Event Transmitter (ComputerCraft)

--[[
    pastebin get hfBQ4wCs evt
--]]

local evtPath = ".evt"
local id = tostring(math.random(0,99999999999))

bannedEvents = {
    ["timer"] = true,
    ["queue_event"] = true,
    ["self_event_check"] = true,
}

curEvent = {} --used to prevent feedback loops

addEvent = function(evt) -- table evt
    if bannedEvents[evt[1]] then return end
    local file = fs.open(evtPath,"a")
    file.writeLine(textutils.serialise({id,evt}):gsub("\n",""):gsub("  ",""):gsub(",}","}"))
    file.close()
end

useEvent = function()
    local contents = {}
    local file = fs.open(evtPath,"r")
    local line = {}
    repeat
        line = file.readLine()
        if line then
            contents[#contents+1] = textutils.unserialize(line) or {}
        end
    until not line
    local usedLines = {}
    for a = 1, #contents do
        if type(contents[a]) == "table" then
            if contents[a][1] ~= id then
                curEvent = contents[a][2]
                os.queueEvent(unpack(contents[a][2]))
                os.queueEvent("self_event_check","true")
                table.remove(contents,a)
                usedLines[#usedLines+1] = a
            else
                os.queueEvent("self_event_check","true")
            end
        else
            os.queueEvent("self_event_check","true")
        end
    end
    for a = #usedLines,1,-1 do
        table.remove(contents,usedLines[a])
    end
    local file = fs.open(evtPath,"w")
    for a = 1, #contents do
        file.writeLine(textutils.serialize(contents[a]):gsub("\n",""):gsub("  ",""):gsub(",}","}"))
    end
end

loopAdd = function()
    while true do
        local event = {os.pullEvent()}
        if event ~= curEvent then
            local a,b = os.pullEvent("self_event_check")
            if b == true then
                addEvent(event)
            end
        end
        curEvent = {}
    end
end

loopUse = function()
    while true do
        useEvent()
        os.queueEvent("queue_event")
        os.pullEvent("queue_event")
    end
end

doShell = function()
    dofile("rom/programs/shell")
end

if not fs.exists(evtPath) then
    local file = fs.open(evtPath,"w")
    file.close()
end

parallel.waitForAny(loopUse,loopAdd,doShell)