[ccraft]Factionet

--  Title: Factionet
--
--  Version: 1.1
--
--  Description: A fairly advanced messaging tool for
--  ComputerCraft. Is both a client and sever rolled into
--  one. Neat GUI and other features.
--
--  Author: margeobur

--test for non-advanced computer:
if not term.isColor() then
    print("Sorry, this program must be run on an advanced")
    print("computer. Press any key to continue...")
    os.pullEvent("key")
    return false
end

-- *** Global Variables (but local to the program) ***
local rootDir = shell.dir()
local hosting = false
local serverName = ""
local running = false

local chatList = {}         --complete history of chat lines
local chatScreenList = {}   --list of lines of chat on the screen
local lastLine = 0          --indice of the last line in the complete history of chat
local lastScreenLine = 0    --indice of the last line in the list of chat lines on screen
local scrollAmount = 0
local chatExistsAlready = false

local userList = {}
local userScreenList = {}
local lastULline = 0
local lastULScreenLine = 0
local ULscrollAmount = 0
local usersAlreadyOn = false

local hostID, myID = nil, os.getComputerID()
local channelOne = nil
local channelTwo = nil
local modem = nil
local modemSide = ""

--hosting variables
local sessionList = {}
local noSessions = 0
local newSession = nil
local sFilePath = nil
local sPassword = ""
local userList = {}

--client variables
local myuser = ""

-- **************** Functions ********************

--[[
eWrite():
    Boy, has this saved space!
]]
local function eWrite(pstring, xCoord, yCoord)
    term.setCursorPos(xCoord,yCoord)
    term.write(pstring)
end

--[[
getLine() and writeLine():
    Well, I was going to use these functions
    but I didn't end up needing them...
]]
local function getLine(filePath,lineNumber)
    if not fs.exists(filePath) then
        return false
    end
    local text = ""
    local fileHandle = fs.open(filePath, "r")
    for i=1,lineNumber do
        text = fileHandle.readLine()
        if not text then
            break
        end
    end
    fileHandle.close()
    if not text then
        return false
    else
        return text
    end
end

local function writeLine(filePath,lineNumber,newText)
    if not fs.exists(filePath) then
        return false
    end
    if type(newText) ~= "string" then
        return false
    end
    local beforeLine, afterLine = "", ""
    local currentLine, i, j = 1, 0, 0           -- i will be the indice of
    local fileHandle = fs.open(filePath, "r")   -- our wanted newline and j
    local wholeFile = fileHandle.readAll()      -- will be the indice of the
    fileHandle.close()                          -- next newline
    for w in string.gmatch(wholeFile, "%a") do
        if w == "\n" then
            currentLine = currentLine + 1
        end
        if currentLine <= lineNumber then
            i = i + 1
        end
        if currentLine <= lineNumber + 1 then
            j = j + 1
        end
    end
    if currentLine < lineNumber then    -- i.e. if lineNumber is past the file
        return nil
    else
        beforeLine = string.sub(wholeFile, 1 , i)
        afterLine = string.sub(wholeFile, j)
        wholeFile = beforeLine .. newText .. afterLine
        fileHandle = fs.open(filePath, "w")
        fileHandle.write(wholeFile)
        fileHandle.close()
        return true -- returns true on success
    end
end





-- ******* Menu Software ******

--[[
displayHomeScreen():
    This displays the FactioNET logo in the menu.
    I looked at the paintutils api to see how files
    were loaded so that I could just 'make' the image
    in-program instead of having a file with the image.
]]
local function displayHomeScreen()
    local image = {}
    image[1] = "                         dd   d ddd ddddd"
    image[2] = "dddd ddd ddd ddd ddd ddd d d  d d     d"
    image[3] = "d    d d d    d   d  d d d  d d ddd   d"
    image[4] = "ddd  ddd d    d   d  d d d   dd d     d"
    image[5] = "d    d d ddd  d  ddd ddd d    d ddd   d"

    term.setBackgroundColour(colours.white)
    term.setTextColour(colours.black)
    term.clear()

    --** coppied direct from paintutils **
    local tColourLookup = {}
    for n=1,16 do
        tColourLookup[ string.byte( "0123456789abcdef",n,n ) ] = 2^(n-1)
    end

    local tImage= {}
    local i = 1
    local sLine = image[i]
    while sLine do
        local tLine = {}
        for x=1,sLine:len() do
            tLine[x] = tColourLookup[ string.byte(sLine,x,x) ] or 0
        end
        table.insert( tImage, tLine )
        i = i + 1
        sLine = image[i]
    end

    --**

    paintutils.drawImage(tImage, 6,3)
    term.setBackgroundColour(colours.white)
    term.setTextColour(colours.red)
    eWrite("by margeobur", 40,8)
end

--[[
displayExit():
    ditto
]]
local function displayExit()
    term.setBackgroundColour(colours.white)
    term.setTextColour(colours.black)
    term.clear()

    local image = {}
    image[1] = "eee   e   e  eeee"
    image[2] = "e  e   e e   e   "
    image[3] = "eee     e    eeee"
    image[4] = "e  e    e    e   "
    image[5] = "eee     e    eeee"

    local tColourLookup = {}
    for n=1,16 do
        tColourLookup[ string.byte( "0123456789abcdef",n,n ) ] = 2^(n-1)
    end

    local tImage= {}
    local i = 1
    local sLine = image[i]
    while sLine do
        local tLine = {}
        for x=1,sLine:len() do
            tLine[x] = tColourLookup[ string.byte(sLine,x,x) ] or 0
        end
        table.insert( tImage, tLine )
        i = i + 1
        sLine = image[i]
    end

    paintutils.drawImage(tImage, 17,8)
end

--[[
homeMenu():
    Determines what the user wants to do.
    it returns values to determine what happens
    in the main loop. I created this first, so it
    is rather disorganised, but it gets the job
    done.
]]
local function homeMenu()
    while true do
        displayHomeScreen()
        for i=11, 17 do
            paintutils.drawLine(14,i,37,i,colours.lightGrey)
        end
        term.setTextColour(colours.black)
        paintutils.drawLine(16,12,35,12,colours.white)
        eWrite("Host",24,12)
        paintutils.drawLine(16,14,35,14,colours.white)
        eWrite("Join",24,14)
        paintutils.drawLine(16,16,35,16,colours.white)
        eWrite("Exit",24,16)

        local event, button, xCoord, yCoord = os.pullEvent("mouse_click")

        if xCoord > 15 and xCoord < 36 and yCoord == 12 then    --Host

            while true do
                for i=11, 17 do
                    paintutils.drawLine(14,i,37,i,colours.lightGrey)
                end
                paintutils.drawLine(16,12,35,12,colours.white)
                paintutils.drawLine(16,14,35,14,colours.white)
                paintutils.drawLine(16,16,35,16,colours.white)
                eWrite("New Server",21,12)
                eWrite("Restore a Server",18,14)
                eWrite("Back",24,16)
                eWrite("                          ",14,18)

                event, button, xCoord, yCoord = os.pullEvent("mouse_click")

                if xCoord > 15 and xCoord < 36 and yCoord == 12 then    --New Server
                    for i=11, 17 do
                        paintutils.drawLine(14,i,37,i,colours.lightGrey)
                    end
                    eWrite("   Enter your chat    ",16,12)
                    eWrite("   server's name*     ",16,13)
                    paintutils.drawLine(16,14,35,14,colours.white)
                    paintutils.drawLine(16,16,25,16,colours.white)
                    eWrite("Back",19,16)
                    paintutils.drawLine(27,16,35,16,colours.white)
                    eWrite("Confirm",28,16)
                    eWrite("*This can only be set once",14,18)
                    while true do
                        event, button, xCoord, yCoord = os.pullEvent("mouse_click")
                        if xCoord > 15 and xCoord < 36 and yCoord == 14 then    -- enter server name
                            paintutils.drawLine(16,14,35,14,colours.white)
                            term.setCursorPos(16,14)
                            serverName = ""
                            serverName = read()
                        elseif xCoord > 26 and xCoord < 36 and yCoord == 16 and serverName then --confirm
                            for i=11, 17 do
                                paintutils.drawLine(14,i,37,i,colours.lightGrey)
                            end
                            term.setBackgroundColour(colours.lightGrey)
                            eWrite("   Enter your chat    ",16,12)
                            eWrite("  server's password   ",16,13)
                            term.setBackgroundColour(colours.white)
                            eWrite("                          ",14,18)
                            paintutils.drawLine(16,14,35,14,colours.white)
                            paintutils.drawLine(16,16,25,16,colours.white)
                            eWrite("Back",19,16)
                            paintutils.drawLine(27,16,35,16,colours.white)
                            eWrite("Start!",29,16)
                            while true do
                                event, button, xCoord, yCoord = os.pullEvent("mouse_click")
                                if xCoord > 15 and xCoord < 36 and yCoord == 14 then    --enter server password
                                    paintutils.drawLine(16,14,35,14,colours.white)
                                    term.setCursorPos(16,14)
                                    sPassword = read()
                                elseif xCoord > 26 and xCoord < 36 and yCoord == 16 then    --start the server
                                    sFilePath = rootDir .. "/sessions/" .. serverName
                                    newSession = true
                                    while true do
                                        for i=11, 17 do
                                            paintutils.drawLine(14,i,37,i,colours.lightGrey)
                                        end
                                        hostID = myID
                                        eWrite("The ID to connect to",16,12)
                                        eWrite("is ".. hostID,23,13)
                                        eWrite("Click to continue...",16,15)
                                        os.pullEvent("mouse_click")
                                        return 1
                                    end
                                elseif xCoord > 15 and xCoord < 26 and yCoord == 16 then    --back
                                    break
                                end
                            end
                        elseif xCoord > 15 and xCoord < 26 and yCoord == 16 then    --back
                            break
                        end
                    end

                elseif xCoord > 15 and xCoord < 36 and yCoord == 14 then    --Restore a Server
                    local selectedSession = nil
                    local posOne, posTwo, posThree = nil, nil, nil

                    if not fs.exists(rootDir .. "/sessions") then
                        fs.makeDir(rootDir .. "/sessions")
                    end
                    for i=10, 18 do
                        paintutils.drawLine(14,i,37,i,colours.lightGrey)
                    end
                    for i=11,13 do
                        paintutils.drawLine(16,i,34,i,colours.white)
                    end
                    paintutils.drawLine(16,15,25,15,colours.white)
                    eWrite("Delete",18,15)
                    paintutils.drawLine(27,15,35,15,colours.white)
                    eWrite("Select",28,15)
                    paintutils.drawLine(16,17,35,17,colours.white)
                    eWrite("Back",24,17)
                    paintutils.drawLine(35,11,35,13,colours.lightBlue)
                    term.setTextColour(colours.blue)
                    eWrite("^",35,11)
                    eWrite("v",35,13)
                    term.setTextColour(colours.black)
                    term.setBackgroundColour(colours.white)

                    sessionList = fs.list(rootDir .. "/sessions")
                    noSessions = 0
                    for i, v in ipairs(sessionList) do
                        noSessions = noSessions + 1
                    end
                    if noSessions > 0 then
                        eWrite(sessionList[1],16,11)
                    end
                    if noSessions > 1 then
                        eWrite(sessionList[2],16,12)
                    end
                    if noSessions > 2 then
                        eWrite(sessionList[3],16,13)
                    end
                    posOne = 1
                    posTwo = 2
                    posThree = 3

                    while true do
                        event, button, xCoord, yCoord = os.pullEvent("mouse_click")
                        if xCoord == 35 and yCoord == 13 then       -- scroll down
                            if noSessions > 3 and posThree ~= noSessions then
                                eWrite("                   ",16,11)
                                eWrite(sessionList[posTwo],16,11)
                                posOne = posOne + 1
                                eWrite("                   ",16,12)
                                eWrite(sessionList[posThree],16,12)
                                posTwo = posTwo + 1
                                eWrite("                   ",16,13)
                                eWrite(sessionList[posThree + 1],16,13)
                                posThree = posThree + 1
                            end
                        elseif xCoord == 35 and yCoord == 11 then       -- scroll up
                            if noSessions > 3 and posOne ~= 1 then
                                eWrite("                   ",16,11)
                                eWrite(sessionList[posOne - 1],16,11)
                                posOne = posOne - 1
                                eWrite("                   ",16,12)
                                eWrite(sessionList[posTwo - 1],16,12)
                                posTwo = posTwo - 1
                                eWrite("                   ",16,13)
                                eWrite(sessionList[posThree - 1],16,13)
                                posThree = posThree - 1
                            end
                        elseif xCoord > 15 and xCoord < 36 and yCoord == 11 then    --select first list item
                            paintutils.drawLine(16,11,34,11,colours.lime)
                            paintutils.drawLine(16,12,34,12,colours.white)
                            paintutils.drawLine(16,13,34,13,colours.white)
                            term.setBackgroundColour(colours.lime)
                            eWrite(sessionList[posOne],16,11)
                            term.setBackgroundColour(colours.white)
                            eWrite(sessionList[posTwo],16,12)
                            eWrite(sessionList[posThree],16,13)
                            selectedSession = sessionList[posOne]

                        elseif xCoord > 15 and xCoord < 36 and yCoord == 12 then    --select second list item
                            paintutils.drawLine(16,11,34,11,colours.white)
                            paintutils.drawLine(16,12,34,12,colours.lime)
                            paintutils.drawLine(16,13,34,13,colours.white)
                            term.setBackgroundColour(colours.white)
                            eWrite(sessionList[posOne],16,11)
                            term.setBackgroundColour(colours.lime)
                            eWrite(sessionList[posTwo],16,12)
                            term.setBackgroundColour(colours.white)
                            eWrite(sessionList[posThree],16,13)
                            selectedSession = sessionList[posTwo]

                        elseif xCoord > 15 and xCoord < 36 and yCoord == 13 then    --select third list item
                            paintutils.drawLine(16,11,34,11,colours.white)
                            paintutils.drawLine(16,12,34,12,colours.white)
                            paintutils.drawLine(16,13,34,13,colours.lime)
                            term.setBackgroundColour(colours.white)
                            eWrite(sessionList[posOne],16,11)
                            eWrite(sessionList[posTwo],16,12)
                            term.setBackgroundColour(colours.lime)
                            eWrite(sessionList[posThree],16,13)
                            selectedSession = sessionList[posThree]
                            term.setBackgroundColour(colours.white)

                        elseif xCoord > 15 and xCoord < 26 and yCoord == 15 and selectedSession then    --delete
                            paintutils.drawLine(15,15,36,15,colours.lightGrey)
                            eWrite("Are you sure you want",15,15)
                            eWrite("to delete that save?",15,16)
                            paintutils.drawPixel(26,17,colours.lightGrey)
                            term.setBackgroundColour(colours.white)
                            eWrite("Yes    ",19,17)
                            eWrite("   No",27,17)

                            while true do
                                event, button, xCoord, yCoord = os.pullEvent("mouse_click")
                                if xCoord > 15 and xCoord < 26 and yCoord == 17 then
                                    fs.delete(rootDir .. "/sessions/" .. selectedSession)
                                    sessionList = fs.list(rootDir .. "/sessions")
                                    noSessions = 0
                                    for i, v in ipairs(sessionList) do
                                        noSessions = noSessions + 1
                                    end
                                    if noSessions > 0 then
                                        eWrite("                   ",16,11)
                                        eWrite(sessionList[1],16,11)
                                    end
                                    if noSessions > 1 then
                                        eWrite("                   ",16,12)
                                        eWrite(sessionList[2],16,12)
                                    end
                                    if noSessions > 2 then
                                        eWrite("                   ",16,13)
                                        eWrite(sessionList[3],16,13)
                                    end
                                    posOne = 1
                                    posTwo = 2
                                    posThree = 3
                                    selectedSession = nil
                                    break
                                elseif xCoord > 26 and xCoord < 36 and yCoord == 17 then
                                    break
                                end
                            end


                            for i=15,16 do
                                paintutils.drawLine(15,i,36,i,colours.lightGrey)
                            end
                            paintutils.drawLine(16,15,25,15,colours.white)
                            eWrite("Delete",18,15)
                            paintutils.drawLine(27,15,35,15,colours.white)
                            eWrite("Select",28,15)
                            paintutils.drawLine(16,17,35,17,colours.white)
                            eWrite("Back",24,17)


                        elseif xCoord > 26 and xCoord < 36 and yCoord == 15  then   --confirm
                            serverName = selectedSession
                            sFilePath = rootDir .. "/sessions/" .. serverName
                            newSession = false
                            return 2

                        elseif xCoord > 15 and xCoord < 36 and yCoord == 17 then --back
                            paintutils.drawLine(14,10,37,10,colours.white)
                            paintutils.drawLine(14,18,37,10,colours.white)
                            break
                        end
                    end

                elseif xCoord > 15 and xCoord < 36 and yCoord == 16 then    --back
                    break
                end
            end

        elseif xCoord > 15 and xCoord < 36 and yCoord == 14 then    --Join
            while true do
                for i=11, 17 do
                    paintutils.drawLine(14,i,37,i,colours.lightGrey)
                end
                eWrite("Enter your host's",18,12)
                eWrite("ID.",25,13)
                paintutils.drawLine(16,14,35,14,colours.white)
                eWrite(hostID,16,14)
                paintutils.drawLine(16,16,25,16,colours.white)
                eWrite("Back",19,16)
                paintutils.drawLine(27,16,35,16,colours.white)
                eWrite("Connect",28,16)

                event, button, xCoord, yCoord = os.pullEvent("mouse_click")
                if xCoord > 15 and xCoord < 35 and yCoord == 14 then    --enter ID
                    hostID = -1
                    while hostID < 0 do
                        for i=11, 17 do
                            paintutils.drawLine(14,i,37,i,colours.lightGrey)
                        end
                        eWrite("Enter your host's",18,12)
                        eWrite("ID.",25,13)
                        paintutils.drawLine(16,14,35,14,colours.white)
                        paintutils.drawLine(16,16,25,16,colours.white)
                        eWrite("Back",19,16)
                        paintutils.drawLine(27,16,35,16,colours.white)
                        eWrite("Connect",28,16)

                        term.setCursorPos(16,14)
                        local temp = read()
                        hostID = tonumber(temp)
                        if not hostID or hostID < 0 then
                            for i=12, 16 do
                                paintutils.drawLine(14,i,37,i,colours.lightGrey)
                            end
                            eWrite("Error, the ID can't",16,13)
                            eWrite(" be below 0 or have",16,14)
                            eWrite("      letters      ",16,15)
                            hostID = -1
                            os.pullEvent("mouse_click")
                        end
                    end

                elseif xCoord > 26 and xCoord < 36 and yCoord == 16 then    --connect
                    return 3

                elseif xCoord > 15 and xCoord < 26 and yCoord == 16 then    --back
                    break
                end
            end
        elseif xCoord > 15 and xCoord < 36 and yCoord == 16 then    --Exit
            break
        end
    end
    return 0
end

-- ***** General Software *****
-- functions for both client and host

--[[ displayLoadScreen(): Dunno why I made this XD
    I derped a bit (it is only used once) ]]
local function displayLoadScreen()
    term.setBackgroundColour(colours.white)
    term.clear()
    for i=9,12 do
        paintutils.drawLine(18,i,33,i,colours.lightGrey)
    end
    eWrite("Starting",22,10)
    eWrite("server ...",21,11)
end

--[[
setupGUI():
    This function draws everything to the screen on
    server startup/after connecting. If the host has
    loaded a save and there is already chat, the chat
    is printed. Likewise if there are already users on
    or chat in the history, this will draw those for the
    client.
]]
local function setupGUI()
    term.setBackgroundColour(colours.white)
    term.clear()

    --HotBar
    paintutils.drawLine(1,1,6,1,colours.orange)
    eWrite("[Menu]",1,1)
    paintutils.drawLine(7,1,51,1,colours.grey)
    term.setTextColour(colours.green)
    eWrite("FactioNET | Server:",20,1)
    term.setTextColour(colours.orange)
    eWrite(serverName,40,1)
    term.setTextColour(colours.black)

    --Chat Window
    paintutils.drawLine(1,2,51,2,colours.lightGrey)
    eWrite("Messages:",1,2)
    paintutils.drawLine(34,3,34,15,colours.lightBlue)
    term.setTextColour(colours.blue)
    eWrite("^",34,3)
    eWrite("v",34,15)
    term.setTextColour(colours.black)
    paintutils.drawLine(35,2,35,19,colours.lightGrey)

    if chatExistsAlready then
        term.setBackgroundColour(colours.white)
        for i=1,lastScreenLine do
            eWrite(chatScreenList[i],1,i + 2)
        end
    end

    --Message Composition Window
    paintutils.drawLine(1,16,35,16,colours.lightGrey)
    eWrite("Compose a message:",1,16)
    paintutils.drawLine(29,17,29,19,colours.lightBlue)
    term.setTextColour(colours.black)
    term.setTextColour(colours.blue)
    eWrite("^",29,17)
    eWrite("v",29,19)
    term.setTextColour(colours.black)
    for i=17,19 do
        paintutils.drawLine(30,i,34,i,colours.lightGrey)
    end
    term.setBackgroundColour(colours.orange)
    eWrite("Send",31,18)

    --Player List
    term.setBackgroundColour(colours.lightGrey)
    eWrite("Players in Chat:",36,2)
    paintutils.drawLine(51,3,51,19,colours.lightBlue)
    term.setTextColour(colours.blue)
    eWrite("^",51,3)
    eWrite("v",51,19)
    term.setTextColour(colours.black)

    if usersAlreadyOn then
        term.setBackgroundColour(colours.white)
        for i=1,lastULScreenLine do
            eWrite(userScreenList[i],36,i + 2)
        end
    end
end

--[[
readMessage():
    Custom read() to stop text from overflowing
    in the message composing box.
]]
local function readMessage()
    term.setBackgroundColour(colours.white)
    term.setTextColour(colours.black)
    local event, param1, param2, param3 = nil,nil,nil,nil
    local currentX, currentY = 1,17
    local string2send = ""
    term.setCursorBlink(true)
    eWrite(" ",0,17)
    while true do
        event, param1, param2, param3 = os.pullEvent()
        if event == "key" then
            if param1 == keys.backspace then
                if currentX == 1 and currentY == 17 then
                    -- do nothing because we can't backspace
                else
                    --remove the last character in our string
                    local temp = string.sub(string2send, 1 , -2)
                    string2send = temp
                end
                if currentX > 1 then
                    eWrite(" ",currentX - 1, currentY)
                    currentX = currentX - 1
                    term.setCursorPos(currentX, currentY)
                elseif currentX == 1 and currentY ~= 17 then
                    eWrite(" ",28,currentY - 1)
                    currentX = 28
                    currentY = currentY - 1
                    term.setCursorPos(currentX, currentY)
                end
            elseif param1 == keys.enter then
                term.setCursorBlink(false)
                for i = 17,19 do
                    paintutils.drawLine(1,i,28,i,colours.white)
                end
                return string2send
            end
        elseif event == "char" then
            if currentX == 28 and currentY < 19 then
                eWrite(param1,currentX,currentY)
                currentX = 1
                currentY = currentY + 1
                term.setCursorPos(currentX, currentY)
                string2send = string2send .. param1
            elseif currentX == 28 and currentY == 19 then
            else
                eWrite(param1,currentX,currentY)
                currentX = currentX + 1
                string2send = string2send .. param1
            end
        elseif event == "mouse_click" then
            if param2 > 30 and param2 < 35 and param3 == 18 then    --send
                term.setCursorBlink(false)
                for i = 17,19 do
                    paintutils.drawLine(1,i,28,i,colours.white)
                end
                return string2send
            end
        end
    end
end

--[[
hotBarMenu():
    A shared menu for the host and client. It
    currently only has one option, and that's 'logout'.
    The function returns a value that either clientUI()
    or hostUI() acts on.
]]
local function hotBarMenu()
    local event, param1, param2, param3 = nil,nil,nil,nil
    for i=2,4 do
        paintutils.drawLine(1,i,6,i, colours.orange)
    end
    eWrite("Logout",1,4)
    while true do
        event, param1, param2, param3 = os.pullEvent("mouse_click")
        if param2 < 7 and param3 == 4 then
            term.setBackgroundColour(colours.red)
            eWrite("Logout",1,4)
            sleep(0.2)
            return 1
        elseif param2 > 7 or param3 > 4 then
            term.setTextColour(colours.black)
            term.setBackgroundColour(colours.lightGrey)
            eWrite("Messages:",1,2)
            term.setBackgroundColour(colours.white)
            eWrite("                                 ",1,3)
            eWrite(chatScreenList[1],1,3)
            eWrite("                                 ",1,4)
            eWrite(chatScreenList[2],1,4)
            return 0
        end
    end
end

--[[
scrollChatWindow:
    This scrolls the contents of the chat
    window, and changes chatScreenList and
    chatList appropriately. First, however
    it tests to see if we should be able to
    scroll up or down or at all.
]]
local function scrollChatWindow(amount)
    local temp = 0
    local bottomRef = 0
    local topRef = 0

    if lastScreenLine < 13 then
        return false
    elseif chatScreenList[1] == chatList[1] and amount < 0 then
        return false
    elseif scrollAmount + 13 == lastLine
    and amount > 0 then
        return false
    end

    if amount > 0 then
        bottomRef = scrollAmount + 13
        -- this is the position on chatList that is equivalent
        -- to the current last line on the screen
    elseif amount < 0 then
        topRef = scrollAmount
        -- this is the position on chatList that is equivalent
        -- to the current first line on the screen
    end

    if amount == 1 then --scroll down once
        temp = 1
        for j=1, 12 do
            eWrite("                                 ",1,temp + 2)
            eWrite(chatScreenList[temp + 1],1,temp + 2)
            chatScreenList[j] = chatScreenList[j + 1]
            temp = temp + 1
        end
        chatScreenList[13] = chatList[bottomRef + 1]
        eWrite("                                 ",1,15)
        eWrite(chatScreenList[13],1,15)
        scrollAmount = scrollAmount + 1
    end
    if amount == -1 then    --scroll up once
        temp = 13
        for j=1, 12 do
            eWrite("                                 ",1,temp + 2)
            eWrite(chatScreenList[temp - 1],1,temp + 2)
            chatScreenList[temp] = chatScreenList[temp - 1]
            temp = temp - 1
        end
        chatScreenList[1] = chatList[topRef]
        eWrite("                                 ",1,3)
        eWrite(chatScreenList[1],1,3)
        scrollAmount = scrollAmount - 1
    end

    return true
end

--[[
printChatWindow():
    OMG THIS WAS SO HARD.
    This is what organises your raw chat message
    into lines with complete words, but stops them from
    overflowing. It then prints them in the chat box.
    This is a handy function because you can use it
    to print anything to the chat window.
]]

local function printChatWindow(wholeMessage)
    local lines = {}
    lines[1] = ""
    lines[2] = ""
    lines[3] = ""
    local numbLines = 0
    local messageLength = string.len(wholeMessage)
    if messageLength > 99 then
        wholeMessage = string.sub(wholeMessage,1,99)
    end
    local word, w = "", ""
    local i,j = 1,1
    local wrapOffset1 = 0
    local wrapOffset2 = 0

    term.setBackgroundColour(colours.white)
    term.setTextColour(colours.black)

    for w in string.gmatch(wholeMessage, ".") do
        if w == " " then
            if i == 33 or i == 66 then
                lines[j] = lines[j] .. word
                word = ""
            else
                lines[j] = lines[j] .. word .. " "
                word = ""
            end
        else
            word = word .. w
        end

        if i == 33 then
            -- if the 1st pixel of the 2nd line contains a
            -- space and is the equivalent of the last character
            -- in wholeMessage, do nothing because the second
            -- line would just be blank otherwise
            if messageLength == 34 and
                string.sub(wholeMessage,34,34) == " " then

            else
                j = 2
                i = 32 + string.len(word)
                wrapOffset1 = string.len(word)
            end

        elseif i == 66 then
            -- if the 1st pixel of the 3rd line contains a
            -- space and is the equivalent of the last character
            -- in wholeMessage, do nothing because the third
            -- line would just be blank otherwise
            if messageLength + wrapOffset1 == 67 and
                string.sub(wholeMessage,messageLength,messageLength) == " " then

            else
                if string.len(word) >= 33 then
                    lines[j] = lines[j] .. string.sub(word,1,33)
                    word = ""
                end
                j = 3
                i = 65 + string.len(word)
                wrapOffset2 = string.len(word)
            end
        end
        i = i + 1
    end
    if string.len(word) > 33 then
        word = string.sub(word,1,33)
        lines[j] = lines[j] .. word
        numbLines = j
    else
        lines[j] = lines[j] .. word
        numbLines = j
    end

    if lastLine < 13 then
        for i=1,numbLines do
            eWrite("                                 ",1,lastScreenLine + 3)
            eWrite(lines[i],1,lastScreenLine + 3)
            lastScreenLine = lastScreenLine + 1
            chatScreenList[lastScreenLine] = lines[i]
            lastLine = lastLine + 1
            chatList[lastLine] = lines[i]
            if lastScreenLine >= 13 then
                for j=i+1,numbLines do
                    lastLine = lastLine + 1
                    chatList[lastLine] = lines[j]
                end
                scrollChatWindow(numbLines - i)
                break
            end
        end
    elseif lastLine == 100 then
        for i=1,numbLines do
            for j=1,99 do
                chatList[j] = chatList[j + 1]
            end
            chatList[100] = lines[i]

            for j=1, 13 do
                chatScreenList[j] = chatList[scrollAmount + j]
                eWrite("                                 ",1,j + 2)
                eWrite(chatScreenList[j],1,j + 2)
            end
        end
    else
        for i=1,numbLines do
            lastLine = lastLine + 1
            chatList[lastLine] = lines[i]
            scrollChatWindow(1)
        end
    end
end

--[[
scrollUserList():
    Like scrollChatWindow() but for the user list.
    I'm not sure if it would work well... I haven't
    tried having that many users on.
]]
local function scrollUserList(amount)
    local temp = 0
    local bottomRef = 0
    local topRef = 0

    if lastULScreenLine < 17 then
        return false
    elseif ULscrollAmount == 0 and amount < 0 then
        return false
    elseif ULscrollAmount + 17 == lastULline
    and amount > 0 and lastULline > 17 then
        return false
    end

    if amount > 0 then
        bottomRef = ULscrollAmount + 17
        -- this is the position on userList that is equivalent
        -- to the current last user displayed on the screen
    elseif amount < 0 then
        topRef = ULscrollAmount
        -- this is the position on userList that is equivalent
        -- to the current first user displayed on the screen
    end

    term.setBackgroundColour(colours.white)

    if amount == 1 then --scroll down once
        temp = 1
        for j=1, 16 do
            eWrite("               ",36,temp + 2)
            eWrite(userScreenList[temp + 1],36,temp + 2)
            userScreenList[j] = userScreenList[j + 1]
            temp = temp + 1
        end
        userScreenList[17] = userList[bottomRef + 1]
        eWrite("               ",36,19)
        eWrite(userScreenList[17],36,19)
        ULscrollAmount = ULscrollAmount + 1
    end
    if amount == -1 then    --scroll up once
        temp = 17
        for j=1, 16 do
            eWrite("               ",36,temp + 2)
            eWrite(userScreenList[temp - 1],36,temp + 2)
            userScreenList[temp] = userScreenList[temp - 1]
            temp = temp - 1
        end
        userScreenList[1] = userList[topRef]
        eWrite("               ",36,3)
        eWrite(userScreenList[1],36,3)
        ULscrollAmount = ULscrollAmount - 1
    end
end

--[[
addUser():
    Adds a user to userList and prints it to the
    screen accordingly.
]]
local function addUser(username)
    term.setBackgroundColour(colours.white)
    if lastULline < 17 then
        if string.len(username) > 15 then
            temp = string.sub(username,1,15)
            eWrite("               ",36,lastULScreenLine + 3)
            eWrite(temp,36,lastULScreenLine + 3)
        else
            eWrite("               ",36,lastULScreenLine + 3)
            eWrite(username,36,lastULScreenLine + 3)
        end

        lastULScreenLine = lastULScreenLine + 1
        userScreenList[lastULScreenLine] = username

        lastULline = lastULline + 1
        userList[lastULline] = username
    else
        lastULline = lastULline + 1
        userList[lastULline] = username
        scrollUserList(1)
    end
end

--[[
removeUser():
    Removes a user from userList and does whatever
    it needs to do.
]]
local function removeUser(username)
    if lastULline == 0 then
        return false
    end

    local userindice = 0

    for i=1,lastULline do
        if userList[i] == username then
            userindice = i
            break
        end
    end

    for i=userindice,lastULline do
        userList[i] = userList[i+1]
    end
    lastULline = lastULline - 1

    for i=1,17 do
        if userList[ULscrollAmount + i] then
            userScreenList[i] = userList[ULscrollAmount + i]
            eWrite("               ",36,i + 2)
            eWrite(userScreenList[i],36,i + 2)
        else
            eWrite("               ",36,i + 2)
        end
    end
    lastULScreenLine = lastULScreenLine - 1
end

-- ******* Host Software ******

--[[
saveServer():
    This function puts all of the necessary
    values and text that are needed to restore
    the server into a file with the name of the
    server in the folder called 'sessions'.
]]
local function saveServer()
    if not fs.exists(rootDir .. "/sessions") then
        fs.makeDir(rootDir .. "/sessions")
    end

    local fileHandle = fs.open(sFilePath, "w")
    if not fileHandle then
        return false
    end

    fileHandle.writeLine("password((" .. sPassword .. "))end")
    fileHandle.writeLine("channel1((" .. channelOne .. "))end")
    fileHandle.writeLine("channel2((" .. channelTwo .. "))end")

    if lastLine > 1 then
        fileHandle.writeLine("((CHAT))")
        fileHandle.writeLine("")

        for i=1,lastLine do
            fileHandle.writeLine("chatLine" .. i .. "((" .. chatList[i] .. "))end")
        end
    end

    fileHandle.close()
    return true
end

--[[
restoreServer():
    Starts a previously made server by loading
    all the values and text from the file
    into the necessary variables.
]]
local function restoreServer()
    local temp1, temp2 = 0,0
    local firstIndice, secondIndice = 0,0

    local fileHandle = fs.open(sFilePath, "r")

    temp = fileHandle.readLine()
    if not temp then
        return false
    elseif string.find(temp,"password((",1,true) and string.find(temp,"))end",1,true) then
        temp1, temp2 = string.find(temp,"password((",1,true)
        firstIndice = temp2 + 1

        temp1, temp2 = string.find(temp,"))end",1,true)
        secondIndice = temp1 - 1

        sPassword = string.sub(temp,firstIndice,secondIndice)
    end

    temp = fileHandle.readLine()
    if not temp then
        return false
    elseif string.find(temp,"channel1((",1,true) and string.find(temp,"))end",1,true) then
        temp1, temp2 = string.find(temp,"channel1((",1,true)
        firstIndice = temp2 + 1

        temp1, temp2 = string.find(temp,"))end",1,true)
        secondIndice = temp1 - 1

        channelOne = tonumber(string.sub(temp,firstIndice,secondIndice))
    end

    temp = fileHandle.readLine()
    if not temp then
        return false
    elseif string.find(temp,"channel2((",1,true) and string.find(temp,"))end",1,true) then
        temp1, temp2 = string.find(temp,"channel2((",1,true)
        firstIndice = temp2 + 1

        temp1, temp2 = string.find(temp,"))end",1,true)
        secondIndice = temp1 - 1

        channelTwo = tonumber(string.sub(temp,firstIndice,secondIndice))
    end

    temp = fileHandle.readLine()
    if temp == "((CHAT))" then
        chatExistsAlready = true
    elseif not temp then
        return false
    end
    temp = fileHandle.readLine()

    for i=1,100 do
        temp = fileHandle.readLine()
        if not temp then
            break
        end

        if string.find(temp,"chatLine" .. i .. "((",1,true) and string.find(temp,"))end",1,true) then
            temp1, temp2 = string.find(temp,"chatLine" .. i .. "((",1,true)
            firstIndice = temp2 + 1

            temp1, temp2 = string.find(temp,"))end",1,true)
            secondIndice = temp1 - 1

            chatList[i] = string.sub(temp,firstIndice,secondIndice)
            lastLine = lastLine + 1

            if i <= 13 then
                chatScreenList[i] = chatList[i]
                lastScreenLine = lastScreenLine + 1
            end
        end
    end

    return true
end

--[[
hostConnectionManager():
    This manages incoming requests to connect to
    or disconnect from the server. I decided to
    use rednet for this in the long run because
    it allows the connecting computer and the
    host to communicate privately without
    disturbing anything else.
]]

local function hostConnectionManager()
    local currentConnectie = nil
    local firstIndice, secondIndice = 0,0
    local temp,temp1, temp2 = 0,0,0
    local username = ""
    local timeout, takenUser = false, false
    rednet.open(modemSide)

    while running == true do
        local tabletosend = {}
        local senderId, message, distance = rednet.receive(7.5)
        if senderId and running then
            if message == "connectme2tsp" then
                currentConnectie = senderId
                for i=1, 10 do              -- times out after 10 times
                    rednet.send(currentConnectie,"login")   -- (about 12 secs)
                    senderId, message, distance = rednet.receive(1.2)
                    if senderId == currentConnectie then
                        if message == sPassword then
                            timeout = false
                            break
                        else
                            rednet.send(currentConnectie,"badpass")
                        end
                    end
                    timeout = true
                end
                if timeout == false then
                    for i=1, 10 do
                        rednet.send(currentConnectie,"enteruser")
                        senderId, message, distance = rednet.receive(1.2)
                        if senderId == currentConnectie then
                            if string.find(message,"user((",1,true) then    --login
                                temp1, temp2 = string.find(message,"user((",1,true) -- get username indices
                                firstIndice = temp2 + 1
                                temp1, temp2 = string.find(message,"))end",1,true)
                                secondIndice = temp1 - 1
                                username = string.sub(message,firstIndice, secondIndice)
                                for key, name in ipairs(userList) do
                                    if username == name then
                                        takenUser = true
                                        break
                                    end
                                    local temp = key
                                end

                                if not takenUser then
                                    addUser(username)

                                    tabletosend[1] = "ch1((" .. channelOne .. "))end"
                                    tabletosend[2] = "ch2((" .. channelTwo .. "))end"
                                    tabletosend[3] = "servername((" .. serverName .. "))end"

                                    if lastLine > 0 then
                                        tabletosend[4] = "((CHAT))"
                                        tabletosend[5] = ""
                                        for i=1,lastLine do
                                            tabletosend[i+5] = "chatLine" .. i .. "((" .. chatList[i] .. "))end"
                                        end
                                    end

                                    if lastULline > 0 then
                                        tabletosend[lastLine + 6] = "((USERS))"
                                        tabletosend[lastLine + 7] = ""
                                        for i=1,lastULline do
                                            tabletosend[lastLine + 7 + i] = "user" .. i .. "((" .. userList[i] .. "))end"
                                        end
                                    end

                                    sTabletosend = textutils.serialize(tabletosend)

                                    modem.transmit(channelTwo,0,"userconnect((" .. username .. "))end")
                                    printChatWindow(username .. " joined the chat server.")

                                    for i=1,3 do-- just in case
                                        rednet.send(currentConnectie, "success((".. sTabletosend)
                                        sleep(0.5)
                                    end

                                    break
                                else
                                    rednet.send(currentConnectie, "takenuser")
                                end
                            else
                                rednet.send(currentConnectie, "badmessage") --some other message has been received
                            end
                        end
                    end
                end
            elseif string.find(message,"disconnectmeFtsp",1,true) then
                temp1, temp2 = string.find(message,"disconnectmeFtsp((",1,true) -- get username indices
                firstIndice = temp2 + 1
                temp1, temp2 = string.find(message,"))end",1,true)
                secondIndice = temp1 - 1
                username = string.sub(message,firstIndice, secondIndice)
                rednet.send(senderId,"disconnected")

                modem.transmit(channelTwo,0,"userdisconnect((" .. username .. "))end")
                printChatWindow(username .. " left the chat server.")
                removeUser(username)
            end
        end
    end
    rednet.close(modemSide)
end

--[[
hostChatManager:
    receives messages from clients,
    distributes them and prints
    them on the host's own screen
]]

local function hostChatManager()
    local user, chatMessage = ""
    local temp, temp2 = 0,0
    local firstIndice, secondIndice = 0,0
    local wholeOut
    local event, side, frequency, replyFreqency, message, distance

    modem.open(channelOne)
    while running == true do
        os.startTimer(5)
        event, side, frequency, replyFreqency, message, distance = os.pullEvent()
        if event == "modem_message" then
            if frequency == channelOne then
                if string.find(message, "user((", 1, true) and string.find(message, "))message((", 1, true) then
                    temp, temp2 = string.find(message,"user((",1,true)  -- get username indices
                    firstIndice = temp2 + 1
                    temp, temp2 = string.find(message,"))message",1,true)
                    secondIndice = temp - 1
                    user = string.sub(message,firstIndice, secondIndice)

                    temp, temp2 = string.find(message,"message((",1,true)   -- get message indices
                    firstIndice = temp2 + 1
                    temp, temp2 = string.find(message,"))end",1,true)
                    secondIndice = temp - 1
                    chatMessage = string.sub(message,firstIndice, secondIndice) --load whole message

                    wholeOut = user.. ": " .. chatMessage
                    modem.transmit(channelTwo,channelOne,wholeOut)

                    printChatWindow(wholeOut)   --print on host machine
                end
            end
        elseif event == "timer" then
            if running == false then
                break
            end
        end
    end
    modem.close(channelOne)
end

--[[
hostHotBarMenu():
    This controls the Host menu, similar to
    hotBarMenu().
]]
local function hostHotBarMenu()
    local event, param1, param2, param3 = nil,nil,nil,nil
    for i=2,4 do
        paintutils.drawLine(8,i,14,i, colours.orange)
    end
    eWrite("Save",8,2)
    eWrite("Shutdown",7,3)
    while true do
        event, param1, param2, param3 = os.pullEvent("mouse_click")
        if param2 > 7 and param2 < 15 and param3 == 2 then
            term.setBackgroundColour(colours.red)
            eWrite("Save",8,2)
            sleep(0.2)
            term.setTextColour(colours.black)
            term.setBackgroundColour(colours.lightGrey)
            paintutils.drawLine(1,2,20,2,colours.lightGrey)
            eWrite("Messages:",1,2)
            term.setBackgroundColour(colours.white)
            eWrite(chatScreenList[1],1,3)
            eWrite(chatScreenList[2],1,4)
            return 1

        elseif param2 > 7 and param2 < 15 and param3 == 3 then
            term.setBackgroundColour(colours.red)
            eWrite("Shutdown",7,3)
            sleep(0.2)
            term.setTextColour(colours.black)
            term.setBackgroundColour(colours.lightGrey)
            paintutils.drawLine(1,2,20,2,colours.lightGrey)
            eWrite("Messages:",1,2)
            term.setBackgroundColour(colours.white)
            eWrite(chatScreenList[1],1,3)
            eWrite(chatScreenList[2],1,4)
            return 2

        elseif param2 < 7 or param2 > 14 or param3 > 4 then
            term.setTextColour(colours.black)
            term.setBackgroundColour(colours.lightGrey)
            paintutils.drawLine(1,2,20,2,colours.lightGrey)
            eWrite("Messages:",1,2)
            term.setBackgroundColour(colours.white)
            eWrite("                                 ",1,3)
            eWrite(chatScreenList[1],1,3)
            eWrite("                                 ",1,4)
            eWrite(chatScreenList[2],1,4)
            return 0
        end
    end
end

--[[
hostUI():
    This function allows the host to interact with
    everything while the server is running.
]]
local function hostUI()
    local action
    local chatString
    local wholeOut
    setupGUI()
    term.setBackgroundColour(colours.orange)
    eWrite("[Host]",8,1)
    term.setBackgroundColour(colours.white)
    while running == true do
        event, param1, param2, param3 = os.pullEvent()
        if event == "mouse_click" then
            if param2 < 28 and param3 > 16 then
                chatString = readMessage()

                wholeOut = "Host: " .. chatString
                modem.transmit(channelTwo,channelOne,wholeOut)
                printChatWindow(wholeOut)
            elseif param2 < 6 and param3 == 1 then
                term.setBackgroundColour(colours.red)
                eWrite("[Menu]",1,1)
                sleep(0.2)
                term.setBackgroundColour(colours.orange)
                eWrite("[Menu]",1,1)
                action = hotBarMenu()
                if action == 1 then
                    printChatWindow("The server is shutting down.")
                    modem.transmit(channelTwo,channelOne,"lionelhuttXX((SERVERSHUTDOWN))Xx")
                    -- had to make it something no one would likely type XD
                    sleep(5)
                    running = false
                    break
                end
            elseif param2 > 7 and param2 < 14 and param3 == 1 then
                term.setBackgroundColour(colours.red)
                eWrite("[Host]",8,1)
                sleep(0.2)
                term.setBackgroundColour(colours.orange)
                eWrite("[Host]",8,1)
                action = hostHotBarMenu()
                if action == 1 then
                    if not saveServer() then
                        printChatWindow("save failed.")
                    end
                elseif action == 2 then
                    printChatWindow("The server is shutting down.")
                    modem.transmit(channelTwo,channelOne,"lionelhuttXX((SERVERSHUTDOWN))Xx")
                    sleep(5)
                    running = false
                end
            elseif param2 == 34 and param3 == 15 then
                scrollChatWindow(1)
            elseif param2 == 34 and param3 == 3 then
                scrollChatWindow(-1)
            end
        end
    end
end


-- ****** Client Software *****

--[[
loadInfo():
    This loads all the values and text received from the
    host into the necessary variables. It's a bit like
    restoreServer() except it's for clients when they
    connect.
]]
local function loadInfo(serverdata)
    local temp, temp1, temp2 = "",0,0
    local firstIndice, secondIndice = 0,0

    if string.find(serverdata[1],"ch1((",1,true) then
        temp1, temp2 = string.find(serverdata[1],"ch1((",1,true)
        firstIndice = temp2 + 1

        temp1, temp2 = string.find(serverdata[1],"))end",1,true)
        secondIndice = temp1 - 1

        temp = string.sub(serverdata[1],firstIndice,secondIndice)
        channelOne = tonumber(temp)
    end

    if string.find(serverdata[2],"ch2((",1,true) then
        temp1, temp2 = string.find(serverdata[2],"ch2((",1,true)
        firstIndice = temp2 + 1

        temp1, temp2 = string.find(serverdata[2],"))end",1,true)
        secondIndice = temp1 - 1

        temp = string.sub(serverdata[2],firstIndice,secondIndice)
        channelTwo = tonumber(temp)
    end

    if string.find(serverdata[3],"servername((",1,true) then
        temp1, temp2 = string.find(serverdata[3],"servername((",1,true)
        firstIndice = temp2 + 1

        temp1, temp2 = string.find(serverdata[3],"))end",1,true)
        secondIndice = temp1 - 1

        temp = string.sub(serverdata[3],firstIndice,secondIndice)
        serverName = temp
    end

    if serverdata[4] == "((CHAT))" then
        chatExistsAlready = true
    elseif not serverdata[4] then
        return true
    end

    for i=1,100 do
        if not serverdata[i+5] then
            break
        end

        if string.find(serverdata[i+5],"chatLine" .. i .. "((",1,true) and string.find(serverdata[i+5],"))end",1,true) then
            temp1, temp2 = string.find(serverdata[i+5],"chatLine" .. i .. "((",1,true)
            firstIndice = temp2 + 1

            temp1, temp2 = string.find(serverdata[i+5],"))end",1,true)
            secondIndice = temp1 - 1

            chatList[i] = string.sub(serverdata[i+5],firstIndice,secondIndice)
            lastLine = lastLine + 1

            if i <= 13 then
                chatScreenList[i] = chatList[i]
                lastScreenLine = lastScreenLine + 1
            end
        end
    end

    if serverdata[lastLine + 6] == "((USERS))" then
        usersAlreadyOn = true
    elseif not serverdata[lastLine + 6] then
        return true
    end

    for i=1,100 do
        if not serverdata[lastLine + 7 + i] then
            break
        end

        if string.find(serverdata[lastLine + 7 + i],"user" .. i .. "((",1,true) and string.find(serverdata[lastLine + 7 + i],"))end",1,true) then
            temp1, temp2 = string.find(serverdata[lastLine + 7 + i],"user" .. i .. "((",1,true)
            firstIndice = temp2 + 1

            temp1, temp2 = string.find(serverdata[lastLine + 7 + i],"))end",1,true)
            secondIndice = temp1 - 1

            userList[i] = string.sub(serverdata[lastLine + 7 + i],firstIndice,secondIndice)
            lastULline = lastULline + 1

            if i <= 17 then
                userScreenList[i] = userList[i]
                lastULScreenLine = lastULScreenLine + 1
            end
        end
    end

    return true
end

--[[
login():
    Does exactly what its name implies. It does all
    the necessary communicating with the server to
    get connnected.
]]
local function login()
    term.setBackgroundColour(colours.white)
    term.clear()
    for i=7,15 do
        paintutils.drawLine(14,i,37,i,colours.lightGrey)
    end
    eWrite("logging in...",20,11)
    local senderId, message, distance
    local timeout = false
    local temp1, temp2, firstIndice, secondIndice = 0,0,0,0
    local password, username = "",""
    local serverdata = {}

    rednet.open(modemSide)
    for i=1, 10 do
        rednet.send(hostID, "connectme2tsp")
        senderId, message, distance = rednet.receive(1.2)
        if senderId == hostID then
            if message == "login" then
                timeout = false
                break
            end
        end
        timeout = true
    end
    if timeout == true then
        for i=7,15 do
            paintutils.drawLine(14,i,37,i,colours.lightGrey)
        end
        eWrite("Could not connect to",16,10)
        eWrite("server",24,11)
        os.pullEvent("mouse_click")
        return false
    end
    for i=1, 12 do
        for i=7,15 do
            paintutils.drawLine(14,i,37,i,colours.lightGrey)
        end
        eWrite("Please enter the",19,8)
        eWrite("server's password.",17,9)
        eWrite("(do this quickly or",16,10)
        eWrite("you will time out)",17,11)
        paintutils.drawLine(16,13,35,13,colours.white)
        term.setCursorPos(16,13)
        password = read()

        rednet.send(hostID,password)
        senderId, message, distance = rednet.receive(1.2)
        if senderId == hostID then
            if message == "enteruser" then
                timeout = false
                break
            elseif message == "badpass" then
                for i=7,15 do
                    paintutils.drawLine(14,i,37,i,colours.lightGrey)
                end
                eWrite("Password was incorrect.",15,11)
                os.pullEvent("mouse_click")
            end
        end
        timeout = true
    end
    if timeout == true then
        for i=7,15 do
            paintutils.drawLine(14,i,37,i,colours.lightGrey)
        end
        eWrite("Lost connection to",19,10)
        eWrite("server",20,11)
        os.pullEvent("mouse_click")
        return false
    end
    for i=1, 12 do
        for i=7,15 do
            paintutils.drawLine(14,i,37,i,colours.lightGrey)
        end
        eWrite("Please enter your",18,8)
        eWrite("username for the",19,9)
        eWrite("server",22,10)
        paintutils.drawLine(16,13,35,13,colours.white)
        term.setCursorPos(16,13)
        username = read()

        rednet.send(hostID, "user((".. username .. "))end")
        senderId, message, distance = rednet.receive(1.2)
        if senderId == hostID then
            if string.find(message, "success((",1,true)  then
                myuser = username

                local temp =  string.sub(message,10)
                serverdata = textutils.unserialize(temp)

                loadInfo(serverdata)

                rednet.close(modemSide)
                return true
            elseif message == "takenuser" then
                for i=7,15 do
                    paintutils.drawLine(14,i,37,i,colours.lightGrey)
                end
                eWrite("That username was",19,10)
                eWrite("already taken",20,11)
                os.pullEvent("mouse_click")
            end
        end
        timeout = true
    end
    return nil
end

--[[
logout():
    Oh boy, I wonder what this one does? :P
]]
local function logout()
    term.setBackgroundColour(colours.white)
    term.clear()
    for i=9,11 do
        paintutils.drawLine(14,i,37,i,colours.lightGrey)
    end
    term.setBackgroundColour(colours.lightGrey)
    term.setTextColour(colours.black)
    eWrite("logging out...",18,10)

    rednet.open(modemSide)
    for i=1,12 do
        rednet.send(hostID,"disconnectmeFtsp((" .. myuser .. "))end")
        local senderId, message, distance = rednet.receive(2.5)
        if senderId then
            if message == "disconnected" then
                eWrite("successful logout",16,10)
                rednet.close(modemSide)
                return true
            end
        end
    end
    rednet.open(modemSide)
    return false
end

--[[
    This guy watches out for incomming messages from
    the host and either calls printChatWindow() to print
    them or acts on them accordingly.
]]
local function clientReceiver()
    local event, side, frequency, replyFreqency, message, distance
    local temp, temp1, temp2 = "",0,0
    local firstIndice, secondIndice = 0,0
    local username = ""

    modem.open(channelTwo)
    while running == true do
        os.startTimer(5)
        event, side, frequency, replyFreqency, message, distance = os.pullEvent()
        if event == "modem_message" then
            if frequency == channelTwo then
                if string.find(message,"userdisconnect((",1,true)
                and string.find(message,"))end",1,true) then
                    temp1, temp2 = string.find(message,"userdisconnect((",1,true)
                    firstIndice = temp2 + 1

                    temp1, temp2 = string.find(message,"))end",1,true)
                    secondIndice = temp1 - 1

                    username = string.sub(message,firstIndice,secondIndice)

                    printChatWindow(username .. " left the chat server.")
                    removeUser(username)

                elseif string.find(message,"userconnect((",1,true)
                and string.find(message,"))end",1,true) then
                    temp1, temp2 = string.find(message,"userconnect((",1,true)
                    firstIndice = temp2 + 1

                    temp1, temp2 = string.find(message,"))end",1,true)
                    secondIndice = temp1 - 1

                    username = string.sub(message,firstIndice,secondIndice)

                    printChatWindow(username .. " joined the chat server.")
                    addUser(username)

                elseif string.find(message,"lionelhuttXX((SERVERSHUTDOWN))Xx",1,true) then
                    printChatWindow("The server is shutting down, please click somewhere on the screen.")
                    running = false
                    sleep(4)
                    break
                else
                    --if scrollAmount < lastLine then
                    --  scrollChatWindow(lastLine - scrollAmount)
                    --end
                    printChatWindow(message)
                end
            end
        elseif event == "timer" then
            if running == false then
                break
            end
        end
    end
    modem.close(channelTwo)
end

--[[
clientUI:
    controls all the user input and interaction
    on the client end.
]]
local function clientUI()
    local action
    local chatString
    setupGUI()
    while running == true do
        event, param1, param2, param3 = os.pullEvent()
        if event == "mouse_click" then
            if param2 < 28 and param3 > 16 then
                chatString = readMessage()
                modem.transmit(channelOne,channelTwo,"user((".. myuser .."))message((".. chatString .."))end")
            elseif param2 < 6 and param3 == 1 then
                term.setBackgroundColour(colours.red)
                eWrite("[Menu]",1,1)
                sleep(0.2)
                term.setBackgroundColour(colours.orange)
                eWrite("[Menu]",1,1)
                action = hotBarMenu()
                if action == 1 then
                    running = false
                    local test = logout()
                    sleep(1)
                    break
                end
            elseif param2 == 34 and param3 == 15 then
                scrollChatWindow(1)
            elseif param2 == 34 and param3 == 3 then
                scrollChatWindow(-1)
            end
        end
    end
end

-- ******** Program Functionality Begins *********

--[[ And here we have the actual stuff; where all the
    magic comes together! ]]

displayHomeScreen()

--Check for Modems
term.setTextColour(colours.black)
    for i=13, 15 do
        paintutils.drawLine(14,i,37,i,colours.lightGrey)
    end
term.setCursorPos(15,14)
term.write("Checking for modems...")
sleep(0.75)

if peripheral.getType("top") == "modem" then
    modem = peripheral.wrap("top")
    modemSide = "top"
elseif peripheral.getType("left") == "modem" then
    modem = peripheral.wrap("left")
    modemSide = "left"
elseif peripheral.getType("right") == "modem" then
    modem = peripheral.wrap("right")
    modemSide = "right"
elseif peripheral.getType("back") == "modem" then
    modem = peripheral.wrap("back")
    modemSide = "back"
else
    term.setBackgroundColour(colours.white)
    term.setTextColour(colours.lightBlue)
    term.clear()
    eWrite("No modems were found, please place",8,4)
    eWrite("a modem either on the top, right, left",8,5)
    eWrite("or back side.",10,6)
    eWrite("Click anywhere to exit",8,8)
    os.pullEvent("mouse_click")
    term.setCursorPos(1,4)
    term.setTextColour(colours.white)
    term.setBackgroundColour(colours.black)
    term.clear()
    return
end

-- ******** Main Loop *********

while true do
    displayHomeScreen()
    choice = homeMenu()
    if choice == 1 then --start new server
        hosting = true
        running = true
        displayLoadScreen()
        math.randomseed(myID)
        channelOne = math.random(0,65535)
        channelTwo = math.random(0,65535)       --is this an OK idea?
        parallel.waitForAll(hostUI,hostConnectionManager,hostChatManager)
    elseif choice == 2 then --restore server
        hosting = true
        running = true
        restoreServer()
        displayLoadScreen()
        parallel.waitForAll(hostUI,hostConnectionManager,hostChatManager)
    elseif choice == 3 then
        running = true
        local success = login()
        if success then
            parallel.waitForAll(clientUI,clientReceiver)
        end
    elseif choice == 0 then --quit
        displayExit()
        sleep(2)
        break
    end

    --reset all the necessary variables

    hosting = false
    serverName = ""
    running = false
    chatList = {}
    chatScreenList = {}
    lastLine = 0
    lastScreenLine = 0
    scrollAmount = 0
    chatExistsAlready = false

    userList = {}
    userScreenList = {}
    lastULline = 0
    lastULScreenLine = 0
    ULscrollAmount = 0
    usersAlreadyOn = false

    hostID, myID = nil, os.getComputerID()
    channelOne = nil
    channelTwo = nil

    sessionList = {}
    noSessions = 0
    newSession = nil
    sFilePath = nil
    sPassword = ""

    myuser = ""
end

-- clean up

term.setBackgroundColour(colours.black)
term.setCursorPos(1,1)
term.clear()

-- Wellp, there's my program! Thanks for reading. :)