local dir = ""
local fileList = {}
local fList = {}
local dList = {}
local offset = 0
 
function drawSquare(x,y,x2,y2,color)
  for xPos=x,x2 do
    for yPos=y,y2 do
      term.setBackgroundColor(color)
      term.setCursorPos(xPos,yPos)
      term.write(" ")
    end
  end
  term.setBackgroundColor(colors.black)
end
 
function drawText(x,y,text,tColor,bColor)
  term.setBackgroundColor(bColor)
  term.setTextColor(tColor)
  term.setCursorPos(x,y)
  term.write(text)
end
 
function makeLists(path)
  fileList = fs.list(path)
  dList = {}
  fList = {}
  if string.len(dir) > 1 then
    table.insert(dList, "..")
  end
  for i=1,#fileList do
    if fs.isDir(path.."/"..fileList[i]) then
      table.insert(dList, fileList[i])
    else
      table.insert(fList, fileList[i])
    end
  end
end
 
while true do
  term.clear()
  drawSquare(1,1,10,19,colors.gray)
  drawSquare(10,1,51,19,colors.white)
  drawSquare(1,1,51,1,colors.lightGray)
  if string.len(dir) > 0 then
    drawText(1,1,dir,colors.black,colors.lightGray)
  else
    drawText(1,1,"/",colors.black,colors.lightGray)
  end
  term.setCursorPos(1,1)
  makeLists(dir)
  for i=1,#dList do
    if dList[i+offset] then
      drawText(1,i+1,dList[i+offset],colors.white,colors.gray)
    end
  end
  local pos = 1
  local offSet = 0
  for i=1,#fList do
    if fList[i+(18*offset)] then
      drawText(10+(offSet*15),i-(18*offSet)+1,fList[i+(18*offset)],colors.black,colors.white)
    end
    pos = pos + 1
    if pos > 18 then
      pos = 1
      offSet = offSet + 1
    end
  end
  local e,b,x,y = os.pullEvent()
  if e == "mouse_click" then
    if x<10 and y>1 then
      if offset < 1 then
        if dList[y-1] then
          if dList[y-1] == ".." then
            dir = fs.getDir(dir)
          else
            dir = dir.."/"..dList[y-1]
          end
          offset = 0
        end
      else
        if dList[(y-1)+offset] then
          if dList[(y-1)+offset] == ".." then
            dir = fs.getDir(dir)
          else
            dir = dir.."/"..dList[(y-1)+offset]
          end
          offset = 0
        end
      end
    elseif x>9 and x<25 and y>1 then
      if offset < 1 then
        if fList[y-1] then
          term.setTextColor(colors.white)
          term.setBackgroundColor(colors.black)
          term.clear()
          term.setCursorPos(1,1)
          shell.run(dir.."/"..fList[y-1])
        end
      else
        if fList[y+(offset*17)] then
          term.setTextColor(colors.white)
          term.setBackgroundColor(colors.black)
          term.clear()
          term.setCursorPos(1,1)
          shell.run(dir.."/"..fList[y+(offset*17)])
        end
      end
    elseif x>25 and x<40 and y>1 then
      if offset < 1 then
        if fList[y+17] then
          term.setTextColor(colors.white)
          term.setBackgroundColor(colors.black)
          term.clear()
          term.setCursorPos(1,1)
          shell.run(dir.."/"..fList[y+17])
        end
      else
        if fList[y+(offset*34)] then
          term.setTextColor(colors.white)
          term.setBackgroundColor(colors.black)
          term.clear()
          term.setCursorPos(1,1)
          shell.run(dir.."/"..fList[y+(offset*34)])
        end
      end
    elseif y == 1 then
      drawSquare(1,1,51,1,colors.lightGray)
      term.setCursorPos(1,1)
      term.setTextColor(colors.black)
      term.setBackgroundColor(colors.lightGray)
      local input = read()
      if fs.exists(input) then
        if fs.isDir(input) then
          dir = input
        else
          shell.run(input)
        end
      else
        drawSquare(1,1,51,1,colors.lightGray)
        drawText(1,1,"Invalid directory or file (Does not exist)", colors.black, colors.lightGray)
        sleep(0.3)
        os.pullEvent()
      end
    else
      if offset < 1 then
        if fList[y+34] then
          term.setTextColor(colors.white)
          term.setBackgroundColor(colors.black)
          term.clear()
          term.setCursorPos(1,1)
          shell.run(dir.."/"..fList[y+34])
        end
      else
        if fList[y+(offset*51)] then
          term.setTextColor(colors.white)
          term.setBackgroundColor(colors.black)
          term.clear()
          term.setCursorPos(1,1)
          shell.run(dir.."/"..fList[y+(offset*51)])
        end
      end
    end
  elseif e == "mouse_scroll" then
    if b == -1 then
      if offset > 0 then
        offset = offset - 1
      end
    elseif b == 1 then
        offset = offset + 1
    end
  end
end