spatial TP

local m = peripheral.find("modem", function(_, o) return o.isWireless() end)
local ec_oc = peripheral.find "ender_chest"
local ec_cc = peripheral.find "minecraft:ender chest"
local spatial = "back"
local spatialp = peripheral.wrap(spatial)
local name = os.getComputerLabel()
local channel = 236
local spatial_ec_loc = settings.get "spatial_ec_loc" or "east"
local busy = false
local needed_energy = 34000

local function send(x)
    print("->", unpack(x))
    m.transmit(channel, channel, x)
end

local function recv_filter(fn)
    while true do
        local _, _, c, rc, msg = os.pullEvent "modem_message"
        print("<-", unpack(msg))
        if type(msg) == "table" and fn(msg) then return msg end
    end
end

local function pick_channel()
    return math.random(0xA00, 0xC00)
end

local function run_spatial()
    rs.setOutput(spatial, true)
    sleep(0.1)
    rs.setOutput(spatial, false)
    sleep(0.1)
    print "Run spatial"
end

local function run_transfer(trg)
    busy = true
    local function run_transfer_internal()
        if spatialp.getNetworkEnergyStored() < needed_energy then print "Insufficient energy" return end
        print "Pinging"
        send { "ping", trg }
        if (recv_filter(function(m) return m[1] == "pong" and m[2] == trg end))[3] then print "Remote busy" return end
        print "Destination available"
        local ec_channel = pick_channel()
        ec_oc.setFrequency(ec_channel)
        send { "transfer", trg, ec_channel }
        if not (recv_filter(function(m) return m[1] == "transfer_ack" and m[2] == trg end))[3] then print "Remote denied transfer" return end
        print "Ack received"
        run_spatial()
        spatialp.pushItems(spatial_ec_loc, 2, 1, 1)
        print "Sent item to remote"
        repeat
            sleep(0.1)
        until ec_cc.getItemMeta(27) ~= nil
        print("Remote sent item")
        spatialp.pullItems(spatial_ec_loc, 27, 1, 1)
        run_spatial()
        spatialp.pullItems("self", 2, 1, 1)
        print "Done"
    end
    parallel.waitForAny(run_transfer_internal, function() sleep(5) print "Transfer timed out" end)
    busy = false
end

local pings_timer = nil
local function list_all()
    pings_timer = os.startTimer(1)
    send { "ping" }
end

local function inbound()
    local function run_transfer_recv(msg)
        print("Transfer request from", msg[2])
        if spatialp.getNetworkEnergyStored() < needed_energy then print "Insufficient energy" send { "transfer_ack", msg[2], false } return end
        if busy then print "Already busy, cannot accept transfer" send { "transfer_ack", msg[2], false } return end
        busy = true
        send { "transfer_ack", msg[2], true }
        print("Accepting transfer from", msg[2])
        ec_oc.setFrequency(msg[3])
        repeat
            sleep(0.1)
        until ec_cc.getItemMeta(1) ~= nil
        print "Remote sent item"
        run_spatial()
        spatialp.pullItems(spatial_ec_loc, 1, 1, 1)
        spatialp.pushItems(spatial_ec_loc, 2, 1, 27)
        print "Sent item to remote"
        run_spatial()
        spatialp.pullItems("self", 2, 1, 1)
        print "Done"
    end

    local function process(msg)
        local cmd = msg[1]
        if cmd == "ping" and (msg[2] == nil or msg[2] == name) then
            send { "pong", name, busy }
        elseif pings_timer and cmd == "pong" then
            print(msg[2])
        elseif cmd == "transfer" and msg[2] == name and type(msg[3]) == "number" then
            parallel.waitForAny(function() run_transfer_recv(msg) end, function() sleep(5) print "Inbound transfer timed out" end)
            busy = false
        end
    end

    m.open(channel)
    while true do
        local ev, timer, c, rc, msg = os.pullEvent()
        if ev == "modem_message" and c == channel and rc == channel and type(msg) == "table" then
            local ok, err = pcall(process, msg)
            if not ok then printError(err) end
        elseif ev == "timer" and timer == pings_timer then
            pings_timer = nil
        end
    end
end

local function split_at_spaces(s)
    local t = {}
    for i in string.gmatch(s, "%S+") do
       table.insert(t, i)
    end
    return t
end

local function update_self()
    print "Downloading update."
    local h = http.get "https://pastebin.com/raw/R4HrijSg"
    local t = h.readAll()
    h.close()
    local fn, err = load(t, "@program")
    if not fn then printError("Not updating: syntax error in new version:\n" .. err) return end
    local f = fs.open("startup", "w")
    f.write(t)
    f.close()
    os.reboot()
end

local function ui()
    local history = {}
    while true do
        write "|> "
        local input = read(nil, history)
        table.insert(history, input)
        local tokens = split_at_spaces(input)
        if tokens[1] == "list" then
            list_all()
            sleep(1)
        elseif tokens[1] == "update" then
            update_self()
        elseif tokens[1] == "tp" then
            table.remove(tokens, 1)
            run_transfer(table.concat(tokens, " "))
        else
            printError "Not found"
        end
    end
end

parallel.waitForAll(ui, inbound)