echat

local args = {...}
local m = peripheral.find("modem") -- Yay for CC1.6
local hist = {}
local histc = 0
local flines = {}
local nick = "Anavrins"
local x, y = term.getSize()
local line = 1
local msg = ""
local lines = {"/logout: Will quit you from the chat","/help: Will list the commands","/nick: Change your Nick","/me: Tell the others what you are doing"}

local aes = dofile("/libs/cryptLib").aes()
local utils = dofile("/libs/cryptLib").utils()

local f = fs.open("/chatrooms/"..args[1]..".id","r")

for fline in f.readLine do
    flines[#flines+1] = fline
end
f.close()

f = fs.open("/chatrooms/"..args[1]..".key", "r")
local key = textutils.unserialize(f.readLine())
f.close()

local function encrypt(plain)
    plain = utils.stringToByteArray(plain)
    local iv = utils.keygen(16)
    local c_text = aes.encrypt_cbc(plain, key, iv)

    return {c_text, iv}
end

local function decrypt(c_text, iv)
    local plain = aes.decrypt_cbc(c_text, key, iv)

    return utils.byteArrayToString(plain)
end

term.clear()
term.setCursorPos(1,1)

print("Welcome to Chat!")
print("IDs im Chatraum:")

for i = 1,#flines do
    print(flines[i])
    m.open(tonumber(flines[i]))
end

sleep(3)
term.clear()

while true do
    term.setCursorPos(1, y)
    term.setBackgroundColor(colors.gray)
    term.clearLine()
    term.write("Message:"..msg)
     term.setBackgroundColor(32768)
    local e = {os.pullEvent()}
    if e[1] == "char" then
        if nick:len()+2 > 8 then
            add = nick:len()+2
        else
            add = 8
        end
        if msg:len()+add < x then
            msg = msg..e[2]
        end

    elseif e[1] == "modem_message" then
        local c_text, iv = aes.validate(e[5])
        if c_text then
            if line == y -1 then
                term.clear()
                line = 1
            end
            rs.setOutput("left",true)
            sleep(0.1)
            rs.setOutput("left",false)
            term.setCursorPos(1, line)
            local plain = decrypt(c_text, iv)
            term.write(plain)
            line = line + 1
        end

    elseif e[1] == "key" then
        if e[2] == keys.backspace then
            term.setCursorPos(1,1)
            msg = msg:sub(0,#msg-1)

        elseif e[2] == keys.enter and msg ~= "" then
            hist[#hist+1] = msg
            if msg:sub(1,1) == "/" then
                local cmd = msg:sub(2,#msg)
                if cmd == "help" then
                    if #lines + line >=y then
                        term.clear()
                        term.setCursorPos(1,1)
                        line = 1
                    end
                    for i = 1,#lines do
                        term.setCursorPos(1,line)
                        print(lines[i])
                        line = line + 1
                    end

                elseif cmd:sub(1,4) == "nick" then
                    if cmd:sub(6) ~= "" then
                        nick = cmd:sub(6)
                    end

                elseif cmd == "logout" then
                    local left = "<"..nick.."> left the chat"
                    left = encrypt(left)
                    m.transmit(os.getComputerID(),os.getComputerID(),left)
                    shell.run("clear")
                    break

                elseif cmd:sub(1,2) == "me" then
                    if cmd:sub(4) ~= "" then
                        local me = "*"..nick.." "..cmd:sub(4)
                        if line == y-1 then
                            term.clear()
                            line = 1
                        end
                        term.setCursorPos(1,line)
                        print(me)
                        line = line + 1
                        me = encrypt(me)
                        m.transmit(os.getComputerID(),os.getComputerID(),me)
                    end
                end
            else
                msg = "<"..nick..">"..msg
                if line == y -1 then
                    term.clear()
                    line = 1
                end
                term.setCursorPos(1, line)
                print(msg)
                line = line + 1
                msg = encrypt(msg)
                m.transmit(os.getComputerID(),os.getComputerID(),msg)
            end
            histc = 0
            msg = ""
        elseif e[2] == keys.up then
            histc = histc + 1
            if histc > #hist then
                histc = histc - 1
            else
                msg = hist[#hist-histc+1]
            end

        elseif e[2] == keys.down then
            histc = histc - 1
            if histc == 0 then
                msg = ""
            elseif histc < 0 then
                histc = histc + 1
            else
                msg = hist[#hist-histc+1]
            end
        end
    end
end