local m = component.modem -- get primary modem component
m.open(321)
print(m.isOpen(321)) -- true
m.setStrength(500)
-- Send some message.

if not term.isAvailable() then
  return
end

local args, options = shell.parse(...)

args[1] = "Menu.txt"

local filename = shell.resolve(args[1])

local readonly = options.r or fs.get(filename) == nil or fs.get(filename).isReadOnly()

if fs.isDirectory(filename) or readonly and not fs.exists(filename) then
  print("file not found")
  return
end

term.clear()
term.setCursorBlink(true)

local running = true
local buffer = {}
local scrollX, scrollY = 0, 0
-------------------------------------------------------------------------------

local function setStatus(value)
  local w, h = component.gpu.getResolution()
  component.gpu.set(1, h, text.padRight(unicode.sub(value, 1, w - 10), w - 10))
end

local function getSize()
  local w, h = component.gpu.getResolution()
  return w, h - 1
end

local function getCursor()
  local cx, cy = term.getCursor()
  return cx + scrollX, cy + scrollY
end

local function line()
  local cbx, cby = getCursor()
  return buffer[cby]
end

local function setCursor(nbx, nby)
  local w, h = getSize()
  nby = math.max(1, math.min(#buffer, nby))

  local ncy = nby - scrollY
  if ncy > h then
    term.setCursorBlink(false)
    local sy = nby - h
    local dy = math.abs(scrollY - sy)
    scrollY = sy
    component.gpu.copy(1, 1 + dy, w, h - dy, 0, -dy)
    for by = nby - (dy - 1), nby do
      local str = text.padRight(unicode.sub(buffer[by], 1 + scrollX), w)
      component.gpu.set(1, by - scrollY, str)
    end
  elseif ncy < 1 then
    term.setCursorBlink(false)
    local sy = nby - 1
    local dy = math.abs(scrollY - sy)
    scrollY = sy
    component.gpu.copy(1, 1, w, h - dy, 0, dy)
    for by = nby, nby + (dy - 1) do
      local str = text.padRight(unicode.sub(buffer[by], 1 + scrollX), w)
      component.gpu.set(1, by - scrollY, str)
    end
  end
  term.setCursor(term.getCursor(), nby - scrollY)

  nbx = math.max(1, math.min(unicode.len(line()) + 1, nbx))
  local ncx = nbx - scrollX
  if ncx > w then
    term.setCursorBlink(false)
    local sx = nbx - w
    local dx = math.abs(scrollX - sx)
    scrollX = sx
    component.gpu.copy(1 + dx, 1, w - dx, h, -dx, 0)
    for by = 1 + scrollY, math.min(h + scrollY, #buffer) do
      local str = unicode.sub(buffer[by], nbx - (dx - 1), nbx)
      str = text.padRight(str, dx)
      component.gpu.set(1 + (w - dx), by - scrollY, str)
    end
  elseif ncx < 1 then
    term.setCursorBlink(false)
    local sx = nbx - 1
    local dx = math.abs(scrollX - sx)
    scrollX = sx
    component.gpu.copy(1, 1, w - dx, h, dx, 0)
    for by = 1 + scrollY, math.min(h + scrollY, #buffer) do
      local str = unicode.sub(buffer[by], nbx, nbx + dx)
      --str = text.padRight(str, dx)
      component.gpu.set(1, by - scrollY, str)
    end
  end
  term.setCursor(nbx - scrollX, nby - scrollY)

  component.gpu.set(w - 9, h + 1, text.padLeft(string.format("%d,%d", nby, nbx), 10))
end

local function up(n)
  n = n or 1
  local cbx, cby = getCursor()
  if cby > 1 then
    setCursor(cbx, cby - n)
  else
		cby = #buffer + 1
    setCursor(cbx, cby - n)
  end
end

local function down(n)
  n = n or 1
  local cbx, cby = getCursor()
  if cby < #buffer then
    setCursor(cbx, cby + n)
  else
    cby = 0
    setCursor(cbx, cby + n)
  end
end

function trim(s)
  return (s:gsub("^%s*(.-)%s*$", "%1"))
end

local function enter()
  term.setCursorBlink(false)
  local cx, cy = term.getCursor()
  local cbx, cby = getCursor()
  local w, h = getSize()
	if cby == #buffer then
	  running = false
	end
	m.broadcast(321, trim(buffer[cby]))
  setCursor(1, cby)
end

local controlKeyCombos = {[keyboard.keys.s]=true,[keyboard.keys.w]=true,
                          [keyboard.keys.c]=true,[keyboard.keys.x]=true}
local function onKeyDown(char, code)
  if code == keyboard.keys.up then
    up()
  elseif code == keyboard.keys.down then
    down()
  elseif code == keyboard.keys.enter and not readonly then
    enter()
  end
end

-------------------------------------------------------------------------------

do
  local f = io.open(filename)
  if f then
    local w, h = getSize()
    local chars = 0
    for line in f:lines() do
      table.insert(buffer, line)
      chars = chars + unicode.len(line)
      if #buffer <= h then
        component.gpu.set(1, #buffer, line)
      end
    end
    f:close()
    if #buffer == 0 then
      table.insert(buffer, "")
    end
  end
  setCursor(1, 1)
end

while running do
  local event, address, arg1, arg2, arg3 = event.pull()
  if type(address) == "string" and component.isPrimary(address) then
    local blink = true
    if event == "key_down" then
      onKeyDown(arg1, arg2)
    else
      blink = false
    end
    if blink then
      term.setCursorBlink(true)
      term.setCursorBlink(true) -- force toggle to caret
    end
  end
end

term.clear()
term.setCursorBlink(false)