local function newIndex(self, key, value)
  if type(value) == "function" then
    local func = setmetatable({}, {
      __call = function(_, ...)
        if rawequal(self, ({...})[1]) then
          return value(...)
        end
        return value(self, ...)
      end;
    })
    rawset(self, key, func)
  else
    rawset(self, key, value)
  end
end

return {
  new = function()
    local obj = setmetatable({act = {pos = {}}; pos = {}; back = colors.white; text = colors.lightGray;}, {__newindex = newIndex;})

    obj.write = function(self, _str)
      local act = self.act
      local selfpos = self.pos
      local append = true
      if selfpos[1] ~= act.pos[1] or selfpos[2] ~= act.pos[2] then
        act[#act + 1] = {term.setCursorPos, selfpos[1], selfpos[2]}
        append = false
      end
      if self.back ~= act.back then
        act[#act + 1] = {term.setBackgroundColor, self.back}
        act.back = self.back
        append = false
      end
      if self.text ~= act.text then
        act[#act + 1] = {term.setTextColor, self.text}
        act.text = self.text
        append = false
      end
      for line, nl in _str:gmatch("([^\n]*)(\n?)") do
        if append then
          act[#act][2] = act[#act][2]..line
          append = false
        else
          act[#act + 1] = {term.write, line}
        end
        selfpos[1] = selfpos[1] + #line
        if nl == "\n" then
          selfpos[1] = 1
          selfpos[2] = selfpos[2] + 1
          act[#act + 1] = {term.setCursorPos, 1, selfpos[2]}
        end
      end
      act.pos = {selfpos[1], selfpos[2]}
      return self
    end
    obj.draw = function(self)
      for i, v in ipairs(self.act) do
        if v[3] then
          v[1](v[2], v[3])
        else
          v[1](v[2])
        end
      end
      self.act = {}
      return self
    end

    return obj
  end;
}