Finance Server

local serial = require('serialization')
local event = require('event')
local term = require('term')
local fs = require('filesystem')
local com = require('component')
local mgpu = com.gpu

-- Таблица констант --
PORT = 72
DEFAULT_CASH = 1000000 -- $
BUFFER = 5

--  Таблица цветов  --
forecolor  = 0xFFFFFF
backcolor  = 0x000000
allowcolor = 0x00FF00
errorcolor = 0xFF0000
warncolor = 0xCCCC00
infocolor = 0x398eb5

--  Коды операций   --
CHANGE_PORT = 0x1
ADD_ACCOUNT = 0x2
DEL_ACCOUNT = 0x3
REMITTANCE  = 0x4
ACC_REQUEST = 0x5
CSH_REQUEST = 0x6
SET_ACCOUNT = 0x7

--   Коды ошибок    --
WRONG_PORT = 0xF1
ANSWER_YES = 0xF2
ANSWER_NO  = 0xF3
WRONG_CRED = 0xF4
TOO_LITTLE = 0xF5
--

function trytofind(name)
  if com.isAvailable(name) then
    return com.getPrimary(name)
  else
    return nil
  end
end

term.clear()
function errout(message)
  mgpu.setForeground(errorcolor)
  print('[ERROR] '..message)
  mgpu.setForeground(forecolor)
end
function warnout(message)
  mgpu.setForeground(warncolor)
  print('[WARNING] '..message)
  mgpu.setForeground(forecolor)
end
function infout(message)
  mgpu.setForeground(infocolor)
  print('[INFO] '..message)
  mgpu.setForeground(forecolor)
end
function helpout(message)
  mgpu.setForeground(allowcolor)
  print(message)
  mgpu.setForeground(forecolor)
end

local modem = trytofind('modem')

if modem == nil then
  errout('Вы прикалываетесь? Финансовый сервер без модема?')
  return
end

-- ======================================== L I S T   M A N A G E R S ======================================== --
function readList(filename)
  if fs.exists(filename) then
    local file = io.open(filename, "r")
    local data = file:read("*a")
    local list = serial.unserialize(data)
    file:close()
    helpout("База данных загружена.")
    return list
  else
    warnout("Файл "..filename.." не найден, создан пустой список!")
    return {}
  end
end
function saveList(list, filename)
  local file = io.open(filename, "w")
  data = serial.serialize(list)
  file:write(data)
  file:close()
  helpout("База данных сохранена.")
end
local opcounter = 0
function toList(list, name, data)
  if data == nil then data = true end
  list[name] = data
  -- резервное сохранение данных каждые BUFFER операций
  opcounter = opcounter + 1
  if opcounter > BUFFER then
    saveList(database, 'database.tot')
    opcounter = 0
  end
  return true
end
function fromList(list, name)
  if list[name] then
    list[name] = nil
    -- резервное сохранение данных каждые BUFFER операций
    opcounter = opcounter + 1
    if opcounter > BUFFER then
      saveList(database, 'database.tot')
      opcounter = 0
    end
    return true
  end
  return false
end
function contains(list, name)
  return list[name] ~= nil
end
function printlist(list)
  if next(list) == nil then print("Таблица пуста.")
  else
    c = 1
    for a,b in pairs(list) do
      print(a, serial.serialize(b))
      c = c + 1
      if c > height-3 then
        print("Любая клавиша для продолжения...")
        event.pull('key_down')
        c = 1
      end
    end
  end
end

-- ========================================= N E T   P A C K A G E S ========================================= --
function send(data)
  local message = data
  if type(message) == 'table' then
    message = serial.serialize(message)
  end
  if answer_address ~= nil then
    modem.broadcast(current_port, message)
  else
    modem.send(answer_address, current_port, message)
  end
end

-- ==================================== F I N A N C E   F U N C T I O N S ==================================== --
function addAccount(name, amount)
  if name == nil then return false
  elseif contains(database, name) then return false
  else
    local cash = amount
    if cash == nil or cash < 0 then cash = DEFAULT_CASH end
    toList(database, name, cash)
    return true
  end
end


-- Инициализация
database = readList('database.tot')
modem.open(PORT)
current_port = PORT
answer_address = nil

infout('Сервер запущен. Ожидание запросов...')
--
while true do
  name, _, answer_address, _, _, message  = event.pull(10)
  if name == 'modem_message' then
    data = serial.unserialize(message)
    if data.code == CHANGE_PORT then
      -- изменяем рабочий порт
      if data.port == nil or data.port < 1 or data.port > 65535 then
        send(WRONG_PORT)
      else
        modem.close()
        modem.open(data.port)
        current_port = data.port
        send(ANSWER_YES)
      end
    elseif data.code == ADD_ACCOUNT then
      -- создаем новую запись
      if addAccount(data.name, data.amount) then
        send(ANSWER_YES)
      else
        send(WRONG_CRED)
      end
    elseif data.code == DEL_ACCOUNT then
      -- удаляем существующую учетку
      if data.name == nil or not contains(database, data.name) then
        send(WRONG_CRED)
      else
        fromList(database, data.name)
        send(ANSWER_YES)
      end
    elseif data.code == ACC_REQUEST then
      -- запрашиваем информацию о существовании аккаунта
      if data.name == nil then
        send(WRONG_CRED)
      else
        if contains(database, data.name) then send(ANSWER_YES)
        else send(ANSWER_NO) end
      end
    elseif data.code == REMITTANCE then
      -- пересылаем деньги со счета на счет
      if not contains(database, data.sender) then
        addAccount(data.sender)
      end
      if not contains(database, data.receiver) then
        addAccount(data.receiver)
      end
      if database[data.sender] < data.amount then
        send(TOO_LITTLE)
      else
        toList(database, data.sender, database[data.sender] - data.amount)
        toList(database, data.receiver, database[data.receiver] + data.amount)
        send(ANSWER_YES)
      end
    elseif data.code == CSH_REQUEST then
      -- запрашиваем состояние счета
      if data.name == nil then
        send({WRONG_CRED})
      else
        if not contains(database, data.name) then
          addAccount(data.name)
        end
        send({ANSWER_YES, database[data.name]})
      end
    elseif data.code == SET_ACCOUNT then
      -- устанавливаем состояние счета
      if data.name == nil then
        send(WRONG_CRED)
      elseif data.amount == nil or data.amount < 0 then
        send(ANSWER_NO)
      else
        if not contains(database, data.name) then
          addAccount(data.name)
        end
        toList(database, data.name, data.amount)
        send(ANSWER_YES)
      end
    end
  elseif name == 'key_down' then break end
end

-- Завершение
saveList(database, 'database.tot')
modem.close()

warnout("Сервер остановлен. Все порты закрыты.")