local crypt

for i,v in pairs(peripheral.getNames()) do
  if peripheral.getType(v) == "modem" then
    rednet.open(v)
  elseif peripheral.getType(v) == "cryptographic accelerator" then
    crypt = peripheral.wrap(v)
  end
end

local d

local pub, priv

local bkey

if fs.exists(".bkey") then
  local file = fs.open(".bkey", "r")
  bkey = crypt.decodeKey("RSA", file.readLine())
  pub = crypt.decodeKey("RSA", file.readLine())
  priv = crypt.decodeKey("RSA", file.readLine())
  file.close()
else
  pub, priv = crypt.generateKeyPair("RSA", 1024)
end

local function rMsg(enc)
  local time = os.startTimer(1)
  while true do
    local e, p1, p2, p3 = os.pullEvent()
    if e == "rednet_message" then
      if p1 == d and p3 == "luabank" then
        if enc == true then
          return priv.decrypt("RSA", p2)
        else
          return p2
        end
      end
    elseif e == "timer" and p1 == time then
      return nil
    end
  end
end

local function sMsg(msg)
  rednet.send(d, "smsgs" .. bkey.encrypt("RSA", msg), "luabank")
end

function connect()
  d = rednet.lookup("luabank", "database")
  if not d then
    return false
  elseif not bkey then
    rednet.send(d, "skeys" .. pub.encode(), "luabank")
    local msg = rMsg()
    if msg and msg:sub(1, 5) == "mkeys" then
      bkey = crypt.decodeKey("RSA", msg:sub(6))
      local file = fs.open(".bkey", "w")
      file.writeLine(msg:sub(6))
      file.writeLine(pub.encode())
      file.writeLine(priv.encode())
      file.close()
    else
      return false
    end
    return true
  else
    return true
  end
end

function register(user, pass)
  sMsg(textutils.serialize({"r", user, pass}))
  local dat = rMsg(true)
  if not dat then
    return false, "No response"
  elseif dat:sub(1, 5) == "error" then
    return false, dat:sub(6)
  else
    return dat
  end
end

function newcard(user, pass)
  sMsg(textutils.serialize({"c", user, pass}))
  local dat = rMsg(true)
  if not dat then
    return false, "No response"
  elseif dat:sub(1, 5) == "error" then
    return false, dat:sub(6)
  else
    return dat
  end
end

function transact(card, user, amount)
  sMsg(textutils.serialize({"t", card, user, amount}))
  local dat = rMsg(true)
  if not dat then
    return false, "No response"
  elseif dat:sub(1, 5) == "error" then
    return false, dat:sub(6)
  else
    return dat
  end
end

function transactu(user, pass, rec, amount)
  sMsg(textutils.serialize({"tu", user, pass, rec, amount}))
  local dat = rMsg(true)
  if not dat then
    return false, "No response"
  elseif dat:sub(1, 5) == "error" then
    return false, dat:sub(6)
  else
    return dat
  end
end