local unicode = require "unicode"
local event = require "event"
local mtmenu = {}
local mx, my

local ssub = (unicode or {}).sub or string.sub

function mtmenu.getScreenSize()
 if mx and my then return mx, my end
 io.write("\27[999;999H")
 mx, my = mtmenu.getCursor()
 return mx, my
end

function mtmenu.getCursor()
 io.write("\27[6n")
 local b = ""
 repeat
  b = b .. io.read(1)
 until b:match("\27%[%d+;%d+R")
 local y,x = b:match("\27%[(%d+);(%d+)R")
 return tonumber(x), tonumber(y)
end

function mtmenu.setStatus(str)
 local ox, oy = mtmenu.getCursor()
 status = str
 io.write(string.format("\27[%d;1H\27[0m\27[7m\27[2K%s\27[0m\27[%i;%iH", my, status, oy, ox))
end

function mtmenu.menu(items, state)
 local mx, my = mtmenu.getScreenSize()
 local state = state or {1,1}
 local i, si = state[1], state[2]
 while true do
  if si > i - 3 then
   si = math.max(1, i-5)
  elseif i > (si+my) - 6 then
   si = math.min(i - (my-3) + 5, #items - (my - 3))
  end
  i = math.max(1,math.min(#items, i))
  print(string.format("\27[H\27[0m\27[7m\27[2K%s\27[0m", items.header or ""))
  for j = si, (si+my)-3 do
   print((i==j and "\27[7m" or "\27[0m") .. "\27[2K" .. (items[j] or ""):sub(1,mx))
  end
  mtmenu.setStatus(items.status)
  local _,_,ch,co = event.pull(60,"key_down")
  ch=string.char(ch or 0)
  if co == 208 then -- down
   i = i + 1
  elseif co == 200 then -- up
   i = i - 1
  elseif co == 201 then -- pgdn
   i = i - (my - 2)
  elseif co == 209 then -- pgdn
   i = i + my - 2
  else
   return i, ch, co, {i, si}
  end
 end
end

function mtmenu.popup(str,title,state)
 local mx, my = mtmenu.getScreenSize()
 local len = (unicode or {}).wlen or string.len
 if title then
  title=string.format("[%s]",title or "")
 else
  title = ""
 end
 local width, height, content = 0, 0, {}
 for line in str:gmatch("[^\n]*") do
  height = height + 1
  width = math.max(width,len(line))
  content[#content+1] = line
 end
 if width < 1 or height < 1 then return false end
 local startx,starty = ((mx//2)-(width//2))-2, ((my//2)-(height//2))-2
 io.write(string.format("\27[%d;%dH╒═%s%s╕",starty,startx,title,("═"):rep((width+1)-len(title))))
 for k,v in pairs(content) do
  io.write(string.format("\27[%d;%dH│ %s%s │",starty+k,startx,v,(" "):rep(width-len(v))))
 end
 io.write(string.format("\27[%d;%dH┕%s┙",starty+1+#content,startx,("━"):rep(width+2)))
end

return mtmenu