function checkDir(path)
    fileCount = 0
    fileTable = fs.list(path)
    for i = 1, 100 do
        if fileTable[i] == nil then
        else
            fileCount = fileCount + 1
        end
    end
end

function updateMenu(menuName)
    checkDir("OS/"..menuName)
    fs.delete("OS/menus/"..menuName)
    update = fs.open("OS/menus/"..menuName, "w")
    update.writeLine(fileCount)
    for i = 1, fileCount do
        update.writeLine(tostring(fileTable[i]))
    end
    update.close()
end

function getMax()
    data = fs.open("OS/menus/menuData")
    maxEntries = data.readLine()
    data.close()
    return(maxEntries)
end

function getMaxLen(filePath)
    maxLen = 0
    data = fs.open(filePath)
    maxEntries = getMax()
    for i = 1, maxEntries do
        x = string.len(data.readLine())
  	    	if x > maxLen then
		          maxLen = x
    	   end
    end
   	return(maxLen)
end

--File writing with modifier to allow different function calls.
function edit(filePath, message, modifier)
    --no modifier will write a block of code to a file
    if modifier == nil then
        data = fs.open(filePath, "w")
        data.write(message)
        data.close()
	   --"Line" modifier will write a line of code to a file
	   elseif modifier == "line" or modifier == "l" or modifier == "Line" or modifier == "L" then
	       data = fs.open(filePath, "w")
        data.writeLine(message.."\n")
        data.close()
	   --"Pre" modifier adds a line of text to the beginning of a file
   	elseif modifier == "pre" or modifier == "p" or modifier == "Pre" or modifier == "P" then
  		    if fs.exists(filePath) then
         			existingData = readFile(filePath)
         			data = fs.open(filePath, "w")
         			data.writeLine(message.."\n")
       	  		data.write(existingData)
       			  data.close()
   	    else
	      	    data = fs.open(filePath, "w")
         			data.writeLine(message.."\n")
      		   	data.write(existingData)
         			data.close()
      		end
	   --"Add" modifier will write a line of text on the end of a file
   	elseif modifier == "add" or modifier == "a" or modifier == "Add" or modifier == "A" then
      		if fs.exists(filePath) then
     	    		existingData = readFile(filePath)
    	     		data = fs.open(filePath, "w")
			         data.write(existingData)
         			data.writeLine(message.."\n")
         			data.close()
       	else
		          data = fs.open(filePath, "w")
     	    		data.writeLine(message.."\n")
         			data.close()
      		end
	   --"Merge" modifier will add a block of code to the end of a file
   	elseif modifier == "merge" or modifier == "m" or modifier == "Merge" or modifier == "M" then
	       if fs.exists(filePath) then
         			existingData = readFile(filePath)
         			data = fs.open(filePath, "w")
         			data.write(existingData)
         			data.write(message)
         			data.close()
     		else
		          data = fs.open(filePath, "w")
         			data.write(message)
         			data.close()
     		end
   	end
end

--File reading with modifier to allow different function calls.
function readFile(filePath, modifier)
    --no modifier returns all of a file as a string
    if modifier == nil then
      		data = fs.open(filePath, "r")
      		fileData = data.readAll()
      		data.close()
      		return(fileData)
	   --"Line" modifier returns the first line of a file
   	elseif modifier == "line" or modifier == "l" or modifier == "Line" or modifier == "L" then
	       data = fs.open(filePath, "r")
      		fileData = data.readLine()
      		data.close()
      		return(fileData)
	   --"End" modifier returns the last line of a file
   	elseif modifier == "end" or modifier == "e" or modifier == "End" or modifier == "E" then
	       data = fs.open(filePath, "r")
      		line = 0
      		while true do
         			if fileData == nil then
         			    break
         			end
      		    line = data.readLine()
      		end
      		data.close()
   	    return(fileData)
   	end
end