Redwood Cutter - Main

local distance = 150

function init()
    print("Init")

    resetSignals()

    print("Fuel = " .. turtle.getFuelLevel())

    while turtle.getFuelLevel() < 500 do
        print("Looking for Fuel")
        for slot = 1,16 do
            if turtle.getFuelLevel() < 500 then
                turtle.select(slot)

                repeat
                until turtle.refuel(1) == false or turtle.getFuelLevel() > 500
            end
        end

        print("Trying to get fuel from interface")
        repeat
        until turtle.up() == false

        useInterface()

        print("Fuel = " .. turtle.getFuelLevel())
    end
end

function fillFuel()
    while turtle.getFuelLevel() < 500 do
        turtle.select(1)
        turtle.refuel(20)
        print("Fuel = " .. turtle.getFuelLevel())
        sleep(5)
    end
end

function findInterface()
    while turtle.detectUp() == false do
        turtle.up()
    end
end

function useInterface()
    for slot = 1,16 do
        turtle.select(slot)
        turtle.dropUp()
    end
    turtle.select(1)
    turtle.suckUp()
end

function chop()
    for x = 1, distance do
        turtle.suckDown()
        turtle.digDown()
        turtle.down()
    end
end

function waitForAll()

    print("Waiting for all turtles to be ready")

    --wait for a pass on a signal from all directions
    repeat
        sleep(1)
    until redstone.getInput("left")
    redstone.setOutput("right", true)
    print("Left Ready")

    repeat
        sleep(1)
    until redstone.getInput("right")
    redstone.setOutput("left", true)
    print("Right Ready")

    repeat
        sleep(1)
    until redstone.getInput("front")
    redstone.setOutput("back", true)
    print("Front Ready")

    repeat
        sleep(1)
    until redstone.getInput("back")
    redstone.setOutput("front", true)
    print("Back Ready")

    --wait to ensure all others get the message
    print("All Ready - Prepare to Move")
    sleep(10)
end

function resetSignals()
    redstone.setOutput("left", false)
    redstone.setOutput("right", false)
    redstone.setOutput("front", false)
    redstone.setOutput("back", false)
end

--Start main code
init()

while true do
    --Stop emitting ready status
    resetSignals()

    --move up until we find the interface
    findInterface()

    --unload and collect fuel
    useInterface()

    --Make sure we have some fuel to move
    fillFuel()

    --check that everyone around us is ready
    waitForAll()

    --chop down a line
    chop()
end