turtle mining

function splash() -- splash screen
  term.clear()
  term.setCursorPos(1,1)
  print("Deep Underground Mining Buddy")
  print("  v1.0  by mrkite\n\n")
end
function gety() -- get the current y position
  print("Stand next to me and tell me your feet position")
  return tonumber(io.read())
end

function getwidth() -- get the width of the quarry
  print("How large an area should I dig? (example: 30)")
  return tonumber(io.read())
end

function emptyInventory() -- dump all but slot 1 (fuel)
  for i=1,16 do
    turtle.select(i)
    turtle.drop()
  end
  turtle.select(1)
end

function refuel() -- refuel all fuel we're carrying
  for i=1,16 do
    turtle.select(i)
    turtle.refuel()
  end
  turtle.select(1)
end

function flip() -- do a 180
  left()
  left()
end

function up() -- move up and keep track of our position
  local moved=false
  while not moved do
    if turtle.detectUp() then
      turtle.digUp()
    end
    if turtle.up() then
      pos.y=pos.y+1
      fromHome=fromHome-1 -- up is always closer to home
      moved=true
    else
      turtle.attackUp()
    end
  end
end

function down() -- move down and keep track of our position
  local moved=false
  while not moved do
    if turtle.detectDown() then
      turtle.digDown()
    end
    if turtle.down() then
      pos.y=pos.y-1
      fromHome=fromHome+1 -- down is always away from home
      moved=true
    else
      turtle.attackDown()
    end
  end
end

function forward() -- more forward and keep track of our position
  local moved=false
  while not moved do
    if turtle.detect() then
      turtle.dig()
    end
    if turtle.forward() then
      if facing==0 then  -- facing home
        pos.x=pos.x-1
        fromHome=fromHome-1
      elseif facing==1 then -- facing sidebranch
        pos.z=pos.z+1
        fromHome=fromHome+1
      elseif facing==2 then -- facing away from home
        pos.x=pos.x+1
        fromHome=fromHome+1
      else                  -- facing main tunnel
        pos.z=pos.z-1
        fromHome=fromHome-1
      end
      moved=true
    else
      turtle.attack()  -- couldn't move, someone in the way?
    end
  end
end

function left() -- turn left and keep track of direction
  turtle.turnLeft()
  if facing==0 then
    facing=3
  else
    facing=facing-1
  end
end
function right() -- turn right and keep track of direction
  turtle.turnRight()
  if facing==3 then
    facing=0
  else
    facing=facing+1
  end
end

function faceMain()
  while facing~=3 do
    left()
  end
end
function faceHome()
  while facing~=0 do
    left()
  end
end

function returnHome(temporary) -- return to home, housekeep, and possibly return
  local oldX=pos.x
  local oldY=pos.y
  local oldZ=pos.z
  local oldFace=facing

  print("returning home")

  faceMain()
  while pos.z~=0 do -- head back to main tunnel if necessary
    forward()
  end
  faceHome()
  while pos.x~=0 do -- head back home if necessary
    forward()
  end
  while pos.y<home do -- we're at home, but below it
    up()
  end
  refuel()  -- lets refuel before we empty our inventory
  emptyInventory()
  if turtle.getFuelLevel()==0 then -- failed to refuel
    print("Waiting for fuel")
    while turtle.getFuelLevel()==0 do
      sleep(1)
      refuel()
    end
  end
  if temporary then -- return to where we left off
    print("returning to duty")
    while pos.y>oldY do
      checkAll()
      down()
    end
    flip()
    while pos.x<oldX do
      checkAll()
      forward()
    end
    left()
    while pos.z<oldZ do
      checkAll()
      forward()
    end
    while facing~=oldFace do
      left()
    end
  end
end

function checkFuel()  -- checks if we only have enough fuel to get home
  if turtle.getFuelLevel()==fromHome then
    print("refueling")
    refuel()
    if turtle.getFuelLevel()==fromHome then -- did we fail?
      returnHome(true)  -- return home to refuel, but come back
    end
  end
end

function checkStorage() -- checks to see if we have any empty slots
  for i=1,16 do
    if turtle.getItemCount(i)==0 then -- we're okay as long as one is empty
      return
    end
  end
  returnHome(true) -- return home to unload, but come back
end

function checkAll() -- checks all reasons for returning home
  checkFuel()
  checkStorage()
end

function downToBottom() -- step 1.. tunnel down to 7
  while pos.y>7 do
    checkAll()
    down()
  end
end

function mainTunnel(cnt) -- dig the main tunnel
  while cnt>0 do
    checkAll()
    forward()
    cnt=cnt-1
  end
end

function sideTunnel(cnt) -- dig a side tunnel
  while cnt>0 do
    checkAll()
    forward()
    turtle.digUp()
    turtle.digDown()
    turtle.turnLeft() -- no need to keep track of position here
    turtle.dig()
    turtle.turnLeft() -- since we spin completely around
    turtle.turnLeft()
    turtle.dig()
    turtle.turnLeft() -- and end up facing the original direction
    cnt=cnt-1
  end
end

function branch() -- do the branch mine from 7 to 15
  for y=7,14 do
    for m=0,mainLength do
      --serpentine
      if m%2==y%2 then
        right()
      else
        left()
      end
      sideTunnel(branchWidth)
      if m%2==y%2 then
        left()
      else
        right()
      end
      mainTunnel(5)
    end
    up()
    flip()
    if y%2==1 then
      mainTunnel(2)
    else
      mainTunnel(3)
    end
  end
end

-- main routine

splash()
pos={}
pos.x=0  --home is always at 0,0
pos.z=0
pos.y=gety()
if pos.y<16 then
  print("Error - I should be started at 16 or above")
  exit()
end
home=pos.y
fromHome=0 -- we start 0 moves from home
facing=2 -- we start facing 2

branchWidth=getwidth()
mainLength=math.floor(branchWidth/5)
if mainLength%2==0 then -- must be an odd number or things will get screwed
  mainLength=mainLength+1
end

print("Make sure there's a chest behind me, then press any key to begin")
a,b=os.pullEvent()
while a~="key" do a,b=os.pullEvent() end

flip() -- turn around to align with chest

checkAll()
downToBottom()
flip() -- face the mine
branch()
returnHome(false) -- we're done, go home and stay there
flip() -- face away from chest

print("All done")