Ice-Mail-server

--[[
    Ice-mail. Mail server
    By: Aron (Gulligagardinen)

    Terms Of Use:
        This file is provided as it is, you may not delete this terms of use protocol from the source code.

        You may change what you want in this code. I even encourage you to do changes after your own preferences! =D
        Provided that you credit the original maker: Gulligagardinen.

        You may use this program in any kind of UI or OS, provided that you credit the original maker: Gulligagardinen.


    If you experience any bugs or glitches, please contact me.
--]]

--Mail Inbox
local mail = {}

--Main variables that contains general information
local modem;
local sSide = "top" --Change this to the side where the modem is.

--Modem functions: open, close and isOpen
local function open()
    modem = peripheral.wrap(sSide)
    modem.open(65535)
end

local function close()
    if sSide ~= "" then
        modem.closeAll()
    end
end

local function isOpen()
    if modem.isOpen(65535) then
        return true;
    end
    return false;
end

--Send and receive functions
local function send(channel, str, rChannel)
    if isOpen() then
        local rec;
        if not rChannel then rec = 65535 else rec = rChannel end
        if sSide ~= "" then
            modem.transmit(channel, rec, str)
        else
            error("No chosen modem side")
        end
    else
        error("Please make sure that the modem is opened")
    end
end

local function receive()
    if isOpen() then
        local event, side, sCh, rCh, msg, sd = os.pullEvent("modem_message")
        return sCh, rCh, msg; --Sender Channel, Reply Channel, Message
    else
        error("Please make sure that the modem is opened")
    end
end

--Server handling
local function receiveCall()
    local sCh, rCh, msg = receive()
    if msg == "pleaseIndex" then
        if mail[rCh] then
            send(rCh, #mail[rCh])
            --print("Sent Amount of messages for "..tostring(rCh))
        end
    elseif msg:find("indexTextMsg") then
        if mail[rCh] then
            local txt = tonumber(msg:sub(14, #msg))
            if mail[rCh][txt] then
                send(rCh, mail[rCh][txt].msg, mail[rCh][txt].sender)
                --print("Forwarding a message for "..tostring(rCh))
            end
        end
    elseif msg:find("]") then
        local mark = msg:find("]")
        if not mail[tonumber(msg:sub(1, mark-1))] then
            mail[tonumber(msg:sub(1, mark-1))] = {[1] = {msg = msg:sub(mark+1, #msg), sender = rCh}}
        else
            mail[tonumber(msg:sub(1, mark-1))][#mail[tonumber(msg:sub(1, mark-1))]+1] = {msg = msg:sub(mark+1, #msg), sender = rCh}
        end
        --print("Received a message for "..msg:sub(1, mark-1))
    elseif msg:find("removeIndex") then
        if mail[rCh] then
            if mail[rCh][tonumber(msg:sub(13, #msg))] then
                table.remove(mail[rCh], tonumber(msg:sub(13, #msg)))
                --print("Removed a message for "..tostring(rCh))
            end
        end
    end
end

--Main loop
term.clear() term.setCursorPos(1, 1)
while true do
    open()
    receiveCall()
end