mystPortal

local backgroundColor = colors.blue
local altBackgroundColor = colors.lightBlue
local greetingOne = "active link: "
--"Please choose your"
local greetingTwo = "no active link"
--"destination"
local timerDelay = 8
local refreshScreenDelay = 4

-- computer front points northward
local dirs = {front="north",left="east",back="south",right="west"}
local dir = nil

local mon = peripheral.find("monitor")

local chest = nil
local slot = nil

for i,v in pairs(rs.getSides()) do
  if peripheral.getType(v) == "ender_chest" then
    chest = peripheral.wrap(v)
    dir = dirs[v]
  elseif peripheral.getType(v) == "book_receptacle" then
    slot = peripheral.wrap(v)
  end
end

if not chest or not dir or not slot or not mon then print("Error while trying to find chest, slot or monitor"); error() end

function removeActiveBook()
  if slot.getStackInSlot(1) then
    if slot.pushItem(dir,1,1) ~= 1 then print("Error while moving book to chest") end
  end
end

removeActiveBook()
sleep(1)

local nDest = nil
--4
local destTable = {}
--local destNames = {}
local timer = nil

function padStr(str, len)
  if #str > len then do return string.sub(str,1,len) end
  else do return str .. string.rep(' ', len - #str) end
  end
end

function waitForTouchEvent()
  local refreshScreenTimer = os.startTimer(refreshScreenDelay)
  repeat
    event, side, monX, monY = os.pullEvent() --"monitor_touch")
    if event == "timer" and (side == timer or side == refreshScreenTimer) then
      if side == timer then removeActiveBook() end
      drawUserInterface()
      if side == refreshScreenTimer then refreshScreenTimer = os.startTimer(refreshScreenDelay) end
    end
  until event == "monitor_touch"
  --removeActiveBook()
  --drawUserInterface()
  if nDest > 0 and (monY-3 > 0) and (monY-3 <= nDest) then
    --if slot.pullItem(dir,destTable[monY - 3][1],1) ~= 1 then print("Error while moving book to slot") end
    local destination = destTable[monY-3][1][2]
    drawUserInterface()
    if destination == destTable[monY-3][1][2] then
      removeActiveBook()
      for _,destinationID in pairs(destTable[monY - 3]) do if slot.pullItem(dir,destinationID[1],1) == 1 then break end end
      timer = os.startTimer(timerDelay)
    end
  else
    removeActiveBook()
  end
end

function drawUserInterface()
  destTable = {}
 -- destNames = {}
  local items = chest.getAllStacks()
  local books = {}
  for n,item in pairs(items) do
    if item.rawName == "item.myst.linkbook" then
      if not books[item.destination] then
        books[item.destination] = {n}
      else
        books[item.destination][#(books[item.destination])+1] = n
      end
    end
  end
  local sortedBooks = {}
  for n in pairs(books) do table.insert(sortedBooks,n) end
  table.sort(sortedBooks)

  local monX, monY = mon.getSize()
  mon.setBackgroundColor(backgroundColor)
  mon.clear()
  mon.setCursorPos(1,1)
  local active = slot.getStackInSlot(1)
  if active and active.rawName == "item.myst.linkbook" then
    mon.write(greetingOne)
    mon.setCursorPos(1,2)
    mon.write(active.destination)
  else
    mon.write(greetingTwo)
  end
  --
  --mon.write(greetingTwo)
  nDest = 0
  local i = 0
  for _,book in ipairs(sortedBooks) do
    i = i + 1
    destTable[i] = {books[book],book}
    mon.setCursorPos(1, i + 3)
    if (i % 2 == 0) then
      mon.setBackgroundColor(altBackgroundColor)
    else
      mon.setBackgroundColor(backgroundColor)
    end
   -- destNames[#destNames+1] = book
    name = padStr(book,monX)
    mon.write(name)
  end
  if not i then
    mon.setCursorPos(1, 4)
    mon.write("No Entries")
  end
  nDest = #destTable
end

while true do
  drawUserInterface()
  waitForTouchEvent()
end