Pocketcomputer Controlled - Strip Mining

rednet.open("left")

local fuelSlot = 16
local mining = false
local distance = 0
local progress = 0

local _fileName = "mining.dat"

function fuel()
    if turtle.getFuelLevel() < 10 then
        turtle.select(fuelSlot)
        turtle.refuel(1)
        turtle.select(1)
    end
    if turtle.getFuelLevel() < 10 then
        for i = 1, 16 do
            turtle.select(i)
            turtle.refuel(1)
        end
        turtle.select(1)
    end
end

function checkProgress()
    if progress >= distance then
        mining = false
    end
end

function createPacket(msg)
    return {id = os.getComputerID(), msg = msg}
end

function receiveCommand()
    local e, id, msg = os.pullEvent("rednet_message")
        if msg.command == "status" then
            rednet.send(id, createPacket({work=mining,dist=distance,prog=progress}))
        end
        if msg.command == "start" then
            mining = true
            distance = msg.msg
            progress = 0
        end
        if msg.command == "stop" then
            mining = false
            progress = 0
            distance = 0
            saveData()
            os.reboot()
        end
        if msg.command == "turn" then
            turtle.turnLeft()
        end
        if msg.command == "dump" then
            dumpContent()
        end
        if msg.command == "down" then
            turtle.down()
        end
    print(id..": "..textutils.serialize(msg))
end

function dumpContent()
    for i = 1, 15 do
        turtle.select(i)
        turtle.dropUp(64)
    end
    turtle.select(1)
end

function loadData()
    if fs.exists(_fileName) then
        local file = fs.open(_fileName, "r")
        local data = textutils.unserialize(file.readAll())
        if data ~= nil then
            progress = data.progress
            distance = data.distance
            mining = data.mining
        end
        file.close()
    end
end

function saveData()
    local file = fs.open(_fileName, "w")
    local data = {mining=mining, progress=progress, distance=distance}
    file.write(textutils.serialize(data))
    file.close()
end

function dig()
    if mining then
        fuel()
        turtle.dig()
        while not turtle.forward() do turtle.dig() end
        turtle.placeDown()
        turtle.digUp()
        turtle.up()
        turtle.digUp()
        turtle.down()
        progress = progress + 1
        checkProgress()
        saveData()
    end
    sleep(.5)
end

loadData()
if distance > 0 then
    dig()
end

receiveCommand()

while true do
    parallel.waitForAny(receiveCommand, dig)
end