rcmenu

os.loadAPI("utils")

--constant
local MAXCHAR = 20
local MAXITEMS = 5
local BLINKTIME = 0.2

--buffer variables
local dy = 0
local dx = 0

local bf = {}
local rClickedPos = {0, 0}

--Private functions
local CloseMenu = function()
 local _clsstr = utils.FillString("", MAXCHAR)

 for i = 0, #bf-1, 1 do
  term.setCursorPos(rClickedPos[1]-dx, rClickedPos[2]+i-dy)
  print(_clsstr)
 end
end

local BLINKTIMEItemMenu = function(num)
 utils.SetPalette("select")
 term.setCursorPos(rClickedPos[1]-dx, rClickedPos[2]+num-dy)
 print(bf[num+1]["text"])

 os.sleep(BLINKTIME)

 utils.SetPalette("os")
 term.setCursorPos(rClickedPos[1]-dx, rClickedPos[2]+num-dy)

 print(bf[num+1]["text"])
end

local DrawMenu = function()
 local _bflen = #bf

 dx = 0
 dy = 0
 _ww, _wh = term.getSize();

 if (rClickedPos[1]+MAXCHAR > _ww) then dx = MAXCHAR end
 if (rClickedPos[2]+_bflen > _wh-1) then dy = _bflen end

 utils.SetPalette("standart")

 for i = 0, _bflen-1, 1 do
  term.setCursorPos(rClickedPos[1]-dx, rClickedPos[2]+i-dy)
  print(bf[i+1]["text"])
 end

 utils.SetPalette("os")
end

--MainFunction
Update = function()
 if (#bf == 0) then error("Error: expected at least one element.") end

 local event, btn, xPos, yPos = os.pullEvent()

 if (event ~= "mouse_click") then return end

 if (btn == 2) then
  CloseMenu()
  rClickedPos[1] = xPos
  rClickedPos[2] = yPos
  DrawMenu()
 elseif (btn == 1) then

  for i = 0, #bf-1, 1 do
   if ((xPos >= rClickedPos[1] and xPos <= rClickedPos[1]+MAXCHAR) and yPos == rClickedPos[2]+i-dy) then
    BLINKTIMEItemMenu(i)
    CloseMenu()
    bf[i+1]["func"]()
    break
   end
  end

  CloseMenu()

 end

end

AddItem = function(id, text, func)
 if (type(id) ~= "number") then
  error("Error: Expected number, got " .. type(text) .. ".")
 elseif (type(text) ~= "string") then
  error("Error: Expected string, got " .. type(text) .. ".")
 elseif (type(func) ~= "function") then
  error("Error: Expected function, got " .. type(text) .. ".")
 elseif (id <= 0) then
  error("Error: Id <= 0.")
 elseif (id > MAXITEMS) then
  error("Error: Id > " .. MAXITEMS .. ".")
 elseif (#text > MAXCHAR) then
  error("Error: The maximum length of this string " .. MAXCHAR .. ".")
 elseif (#bf == MAXITEMS) then
  error("Error: The maximum number of elements " .. MAXITEMS .. ".")
 end

 bf[id] = {}
 bf[id]["text"] = utils.FillString(text, MAXCHAR)
 bf[id]["func"] = func
end

RemoveItem = function(id)
 if (type(id) ~= "number") then
  error("Error: Expected number, got " .. type(text) .. ".")
 elseif (id <= 0) then
  error("Error: Id <= 0.")
 elseif (id > MAXITEMS) then
  error("Error: Id > " .. MAXITEMS .. ".")
 end

 table.remove(bf, id)
end