Rednet Snooper

-- Rednet Snooper
local tArgs = {...}
local RUNNING = true
local w,h = term.getSize()
local scrollpos = 1
local data = {}
local blink = true
local minchan, maxchan = nil
if not term.isColor() or not term.isColour() then
    RUNNING = false
    print("Get an advanced computer. It likely will not be this way in the future.")
end
if #tArgs < 2 then
    print(fs.getName(shell.getRunningProgram()).." <minchan> <maxchan>")
    RUNNING = false
else
    minchan = tonumber(tArgs[1])
    maxchan = tonumber(tArgs[2])
    if maxchan - minchan > 127 then
        print("Only 128 channels can be open at once")
        RUNNING = false
    end
end
local m = nil
local pospossible = 1
local input = ""
local function drawTopBar()
    term.setBackgroundColor(colors.gray)
    term.setCursorPos(1,1)
    term.clearLine()
    term.write(" Rednet Snooper "..minchan.."-"..maxchan)
    term.setCursorPos(w-4,1)
    term.write(" ? ")
    term.setBackgroundColor(colors.red)
    term.setCursorPos(w,1)
    term.write("X")
end
local function drawBottomBar()
    term.setBackgroundColor(colors.gray)
    term.setCursorPos(1,h)
    term.clearLine()
    term.write("> ")
end
local function drawListen()
    term.setBackgroundColor(colors.black)
    for y = 2,h-1 do
        term.setCursorPos(1,y)
        term.clearLine()
    end
    term.setCursorPos(1,2)
    for i = scrollpos,#data do
        if i > #data then break end
        term.write(data[i])
        local x,y = term.getCursorPos()
        y = y+1
        if y > h-1 then break end
        term.setCursorPos(1,y)
    end
    term.setBackgroundColor(colors.gray)
    term.setCursorPos(3,h)
end
local function drawScreen()
    term.clear()
    drawTopBar()
    drawBottomBar()
    drawListen()
end
local function scanPeripherals()
    local sides = {"top", "bottom", "left", "right", "front", "back"}
    for i = 1,#sides do
        if peripheral.isPresent(sides[i]) then
            if peripheral.getType(sides[i]) == "modem" then
                m = peripheral.wrap(sides[i])
                m.closeAll()
            end
        end
    end
    if m == nil then
        print("Please attach a modem")
        RUNNING = false
    end
end
local function openRange()
    if RUNNING then
        for i = minchan,maxchan do
            if not m.isOpen(i) then m.open(i) end
        end
    end
end
local function processInput()
    local chan = nil
    local msg = nil
    for i = 1,input:len() do
        if string.sub(input,i,i) == " " then
            chan = tonumber(string.sub(input,1,i-1))
            msg = string.sub(input,i+1)
            break
        end
    end
    if chan then
        local nMessageID = math.random( 1, 2147483647 ) -- transmit with rednet protocol
        local tMessage = {
            nMessageID = nMessageID,
            nRecipient = chan,
            message = msg,
            sProtocol = nil,
        }
        local temp = nil
        if not m.isOpen(chan) then
            m.close(maxchan)
            m.open(chan)
            m.transmit(chan,maxchan,msg)
            m.transmit(chan,maxchan,tMessage)
            temp = "C"..chan.."/"..maxchan.." D:0: "
        else
            m.transmit(chan,chan,msg)
            m.transmit(chan,chan,tMessage)
            temp = "C"..chan.."/"..chan.." D:0: "
        end
        -- insert sent message to data table
        if msg:len() + temp:len() > w then
            table.insert(data, temp .. string.sub(msg,1,w - temp:len()))
            for i = w-temp:len()+1,msg:len(),w do
                table.insert(data, string.sub(msg,i,i+w))
            end
        else
            table.insert(data, temp .. msg)
        end
        pospossible = #data-(h-3)
        if pospossible < 1 then pospossible = 1 end
        scrollpos = pospossible
        drawListen()
        if not m.isOpen(maxchan) then
            m.close(chan)
            m.open(maxchan)
        end
    end
end
local function helpMenu()
    term.setBackgroundColor(colors.lightGray)
    term.setCursorPos(w-4,1)
    term.write(" ? ")
    term.setBackgroundColor(colors.black)
    for y = 2,h-1 do
        for x = 1,w do
            term.setCursorPos(x,y)
            term.write(" ")
        end
    end
    term.setCursorPos(1,3)
    print("Help Menu:")
    print()
    print("Message data:")
    print("C<channel>/<replychannel> D:<distance>: ")
    print()
    print("To send a message:")
    print("<channel> <message>")
    print("and press enter")
    while true do
        local e = {os.pullEvent()}
        if e[1] == "mouse_click" and e[2] == 1 and e[3] == w and e[4] == 1 then
            RUNNING = false
            break
        elseif e[1] == "mouse_click" and e[2] == 1 and e[3] >= w-4 and e[3] <= w-2 and e[4] == 1 then
            break
        elseif e[1] == "modem_message" then -- Receiving messages
            local temp = "C"..e[3].."/"..e[4].." D:"..e[6]..": "
            if type(e[5]) == "table" then
                if e[5].message:len() + temp:len() > w then -- text wrapping
                    table.insert(data, temp .. string.sub(e[5].message,1,w - temp:len()))
                    for i = w-temp:len()+1,e[5].message:len(),w do
                        table.insert(data, string.sub(e[5].message,i,i+w))
                    end
                else
                    table.insert(data, temp .. e[5].message)
                end
            else
                if e[5]:len() + temp:len() > w then -- text wrapping
                    table.insert(data, temp .. string.sub(e[5],1,w - temp:len()))
                    for i = w-temp:len()+1,e[5]:len(),w do
                        table.insert(data, string.sub(e[5],i,i+w))
                    end
                else
                    table.insert(data, temp .. e[5])
                end
            end
            pospossible = #data-(h-3)
            if pospossible < 1 then pospossible = 1 end
            scrollpos = pospossible
        end
    end
end
local function evtListen()
    openRange()
    drawScreen()
    term.setBackgroundColor(colors.gray)
    term.setCursorPos(3,h)
    local xread = 3
    local cursor = os.startTimer(0.3)
    while RUNNING do
        local e = {os.pullEvent()}
        if e[1] == "modem_message" then -- Receiving messages
            local temp = "C"..e[3].."/"..e[4].." D:"..e[6]..": "
            if type(e[5]) == "table" then
                if e[5].message:len() + temp:len() > w then -- text wrapping
                    table.insert(data, temp .. string.sub(e[5].message,1,w - temp:len()))
                    for i = w-temp:len()+1,e[5].message:len(),w do
                        table.insert(data, string.sub(e[5].message,i,i+w))
                    end
                else
                    table.insert(data, temp .. e[5].message)
                end
            else
                if e[5]:len() + temp:len() > w then -- text wrapping
                    table.insert(data, temp .. string.sub(e[5],1,w - temp:len()))
                    for i = w-temp:len()+1,e[5]:len(),w do
                        table.insert(data, string.sub(e[5],i,i+w))
                    end
                else
                    table.insert(data, temp .. e[5])
                end
            end
            pospossible = #data-(h-3)
            if pospossible < 1 then pospossible = 1 end
            scrollpos = pospossible
            drawListen()
        elseif e[1] == "mouse_scroll" then -- Mouse Input
            if e[2] == 1 and scrollpos < pospossible then
                scrollpos = scrollpos+1
                drawListen()
            elseif e[2] == -1 and scrollpos > 1 then
                scrollpos = scrollpos-1
                drawListen()
            end
        elseif e[1] == "mouse_click" and e[2] == 1 and e[3] == w and e[4] == 1 then
            RUNNING = false
        elseif e[1] == "mouse_click" and e[2] == 1 and e[3] >= w-4 and e[3] <= w-2 and e[4] == 1 then
            helpMenu()
            drawScreen()
            cursor = os.startTimer(0.3)
        elseif e[1] == "key" then -- custom read() function
            if e[2] == keys.enter then
                processInput()
                input = ""
                xread = 3
                drawBottomBar()
            elseif e[2] == keys.backspace and input ~= "" then
                input = string.sub(input,1,input:len()-1)
                xread = xread-1
                term.setBackgroundColor(colors.gray)
                term.setCursorPos(xread,h)
                term.write("  ")
                term.setCursorPos(xread,h)
            end
        elseif e[1] == "char" then
            input = input .. e[2]
            term.setBackgroundColor(colors.gray)
            term.setCursorPos(xread,h)
            term.write(e[2])
            xread = xread+1
        elseif e[1] == "timer" and e[2] == cursor then
            if blink then term.setBackgroundColor(colors.lightGray)
            else term.setBackgroundColor(colors.gray) end
            term.setCursorPos(xread,h)
            term.write(" ")
            blink = not blink
            cursor = os.startTimer(0.3)
        end
    end
end
scanPeripherals()
if RUNNING then
    parallel.waitForAll(evtListen, userInput)
    term.setBackgroundColor(colors.black)
    term.clear()
    term.setCursorPos(1,1)
    m.closeAll()
end