Color API for Shell

local textColorBuffer = colors.white -- The color that is currently being used for the default text color.
local backgroundColorBuffer = colors.black -- The color that is currently being used for the default background color.
-- Set the text and background colors to their defaults.
term.setTextColor(textColorBuffer)
term.setBackgroundColor(backgroundColorBuffer)

-- Sets the  cursor to the given position and the text and background colors if provided, then
-- writes the text to the screen.
function positionAndWrite(xPos, yPos, text, textColor, backgroundColor)
      term.setCursorPos(xPos, yPos)
      term.setTextColor(isColorValid(textColor) or textColorBuffer)
      term.setBackgroundColor(isColorValid(backgroundColor) or backgroundColorBuffer)
      term.write(text)
end

-- Writes the given text to the screen with the given text and background colors.
function writeWithColor(text, textColor, backgroundColor)
      term.setTextColor(isColorValid(textColor) or textColorBuffer)
      term.setBackgroundColor(isColorValid(backgroundColor) or backgroundColorBuffer)
      term.write(text)
end

-- Returns the color given if it is valid, and nil if it was false.
function isColorValid(color)
      for index, colorVal in pairs(colors) do
            if colorVal == color then
                  return color
            end
      end

      return nil
end

-- Returns the current text and background colors in the buffer.
function getBufferColors()
      return textColorBuffer, backgroundColorBuffer
end