startup

if posx == nil then posx = 1 end
if posy == nil then posy = 0 end

if north == nil then north = 1 end
if east == nil then east = 2 end
if south == nil then south = 3 end
if west == nil then west = 4 end

if crashcount == nil then crashcount = 0 end

if fieldx == nil then fieldx = 9 end
if fieldy == nil then fieldy = 9 end

if wait == nil then wait = 4200 end
if waitafter == nil then waitafter = true end



function refuel()
  if turtle.getFuelLevel() < 324 then
    turtle.select(15)
    turtle.refuel()
    turtle.select(1)
  end
end

if direction == nil then direction = 0 end

function turn(newdirection)
    if newdirection==direction then
        return true
    else
        while not (direction==newdirection) do
          if newdirection > direction then
              turtle.turnLeft((newdirection - direction))
              direction = direction + 1
          else turtle.turnRight((newdirection - direction))
              direction = direction + 1
          end
        end
    end
end

function coord()
print("Position: "..posx.." / "..posy)
end

function iposx()
posx = posx + 1
end

function iposy()
posy = posy + 1
end

function dposx()
posx = posx - 1
end

function dposy()
posy = posy - 1
end

function mine()
    print("doing stuff here")
    turtle.select(1)
    turtle.placeDown()
    turtle.digDown()

    for i=14,9,-1 do
      turtle.select(i)
      turtle.placeDown()
    end
    turtle.select(1)
end

function move(dx, dy)
--coord()
  retr = nil
  if dy >= posy then
    retr = (moveDirY(posy, dy) and moveDirX(posx, dx))
  else
    retr = (moveDirX(posx, dx) and moveDirY(posy, dy))
  end

  --print("move() :: "..tostring(retr).." ::")
return retr
  --coord()
end

function moveDirX(ax, dx)
    if ax==dx then return (not detect()) end
    if ax == 0 then return step(dx,0) else
        delta = dx - ax
        --print("dX: "..tostring(delta))
        return step(delta, 0)
    end
end

function moveDirY(ay, dy)
    if (ay==dy) then return (not detect())
    else
        if ay == 0 then return step(dy, 1)
          else
            delta = dy - ay
            --print("dY: "..tostring(delta))
            return step(delta, 1)
        end
    end
end

function betrag(zahl1)
    if zahl1 < 0 then return zahl1 * -1
    else return zahl1
    end
end

function step(count, axis)
    refuel()
    retr = nil
    if axis == 0 then
        if count < 0 then
            retr = moveLeft(betrag(count))
        else
            retr = moveRight(betrag(count))
        end
    else
        if count > 0 then
            retr = moveForward(betrag(count))
        else
            retr = moveBack(betrag(count))
        end
    end

--print("step() :: "..tostring(retr).." ::")
--sleep(3)
return retr
end

function problem()
    if turtle.getFuelLevel() < (fieldx*fieldy) and turtle.getItemCount(16) == 0 then
        print("not enough fuel. Homing!")
        return true
    else
      return false
    end
end

function detect()
    if turtle.detect() then
        crashcount = crashcount + 1
        return true
    else
        return false
    end
end

function moveRight(ci)
    if problem() then return false end

    refuel()
    turtle.turnRight(1)
        for i=1, ci do
            print("Moving right. New: "..(posx+1).." / "..posy)
            if not detect() and turtle.forward() then
                iposx()
            else
              return false
            end
        end
    turtle.turnLeft(1)
    return true
end

function moveLeft(ci)
    if problem() then return false end

    refuel()
    turtle.turnLeft(1)
        for i=1, ci do
            print("Moving left. New: "..(posx-1).." / "..posy)
            if not detect() and turtle.forward() then
              dposx()
            else
              return false

            end
        end
    turtle.turnRight(1)
    return true
end

function moveForward(ci)
    if problem() then return false end

    refuel()
    for i=1, ci do
        print("Moving forward. New: "..posx.." / "..(posy+1))
        if not detect() and turtle.forward() then
            iposy()
        else return false
        end
    end
    return true
end

function moveBack(ci)
    if problem() then return false end

    refuel()
    turn180()
    for i=1, ci do
        print("Moving back. New: "..posx.." / "..(posy-1))
        if not detect() and turtle.forward() then
            dposy()
        else return false
        end
    end

    turn180()
    return true
end

function turn180()
    turtle.turnRight()
    turtle.turnRight()
end

function moveup(uct)
    for i=1, uct do
      turtle.up(1)
    end
end

function movedown(dct)
    for i=1, dct do
      turtle.down(1)
    end
end

function homing()
    print("Assuming crash. Homing...")
    turtle.select(15)
    while not turtle.compareDown() do
      if not turtle.forward(1) then
      turtle.turnLeft(1)

      end

    end
    turtle.turnLeft(1)
    turtle.forward(1)
    turtle.turnLeft(1)
    posx=1
    posy=0
    direction = 0
    crashcount= -1
    print("Sending -true- to caller")
    return true

end

function unlocked()
  if turtle.getItemCount(15) > 0 then
    return true
  else
    return false
  end
end

function empty()
  turtle.turnLeft(1)
  turtle.forward()
  turtle.select(15)
  if turtle.compareDown() then
    for i=14,9,-1 do
      turtle.dropDown()
    end
  else return false
  end
  turtle.back()
  turtle.select(1)
  turtle.turnRight(1)
end

function restock()
  turtle.turnRight(1)
  turtle.forward()
  turtle.down(1)
  turtle.select(15)
  if turtle.compareDown() then
    turtle.select(16)
    turtle.suckDown()
    turtle.select(1)
    turtle.up()
    turtle.back()
    turtle.turnLeft(1)
    return true
  else return false
  end

end

function loop1()
print("Initializing Harvester GPS alpha 1.101")
sleep(3)
while unlocked() do
for f=1, 8 do

  for i=1, fieldx do
    for j=1, fieldy do
      --if crashcount > 4 then homing() end
      if not ((i==5) and (j==5)) then
        --move(i,j)
        if not move(i,j) then return false end
        mine()
      else
        if not move(i,j) then return false end
      end
    end
    refuel()
  end
  move(1,0)
  empty()
  moveup(4)
end
return true
end

end


while true do

if not waitafter then
    print("Sleep before farming...")
else
    print("\\")
    print("Getting shit done.")
end


if not waitafter then
    sleep(wait)
end

while(loop1()) do end

while not homing() do
 if not unlocked() then
  return false
 end

 end
print("Homing done.")
print("Restarting Harvester...")

empty()
restock()

if waitafter and (crashcount >= 0) then
 print("Sleeping after...") sleep(wait)
 else print("sleep is for the poor." )
 crashcount = 0
 end

end