self.playerCameraModeChangeConn = player:GetPropertyChangedSignal("CameraMode"):Connect(function()
		self:OnPlayerCameraPropertyChange()
	end)

	if self.minDistanceChangeConn then self.minDistanceChangeConn:Disconnect() end
	self.minDistanceChangeConn = player:GetPropertyChangedSignal("CameraMinZoomDistance"):Connect(function()
		self:OnPlayerCameraPropertyChange()
	end)

	if self.maxDistanceChangeConn then self.maxDistanceChangeConn:Disconnect() end
	self.maxDistanceChangeConn = player:GetPropertyChangedSignal("CameraMaxZoomDistance"):Connect(function()
		self:OnPlayerCameraPropertyChange()
	end)

	if self.playerDevTouchMoveModeChangeConn then self.playerDevTouchMoveModeChangeConn:Disconnect() end
	self.playerDevTouchMoveModeChangeConn = player:GetPropertyChangedSignal("DevTouchMovementMode"):Connect(function()
		self:OnDevTouchMovementModeChanged()
	end)
	self:OnDevTouchMovementModeChanged() -- Init

	if self.gameSettingsTouchMoveMoveChangeConn then self.gameSettingsTouchMoveMoveChangeConn:Disconnect() end
	self.gameSettingsTouchMoveMoveChangeConn = UserGameSettings:GetPropertyChangedSignal("TouchMovementMode"):Connect(function()
		self:OnGameSettingsTouchMovementModeChanged()
	end)
	self:OnGameSettingsTouchMovementModeChanged() -- Init

	UserGameSettings:SetCameraYInvertVisible()
	UserGameSettings:SetGamepadCameraSensitivityVisible()

	self.hasGameLoaded = game:IsLoaded()
	if not self.hasGameLoaded then
		self.gameLoadedConn = game.Loaded:Connect(function()
			self.hasGameLoaded = true
			self.gameLoadedConn:Disconnect()
			self.gameLoadedConn = nil
		end)
	end

	self:OnPlayerCameraPropertyChange()

	return self
end

function BaseCamera:GetModuleName()
	return "BaseCamera"
end

function BaseCamera:OnCharacterAdded(char)
	self.resetCameraAngle = self.resetCameraAngle or self:GetEnabled()
	self.humanoidRootPart = nil
	if UserInputService.TouchEnabled then
		self.PlayerGui = player:WaitForChild("PlayerGui")
		for _, child in ipairs(char:GetChildren()) do
			if child:IsA("Tool") then
				self.isAToolEquipped = true
			end
		end
		char.ChildAdded:Connect(function(child)
			if child:IsA("Tool") then
				self.isAToolEquipped = true
			end
		end)
		char.ChildRemoved:Connect(function(child)
			if child:IsA("Tool") then
				self.isAToolEquipped = false
			end
		end)
	end
end

function BaseCamera:GetHumanoidRootPart(): BasePart
	if not self.humanoidRootPart then
		if player.Character then
			local humanoid = player.Character:FindFirstChildOfClass("Humanoid")
			if humanoid then
				self.humanoidRootPart = humanoid.RootPart
			end
		end
	end
	return self.humanoidRootPart
end

function BaseCamera:GetBodyPartToFollow(humanoid: Humanoid, isDead: boolean) -- BasePart
	-- If the humanoid is dead, prefer the head part if one still exists as a sibling of the humanoid
	if humanoid:GetState() == Enum.HumanoidStateType.Dead then
		local character = humanoid.Parent
		if character and character:IsA("Model") then
			return character:FindFirstChild("Head") or humanoid.RootPart
		end
	end

	return humanoid.RootPart
end

function BaseCamera:GetSubjectCFrame(): CFrame
	local result = self.lastSubjectCFrame
	local camera = workspace.CurrentCamera
	local cameraSubject = camera and camera.CameraSubject

	if not cameraSubject then
		return result
	end

	if cameraSubject:IsA("Humanoid") then
		local humanoid = cameraSubject
		local humanoidIsDead = humanoid:GetState() == Enum.HumanoidStateType.Dead

		if VRService.VREnabled and humanoidIsDead and humanoid == self.lastSubject then
			result = self.lastSubjectCFrame
		else
			local bodyPartToFollow = humanoid.RootPart

			-- If the humanoid is dead, prefer their head part as a follow target, if it exists
			if humanoidIsDead then
				if humanoid.Parent and humanoid.Parent:IsA("Model") then
					bodyPartToFollow = humanoid.Parent:FindFirstChild("Head") or bodyPartToFollow
				end
			end

			if bodyPartToFollow and bodyPartToFollow:IsA("BasePart") then
				local heightOffset
				if humanoid.RigType == Enum.HumanoidRigType.R15 then
					if humanoid.AutomaticScalingEnabled then
						heightOffset = R15_HEAD_OFFSET

						local rootPart = humanoid.RootPart
						if bodyPartToFollow == rootPart then
							local rootPartSizeOffset = (rootPart.Size.Y - HUMANOID_ROOT_PART_SIZE.Y)/2
							heightOffset = heightOffset + Vector3.new(0, rootPartSizeOffset, 0)
						end
					else
						heightOffset = R15_HEAD_OFFSET_NO_SCALING
					end
				else
					heightOffset = HEAD_OFFSET
				end

				if humanoidIsDead then
					heightOffset = ZERO_VECTOR3
				end

				result = bodyPartToFollow.CFrame*CFrame.new(heightOffset + humanoid.CameraOffset)
			end
		end

	elseif cameraSubject:IsA("BasePart") then
		result = cameraSubject.CFrame

	elseif cameraSubject:IsA("Model") then
		-- Model subjects are expected to have a PrimaryPart to determine orientation
		if cameraSubject.PrimaryPart then
			result = cameraSubject:GetPrimaryPartCFrame()
		else
			result = CFrame.new()
		end
	end

	if result then
		self.lastSubjectCFrame = result
	end

	return result
end

function BaseCamera:GetSubjectVelocity(): Vector3
	local camera = workspace.CurrentCamera
	local cameraSubject = camera and camera.CameraSubject

	if not cameraSubject then
		return ZERO_VECTOR3
	end

	if cameraSubject:IsA("BasePart") then
		return cameraSubject.Velocity

	elseif cameraSubject:IsA("Humanoid") then
		local rootPart = cameraSubject.RootPart

		if rootPart then
			return rootPart.Velocity
		end

	elseif cameraSubject:IsA("Model") then
		local primaryPart = cameraSubject.PrimaryPart

		if primaryPart then
			return primaryPart.Velocity
		end
	end

	return ZERO_VECTOR3
end

function BaseCamera:GetSubjectRotVelocity(): Vector3
	local camera = workspace.CurrentCamera
	local cameraSubject = camera and camera.CameraSubject

	if not cameraSubject then
		return ZERO_VECTOR3
	end

	if cameraSubject:IsA("BasePart") then
		return cameraSubject.RotVelocity

	elseif cameraSubject:IsA("Humanoid") then
		local rootPart = cameraSubject.RootPart

		if rootPart then
			return rootPart.RotVelocity
		end

	elseif cameraSubject:IsA("Model") then
		local primaryPart = cameraSubject.PrimaryPart

		if primaryPart then
			return primaryPart.RotVelocity
		end
	end

	return ZERO_VECTOR3
end

function BaseCamera:StepZoom()
	local zoom: number = self.currentSubjectDistance
	local zoomDelta: number = CameraInput.getZoomDelta()

	if math.abs(zoomDelta) > 0 then
		local newZoom

		if zoomDelta > 0 then
			newZoom = zoom + zoomDelta*(1 + zoom*ZOOM_SENSITIVITY_CURVATURE)
			newZoom = math.max(newZoom, self.FIRST_PERSON_DISTANCE_THRESHOLD)
		else
			newZoom = (zoom + zoomDelta)/(1 - zoomDelta*ZOOM_SENSITIVITY_CURVATURE)
			newZoom = math.max(newZoom, FIRST_PERSON_DISTANCE_MIN)
		end

		if newZoom < self.FIRST_PERSON_DISTANCE_THRESHOLD then
			newZoom = FIRST_PERSON_DISTANCE_MIN
		end

		self:SetCameraToSubjectDistance(newZoom)
	end
	
	return ZoomController.GetZoomRadius()
end

function BaseCamera:GetSubjectPosition(): Vector3
	local result = self.lastSubjectPosition
	local camera = game.Workspace.CurrentCamera
	local cameraSubject = camera and camera.CameraSubject

	if cameraSubject then
		if cameraSubject:IsA("Humanoid") then
			local humanoid = cameraSubject
			local humanoidIsDead = humanoid:GetState() == Enum.HumanoidStateType.Dead

			if VRService.VREnabled and humanoidIsDead and humanoid == self.lastSubject then
				result = self.lastSubjectPosition
			else
				local bodyPartToFollow = humanoid.RootPart

				-- If the humanoid is dead, prefer their head part as a follow target, if it exists
				if humanoidIsDead then
					if humanoid.Parent and humanoid.Parent:IsA("Model") then
						bodyPartToFollow = humanoid.Parent:FindFirstChild("Head") or bodyPartToFollow
					end
				end

				if bodyPartToFollow and bodyPartToFollow:IsA("BasePart") then
					local heightOffset
					if humanoid.RigType == Enum.HumanoidRigType.R15 then
						if humanoid.AutomaticScalingEnabled then
							heightOffset = R15_HEAD_OFFSET
							if bodyPartToFollow == humanoid.RootPart then
								local rootPartSizeOffset = (humanoid.RootPart.Size.Y/2) - (HUMANOID_ROOT_PART_SIZE.Y/2)
								heightOffset = heightOffset + Vector3.new(0, rootPartSizeOffset, 0)
							end
						else
							heightOffset = R15_HEAD_OFFSET_NO_SCALING
						end
					else
						heightOffset = HEAD_OFFSET
					end

					if humanoidIsDead then
						heightOffset = ZERO_VECTOR3
					end

					result = bodyPartToFollow.CFrame.p + bodyPartToFollow.CFrame:vectorToWorldSpace(heightOffset + humanoid.CameraOffset)
				end
			end

		elseif cameraSubject:IsA("VehicleSeat") then
			local offset = SEAT_OFFSET
			if VRService.VREnabled then
				offset = VR_SEAT_OFFSET
			end
			result = cameraSubject.CFrame.p + cameraSubject.CFrame:vectorToWorldSpace(offset)
		elseif cameraSubject:IsA("SkateboardPlatform") then
			result = cameraSubject.CFrame.p + SEAT_OFFSET
		elseif cameraSubject:IsA("BasePart") then
			result = cameraSubject.CFrame.p
		elseif cameraSubject:IsA("Model") then
			if cameraSubject.PrimaryPart then
				result = cameraSubject:GetPrimaryPartCFrame().p
			else
				result = cameraSubject:GetModelCFrame().p
			end
		end
	else
		-- cameraSubject is nil
		-- Note: Previous RootCamera did not have this else case and let self.lastSubject and self.lastSubjectPosition
		-- both get set to nil in the case of cameraSubject being nil. This function now exits here to preserve the
		-- last set valid values for these, as nil values are not handled cases
		return
	end

	self.lastSubject = cameraSubject
	self.lastSubjectPosition = result

	return result
end

function BaseCamera:UpdateDefaultSubjectDistance()
	if self.portraitMode then
		self.defaultSubjectDistance = math.clamp(PORTRAIT_DEFAULT_DISTANCE, player.CameraMinZoomDistance, player.CameraMaxZoomDistance)
	else
		self.defaultSubjectDistance = math.clamp(DEFAULT_DISTANCE, player.CameraMinZoomDistance, player.CameraMaxZoomDistance)
	end
end

function BaseCamera:OnViewportSizeChanged()
	local camera = game.Workspace.CurrentCamera
	local size = camera.ViewportSize
	self.portraitMode = size.X < size.Y
	self.isSmallTouchScreen = UserInputService.TouchEnabled and (size.Y < 500 or size.X < 700)

	self:UpdateDefaultSubjectDistance()
end
