--!strict
--[=[
	Utility functions for Hoarcekat stories.
	@class CameraStoryUtils
]=]

local require = require(script.Parent.loader).load(script)

local RunService = game:GetService("RunService")
local TextService = game:GetService("TextService")

local Maid = require("Maid")
local Math = require("Math")
local Promise = require("Promise")
local RenderCrateUtils = require("RenderCrateUtils")

local CameraStoryUtils = {}

--[=[
	Reflects the camera state to the original camera
	@param maid Maid
	@param topCamera Camera
	@return Camera
]=]
function CameraStoryUtils.reflectCamera(maid: Maid.Maid, topCamera: Camera): Camera
	local camera = Instance.new("Camera")
	camera.Name = "ReflectedCamera"
	maid:GiveTask(camera)

	local function update()
		camera.FieldOfView = topCamera.FieldOfView
		camera.CFrame = topCamera.CFrame
	end
	maid:GiveTask(topCamera:GetPropertyChangedSignal("CFrame"):Connect(update))
	maid:GiveTask(topCamera:GetPropertyChangedSignal("FieldOfView"):Connect(update))

	update()

	return camera
end

--[=[
	Sets up a viewport frame
	@param maid Maid
	@param target GuiBase
	@return ViewportFrame
]=]
function CameraStoryUtils.setupViewportFrame(maid: Maid.Maid, target: GuiBase)
	local viewportFrame = Instance.new("ViewportFrame")
	viewportFrame.ZIndex = 0
	viewportFrame.BorderSizePixel = 0
	viewportFrame.BackgroundColor3 = Color3.new(0.9, 0.9, 0.85)
	viewportFrame.Size = UDim2.fromScale(1, 1)
	maid:GiveTask(viewportFrame)

	local reflectedCamera = CameraStoryUtils.reflectCamera(maid, workspace.CurrentCamera)
	reflectedCamera.Parent = viewportFrame
	viewportFrame.CurrentCamera = reflectedCamera

	viewportFrame.Parent = target

	return viewportFrame
end

--[=[
	Returns a promise that resolves to a crate in front of the camera.
	@param maid Maid
	@param viewportFrame ViewportFrame
	@param properties { [string}: any }
	@return Promise<Instance>
]=]
function CameraStoryUtils.promiseCrate(
	maid: Maid.Maid,
	viewportFrame: ViewportFrame?,
	properties: { [string]: any }?
): Promise.Promise<Instance>
	local promise = maid:GivePromise(Promise.new())

	maid:GiveTask(RenderCrateUtils.crate():Subscribe(function(crate)
		promise:Resolve(crate)
	end))

	return promise:Then(function(crate)
		if properties then
			for _, item in crate:GetDescendants() do
				if item:IsA("BasePart") then
					for property, value in properties do
						item[property] = value
					end
				end
			end
		end

		if viewportFrame then
			crate.Parent = viewportFrame

			local camera = viewportFrame.CurrentCamera
			if camera then
				local cameraCFrame = camera.CFrame
				local cframe = CFrame.new(cameraCFrame.Position + cameraCFrame.LookVector * 25)
				crate:SetPrimaryPartCFrame(cframe)
			end
		end

		return Promise.resolved(crate)
	end)
end

--[=[
	Retrieves the interpolation
	@param maid Maid
	@param viewportFrame ViewportFrame
	@param low number
	@param high number
	@param period number
	@param toCFrame CFrame
	@return (interpolate: function, color: Color3, label: string?, labelOffset: Vector2?) -> ()
]=]
function CameraStoryUtils.getInterpolationFactory(
	maid: Maid.Maid,
	viewportFrame: ViewportFrame,
	low: number,
	high: number,
	period: number,
	toCFrame: CFrame
)
	assert(maid, "Bad maid")
	assert(viewportFrame, "Bad viewportFrame")
	assert(type(low) == "number", "Bad low")
	assert(type(high) == "number", "Bad high")
	assert(type(period) == "number", "Bad period")
	assert(type(toCFrame) == "function", "Bad toCFrame")

	return function(interpolate, color, labelText, labelOffset)
		assert(type(interpolate) == "function", "Bad interpolate")
		assert(typeof(color) == "Color3", "Bad color")

		labelOffset = labelOffset or Vector2.zero

		maid:GivePromise(CameraStoryUtils.promiseCrate(maid, viewportFrame, {
			Color = color,
			Transparency = 0.5,
		})):Then(function(crate)
			local label
			if labelText then
				local h, s, _ = Color3.toHSV(color)
				label = Instance.new("TextLabel")
				label.AnchorPoint = Vector2.new(0.5, 0.5)
				label.Text = labelText
				label.BorderSizePixel = 0
				label.BackgroundTransparency = 0.5
				label.BackgroundColor3 = Color3.fromHSV(h, math.clamp(s / (s + 0.1), 0, 1), 0.25)
				label.TextColor3 = Color3.new(1, 1, 1)
				label.Font = Enum.Font.FredokaOne
				label.TextSize = 15
				label.Parent = viewportFrame
				label.Visible = false
				maid:GiveTask(label)

				local size = TextService:GetTextSize(labelText, label.TextSize, label.Font, Vector2.new(1e6, 1e6))
				label.Size = UDim2.fromOffset(size.x + 20, 20)

				local uiCorner = Instance.new("UICorner")
				uiCorner.CornerRadius = UDim.new(0.5, 0)
				uiCorner.Parent = label
				maid:GiveTask(label)
			end

			-- avoid floating point numbers from :SetPrimaryPartCFrame
			local primaryPart, primaryCFrame
			local relCFrame = {}
			for _, part in crate:GetDescendants() do
				if part:IsA("BasePart") then
					if primaryPart then
						relCFrame[part] = primaryCFrame:toObjectSpace(part.CFrame)
					else
						primaryPart = part
						primaryCFrame = part.CFrame
						relCFrame[part] = CFrame.new()
					end
				end
			end

			maid:GiveTask(RunService.RenderStepped:Connect(function()
				local t = (os.clock() / period % 2 / period) * period
				if t >= 1 then
					t = 1 - (t % 1)
				end

				t = Math.map(t, 0, 1, low, high)
				t = math.clamp(t, low, high)

				local cframe = toCFrame(interpolate(t))

				if label then
					local camera = viewportFrame.CurrentCamera
					local pos = camera:WorldToViewportPoint(cframe.p)
					local viewportSize = viewportFrame.AbsoluteSize
					local aspectRatio = viewportSize.X / viewportSize.Y
					if pos.Z > 0 then
						label.Position =
							UDim2.new((pos.X - 0.5) / aspectRatio + 0.5, labelOffset.X, pos.Y, 0 + labelOffset.Y)
						label.Visible = true
					else
						label.Visible = false
					end
				end

				for part, rel in relCFrame do
					part.CFrame = cframe:toWorldSpace(rel)
				end
			end))
		end)
	end
end

return CameraStoryUtils