v2

os.loadAPI("sha256.lua")
local chatBox = peripheral.find("chat_box")
local name = "\167l\1672KristList"
local prefixColor = "\1670"
local lines = {}

local function countLines()
    local file = fs.open("posts","r")

    if file then
        lines = {}
        local line = file.readLine()

        while line do
            table.insert(lines,line)
            line = file.readLine()
        end
        file.close()
    end
end

while true do
 local event, user, command, args = os.pullEvent("command")
    if command == "kristlist" then
        countLines()

        if args[1] == "post" then
            table.remove(args,1)
            local message = table.concat(args, " ")
            local file = fs.open("posts","a")
            file.writeLine(user..": "..message)
            file.close()

        elseif args[1] == "read" then

            if args[2] == nil then
                chatBox.tell(user,"\167rInsufficient arguments, \1674\\kristlist help <command> \167r for more information on how to use kristlist",name,prefixColor)

            elseif tonumber(args[2]) > 0 and tonumber(args[2]) <= #lines then
                local file = fs.open("posts","r")

                for i = 1, args[2] do
                    chatBox.tell(user,"\167r"..file.readLine(),name,prefixColor)
                end
            end

        elseif args[1] == "register" then

            if args[2] == nil then
                chatBox.tell(user,"\167Please provide a password to register. NOTE: Your passwords are not stored in plaintext.",name,prefixColor)
            else
                local file = fs.open("users","a")
                local input = tostring(args[2])
                local hashedPassword = sha256.hash(input)
                local salt = math.random(1,1000)
                local password = hashedPassword..salt
                local newUser =file.writeLine(user.." : "..password)
                file.close()
            end


        elseif args[1] == "help" then

            if args[2] == nil then
                chatBox.tell(user,"167rThe following arguments are accepted: \1674\kstlist post, \kstlist read",name,prefixColor)
            end

        elseif args[1] == nil then
            chatBox.tell(user,"\167rInsufficient arguments, \1674\\kristlist help <command> \167r for more information on how to use kristlist",name,prefixColor)
        else
            chatBox.tell(user,"\167rInvalid argument, \1674\\kristlist help <command> \167r for more information on how to use kristlist",name,prefixColor)
        end
    end
end