--Menu

function menu( title, ... )
    --edit the background color to make the GUI more unique
        term.setBackgroundColor( colors.black )
        local debug = false --#turn to true to see what it's thinking
        local tArgs = { ... }
        local pages = {[1]={}}
        for i = 1, #tArgs, 1 do
                if #pages[ #pages ] == 7 then
                        pages[ #pages + 1 ] = {}
                end
                pages[ #pages ][ #pages[#pages] + 1 ] = tArgs[ i ]
        end
        local maxLen = 0
        for k, v in ipairs( tArgs ) do
                if #v > maxLen then maxLen = #v end
        end
        local maxx, maxy = term.getSize()
        if maxLen > maxx - 20 then
                error( 'largest string is too large', 2 )
        end
        local centerx = math.ceil( maxx/2 )
        local centery
        local yValue = {}
        local page = 1
        local selected = math.ceil( #pages[ page ] / 2 )
        local function render()
                local tbl = pages[ page ]
                centery = (maxy/2) - #tbl/2
                term.clear()
                term.setCursorPos( centerx - #title/2 + 1, 2 )
                term.write( title )
                for i = 1, #tbl do
                        term.setCursorPos( centerx - (#tbl[i]/2), centery + i )
                        yValue[ i ] = centery + i
                        term.write( tbl[ i ] )
                end
                if pages[ page - 1 ] then
                        term.setCursorPos( 3, centery + #tbl/2 + 1 )
                        term.write( "previous" )
                end
                if pages[ page + 1 ] then
                        term.setCursorPos( maxx - 5, centery + #tbl/2 + 1 )
                        term.write( "next" )
                end
                local str = "(" .. page .. "/" .. #pages .. ")"
                term.setCursorPos( centerx - (#str/2), maxy )
                term.write( str )
        end
        while true do
                render()
                if debug then
                        term.setCursorPos( 1, 1 )
                        term.write( selected )
                        term.setCursorPos( 1, 2 )
                        term.write( page )
                end
                if term.isColor() then
                        term.setTextColor( colors.yellow )
                end
                if selected == "previous" and not pages[ page - 1 ] then
                        selected = math.ceil( #pages[ page ]/2 )
                elseif selected == "next" and not pages[ page + 1 ] then
                        selected = math.ceil( #pages[ page ]/2 )
                end
                if type( selected ) == "number" then
                        term.setCursorPos( centerx - (#pages[page][selected]/2) - 3, yValue[ selected ] )
                        term.write( "[" )
                        term.setCursorPos( centerx + (#pages[page][selected]/2) + 2, yValue[ selected ] )
                        term.write( "]" )
                elseif selected == "previous" then
                        term.setCursorPos( 1, centery + #pages[ page ]/2 + 1 )
                        term.write( "[" )
                        term.setCursorPos( 12, centery + #pages[ page ]/2 + 1 )
                        term.write( "]" )
                elseif selected == "next" then
                        term.setCursorPos( maxx - 7, centery + #pages[ page ]/2 + 1 )
                        term.write( "[" )
                        term.setCursorPos( maxx, centery + #pages[ page ]/2 + 1 )
                        term.write( "]" )
                end
                if term.isColor() then
                        term.setTextColor( colors.white )
                end
                local event, key = os.pullEvent( "key" )
                local old = selected
                if key == 200 and type( selected ) == "number" and pages[ page ][ selected - 1 ] then
                        selected = selected - 1
                elseif key == 208 and type( selected ) == "number" and pages[ page ][ selected + 1 ] then
                        selected = selected + 1
                elseif key == 28 then
                        if type( selected ) == "number" then
                                return pages[ page ][ selected ]
                        elseif selected == "next" and pages[ page + 1 ] then
                                page = page + 1
                        elseif selected == "previous" and pages[ page - 1 ] then
                                page = page - 1
                        end
                elseif key == 203 then
                        if selected == "next" then
                                selected = math.ceil( #pages[ page ]/2 )
                        elseif type( selected ) == "number" and pages[ page - 1 ] then
                                selected = "previous"
                        end
                elseif key == 205 then
                        if selected == "previous" then
                                selected = math.ceil( #pages[ page ]/2 )
                        elseif type( selected ) == "number" and pages[ page + 1 ] then
                                selected = "next"
                        end
                end
        end
end

--End

print("Welcome to the Immersive Engineering")
print("Construction Program")
print("Press enter to choose your structure...")

repeat
  local event, key = os.pullEvent("key")
until key == keys.enter

local structure = menu("Choose a Structure", 'Harvester', 'Crusher', 'Diesel Gen', 'Coke Oven',
'Crude Blast Furnace', 'Improved Blast Furnace', 'Industrial Squeezer', 'Fermenter', 'Refinery',
'Arc Furnace', 'Excavator', 'Assembler', 'Bottling Machine', 'Metal Press' )

	term.clear()
	term.setCursorPos(1,1)

	if selection == "Harvester" then
		shell.run("harvester")
	end

	elseif selection == "Crusher" then
		shell.run("crusher")
	end

	elseif selection == "Diesel Gen" then
		shell.run("diesGen")
	end

	elseif selection == "Coke Oven" then
		shell.run("cokeOven")
	end

	elseif selection == "Crude Blast Furnace" then
		shell.run("crudeBlast")
	end

	elseif selection == "Improved Blast Furnace" then
		shell.run("impBlast")
	end

	elseif selection == "Industrial Squeezer" then
		shell.run("indSqueezer")
	end

	elseif selection == "Fermenter" then
		shell.run("fermenter")
	end

	elseif selection == "Arc Furnace" then
		shell.run("arcFurnace")
	end

	elseif selection == "Excavator" then
		shell.run("excavator")
	end

	elseif selection == "Assembler" then
		shell.run("assembler")
	end

	elseif selection == "Bottling Machine" then
		shell.run("bottleMach")
	end

	elseif selection == "Refinery" then
		shell.run("refinery")
	end

	elseif selection == "Metal Press" then
		shell.run("metalPress")
	end