hopper.lua

modem1 = 6565
modem2 = 6566
modem3 = 6567
modem4 = 6568

local channel = 3000

if fs.exists(".channel") then
    local f = fs.open(".channel","r")
    local n = f.readLine()
    if not tonumber(n) then error("contents of .channel is not a number") end
    channel = tonumber(n)
    f.close()
end

os.setComputerLabel("Hopper | "..channel)

local modems = {peripheral.find("modem")}

if #modems == 0 then error("no modems attached") end
local modem = modems[1]

modem.open(channel)

while turtle.forward() do end

function normalOperation()
    while true do
        local e,side,chnl,rChnl,msg,dist = os.pullEvent("modem_message")
        if chnl == channel then
            while turtle.back() do end
            while turtle.forward() do
                local b,insp = turtle.inspectUp()
                if b and (insp.name == "minecraft:chest" or insp.name == "minecraft:trapped_chest") then
                    while turtle.suckUp() and turtle.getItemCount(16) == 0 do turtle.select(1) end
                end
            end
            for slot = 1,16 do
                if turtle.getItemCount(slot) ~= 0 then
                    turtle.select(slot)
                    turtle.drop()
                end
            end
        end
    end
end

function modemListener()
    while true do
        local e,side,chnl,rChnl,msg,dist = os.pullEvent("modem_message")
        if chnl == modem1 then
            local x,y,z = gps.locate()

            local inv = {}

            for slot = 1,16 do
                local detail = turtle.getItemDetail(slot)
                if detail == nil then
                    inv[slot] = {}
                else
                    inv[slot] = detail
                end
            end

            modem.transmit(rChnl,chnl,{type="infoHopperResponse",fuel=turtle.getFuelLevel(),location={x=x,y=y,z=z},inventory=inv,channel=channel})
            print("Sent info")
        end
    end
end

modem.open(modem1)
parallel.waitForAny(normalOperation,modemListener)