Intercept

-- Rednet activity logger, written by PaymentOption --
-- Freeware as long as proper credits are given --

-- HTTP related methods --
function GetTimePage()
    local sRespone = nil
    local sLine = ""

    sResponse = http.get( "http://www.timeanddate.com/library/abbreviations/timezones/na/pst.html" )

    if sResponse then
        for nLine = 1, 31 do
            sLine = sResponse.readLine()
        end
        sResponse.close()

        return true, sLine
    else
        return false, nil
    end
end

function GetTimeFromLine()
    local bSuccess, sLine = GetTimePage()

    if bSuccess then
        _, nTimePos = string.find( sLine, '<span id="ij0">' )
        nEndTimePos = string.find( sLine, '</span>', nTimePos )

        local sTime = string.sub( sLine, nTimePos + 1, nEndTimePos - 1 )
        return sTime
    else
        return nil
    end
end
--------------------------

-- Variables --
nScreenWidth, nScreenHeight = term.getSize()

nLines = 0
sTime = GetTimeFromLine()
sDirectory = "Rednet_Logs"
file = nil

sStatus = "Logging"

-- Check if the log file already exists --
if not fs.exists( sDirectory ) then
    fs.makeDir( sDirectory )
end

local tLogFiles = fs.list( sDirectory )
file = fs.open( sDirectory .. "/" .. #tLogFiles+1 .. "_Log" , "w" )
tLogFile = nil -- Remove the variable from memeory.
------------------------------------------
---------------

-- GUI Methods --
function printCentered( nHeight, sString )
    term.setCursorPos( nScreenWidth/2 - string.len( sString )/2, nHeight )
    term.write( sString )
end

function printRight( nHeight, sString )
    term.setCursorPos( nScreenWidth - string.len( sString ), nHeight )
    term.write( sString )
end

function printBorder()
    term.setCursorPos( 1, 1 )
    term.write( "+" .. string.rep( "-", nScreenWidth - 2 ) .. "+" )

    for nHeight = 2, nScreenHeight - 1 do
        term.setCursorPos( 1, nHeight )
        term.write( "|" )

        term.setCursorPos( nScreenWidth, nHeight )
        term.write( "|" )
    end

    term.setCursorPos( 1, nScreenHeight )
    term.write( "+" .. string.rep( "-", nScreenWidth - 2 ) .. "+" )

    printRight( nScreenHeight - 1, "[S]top" )
end

function printStatus( nHeight )
    printCentered( nHeight, sStatus .. "..." )
    printCentered( nHeight + 2, "Messages logged: " .. nLines )

    term.setCursorPos( 2, nScreenHeight - 1 )
    term.write( "Rednet Logger by PaymentOption")
end

function clearScreen()
    term.clear()
    term.setCursorPos( 1, 1 )
end
-----------------

-- Interception Methods --
function interceptMessages()
    while true do
        local nSender, sMessage = rednet.receive()
        sTime = GetTimeFromLine()

        file.writeLine( sTime .. ":" .. nSender .. ":" .. sMessage )
        nLines = nLines + 1
        printStatus( 2 )
    end
end

function openExistantModem()
    local tSides = rs.getSides()

    for index, side in ipairs( tSides ) do
        if peripheral.isPresent( side ) and peripheral.getType( side ) == "modem" then
            rednet.open( side )
            return true
        end
    end

    return false
end

function waitForKeyPress()
    while true do
        local t = os.startTimer( 0.2 )
        local event, key = os.pullEvent()

        if event == "timer" and key == t then
            return
        elseif event == "key" and key == 31 then
            file.close()
            clearScreen()
            printBorder()
            printCentered( 9, "System rebooting..." )
            os.reboot()
        end
    end
end
--------------------------

-- Main loop --
-- Check if a modem exists.
if not openExistantModem() then
    error( "No modem found." )
end

while true do
    clearScreen()
    printBorder()
    printStatus( 2 )

    parallel.waitForAny( waitForKeyPress, interceptMessages )
end
---------------