rednet.open("left")

local connected = {}
local keepAliveTimer = os.startTimer(1)

local configFile = fs.open("server.cfg", "r")
local config = textutils.unserialise(configFile.readAll())
configFile.close()

local map = paintutils.loadImage(config.mapFile)

local function serverLoop(eventData)
    local e, p1, p2, p3, p4, p5 = unpack(eventData)
    if e == "rednet_message" then
        local id, tbl = p1, p2
        if tbl.type ~= "connect" and connected[id] == nil then
            print("Rejected unconnected message from " .. id)
            return true
        end

        if tbl.type == "connect" then
            connected[id] = {
                keepAliveResponded = true,
                suspicious = false
            }

            print("Connection from " .. id)

            rednet.send(id, {
                type = "accepted"
            })
        elseif tbl.type == "disconnect" then
            print(id .. " has disconnected.")
            connected[id] = nil
        elseif tbl.type == "keepalive" then
            connected[id].keepAliveResponded = true
        elseif tbl.type == "suspicious_computer" then
            if connected[tbl.id] == nil then
                print(id .. " marked unknown computer suspicious.")
                print("Cheating attempt?")
            else
                print(id .. " marked " .. tbl.id .. " suspicious.")
                connected[tbl.id].suspicious = true
            end
        elseif tbl.type == "map" then
            rednet.send(id, {
                type = "map",
                data = map
            })
        end
    elseif e == "timer" and p1 == keepAliveTimer then
        local toDelete = {}

        for k,v in pairs(connected) do
            if not v.keepAliveResponded then
                table.insert(toDelete, k)
                print(k .. " timed out.")
                rednet.send(k, { type = "disconnect", reason = "You timed out." }) -- just to make sure
            end

            rednet.send(k, {
                type = "keepalive"
            })

            v.keepAliveResponded = false
        end

        for _,v in pairs(toDelete) do
            connected[v] = nil
        end

        keepAliveTimer = os.startTimer(1)
    elseif e == "terminate" then
        for k,v in pairs(connected) do
            rednet.send(k, {
                type = "disconnect",
                reason = "Server shutting down"
            })
        end

        return false
    end

    return true
end

print("Hosting server on ID " .. os.getComputerID())

while true do
    local eventData = { os.pullEventRaw() }
    if not serverLoop(eventData) then break end
end