while game == nil do
	wait(1 / 30)
end

local ChangeHistoryService = game:GetService "ChangeHistoryService"
local CoreGui = game:GetService "CoreGui"

---------------
--PLUGIN SETUP-
---------------
local loaded = false
-- True if the plugin is on, false if not.
local on = false

local On, Off

local plugin = PluginManager():CreatePlugin()
local mouse = plugin:GetMouse()
mouse.Button1Down:connect(function()
	onClicked(mouse)
end)
local toolbar = plugin:CreateToolbar "Terrain"
local toolbarbutton = toolbar:CreateButton("Builder", "Builder", "builder.png")
toolbarbutton.Click:connect(function()
	if on then
		Off()
	elseif loaded then
		On()
	end
end)

game:WaitForChild "Workspace"
game.Workspace:WaitForChild "Terrain"

local c = game.Workspace.Terrain
local SetCell = c.SetCell
local GetCell = c.GetCell
local WorldToCellPreferSolid = c.WorldToCellPreferSolid
local CellCenterToWorld = c.CellCenterToWorld
local AutoWedge = c.AutowedgeCells
local WorldToCellPreferEmpty = c.WorldToCellPreferEmpty
local GetWaterCell = c.GetWaterCell
local SetWaterCell = c.SetWaterCell

-----------------
--DEFAULT VALUES-
-----------------

-- Stores selection properties.
local selectionProps = {}
selectionProps.isWater = nil -- True if what will be built is water.
selectionProps.waterForce = nil -- Water force.
selectionProps.waterDirection = nil -- Water direction.
selectionProps.terrainMaterial = 0 -- Terrain material to use

-- What color to use for the mouse highlighter.
local mouseHighlightColor = BrickColor.new "Lime green"

-- Used to create a highlighter that follows the mouse.
-- It is a class mouse highlighter.  To use, call MouseHighlighter.Create(mouse) where mouse is the mouse to track.
local MouseHighlighter = {}
MouseHighlighter.__index = MouseHighlighter

local PlaneIntersection, UpdatePosition

-- Create a mouse movement highlighter.
-- plugin - Plugin to get the mouse from.
function MouseHighlighter.Create(mouseUse)
	local highlighter = {}

	local mouseH = mouseUse
	highlighter.OnClicked = nil
	highlighter.mouseDown = false

	-- Store the last point used to draw.
	highlighter.lastUsedPoint = nil

	-- Will hold a part the highlighter will be attached to.  This will be moved where the mouse is.
	highlighter.selectionPart = nil

	-- Function to call when the mouse has moved.  Updates where to display the highlighter.
	local function MouseMoved()
		if on then
			UpdatePosition(mouseH.Hit)
		end
	end

	-- Hook the mouse up to check for movement.
	mouseH.Move:connect(function()
		MouseMoved()
	end)

	mouseH.Button1Down:connect(function()
		highlighter.mouseDown = true
	end)
	mouseH.Button1Up:connect(function()
		highlighter.mouseDown = false
	end)

	-- Create the part that the highlighter will be attached to.
	highlighter.selectionPart = Instance.new "Part"
	highlighter.selectionPart.Name = "SelectionPart"
	highlighter.selectionPart.Archivable = false
	highlighter.selectionPart.Transparency = 1
	highlighter.selectionPart.Anchored = true
	highlighter.selectionPart.Locked = true
	highlighter.selectionPart.CanCollide = false
	highlighter.selectionPart.FormFactor = Enum.FormFactor.Custom

	highlighter.selectionBox = Instance.new "SelectionBox"
	highlighter.selectionBox.Archivable = false
	highlighter.selectionBox.Color = mouseHighlightColor
	highlighter.selectionBox.Adornee = highlighter.selectionPart
	mouseH.TargetFilter = highlighter.selectionPart
	setmetatable(highlighter, MouseHighlighter)

	-- Do a line/plane intersection.  The line starts at the camera.  The plane is at y == 0, normal(0, 1, 0)
	--
	-- vectorPos - End point of the line.
	--
	-- Return:
	-- success - Value is true if there was a plane intersection, false if not.
	-- cellPos - Value is the terrain cell intersection point if there is one, vectorPos if there isn't.
	PlaneIntersection = function(vectorPos)
		local currCamera = game.Workspace.CurrentCamera
		local startPos = Vector3.new(
			currCamera.CoordinateFrame.p.X,
			currCamera.CoordinateFrame.p.Y,
			currCamera.CoordinateFrame.p.Z
		)
		local endPos = Vector3.new(vectorPos.X, vectorPos.Y, vectorPos.Z)
		local normal = Vector3.new(0, 1, 0)
		local p3 = Vector3.new(0, 0, 0)
		local startEndDot = normal:Dot(endPos - startPos)
		local cellPos = vectorPos
		local success = false

		if startEndDot ~= 0 then
			local t = normal:Dot(p3 - startPos) / startEndDot
			if t >= 0 and t <= 1 then
				local intersection = ((endPos - startPos) * t) + startPos
				cellPos = c:WorldToCell(intersection)
				success = true
			end
		end

		return success, cellPos
	end

	-- Update where the highlighter is displayed.
	-- position - Where to display the highlighter, in world space.
	UpdatePosition = function(position)
		if not position then
			return
		end

		-- NOTE:
		-- Change this gui to be the one you want to use.
		highlighter.selectionBox.Parent = CoreGui

		local vectorPos = Vector3.new(position.x, position.y, position.z)
		local cellPos = WorldToCellPreferEmpty(c, vectorPos)
		local solidCell = WorldToCellPreferSolid(c, vectorPos)
		local success = false

		-- If nothing was hit, do the plane intersection.
		if 0 == GetCell(c, solidCell.X, solidCell.Y, solidCell.Z).Value then
			success, cellPos = PlaneIntersection(vectorPos)
			if not success then
				cellPos = solidCell
			end
		else
			highlighter.lastUsedPoint = cellPos
		end

		local regionToSelect

		local lowVec = CellCenterToWorld(c, cellPos.x, cellPos.y - 1, cellPos.z)
		local highVec =
			CellCenterToWorld(c, cellPos.x, cellPos.y + 1, cellPos.z)
		regionToSelect = Region3.new(lowVec, highVec)

		highlighter.selectionPart.Size = regionToSelect.Size
			- Vector3.new(-4, 4, -4)
		highlighter.selectionPart.CFrame = regionToSelect.CFrame

		if nil ~= highlighter.OnClicked and highlighter.mouseDown then
			if nil == highlighter.lastUsedPoint then
				highlighter.lastUsedPoint = WorldToCellPreferEmpty(
					c,
					Vector3.new(mouseH.Hit.x, mouseH.Hit.y, mouseH.Hit.z)
				)
			else
				cellPos = WorldToCellPreferEmpty(
					c,
					Vector3.new(mouseH.Hit.x, mouseH.Hit.y, mouseH.Hit.z)
				)
			end
		end
	end

	return highlighter
end

-- Hide the highlighter.
function MouseHighlighter:DisablePreview()
	self.selectionBox.Parent = nil
end

-- Show the highlighter.
function MouseHighlighter:EnablePreview()
	self.selectionBox.Parent = CoreGui -- This will make it not show up in workspace.
end

-- Create the mouse movement highlighter.
local mouseHighlighter = MouseHighlighter.Create(mouse)
mouseHighlighter:DisablePreview()

-- Create a standard text label.  Use this for all lables in the popup so it is easy to standardize.
-- labelName - What to set the text label name as.
-- pos    	 - Where to position the label.  Should be of type UDim2.
-- size   	 - How large to make the label.	 Should be of type UDim2.
-- text   	 - Text to display.
-- parent 	 - What to set the text parent as.
-- Return:
-- Value is the created label.
function CreateStandardLabel(labelName, pos, size, text, parent)
	local label = Instance.new "TextLabel"
	label.Name = labelName
	label.Position = pos
	label.Size = size
	label.Text = text
	label.TextColor3 = Color3.new(0.95, 0.95, 0.95)
	label.Font = Enum.Font.ArialBold
	label.FontSize = Enum.FontSize.Size14
	label.TextXAlignment = Enum.TextXAlignment.Left
	label.BackgroundTransparency = 1
	label.Parent = parent

	return label
end

------
--GUI-
------
--screengui
local g = Instance.new "ScreenGui"
g.Name = "BuilderGui"
g.Parent = CoreGui

-- UI gui load.  Required for sliders.
local RbxGui = LoadLibrary "RbxGui"

-- Store properties here.
local properties = { autoWedgeEnabled = false }

-- Gui frame for the plugin.
local builderPropertiesDragBar, builderFrame, builderHelpFrame, builderCloseEvent =
	RbxGui.CreatePluginFrame(
		"Builder",
		UDim2.new(0, 123, 0, 40),
		UDim2.new(0, 0, 0, 0),
		false,
		g
	)
builderPropertiesDragBar.Visible = false
builderCloseEvent.Event:connect(function()
	Off()
end)

builderHelpFrame.Size = UDim2.new(0, 160, 0, 85)

local builderHelpText = Instance.new "TextLabel"
builderHelpText.Name = "HelpText"
builderHelpText.Font = Enum.Font.ArialBold
builderHelpText.FontSize = Enum.FontSize.Size12
builderHelpText.TextColor3 = Color3.new(227 / 255, 227 / 255, 227 / 255)
builderHelpText.TextXAlignment = Enum.TextXAlignment.Left
builderHelpText.TextYAlignment = Enum.TextYAlignment.Top
builderHelpText.Position = UDim2.new(0, 4, 0, 4)
builderHelpText.Size = UDim2.new(1, -8, 0, 177)
builderHelpText.BackgroundTransparency = 1
builderHelpText.TextWrap = true
builderHelpText.Text = [[
Clicking terrain adds a single block into the selection box shown. The terrain material and type will be the same as the cell that was clicked on.]]
builderHelpText.Parent = builderHelpFrame

CreateStandardLabel(
	"AddText",
	UDim2.new(0, 8, 0, 10),
	UDim2.new(0, 67, 0, 14),
	"Click to add terrain.",
	builderFrame
)

-- Function to connect to the mouse button 1 down event.  This is what will run when the user clicks.
-- Adding and autowedging done here.
-- mouse 	- Mouse data.
function onClicked(mouseC)
	if on then
		local cellPos = WorldToCellPreferEmpty(
			c,
			Vector3.new(mouseC.Hit.x, mouseC.Hit.y, mouseC.Hit.z)
		)
		local x = cellPos.x
		local y = cellPos.y
		local z = cellPos.z

		local solidCellPos = WorldToCellPreferSolid(
			c,
			Vector3.new(mouseC.Hit.x, mouseC.Hit.y, mouseC.Hit.z)
		)

		local celMat =
			GetCell(c, solidCellPos.x, solidCellPos.y, solidCellPos.z)
		local success = false

		if celMat.Value > 0 then
			selectionProps.terrainMaterial = celMat.Value
			selectionProps.isWater, selectionProps.waterForce, selectionProps.waterDirection =
				GetWaterCell(c, solidCellPos.X, solidCellPos.Y, solidCellPos.Z)
		else
			if 0 == selectionProps.terrainMaterial then
				-- It was nothing, give it a default type and the plane intersection.
				selectionProps.isWater = false
				selectionProps.terrainMaterial = 1
			end

			success, cellPos = PlaneIntersection(
				Vector3.new(mouseC.Hit.x, mouseC.Hit.y, mouseC.Hit.z)
			)
			if not success then
				cellPos = solidCellPos
			end

			x = cellPos.x
			y = cellPos.y
			z = cellPos.z
		end

		if selectionProps.isWater and 17 == selectionProps.terrainMaterial then
			SetWaterCell(
				c,
				x,
				y,
				z,
				selectionProps.waterForce,
				selectionProps.waterDirection
			)
		else
			SetCell(c, x, y, z, selectionProps.terrainMaterial, 0, 0)
		end

		if properties.autoWedgeEnabled then
			AutoWedge(
				c,
				Region3int16.new(
					Vector3int16.new(x - 1, y - 1, z - 1),
					Vector3int16.new(x + 1, y + 1, z + 1)
				)
			)
		end

		-- Mark undo point.
		ChangeHistoryService:SetWaypoint "Builder"

		UpdatePosition(mouseC.Hit)
	end
end

mouseHighlighter.OnClicked = onClicked

-- Run when the popup is activated.
On = function()
	if not c then
		return
	end
	plugin:Activate(true)
	toolbarbutton:SetActive(true)
	builderPropertiesDragBar.Visible = true
	on = true
end

-- Run when the popup is deactivated.
Off = function()
	toolbarbutton:SetActive(false)
	on = false

	-- Hide the popup gui.
	builderPropertiesDragBar.Visible = false
	mouseHighlighter:DisablePreview()
end

plugin.Deactivation:connect(function()
	Off()
end)

loaded = true