Tree Mine

--[[
    A simple program that will mine out trees from top to bottom.
]]

local isBig = false

function treeLoop()
    local height = 0

    --Basic going up code
    while turtle.compareUp() do
        height = height+1
        turtle.digUp()
        if isBig then turtle.dig() end
        turtle.up()
    end

    if isBig then
        --A quick adjustment if the tree is a 2x2
        turtle.turnRight()
        turtle.fForward()
        turtle.turnLeft()
    end

    --Here is where we bring him down
    for i=1,height do
        turtle.digDown()
        if isBig then turtle.dig() end
        turtle.down()
    end

    --A little pizzazz
    if isBig then
        --Just going to bring him back to start pos
        turtle.turnLeft()
        turtle.forward()
        turtle.turnRight()
    end

    --And he's done!
    turtle.turnLeft()
    turtle.turnLeft()
    turtle.forward()
end

function fuelCheck()
    if turtle.getFuelLevel() < 99 then
        return false
    else
        return true
    end
end

function startup()
    turtle.fForward()
    turtle.select(1)
    if turtle.compare() then
        isBig = true
        print("We've got a big'un!")
    end
    treeLoop()
end

--Execution Code
if fuelCheck() then
    startup()
    print("Finished! Any key to continue...")
    read()
else
    print("Not enough fuel to continue, please refuel and retry. Any key to continue...")
    read()
end