BlueBank Server

--os.pullEvent = os.pullEventRaw CC bug makes this break

local modem = peripheral.find("modem")
local event, side, sChannel, id, data, dist
local sessions = {}

modem.open(os.getComputerID())

local function send(to, msg)
  modem.transmit(to, os.getComputerID(), msg);
end

local function listen()
  event, side, sChannel, id, data, dist = os.pullEvent("modem_message")
end

local function receive()
  modem.close(os.getComputerID())
  local rand = math.random(60000, 65000)
  modem.transmit(id, rand)
  modem.open(rand)
  listen()
  modem.close(rand)
  modem.open(os.getComputerID())
end

local function getSID()
  local rand = math.random(0, 10000)
  for index, tmp in pairs(sessions) do
    if tmp == rand then
      return getSID()
    end
  end
  return rand
end

local function indexOf(table, val)
  for index, tmp in pairs(table) do
    if tmp == val then
      return index
    end
  end
  return nil
end

local function login()
  receive()
  if not data:find(":") then
    send(id, "MessageFormatException")
    return
  end
  local c = data:find(":")
  local user = data:sub(0, c - 1)
  local pass = data:sub(c + 1)
  local file = fs.open("user/" .. user,  "r")
  if file ~= nil then
    if pass == file.readLine() then
      local sid = getSID()
      sessions[user] = sid;
      if fs.exists("admin/" .. user) then
        send(id, "Login Successful:" .. sid .. ":")
      else
        send(id, "Login Successful:" .. sid)
      end
    else
      send(id, "Password Incorrect")
    end
    file.close()
  else
    send(id, "Unknown User")
  end
end

local function balance()
  receive()
  local user = indexOf(sessions, tonumber(data))
  if user == nil then
    return
  end
  local file = fs.open("$/" .. user,  "r")
  send(id, file.readLine())
  file.close()
end

local function transfer()
  receive()
  if not data:find(":") then
    send(id, "MessageFormatException")
    return
  end
  local c1 = data:find(":")
  local c2 = data:find(":", c1 + 1)
  local user1 = indexOf(sessions, tonumber(data:sub(0, c1 - 1)))
  if user1 == nil then
    return
  end
  local user2 = data:sub(c1 + 1, c2 - 1)
  local amt = tonumber(data:sub(c2 + 1))
  local f1 = fs.open("$/" .. user1, "r")
  local f2 = fs.open("$/" .. user2, "r")
  if f1 ~= nil and f2 ~= nil then
    local bal1 = tonumber(f1.readLine());
    local bal2 = tonumber(f2.readLine());
    if bal1 >= amt and amt > 0 then
      f1.close()
      f2.close()
      f1 = fs.open("$/" .. user1, "w")
      f2 = fs.open("$/" .. user2, "w")
      f1.write(bal1 - amt)
      f2.write(bal2 + amt)
      f1.close()
      f2.close()
      send(id, "Funds Transfered")
    else
      send(id, "Not enough funds or invalid amount")
    end
  else
    send(id, "User(s) Not Found")
  end
end

local function create()
  receive()
  if not data:find(":") then
    send(id, "MessageFormatException")
    return
  end
  local c = data:find(":")
  local user = data:sub(0, c - 1)
  local pass = data:sub(c + 1)
  if fs.exists("user/" .. user) then
    send(id, "User Exists")
  else
    local file = fs.open("user/" .. user,  "w")
    file.write(pass)
    file.close()
    file = fs.open("$/" .. user, "w")
    file.write("0")
    file.close()
    send(id, "Account Created")
  end
end

local function add()
  receive()
  if not data:find(":") then
    send(id, "MessageFormatException")
    return
  end
  local c1 = data:find(":")
  local c2 = data:find(":", c1 + 1)
  local user1 = indexOf(sessions, tonumber(data:sub(0, c1 - 1)))
  if user1 == nil then
    return
  end
  local user2 = data:sub(c1 + 1, c2 - 1)
  local amt = tonumber(data:sub(c2 + 1))
  if fs.exists("admin/" .. user1) then
    if fs.exists("user/".. user2) then
      local file = fs.open("$/" .. user2, "r")
      local bal = tonumber(file.readLine())
      file.close()
      bal = bal + amt
      file = fs.open("$/" .. user2, "w")
      file.write(bal)
      file.close()
      send(id, "$" .. amt .. " added to " .. user2)
    else
      send(id, "No Such User")
    end
  else
    send(id, "You are not an admin")
  end
end

local function delete()
  receive()
  if not data:find(":") then
    send(id, "MessageFormatException")
    return
  end
  local c = data:find(":")
  local user1 = indexOf(sessions, tonumber(data:sub(0, c - 1)))
  if user1 == nil then
    return
  end
  if fs.exists("admin/" .. user1) then
    local user2 = data:sub(c + 1)
    fs.delete("user/" .. user2)
    fs.delete("$/" .. user2)
    fs.delete("admin/" .. user2)
    send(id, "User deleted")
  else
    send(id, "You are not an admin")
  end
end

local function chmod()
  receive()
  if not data:find(":") then
    send(id, "MessageFormatException")
    return
  end
  local c1 = data:find(":")
  local c2 = data:find(":", c1 + 1)
  local user1 = indexOf(sessions, tonumber(data:sub(0, c1 - 1)))
  if user1 == nil then
    return
  end
  if fs.exists("admin/" .. user1) then
    local user2 = data:sub(c1 + 1, c2 - 1)
    local status = data:sub(c2 + 1)
    if fs.exists("user/" .. user2) then
      if status == "true" then
        fs.open("admin/" .. user2, "w").close()
      else
        fs.delete("admin/" .. user2)
      end
    send(id, "User Status Successfully Edited")
    else
      send(id, "No such user")
    end
  else
    send(id, "You are not an admin")
  end

end

local function logout()
  receive()
  local user = indexOf(sessions, tonumber(data))
  if user == nil then
    return
  end
  sessions[user] = nil
  send(id, "You have been logged out!")
end

local function drawStart()
  term.clear()
  term.setCursorPos(1, 1)
  print("BlueBank Server 3.0 Status: Online")
  print("--------------------------------------")
  while true do
    listen()
    if data == "login" then
      login()
    elseif data == "balance" then
      balance()
    elseif data == "transfer" then
      transfer()
    elseif data == "create" then
      create()
    elseif data == "delete" then
      delete()
    elseif data == "rename" then
      rename()
    elseif data == "passcode" then
      passcode()
    elseif data == "add" then
      add()
    elseif data == "auth" then
      auth()
    elseif data == "logout" then
      logout()
    elseif data == "chmod" then
    chmod()
  else
      send(id, "Command Not Found")
    end
  end
end

drawStart()