Rayzin's DISCOVERY

local component = require("component")
local computer = require("computer")
local fs = require("filesystem")
local term = require("term")
local md = component.modem
local netAddr = component.modem.address
local event = require("event")
local databasePath = "/home/discov.dat"
local ftpPath = "/home/ftplist.dat"
--local tnl = component.tunnel


local ftpNum = 0
local ftpsession = 1

local discovPort = 0
local ftpPort = 0
local dnsRead = 0
local dnsListen = 0
local alarmPort = 0
local reactorStatus = 0
--SET THESE VARIABLES IN THE FILE LOCATED AT databasePath variable



--dns reverse lookup
function reverseLookup(addrQuery)
md.close(1)
md.open(dnsSend)
md.broadcast(dnsListen,"GET_REVERSE",addrQuery)
local _,_,from,port,_,dnsRes= event.pull("modem_message")
md.close(dnsSend)
md.open(1)
dnsRes = tostring(dnsRes)
return dnsRes
end

--file read
function readDisc(value)
print("Reading " .. value .. " from DISCOVERY database.")
local nextLine = ""
local fileContents = ""
local newNextLine = ""
local file = io.open(databasePath, "r")
repeat
local nextLine = file : read("*l")
newNextLine = nextLine
if nextLine == nil then break end
if newNextLine == nil then break break end
--print("Checking entry: " .. nextLine)
until string.match(nextLine, value)
nextLine = newNextLine
print("Found: ".. newNextLine)
nextLine = string.gsub(nextLine, value, "")
nextLine = string.gsub(nextLine, " ", "")
--print("Resolved: "..nextLine)
file : close()
return nextLine

end


--Number getter
function getNameNum (name)
local file = io.open(databasePath,"r")
contents = file : read(1000)
local i,j = string.find(contents, name)
local endNum = string.sub(contents,j+1,j+3)
endNum = tonumber(endNum)
file : close()
return endNum
end

--address getter  DEPRECIATED  (Replaced by readDisc function)
function getAddr (addrId)
local file = io.open(databasePath,"r")
contents = file : read(1000)
local i,j = string.find(contents,addrId)
local addrLen = tonumber(string.sub(contents,j+1,j+2))
j = j + 3
local addr = string.sub(contents,j,j+addLen)
return tostring(addr)
end

--ftp logger
function ftpLog(numftp,addr)
addr = string.gsub(addr,"-"," ")
print("Checking if address already present...")
--check if address is in ftp list
local file = io.open(ftpPath,"r")
print("Reading file")
contents = file : read(1000)
contents = string.gsub(contents, "-"," ")
file : close()
print("Closed file")
findResult = string.find(contents,addr)
print(findResult)
if findResult == nil then
print("No result")
addr = string.gsub(addr," ", "-")
ftpId = ("ftpHost" .. numftp.. " " .. addr)
local file = io.open(ftpPath,"a")
file : write(ftpId.." \n")
print("Writing ftphost to file")
file : close()
result = ("Ftphost added to ftp list")
else
print("Ftphost already exists")
result = ("Ftphost already exists")
end
return result
end

--number to id
function numToId(num)
num = tostring(num)
if num < 10 then
num = ("00" .. num)
elseif num < 100 then
num = ("0" .. num)
elseif num < 1000 then
num = ("" .. num)
end
return result
end

--end of functions

term.clear()
print("Initialize DISCOVERY server")
--check for database
print("Checking for database...")
dExists = fs.exists(databasePath)
ftpExists = fs.exists(ftpPath)
dExists = tostring(dExists)
ftpExists = tostring(ftpExists)

if dExists == "true" then
print("Database found!")
end
if ftpExists == "true" then
print("FTP hostlist found!")
end
if dExists == "false" then
print("Database missing!")
print("Creating new database...")
local file = io.open(databasePath,"w")
file : write("Please enter system variables as so: Variable_idNum\ndiscoveryPort1\nftpNum1\nftpPort80\nalarmPort40\ndnsListen52\ndnsSend53\n")
file : close()
print("Database created!")
end
if ftpExists == "false" then
print("FTP hostlist missing!")
print("Creating new hostlist...")
local file = io.open(ftpPath,"w")
file : write("FTP_HOSTLIST\n")
file : close()
print("FTP hostlist created!")
end

--get ftphost num
ftpNum = tonumber(readDisc("ftpNum"))

--get ftp port
ftpPort = tonumber(readDisc("ftpPort"))
print("FTP Port open! "..ftpPort)

--get dns port
dnsListen = tonumber(readDisc("dnsListen"))
print("DNS Listen Port found! "..dnsListen)
dnsSend = tonumber(readDisc("dnsSend"))
print("DNS Send Port found! " .. dnsSend)

--open DISCOVERY port
discovPort = tonumber(readDisc("discoveryPort"))
md.open(discovPort)
print("Discovery port open! " .. discovPort)


--get alarm port
alarmPort = tonumber(readDisc("alarmPort"))

--begin main loop
print("Initialized!")
while true do

--listen for incoming requests
term.write("Listening for requests...\n")
local _,_,from,port,_,message = event.pull("modem_message")
from = tostring(from)
port = tonumber(port)
messsage = tostring(messsage)
local dnsResolved = reverseLookup(from)
term.write("Received " .. message .. " from ("..dnsResolved..") " .. from .. "\n")
os.sleep(0.2)

--check if request is a DISCOVERY request
if message == "DISCOVERY" then
md.send(from,discovPort,"1")
md.send(from, discovPort , "DISCOVERY_RECEIVE")
term.write("Sent net address to " .. from .. "\n")
end

--check if request is a FTP_INFO request
if message == "FTP_INFO" then
md.send(from, discovPort,  "2")
print("Sending FTP_INFO to " .. from)
md.send(from, discovPort, ftpPort)
md.send(from,discovPort, ftpAddr)
print("FTP_INFO transfer complete!")
end

--check for a clear command
if message == "CLEAR_DATABASE" then
md.send(from,discovPort,"2")
md.send(from, discovPort, "Clearing database")
print("CLEARING DATABASE..")
fs.remove(databasePath)
fs.remove(ftpPath)
print("DONE")
md.send(from,discovPort,"DONE!")
computer.shutdown(true)
end

if message == "FTP_LOG" then
local ftpResult = tostring(ftpLog(ftpNum,from))
md.send(from,discovPort,"1")
md.send(from, discovPort, ftpResult)
if ftpResult == "Ftphost added to ftp list" then
ftpNum = ftpNum + 1
end

end

if message == "TERMINATE" then
print("Terminating process!")
md.send(from,discovPort,"4")
md.send(from,discovPort,"Terminating process!")
print("END!")
os.sleep(1)
md.send(from,discovPort,"END!")
os.exit()
end

if message == "FTP_GET" then
numIds = -1
print("FTP session: ".. ftpsession)
file = io.open("ftplist.dat","r")
contents = file : read(1000)
contents = tostring(contents)
for word in string.gmatch(contents, "%\n") do
numIds = numIds + 1
end
file : close()
firstMessage = ("There are ".. numIds .. " ftp hosts on file.")
print(firstMessage)
md.send(from,discovPort, numIds)

words = {}
i = 0
for word in string.gmatch(contents, "%S+") do
os.sleep(0.2)
i = i + 1
words[i] = word
if (i % 2 == 1) and (i > 1) then
print("Sending "..words[i].. " to ".. from)
md.send(from,discovPort,words[i])
end

end

print("Creating new FTP session...")
ftpsession = ftpsession + 1
file = io.open("ftplist.dat","w")
file : write("FTP_HOSTLIST\n")
file : close()
print("FTP Session " .. ftpsession .. " created!")
end

if message == "REACTOR_DOWN" then
md.broadcast(alarmPort,"ALARM_BEGIN")
print("Reactor Down!")
reactorStatus = 0
end

if message == "REACTOR_UP" then
md.broadcast(alarmPort,"ALARM_END")
print("Reactor Up!")
reactorStatus = 1
end

if message == "REACTOR_STATUS" then
if reactorStatus == 1 then
md.send(from,discovPort,"1")
md.send(from,discovPort,"Reactor Online")
end
if reactorStatus == 0 then
md.send(from,discovPort,"1")
md.send(from,discovPort,"Reactor Offline")
end

end

if message == "INFO" then
print("Getting Info...")
print("Sending command list")
md.send(from,discovPort,"DISCOVERY FTP_INFO CLEAR_DATABASE FTP_LOG TERMINATE FTP_GET REACTOR_STATUS")
end

if message == "DNS" then
md.send(from,discovPort,dnsListen,dnsSend)
end

end