atupd

-- ============================================
-- == Utilities
-- ============================================
local function fileReadAll(filePath)
  local hFile = fs.open(filePath, "r")
  if nil == hFile then
    return nill
  end
  local txt = hFile.readAll()
  hFile.close()
  return txt
end
local function fileOverwrite(filePath, text)
  local hFile = fs.open(filePath, "w")
  hFile.writeLine(text)
  hFile.close()
end
local function saveFile(filePath, data)
  fileOverwrite(filePath, textutils.serialize(data))
end
local function loadFile(filePath)
  local dat = fileReadAll(filePath)
  if nil == dat then
    return nil
  end
  return textutils.unserialize(dat)
end
local function deleteWhenExists(filePath)
  if fs.exists(filePath) then
    fs.delete(filePath)
  end
end
local function startsWith(subject, keyword)
  if nil == subject then
    return false
  end
  if nil == keyword then
    return false
  end
  if string.len(subject) < string.len(keyword) then
    return false
  end
  if string.sub(subject, 1, string.len(keyword)) == keyword then
    return true
  else
    return false
  end
end
-- ============================================
-- == Configuration
-- ============================================
local APP_FILE_NAME  = "/atupd"
local THE_CHANNEL    = 3951
local MSG_SIGNATURE  = "kssr3951's network system"
local BASE_DIRECTORY = "/network"
local STATUS_DIRECTORY = BASE_DIRECTORY .. "/status"
-- ============================================
-- == Application Common
-- ============================================
local MSGTYPE_SYS_UPDATE = "MSGTYPE_SYS_UPDATE"
local function MsgSysUpdateNew()
  return {
      senderId,
      type = MSGTYPE_SYS_UPDATE,
      timestamp,
      appFileName,
      source
    }
end
local function serializeMessage(data)
  data.senderId = os.getComputerID()
  return MSG_SIGNATURE .. textutils.serialize(data)
end
local function unserializeMessage(data)
  if false == startsWith(data, MSG_SIGNATURE) then
    return nil
  else
    return textutils.unserialize(string.sub(data, string.len(MSG_SIGNATURE) + 1))
  end
end
-- ============================================
-- == Application
-- ============================================
local SIDES = {"top", "bottom", "left", "right", "front", "back"}
local modems = { }
local function receiveSysUpdate(msg)
  local message = unserializeMessage(msg)
  if nil == message then
    return
  end
  if nil ~= message and MSGTYPE_SYS_UPDATE == message.type then
    print("sysUpdate")
    local timestamp = loadFile(STATUS_DIRECTORY .. "/systemUpdateDate")
    print("system update required. timestamp=[" .. message.timestamp .. "]")
    if nil ~= timestamp and timestamp == message.timestamp then
      print("  already latest. (no need to update.)")
    else
      print("  need to be updated.")
      saveFile(STATUS_DIRECTORY .. "/updateMessage", message)
      deleteWhenExists(message.appFileName)
      fileOverwrite(message.appFileName, message.source)
      fileOverwrite("/startup", "shell.run(\"" .. message.appFileName .. "\")")
      saveFile(STATUS_DIRECTORY .. "/updateNetSlave", true)
      os.reboot()
    end
  end
end
local function modemAction(modemSide, senderChannel, replyChannel, msg, senderDistance)
  -- print("== =========================================")
  -- print("I just received a message from: "..senderChannel)
  -- print("I should apparently reply on: "..replyChannel)
  -- print("The modem receiving this is located on the "..modemSide.." side")
  -- print("The message was: "..msg)
  -- print("The sender is: "..senderDistance.." blocks away from me.")
  -- print("== =========================================")
  if true then
    receiveSysUpdate(msg)
  end
  print("waiting.")
end
-- ============================================
-- == main
-- ============================================
fs.makeDir(STATUS_DIRECTORY)
local args = { ... }
if true then
  local mdmCnt = 0
  for _, side in ipairs(SIDES) do
    if "modem" == peripheral.getType(side) then
      modems[side] = peripheral.wrap(side)
      modems[side].open(THE_CHANNEL)
      mdmCnt = mdmCnt + 1
    end
  end
  print("modemCount = " .. tostring(mdmCnt))
end
if 1 <= #args then
  -- ----------------------------------------
  -- net update (root)
  -- ----------------------------------------
  if "appUpdate" == args[1] then
    local message = MsgSysUpdateNew()
    message.timestamp   = os.day() .. "-" .. os.time()
    message.appFileName = APP_FILE_NAME
    message.source      = fileReadAll(APP_FILE_NAME)
    saveFile(STATUS_DIRECTORY .. "/systemUpdateDate", message.timestamp)
    for _, mdm in pairs(modems) do
      print("transmit begin")
      mdm.transmit(THE_CHANNEL, 10, serializeMessage(message))
      print("    transmit end")
    end
  end
end
if true then
  -- ----------------------------------------
  -- net update (not root)
  -- ----------------------------------------
  local tmp = loadFile(STATUS_DIRECTORY .. "/updateNetSlave")
  deleteWhenExists(STATUS_DIRECTORY .. "/updateNetSlave")
  if nil ~= tmp and true == tmp then
    local message = loadFile(STATUS_DIRECTORY .. "/updateMessage")
    for _, mdm in pairs(modems) do
      mdm.transmit(THE_CHANNEL, 10, serializeMessage(message))
    end
    saveFile(STATUS_DIRECTORY .. "/systemUpdateDate", message.timestamp)
  end
end
local timestamp = loadFile(STATUS_DIRECTORY .. "/systemUpdateDate")
print("== =========================================")
print("== kssr3951's network component.")
print("== last update : " .. tostring(timestamp))
print("== computer ID : " .. os.getComputerID())
print("== =========================================")
print("waiting.")
while true do
  local event, r1, r2, r3, r4, r5 = os.pullEvent()
  if "modem_message" == event then
    print("modem_message!!")
    modemAction(r1, r2, r3, r4, r5)
  end
end