Eluna Broadcaster

local Broadcast = {
    Register = {
        -- {"String", day, time}
        --    Day is from 1 to 7, where Monday is 1 and Sunday is 7
        --    Time is either seconds if day is 0 or format hour.minutes if day is specified
        {"Announce message here", 0, 1800},
    }
}

local function SeparateTime(t)
    local h = math.floor(t)
    local m = ((t*1000)-(h*1000))/10
    return h, m;
end

local function GetTimeDiff(weekday, h, m, s)
    local d = os.date("*t")

    d.sec = s or 0
    d.min = m
    d.hour = h

    local ddiff = weekday-d.wday+1
    d.day = d.day+ddiff
    local now = os.date("*t")
    if (ddiff < 0) then
        -- Take into consideration that it is tuesday and we want monday
        d.day = d.day+7
    elseif (ddiff == 0 and d.hour*60*60+d.min*60+d.sec < now.hour*60*60+now.min*60+now.sec) then
        -- Take into consideration that it is the same date, but its already past the wanted time
        d.day = d.day+7
    end

    -- get final times
    local e = os.time(d)
    local diff = e-os.time() -- this is the time in seconds until the wanted date is achieved

    return diff;
end

function Broadcast.SendAndReset(msg, d, t)
    SendWorldMessage(msg)
    if(d > 0) then
        local regtime = GetTimeDiff(d, SeparateTime(t))
        CreateLuaEvent(function() Broadcast.SendAndReset(msg, d, t) end, regtime*1000, 1)
    end
end

function Broadcast.OnLoad()
    for i, v in ipairs(Broadcast.Register) do
        local msg, d, t = table.unpack(Broadcast.Register[i])
        if d == 0 then
            CreateLuaEvent(function() Broadcast.SendAndReset(msg, d, t) end, t*1000, 0)
        else
            local regtime = GetTimeDiff(d, SeparateTime(t))
            CreateLuaEvent(function() Broadcast.SendAndReset(msg, d, t) end, regtime*1000, 1)
        end
    end
end

Broadcast.OnLoad()