CCGUI

local mSel = 1
local l = 1
local flag = false
local rsType,rtData
local w,h = term.getSize()

local defaultColourSet = {
	overlayHF = colours.grey;
	overlayBack = colours.black;
	overlayText = colours.white;
	menuItem = colours.white;
	msgBoxText = colours.white;
	msgBoxBack = colours.grey;
	inpBoxText = colours.white;
	inpBoxBack  = colours.grey;
	inpBoxInput = colours.orange;
}
local defaultTextSet ={
	overlayHeaderText = {"Menu"};
	overlayFooterText = {"Lift by Spenk96"};
	itemName = "Default";
}

function defineDefaultColour(overlayHF,overlayBack,overlayText,menuItem,msgBoxText,msgBoxBack,inpBoxText,inpBoxBack,inpBoxInput)
	defaultColourSet.overlayHF = overlayHF
	defaultColourSet.overlayBack = overlayBack
	defaultColourSet.overlayText = overlayText
	defaultColourSet.menuItem = menuItem
	defaultColourSet.msgBoxText = msgBoxText
	defaultColourSet.msgBoxBack = msgBoxBack
	defaultColourSet.inpBoxText = inpBoxText
	defaultColourSet.inpBoxBack = inpBoxBack
	defaultColourSet.inpBoxInput = inpBoxInput
end
function defineDefaultColourTable(tColours)
	defaultColourSet = tColours
end
function defineDefaultValues(HeaderText, FooterText, MenuItem)
	defaultTextSet.overlayHeaderText = HeaderText
	defaultTextSet.overlayFooterText = FooterText
	defaultTextSet.itemName = MenuItem
end

function isInteger(nIn)
	if math.floor(nIn) == nIn then return true
	else return false end
end
function printCentred(str , h)
	term.setCursorPos(w/2 - #str/2, h)
	term.write(str)
end
function printRight(str , h)
	term.setCursorPos(w - #str, h)
	term.write(str)
end
function printLeft(str , h)
	term.setCursorPos(1, h)
	term.write(str)
end

function reduceMenu(height, head, foot)
	return math.floor(math.floor(height - head - foot -1)/2)
end

--Presenting the Menu--

function drawMenu(tMenu)
	l = 0
	if #tMenu.tItems > tMenu.iMenuLen then l = tMenu.iMenuLen
	else l = #tMenu.tItems end
	local j = 4
	term.setBackgroundColour(tMenu.tOverlay.cOverlayBackground)
	for i = tMenu.iFItem, l+tMenu.iFItem-1 do
		if tMenu.tItems[i] then
			term.setTextColour(tMenu.tItems[i].nColour)
			printCentred(tMenu.tItems[i].sDisp, j)
			j = j +2
		end
	end

	term.setTextColour(tMenu.tItems[tMenu.iCursorPos].nColour)
	local selpos = tMenu.iRSel*2 + 2
	printCentred("[  "..tMenu.tItems[tMenu.iCursorPos].sDisp.."  ]", selpos)
	term.setBackgroundColour(tMenu.tOverlay.cOverlayColour)



end

function reDraw(tMenu)
	tMenu:draw()
end

-- Display functions --


function msgBox(tMsg)
	term.setTextColour(defaultColourSet.msgBoxText)
	term.setBackgroundColour(defaultColourSet.msgBoxBack)
	assert(type(tMsg)=="table", "Message Box must contain a table")
	local tStrLen = {}
	for i,v in ipairs(tMsg) do
		tStrLen[i] = #v
	end
	local boxHeight = #tMsg
	local boxWidth = math.max(unpack(tStrLen)) +2
	printCentred("+"..string.rep("-",boxWidth).."+", math.floor(h/2 -boxHeight/2))
	for i = math.floor(h/2 -boxHeight/2)+1, math.floor(h/2 +boxHeight/2) do
		printCentred("I"..string.rep(" ",boxWidth).."I", i)
	end
	printCentred("+"..string.rep("-",boxWidth).."+", math.floor(h/2 +boxHeight/2)+1)
	printCentred("{[ENTER]}", math.floor(h/2 +boxHeight/2)+1)
	local j = 1
	for i = math.floor(h/2 -boxHeight/2)+1, math.floor(h/2 +boxHeight/2) do
		printCentred(tMsg[j], i)
		j = j+1
	end
	do sleep(5); end
end


function inpBox(tMsg)
	term.setTextColour(defaultColourSet.inpBoxText)
	term.setBackgroundColour(defaultColourSet.inpBoxBack)
	assert(type(tMsg)=="table", "Message Box must contain a table")
	local tStrLen = {}
	for i,v in ipairs(tMsg) do
		tStrLen[i] = #v
	end
	local boxHeight = #tMsg
	local boxWidth = math.max(unpack(tStrLen)) +2
	printCentred("+"..string.rep("-",boxWidth).."+", math.floor(h/2 -boxHeight/2))
	for i = math.floor(h/2 -boxHeight/2)+1, math.floor(h/2 +boxHeight/2)+1 do
		printCentred("I"..string.rep(" ",boxWidth).."I", i)
	end
	printCentred("+"..string.rep("-",boxWidth).."+", math.floor(h/2 +boxHeight/2)+2)
	printCentred("{[ENTER]}", math.floor(h/2 +boxHeight/2)+2)
	local j = 1
	for i = math.floor(h/2 -boxHeight/2)+1, math.floor(h/2 +boxHeight/2) do
		printCentred(tMsg[j], i)
		j = j+1
	end
	term.setCursorPos((w-boxWidth)/2+1, (h+boxHeight)/2+1)
	term.setTextColour(defaultColourSet.inpBoxInput)
	return read()
end

-- The API functions --

function newOverlay()
	local tOverlay = {
		nHeadLen = 2;
		nFootLen = 2;
		cOverlayColour = defaultColourSet.overlayText;
		cOverlayBackground = defaultColourSet.overlayBack;
		cOverlayHF = defaultColourSet.overlayHF;
		tTitle = defaultTextSet.overlayHeaderText;
		tFoot = defaultTextSet.overlayFooterText;
		setHeaderTitle = function(self,...)
			if arg.n < h then
				self.tTitle = {}
				for i,v in ipairs(arg) do
					table.insert(self.tTitle, v)
				end
				self.nHeadLen = arg.n+1
			else error("Too Many Lines to set Header Title") end
		end;
		setFooterText = function(self,...)
			if arg.n < h then
				self.tFoot = {}
				for i,v in ipairs(arg) do
					table.insert(self.tFoot, v)
				end
				self.nFootLen = arg.n +1
			else error("Too Many Lines to set Footer text") end
		end;
		setOverlayColour = function(self, colour)
			self.cOverlayColour = colour
		end;
		setBackgroundColour = function(self, colour)
			self.cOverlayBackground = colour
		end;
		setBackgroundHF = function(self, colour)
			self.cOverlayHF = colour
		end;
		draw = function(self)
			term.setBackgroundColour(self.cOverlayBackground)
			term.clear()
			term.setBackgroundColour(self.cOverlayHF)
			term.setTextColour(self.cOverlayColour)

			for i,v in ipairs(self.tTitle) do
				term.setCursorPos(1,i)
				term.clearLine()
				printCentred(v, i)
			end
			printLeft(string.rep("-",w),self.nHeadLen)
			printLeft(string.rep("-",w),h-self.nFootLen+1)
			for i,v in ipairs(self.tFoot) do
				term.setCursorPos(1,h-i+1)
				term.clearLine()
				printRight(v, h - i +1)
			end
			term.setTextColour(1)
			term.setBackgroundColour(colours.black)
		end;
	}
	return tOverlay
end

function newItem()
	local tItem = {
		sDisp = defaultTextSet.itemName;
		sType = "text";
		nColour = defaultColourSet.menuItem;
		tData = {};
		newName = function(self, sName)
			self.sDisp = sName
		end;
		newType = function(self, sType)
			self.sType = sType
		end;
		newColour = function(self, nColour)
			self.nColour = nColour
		end;
		newColor = function(self, nColour)
			self.nColour = nColour
		end;
		setData = function(self, tData)
			self.tData = tData
		end;
		addData = function(self, aData)
			table.insert(self.tData, aData)
		end;
	}
	return tItem
end

function newMenu()
	local tMenu = {
		tOverlay = newOverlay();
		tItems = {};
		iCursorPos = 1;
		iFItem = 1;
		iRSel = 1;
		iMenuLen = 0;
		newOverlay = function(self, tOver)
			self.tOverlay = tOver
		end;
		resetItems = function(self) self.tItems = {} end;
		newItem = function(self, tItem) table.insert(self.tItems, tItem) end;
		checkSel = function(self)
			if self.iRSel > self.iMenuLen -1 and self.iCursorPos<#self.tItems then
				self.iRSel = self.iRSel -1
				self.iFItem = self.iFItem+1
			elseif self.iRSel == 1 and self.iCursorPos > 1 then
				self.iRSel = self.iRSel +1
				self.iFItem = self.iFItem -1
			end
		end;
		draw = function(self)
			local id
			local key
			local param2
			local param3
			flag = false
			while true do
				if not flag then
					self.tOverlay:draw()
					drawMenu(self)
					do sleep(0.02); id, key, param2, param3 = os.pullEvent(); repeat until id == "key" or id =="mouse_click" or id == "mouse_scroll" end
					if id == "key" then
						if key == 200 and self.iCursorPos > 1 then self.iCursorPos = self.iCursorPos-1 ; self.iRSel=self.iRSel-1 ; self:checkSel();
						elseif key == 208 and self.iCursorPos < #self.tItems then self.iCursorPos = self.iCursorPos + 1 ; self.iRSel = self.iRSel +1 ; self:checkSel();
						elseif key == 28 then
							if self.tItems[self.iCursorPos].sType == "menu" then reDraw(self.tItems[self.iCursorPos].tData[1])
							elseif self.tItems[self.iCursorPos].sType == "text" then
							elseif self.tItems[self.iCursorPos].sType == "msgbox" then msgBox(self.tItems[self.iCursorPos].tData);
							else rsType,rtData = self.tItems[self.iCursorPos].sType,self.tItems[self.iCursorPos].tData flag = true; break end
						end
					elseif id =="mouse_click" then
						local mSel = param3/2 -1
						if isInteger(mSel) and key == 1 and mSel <= l then  self.iCursorPos = mSel+self.iFItem -1; self.iRSel=mSel;
							if self.tItems[self.iCursorPos].sType == "menu" then reDraw(self.tItems[self.iCursorPos].tData[1])
							elseif self.tItems[self.iCursorPos].sType == "text" then
							elseif self.tItems[self.iCursorPos].sType == "msgbox" then msgBox(self.tItems[self.iCursorPos].tData);
							else rsType,rtData = self.tItems[self.iCursorPos].sType,self.tItems[self.iCursorPos].tData flag = true; break end
						end
					elseif id =="mouse_scroll" then
						if key == -1 and self.iFItem > 1 then self.iFItem = self.iFItem-1 ; self.iCursorPos=self.iCursorPos-1 ; self:checkSel() ;
						elseif key == -1 and self.iFItem == 1 and self.iCursorPos > 1 then self.iCursorPos = self.iCursorPos - 1 ; self.iRSel = self.iRSel -1 ;
						elseif key == 1 and self.iFItem +l -1< #self.tItems then self.iCursorPos = self.iCursorPos + 1 ; self.iFItem = self.iFItem+1 ; self:checkSel() ;
						elseif key == 1 and self.iFItem +l-1 >= #self.tItems and self.iCursorPos < #self.tItems then self.iCursorPos = self.iCursorPos + 1 ; self.iRSel = self.iRSel +1;
						end
					end
				else break end
			end
			return rsType, rtData
		end;
	}
	tMenu.iMenuLen = reduceMenu(h, tMenu.tOverlay.nHeadLen, tMenu.tOverlay.nFootLen)
	return tMenu
end