Quarry Repeater

--Version 1.0.3
--This program will act as a repeater between a turtle and a receiver computer
--important options are doAcceptPing and arbitraryNumber
--expected message format: {message, id, distance, fingerprint}
--added modifications similar to receiver program

--Config
local doDebug = false --...
local arbitraryNumber = 100 --How many messages to keep between deletions
local saveFile = "QuarryRepeaterSave"
local expectedFingerprints = {quarry = true, quarryReceiver = true}
local acceptLegacy = true --This will auto-format old messages that come along
local doAcceptPing = true --Accept pings. Can be turned off for tight quarters
local pingFingerprint = "ping"
local pingSide = "top"
--Init
local sentMessages = {} --Table of received message ids
local counter = 0
local tempCounter = 0 --How many messages since last delete
local recentID = 1 --Most recent message ID received, used for restore in delete
local channels = {} --List of channels to open listen on
local modem --The wireless modem
local modemSide --Will not necessarily be set


--Function Declarations--
local function debug(...) if doDebug then return print(...) end end --Debug print

local function newID()
  return math.random(1,2000000000) --1 through 2 billion; close enough
end
local function save()
  debug("Saving File")
  local file = fs.open(saveFile, "w")
  file.writeLine(textutils.serialize(channels):gsub("[\n\r]","")) --All the channels
  file.writeLine(counter) --Total number of messages received
  file.writeLine(modemSide) --The side the modem is on, helps for old MC
  return file.close()
end
local function addID(id)
    sentMessages[id] = true
    tempCounter = tempCounter + 1
    counter = counter + 1
    recentID = id
    save()
end
local function openChannels()
  for a,b in pairs(channels) do
    debug("Checking channel ",b)
    if not modem.isOpen(b) then
      debug("Opening channel ",b)
      modem.open(b)
    end
  end
end
local function testPeripheral(periph, periphFunc)
  if type(periph) ~= "table" then return false end
  if type(periph[periphFunc]) ~= "function" then return false end
  if periph[periphFunc]() == nil then --Expects string because the function could access nil
    return false
  end
  return true
end
local function initModem() --Sets up modem, returns true if modem exists
  if not testPeripheral(modem, "isWireless") then
    if peripheral.getType(modemSide or "") == "modem" then
      modem = peripheral.wrap(modemSide)
      if not modem.isWireless() then --Apparently this is a thing
        modem = nil
        return false
      end
      return true
    end
    if peripheral.find then
      modem = peripheral.find("modem", function(side, obj) return obj.isWireless() end)
    end
    return modem and true or false
  end
  return true
end
local function addChannel(num, doPrint) --Tries to add channel number. Checks if channel not already added. Speaks if doPrint set to true.
  num = tonumber(num)
  for a, b in pairs(channels) do
    if b == num then
      if doPrint then
        print("Channel "..num.." already added.")
      end
      return false
    end
  end
  if num >= 1 and num <= 65535 then
    table.insert(channels, num)
    if doPrint then
      print("Channel "..num.." added.")
    end
  end
end

--Actual Program Part Starts Here--
if fs.exists(saveFile) then
  local file = fs.open(saveFile,"r")
  channels = textutils.unserialize(file.readLine()) or (print("Channels could not be read") and {})
  counter = tonumber(file.readLine()) or (print("Counter could not be read") and 0)
  modemSide = file.readLine() or (print("Modem Side not read") and "")
  print("Done reading save file")
  file.close()
end

while not initModem() do
  print("No modem is connected, please attach one")
  if not peripheral.find then
    print("What side was that on?")
    modemSide = read()
  else
    os.pullEvent("peripheral")
  end
end
openChannels()

sleep(2) --Give users a second to read this stuff.

local continue = true
while continue do
  print("\nHit 'q' to quit, 'r' to remove channels, 'p' to ping or any other key to add channels")
  local event, key, receivedFreq, replyFreq, received, dist = os.pullEvent()
  term.clear()
  term.setCursorPos(1,1)
  if event == "modem_message" then
    print("Modem Message Received")
    debug("Received on channel "..receivedFreq.."\nReply channel is "..replyFreq.."\nDistance is "..dist)
    if acceptLegacy and type(received) ~= "table" then
      debug("Unformatted message, formatting for quarry")
      received = { message = received, id = newID(), distance = 0, fingerprint = "quarry"}
    end

    debug("Message Properties")
    for a, b in pairs(received) do
      debug(a,"   ",b)
    end

    if expectedFingerprints[received.fingerprint] and not sentMessages[received.id] then --A regular expected message
      if received.distance then
        received.distance = received.distance + dist --Add on to repeater how far message had to go
      else
        received.distance = dist
      end
      debug("Adding return channel "..replyFreq.." to channels")
      addChannel(replyFreq,false)
      debug("Sending Return Message")
      modem.transmit(receivedFreq, replyFreq, received) --Send back exactly what we got
      addID(received.id)
    elseif doAcceptPing and received.fingerprint == pingFingerprint then --We got a ping!
      debug("We got a ping!")
      redstone.setOutput(pingSide, true) --Just a toggle should be fine
      sleep(1)
      redstone.setOutput(pingSide, false)
    end

    if tempCounter > arbitraryNumber then --Purge messages to save memory
      debug("Purging messages")
      sleep(0.05) --Wait a tick for no good reason
      sentMessages = {} --Completely reset table
      sentMessages[recentID] = true --Reset last message (not sure if really needed. Oh well.)
      tempCounter = 0
    end

    print("Messages Received: "..counter)

  elseif event == "char" then
    if key == "q" then --Quitting
      print("Quitting")
      continue = false
    elseif key == "p" then --Ping other channels
      for a,b in pairs(channels) do --Ping all open channels
        debug("Pinging channel ",b)
        modem.transmit(b,b,{message = "I am ping! Wrar!", fingerprint = "ping"})
        sleep(1)
      end
    elseif key == "r" then --Removing Channels
      print("Enter a comma separated list of channels to remove")
      local str = "" --Concatenate all the channels into one, maybe restructure this for sorting?
      for i=1,#channels do
        str = str..tostring(channels[i])..", "
      end
      print("Channels: ",str:sub(1,-2)) --Sub for removing comma and space
      local input = io.read()
      local toRemove = {} --We have to use this table because user list will not be in reverse numerical order. Because modifying while iterating is bad...
      for num in input:gmatch("%d+") do
        for a, b in pairs(channels) do
          if b == tonumber(num) then
            debug("Removing ",b)
            table.insert(toRemove, a, 1) --This way it will remove indexes from the back of the table
            modem.close(b)
            break --No use checking the rest of the table for this number
          end
        end
      end
      for i=1, #toRemove do
        table.remove(channels, toRemove[i])
      end
    else  --Adding Channels
      print("What channels would you like to open. Enter a comma-separated list.\nAdd only sending channels. Receiving ones will be added automatically.\n")
      local input = io.read()
      for num in input:gmatch("%d+") do
        addChannel(num,true)
      end
      sleep(2)
    end
    save()
    openChannels() --This will only open channels if they aren't open

  end
end

for i=1, #channels do
  modem.close(channels[i])
end