shaftBot

-- Simple shaft mining program by Xenogami

-- If the inventory is full, put down a chest and empty inventory.
local function dropStash()
    if turtle.getItemCount(16) > 0 then
        turtle.select(1)
        turtle.placeDown()
        for a=2,16 do
            turtle.select(a)
            turtle.dropDown()
        end
        turtle.select(1)
    end
end

-- Makes sure the turtle can move forward, else digs away obstacle.
local function moveForward()
    while not turtle.forward() do
        turtle.dig()
    end
end

-- Mines then check if inventory is full.
local function mineTime()
    turtle.dig()
    turtle.digUp()
    turtle.digDown()
    dropStash()
end


-- Turns right and move to start of next shaft.
local function turnRight()
    turtle.turnRight()
    mineTime()
    moveForward()
    mineTime()
    moveForward()
    mineTime()
    moveForward()
    mineTime()
    turtle.turnRight()
end

-- Turns left and move to start of next shaft.
local function turnLeft()
    turtle.turnLeft()
    mineTime()
    moveForward()
    mineTime()
    moveForward()
    mineTime()
    moveForward()
    mineTime()
    turtle.turnLeft()
end

-- Digs out a double length shaft with a space in the center for the return shaft.
local function digShaft()
    for a=1,121 do
        mineTime()
        moveForward()
    end
end

-- Digs out the first and last shaft.
local function shortShaft()
    for a=1,60 do
        mineTime()
        moveForward()
    end
end

-- Track what direction the turtle needs to turn.
local function findFacing()
    if facing == 1 then
        turnRight()
        facing = 2
    else
        turnLeft()
        facing = 1
    end
end

-- Initializes tracking bit to control what direction to face when starting a new shaft.
facing = 1

moveForward()
mineTime()
turtle.turnLeft()
shortShaft()
for b=1,5 do
    findFacing()
    digShaft()
end
findFacing()
shortShaft()
mineTime()
turtle.forward()
if facing == 1 then
    turtle.turnLeft()
else
    turtle.turnRight()
end
for b=1,20 do
    mineTime()
    moveForward()
end