os.loadAPI("api/devices")

-- GLOBAL VARIABLES --
local ver="1.1"
local id=os.getComputerID()
local wifi
local dest
local sfile
local sender
local dcat
local dfile
local dpath
-- /GLOBAL VARIABLES --

function Main()
  Clear()
  write("Initializing")
  textutils.slowWrite(".....\n\n")

  wifi=devices.find("modem")
  if wifi~="none" then
    print("Wireless device found!")
    write("Opening connection")
    textutils.slowWrite(".....\n\n")
    rednet.open(wifi)
    print("Done!")
    sleep(1)
    Menu()
  else
    print("Wireless device not found!\nConnect a device and try again!")
    return 0
  end
end

function Menu()
  Clear()
  print("Your ID: "..id.."\n")
  print("\t1. Send file")
  print("\t2. Receive file")
  print("\t0. Exit")

  local event,p1=os.pullEvent("key")
    if p1==2 then
          SendMenu()
    elseif p1==3 then
          DownMenu()
    elseif p1==11 then
         term.clear()
        term.setCursorPos(1,1)
        print("Thanks for using rFTP!")
        rednet.close(wifi)
        return 0
    else
          Menu()
    end
end

function SendMenu()
  Clear()
  print("Enter destination ID (not label):")
  dest=tonumber(read())
  print("File to send: ")
  sfile=read()
  write("\nChecking file")
  textutils.slowWrite(".....")
  if fs.exists(sfile)==true then
    write(" File OK!\n")
  else
    print("\nFile not found! Any key to continue...")
    os.pullEvent("key")
    Menu()
  end
  print("Estabilishing connection")
  rednet.send(dest,"@rftpstart")
  rednet.send(dest,sfile)
  print("Waiting for device #"..dest.." to respond...\n[Press SPACE to cancel]")
  Waiting()
end

function Waiting()
  while true do
    local event,p1,p2=os.pullEvent()

    if (event=="rednet_message") and (p2=="@rftpagree") then
        print("File accepted by #"..dest.."\n")
        sleep(1)
        Transfer()
        break
    elseif (event=="rednet_message") and (p2=="@rftpdeny") then
        print("#"..dest.." denied connection! Any key to continue...")
        os.pullEvent("key")
        Menu()
        break
    elseif (event=="key") and (p1==57) then
        Menu()
        break
    end
  end
end

function Transfer()
    local plik=fs.open(sfile,"r")
    local tresc=plik.readAll()
    rednet.send(dest,tresc)
    sleep(0.3)
    rednet.send(dest,"@rftpend")
    plik.close()
    print("Transfer complete! Any key to continue...")
    os.pullEvent("key")
    Menu()
end

function DownMenu()
    Clear()
    print("Your ID: "..id.."\n")
    print("Waiting for an oncoming file...\n[Press SPACE to cancel]")
    local event,p1,p2
    repeat
    event,p1,p2=os.pullEvent()
    until ((event=="rednet_message") and (p2=="@rftpstart")) or ((event=="key") and (p1==57))
    if (event=="rednet_message") and (p2=="@rftpstart") then
        sender=p1
        event,p1,p2=os.pullEvent("rednet_message")
        print("Device "..p1.." want to send you a file: "..p2..". Accept? [y/N]")
        local event,pp1=os.pullEvent("key")
        if (pp1==20) or (pp1==21) then
            Download()
        else
            rednet.send(p1,"@rftpdeny")
            Menu()
        end
    elseif (event=="key") and (p1==57) then
        Menu()
    end
end

function Download()
    Clear()

    print("Select the folder: [default: dl]")
    dcat=read()
    if dcat=="" then
        dcat="dl"
    end
    fs.makeDir(dcat)

    print("Select filename:")
    dfile=read()

    dpath=fs.combine(dcat,dfile)

    if fs.exists(dpath)==false then
        SaveFile()
    else
        print("File already exists! Try again? [y/N]")
        local event,p1=os.pullEvent("key")
        if (p1==20) or (p1==21) then
            Download()
        else
            rednet.send(p1,"@rftpdeny")
            Menu()
        end
    end
end

function SaveFile()
    local plik=fs.open(dpath,"w")
    rednet.send(p1,"@rftpagree")
    local event,p1,p2
    repeat
        event,p1,p2=os.pullEvent("rednet_message")
    until p1==sender
    if p2~="@rftpend" then
        plik.write(p2)
    end
    os.startTimer(10)
    while true do
        local event,p1,p2=os.pullEvent()
        if event=="rednet_message" and p1==sender and p2=="@rftpend" then
            write("\nTransfer completed! ")
            break
        elseif event=="timer" then
            write("\nTimed out! Check the file. ")
            break
        end
    end
    plik.close()
    print("Any key to continue...")
    os.pullEvent("key")
    Menu()
end

function Clear()
  term.clear()
  term.setCursorPos(1,1)
  print("rFTP v"..ver.."\nby Jahmaican\n~~~~~~~~~~~~\n")
end

Main()